Battery Backup recommedations

[emtunderwood]

Hello,

Our FD is moving to a new site.. No permanent gen access, only in case of grid power failure and batterys depleat then its the SXS up the mountain for a gen to power the system and recharge batterys until grid power is restored.

We are considering purchasing a Kairos with 100w amp which during key-up of the Kairos and amp watt draw woul be 400w on the high side. But we have a quantar thats at 100W that we could use as well. The reason for the kairos was the low draw till the dealer sent specs on the kairos. I like the fact that everything is 13.8v and could have all the same batteries.

I know the quantar is 24v revert but still deciding on batterys and a system and this is where we are at a crossroads. (24v is basically out of the question.)

Do we spend the $x.xx on the Kairos and use 2x640ah batteries for roughly 16kwh power thats 40hr keyed and 106 standby. Using a ICT PS with Charger (87A) to supply the kairos and amp.

Or do we use the Quantar which we have and have it retuned due to new freqs at this site. Use a Victron inverter and say 4 - 48v-100ah batteries and just leave everything on the inverter at 120v ac and use a stepdown coverter from 48v to 13.8v in the event the inverter fails. and having the inverter charger would allow us to use the batteries, pass-through grid power, and if the site owner allowsw a couple solar panels outside.

Difference in the 2 systems estimated

Kairos system with everything (13.8v batteries and grid only) $15,000

Quantar system 120v (48v batteries with inverter charger) $7-8k max.

I mean these are our known options..

What are your opinions and suggestions on how we should mitigate the power situation and future proof for a decent amount of time. Or what have you all done in the past.

This is not a amatuer system or site. Radio shops local are like ughhhh most have generators... I said well, if our county leaders gave a crap we would too.. They don't even pay for our systems, but they make sure the 911 center has whatever it needs to talk to said department.

Hope to hear some options, opinions and suggestions..


Thanks

 

[mmckenna]

I'm just going to toss out a few things to start a conversation. You have many options here and a number of things to consider, so maybe some discussion will help.

Hello,

Our FD is moving to a new site.. No permanent gen access, only in case of grid power failure and batterys depleat then its the SXS up the mountain for a gen to power the system and recharge batterys until grid power is restored.

I'd never rely on utility power as your only source. Batteries are good for backup in the short term, but you need to consider a long term power outage.

If snow is an issue, a SxS won't be enough, so more run time until you can find someone with a snow machine to get you in might be important.
If snow is not a risk, downed trees, mud, washed out trails, all something to consider as blockers that would keep you from getting a generator on site.

Solar/wind might give you what you need to keep the site on the air and running.

We are considering purchasing a Kairos with 100w amp which during key-up of the Kairos and amp watt draw woul be 400w on the high side. But we have a quantar thats at 100W that we could use as well. The reason for the kairos was the low draw till the dealer sent specs on the kairos. I like the fact that everything is 13.8v and could have all the same batteries.

I know the quantar is 24v revert but still deciding on batterys and a system and this is where we are at a crossroads. (24v is basically out of the question.)

24 volts gives you some more options. Most higher end commercial gear is going to be 24 or 48 volts, and there are many more power solutions for those voltages.

12 volts is easier for putting together smaller systems, though.

Do we spend the $x.xx on the Kairos and use 2x640ah batteries for roughly 16kwh power thats 40hr keyed and 106 standby. Using a ICT PS with Charger (87A) to supply the kairos and amp.

New repeater is an attractive solution. Warranty, all new, smaller, maybe a bit more efficient, all good things to consider. Better vendor support should be high on your list.

Or do we use the Quantar which we have and have it retuned due to new freqs at this site. Use a Victron inverter and say 4 - 48v-100ah batteries and just leave everything on the inverter at 120v ac and use a stepdown coverter from 48v to 13.8v in the event the inverter fails. and having the inverter charger would allow us to use the batteries, pass-through grid power, and if the site owner allowsw a couple solar panels outside.

Quantars are great repeaters, and there are a lot of used parts available to keep it running for years to come. Lots of people that understand them and can help, but Motorola won't be one of them.

Do you already own the Victron, or is that going to be part of the investment?

Double conversion (110 vac —> 12 vdc —> 110 vac —> 12 vdc) is going to result in loss of efficiency and more failure points. Not ideal, but you can design around the loss in efficiency, but not the loss of redundancy. If the internal rectifier or inverter fails, then you've got problems.

Difference in the 2 systems estimated

Kairos system with everything (13.8v batteries and grid only) $15,000

Quantar system 120v (48v batteries with inverter charger) $7-8k max.

What is your budget? Is the extra $7-8000 going to be an issue, or is the department flush with cash?

There's some more power options to consider.
Keeping everything DC power and removing the inverter from the equation is going to remove a failure point and improve efficiency.
A purpose built power system that has N+1 rectifier modules gives you some fault tolerance that the other two solutions will not have.

Add in solar and/or wind to give yourself an alternate power source would be something to carefully consider. No reason to rely just on utility power if access to the site is that difficult.


Separate question:
Do you actually need 100 watts? Using a lower RF power and going with more antenna gain can be more power efficient, plus the higher antenna gain will help with talk-in from portables. Dropping to 50 or even 25 watts will greatly extend your battery run time.

I mean these are our known options..

What are your opinions and suggestions on how we should mitigate the power situation and future proof for a decent amount of time. Or what have you all done in the past.

My experience from doing this for almost 30 years:

-Redundancy should be part of your design.

Power supplies/rectifiers will fail. One power supply failing and you are off the air. A redundant module with monitoring means you stay on the air and you have time to send someone up to swap it out.​

-Running inverters reduce efficiency. Keeping everything DC will save some power and reduce failure points.

-One box that does everything for your power means you have multiple failure points all in one sealed box.

If the rectifier fails, then the entire box is useless. Same if the inverter fails. That means that if the box fails, you can't repair it, and you'll need to have a spare on hand, or wait for purchase/shipping/delivery to site/installation. If your budget allows, buy an extra one now and have it ready to go.​

-Never rely on utility power for life safety systems.

You are on the right track here, but your system relies on batteries and the utility responding quickly. A generator with automatic transfer switch and an automatic test function would be the ideal solution, but it sounds like getting fuel on site is a challenge. They are also expensive and require their own maintenance. If this site just houses this single repeater, then it's likely not a cost effective solution. If there are other tenants on site, then maybe cooperating on backup power is something to consider. Everyone paying their share can lower the costs.​

​

-I would not ignore alternative power options at a remote/difficult access site like this.

No matter what you go with, you are putting all your eggs in the basket that the electric utility holds. They are usually responsive for public safety radio sites like this, but having the resources might be a bigger question. Snow, mud, roads washed out, trees down, damaged poles, lots of damage, it's all going to result in longer times to restoration. Easy to have a site lose power for a week or more in situations like this. A DC power plant with some redundancy would be something to seriously consider. Rely on utility power if it's there, but have the option to run the site off solar only. You might be able to run a smaller battery plant and save some costs. It'll need to be something that is carefully designed based on your latitude and weather, but most manufacturers will help you with that. There are a lot of radio sites that run this way, and if done right, it's a reliable and cost effective solution.​

​

This is not a amatuer system or site. Radio shops local are like ughhhh most have generators... I said well, if our county leaders gave a crap we would too.. They don't even pay for our systems, but they make sure the 911 center has whatever it needs to talk to said department.

OK, that is useful info.

Does this radio site have other tenants that would be willing to share costs, or is it just your system at this location?

As I said above, generators are the easy solution, and why the radio shop is recommending that. But that's thinking inside a small, old, smelly box. Better solutions out there now, especially if fuel delivery is a concern (and it sounds like it is).

Utility power with an actual back up power source that doesn't rely on someone hauling propane/gas/Diesel up the hill would be what I'd do. I'd focus on a large enough solar plant to support the site full time. It's not going to be cheap, but it's going to be a better long term solution. I've been running some radio sites this way for a decade now and it works well.

 

[emtunderwood]

Victron system we were going to purhcase.. We have a eco worthy inverter charger at the other site to the north but it will be coming down.. I know the eco-worthy is some chinese stuff. It's worked for now. But the remote monitoring does not work and we've been caught between a rock and a hard place in the last 5-6yr from it not working correctly.

The victron system has cerbo and we have remote firstnet wifi units available for up there for monitoring.

Tennants at the site.. Old paging company transmitter, Forrestry repeater (which is rarely used - possible hasn't been used in 8-10yr) and a UHF (FD non-911 repeater) and the department is on their own system on a totally different tower now. There's not going to be anyone to share costs with. Basically, we are just paying for our power and that's it.

We were looking at something like this

Grid to inverter/charger wether it be 12/24/48 whichever would be more efficient and economical. That would feed pass-through to the equipment 120v, plus would keep the large solar batteries charged and floating. In the event of grid failure we would be purely on the inverter using battery power until the grid came back online.

Or the other option is using something like a ICT 1600w12v power supply and charging the 12v batteries.

The company that has the tower stated we could put solar out there.. However, there's a caviat to that... Theres a pipeline right next to the building and the guye's on that side clear just barely 16ft to the road that runs past and there may only be 20ft square space... Maybe... So, i'd have to figure that out and the building is shaded pretty well to the S-SE, so fighting the shade line would be another issue to add to the equation of encroaching on the pipeline company easement.

But not saying that it can't happen, but I'd have to do alot of measuring and determing where the best place that the at least 2 panels could go.

Wind? I don't know anything about that.. It's on top of a mountain and there's wind and a large tunnel rideofway for the pipeline that wind blows through, we could probably catch some of it for sure..

But what would be the best solution?

Keep the quantar.. Which have never failed us (lightning strike hit the cell tower we currently are at, destroyed all the carrier equipment and ours... only thing that died was the receiver, but we have several in storage in the event something would happen.)

I don't think the quantar can charge LifPO4 batteries or just use battery backup in the event main power goes out without the charger running.

I could use the victron system to give the quantar 120v power as pass-through and the event of power failure either pull from the batteries and invert to 120v from 24v batteries or do nothing but charge them when the grid power comes back on.

And the victron would be upgradeable to MPPT solar easily and could remote monitor 24/7 right from the rip.

Or invest in the Kairos with amplifier which has about 100w less power draw on tx and less standby than the Quantar and basically feed the same way. But the kairos is limited to 13.8v.

Just needing to figure out the best economical way to do the battery setup for at least 4 days max. The longest I've seen power out in the last 5yr there that I know of was 3 days 2yr ago and several times since for maybe 8-24hr. I know the principal and how to make it work, just not enough of the industry or options that are available. Or the right voltages to use.

Funding for the department.. We have some money.. Not would say flush with cash, but to do it right, we would do it or the closest we could afford.. Budget wise we have 10-15k with new repeater and without probably 7-8. I got the ok to buy the repeater if need be.

Our radio shop bascially has cookie cutter systems.. Repeater, PA, PS, RACK, same for everyone, not much changing unless requested. And the way things are with them. We don't know what's out there and what is not.. Consider other radio companies... They are few and far between... Shade Tree ham operator turned two-way shop selling, Tait everything and some L3 Harris stuff. Which doesn't have a fond track-record.. Somethings they've done have been great others not so great. The other shop has people from the longtime king of the area radio shop, but they just worked there, they know how to install things in cruisers and fire apparatus, program radios, install emergency lighting, etc. But nobody really talks of them doing site equipment, towers and antennas. Then there's the one motorola shop.......... Well, they want first born for everything and then its like.... Well, you'd thought it would have worked better than that... So, we are in radio shop limbo, and really no where solid to turn.

 

[prcguy]

You mention LifPO4 batteries, how cold will it get in the building? LifPO4 batteries have problems in low temps.

 

[emtunderwood]

You mention LifPO4 batteries, how cold will it get in the building? LifPO4 batteries have problems in low temps.

It doesn't get below freezing. With the other equipment running, nothing freezes.

 

[MUTNAV]

It doesn't get below freezing. With the other equipment running, nothing freezes.

Just make sure the batteries are in that warmed area though, sometimes lithium batteries have to have their own space (like outside in a metal box), for fire purposes, especially LiPO4, the ones with iron I hear are safer though.

 

[emtunderwood]

Just make sure the batteries are in that warmed area though, sometimes lithium batteries have to have their own space (like outside in a metal box), for fire purposes, especially LiPO4, the ones with iron I hear are safer though.

Isn't that what those are, Lithium Iron Phosphate?

 

[MUTNAV]

I may have gotten a little confused since there was no Fe in the LiPO4, indicating a Lithium Iron Phosphate battery

Lithium polymer (LiPO) batteries are fire / safety risks,

The Lithium Iron Phosphate LiFePO4 batteries are lower energy but way safer.

Although I don't trust either of them fire safety wise.

 

[mmckenna]

Victron system we were going to purhcase.. We have a eco worthy inverter charger at the other site to the north but it will be coming down.. I know the eco-worthy is some chinese stuff. It's worked for now. But the remote monitoring does not work and we've been caught between a rock and a hard place in the last 5-6yr from it not working correctly.

The victron system has cerbo and we have remote firstnet wifi units available for up there for monitoring.

Tennants at the site.. Old paging company transmitter, Forrestry repeater (which is rarely used - possible hasn't been used in 8-10yr) and a UHF (FD non-911 repeater) and the department is on their own system on a totally different tower now. There's not going to be anyone to share costs with. Basically, we are just paying for our power and that's it.

We were looking at something like this

Grid to inverter/charger wether it be 12/24/48 whichever would be more efficient and economical. That would feed pass-through to the equipment 120v, plus would keep the large solar batteries charged and floating. In the event of grid failure we would be purely on the inverter using battery power until the grid came back online.

Or the other option is using something like a ICT 1600w12v power supply and charging the 12v batteries.

The company that has the tower stated we could put solar out there.. However, there's a caviat to that... Theres a pipeline right next to the building and the guye's on that side clear just barely 16ft to the road that runs past and there may only be 20ft square space... Maybe... So, i'd have to figure that out and the building is shaded pretty well to the S-SE, so fighting the shade line would be another issue to add to the equation of encroaching on the pipeline company easement.

But not saying that it can't happen, but I'd have to do alot of measuring and determing where the best place that the at least 2 panels could go.

Wind? I don't know anything about that.. It's on top of a mountain and there's wind and a large tunnel rideofway for the pipeline that wind blows through, we could probably catch some of it for sure..

But what would be the best solution?

Keep the quantar.. Which have never failed us (lightning strike hit the cell tower we currently are at, destroyed all the carrier equipment and ours... only thing that died was the receiver, but we have several in storage in the event something would happen.)

I don't think the quantar can charge LifPO4 batteries or just use battery backup in the event main power goes out without the charger running.

I'd need to look at the power supply for the Quantar to confirm, but there should be a voltage adjustment. I know the MSF5000's had that. Setting the voltage right, and feeding a battery manager would work.

I could use the victron system to give the quantar 120v power as pass-through and the event of power failure either pull from the batteries and invert to 120v from 24v batteries or do nothing but charge them when the grid power comes back on.

And the victron would be upgradeable to MPPT solar easily and could remote monitor 24/7 right from the rip.

So, you've mentioned this Vintron system a few times. That suggests that is the direction you want to go. If you are comfortable with that system, it does everything you need, and you understand the shortcomings of it, then it's probably the right answer for you.

If it has the option to run in a solar array (I think you need to seriously consider that), and it has the monitoring capability, then it sounds like it'll do everything you need.

Or invest in the Kairos with amplifier which has about 100w less power draw on tx and less standby than the Quantar and basically feed the same way. But the kairos is limited to 13.8v.

The $7000 to $8000 extra cost to save 100 watts may not be a good financial justification.

But, a brand new repeater that is under support from the manufacturer and has better remote monitoring capabilities might make a lot of sense.

Quantar repeaters are solid, parts are readily available, but no longer under support. Is that worth 7-8K?

Just needing to figure out the best economical way to do the battery setup for at least 4 days max. The longest I've seen power out in the last 5yr there that I know of was 3 days 2yr ago and several times since for maybe 8-24hr. I know the principal and how to make it work, just not enough of the industry or options that are available. Or the right voltages to use.

The new high tech batteries are nice, and I've considered them for a few applications. But I keep coming back to the VRLA systems. They are proven, reliable and cost effective if maintained correctly.

Be realistic about your needs. 4-5 days sounds like what you need, but how often does the repeater get used? If it's idle 90-95% of the time, you may not need as much battery as you think.

Adding the solar panels would let them recharge during the day and reduce the amount of battery back up you may need. Less money spent on batteries, less on the new repeater and having the Quantar battery charge built in might offset the solar panel costs quite a bit.

Funding for the department.. We have some money.. Not would say flush with cash, but to do it right, we would do it or the closest we could afford.. Budget wise we have 10-15k with new repeater and without probably 7-8. I got the ok to buy the repeater if need be.

That's good. There's a lot of people that come here with similar radio challenges with totally unrealistic budgets. I think your budget is pretty low, but it'll get you started. You can always expand on it later on.

Our radio shop bascially has cookie cutter systems.. Repeater, PA, PS, RACK, same for everyone, not much changing unless requested. And the way things are with them.

Common to see that at County/State levels. Makes sense from a spare parts standpoint. Makes it easier for the technicians. Not always the right solution though.

We don't know what's out there and what is not.. Consider other radio companies... They are few and far between... Shade Tree ham operator turned two-way shop selling, Tait everything and some L3 Harris stuff. Which doesn't have a fond track-record.. Somethings they've done have been great others not so great.

I'd be wary. I've run into this in the past and it usually results in a lower upfront cost, but ends up costing more down the road when you need to start fixing all the corners that were cut. Amateur/hobby isn't the same as public safety, and while some hams can do it right, I tend to find that they revert to old ways when they run into a challenge. I've had to fix a few installs like this.

The other shop has people from the longtime king of the area radio shop, but they just worked there, they know how to install things in cruisers and fire apparatus, program radios, install emergency lighting, etc. But nobody really talks of them doing site equipment, towers and antennas.

There are certainly shops that have their specialties. Some are better at upfitting, some are better at infrastructure. Rare to find one that is good at both.

Then there's the one motorola shop.......... Well, they want first born for everything and then its like.... Well, you'd thought it would have worked better than that... So, we are in radio shop limbo, and really no where solid to turn.

I'd split this up into two separate projects:

Electrical/power/battery/solar. Find an electrician who has done off grid solutions before. They'll know how to do this right. Or, find a solar installer that has done off grid installs. And I do really think you need to look at this as an 'off grid' system with utility backup.

RF. Let the radio guys do the radio stuff. Expecting them to do electrical is probably going to be a disappointment. They'll tell you they can do it, but often it's an after thought.

And I'd still look at reducing RF power output and investing in a better antenna system. High transmitter power only works in one direction and uses more power. Lower RF power with a better antenna system works in both directions and uses less power.

 

[emtunderwood]

I'd need to look at the power supply for the Quantar to confirm, but there should be a voltage adjustment. I know the MSF5000's had that. Setting the voltage right, and feeding a battery manager would work.



So, you've mentioned this Vintron system a few times. That suggests that is the direction you want to go. If you are comfortable with that system, it does everything you need, and you understand the shortcomings of it, then it's probably the right answer for you.

If it has the option to run in a solar array (I think you need to seriously consider that), and it has the monitoring capability, then it sounds like it'll do everything you need.



The $7000 to $8000 extra cost to save 100 watts may not be a good financial justification.

But, a brand new repeater that is under support from the manufacturer and has better remote monitoring capabilities might make a lot of sense.

Quantar repeaters are solid, parts are readily available, but no longer under support. Is that worth 7-8K?



The new high tech batteries are nice, and I've considered them for a few applications. But I keep coming back to the VRLA systems. They are proven, reliable and cost effective if maintained correctly.

Be realistic about your needs. 4-5 days sounds like what you need, but how often does the repeater get used? If it's idle 90-95% of the time, you may not need as much battery as you think.

Adding the solar panels would let them recharge during the day and reduce the amount of battery back up you may need. Less money spent on batteries, less on the new repeater and having the Quantar battery charge built in might offset the solar panel costs quite a bit.



That's good. There's a lot of people that come here with similar radio challenges with totally unrealistic budgets. I think your budget is pretty low, but it'll get you started. You can always expand on it later on.



Common to see that at County/State levels. Makes sense from a spare parts standpoint. Makes it easier for the technicians. Not always the right solution though.



I'd be wary. I've run into this in the past and it usually results in a lower upfront cost, but ends up costing more down the road when you need to start fixing all the corners that were cut. Amateur/hobby isn't the same as public safety, and while some hams can do it right, I tend to find that they revert to old ways when they run into a challenge. I've had to fix a few installs like this.



There are certainly shops that have their specialties. Some are better at upfitting, some are better at infrastructure. Rare to find one that is good at both.



I'd split this up into two separate projects:

Electrical/power/battery/solar. Find an electrician who has done off grid solutions before. They'll know how to do this right. Or, find a solar installer that has done off grid installs. And I do really think you need to look at this as an 'off grid' system with utility backup.

RF. Let the radio guys do the radio stuff. Expecting them to do electrical is probably going to be a disappointment. They'll tell you they can do it, but often it's an after thought.

And I'd still look at reducing RF power output and investing in a better antenna system. High transmitter power only works in one direction and uses more power. Lower RF power with a better antenna system works in both directions and uses less power.

I'll have to look at the RSS in the quantar to see if it can accept DC without trying to charge. I know it has battery revert and at one time had 24v batteries.

I know the last 2yr with the other inverter charger we had with 120v passthrough is the chinese whatever cloned from something else. Its been ok and done what it was supposed to do other than a hiccup or 2 and the 5kw batterys have been decent just that they don't last as advertized and weve gotten busy when the power goes out. Batteries are good for ehh 20-25hr keyed about 72 standby... They lasted about 12-14 we got super busy and had a structure fire and they got worked really hard and I understand not every time will there be a coincidence like that but it happens.. I think the batteries died at like 6am and the power was back on little before 8 we didn't even know they had died. The stupid remote software is connected but will not read remotely, so idk chinese whatever. IF anything that site at 180w running 12-14hr with 2 5kw batteries lasted that long probably 1 more 5kw battery and we should be decent with the quantar and if the coordinator is correct the 50-75w that just less power we need and less drain on quantar PA and ask the tower owner about a couple solar panels and we shouldn't have to go up there but a couple times a year for PM and mowing. And the site has internet and the Victron will work and we will provide cameras at the site... When I say remote... It's remote. Goat path to a muddy goat face hill in the middle of nowhere wv where you can literally see the horizon with no obstructions and everything else is way down below... I think it should work fine.

And your right on the antenna.. I posted in the forums about an antenna previously in another section.. When I talked with the frequency coordinator about the site.

He did state that terrain where your antenna is significantly higher average than normal. He stated that this was the highest peak to the west - nw 1700ft the way we need to be and everything else peak is 1100ft or down to 400-500ft that he would be hard pressed to come up with 100w tx that it may be too much and talk all the way into ohio. We did discuss the antennas as well. He mentioned the same deal and then some more electro-phyisics than anything.

He basically said you probably will be hard pressed to need 100w or maybe even get it from the FCC. But put people in the far reaches of your area and adjust the power accordingly you will find the sweet spot and more than likely will not need 100w with a offest 9db gain antenna more like 50w-75w.

Like your other site (the one we are leaving) not being very high above average terrain you got a power of 180w and like 500erp and it barely goes 12-15km.

 

[MUTNAV]

I'd need to look at the power supply for the Quantar to confirm, but there should be a voltage adjustment. I know the MSF5000's had that. Setting the voltage right, and feeding a battery manager would work.



So, you've mentioned this Vintron system a few times. That suggests that is the direction you want to go. If you are comfortable with that system, it does everything you need, and you understand the shortcomings of it, then it's probably the right answer for you.

If it has the option to run in a solar array (I think you need to seriously consider that), and it has the monitoring capability, then it sounds like it'll do everything you need.



The $7000 to $8000 extra cost to save 100 watts may not be a good financial justification.

But, a brand new repeater that is under support from the manufacturer and has better remote monitoring capabilities might make a lot of sense.

Quantar repeaters are solid, parts are readily available, but no longer under support. Is that worth 7-8K?



The new high tech batteries are nice, and I've considered them for a few applications. But I keep coming back to the VRLA systems. They are proven, reliable and cost effective if maintained correctly.

Be realistic about your needs. 4-5 days sounds like what you need, but how often does the repeater get used? If it's idle 90-95% of the time, you may not need as much battery as you think.

Adding the solar panels would let them recharge during the day and reduce the amount of battery back up you may need. Less money spent on batteries, less on the new repeater and having the Quantar battery charge built in might offset the solar panel costs quite a bit.



That's good. There's a lot of people that come here with similar radio challenges with totally unrealistic budgets. I think your budget is pretty low, but it'll get you started. You can always expand on it later on.



Common to see that at County/State levels. Makes sense from a spare parts standpoint. Makes it easier for the technicians. Not always the right solution though.



I'd be wary. I've run into this in the past and it usually results in a lower upfront cost, but ends up costing more down the road when you need to start fixing all the corners that were cut. Amateur/hobby isn't the same as public safety, and while some hams can do it right, I tend to find that they revert to old ways when they run into a challenge. I've had to fix a few installs like this.



There are certainly shops that have their specialties. Some are better at upfitting, some are better at infrastructure. Rare to find one that is good at both.



I'd split this up into two separate projects:

Electrical/power/battery/solar. Find an electrician who has done off grid solutions before. They'll know how to do this right. Or, find a solar installer that has done off grid installs. And I do really think you need to look at this as an 'off grid' system with utility backup.

RF. Let the radio guys do the radio stuff. Expecting them to do electrical is probably going to be a disappointment. They'll tell you they can do it, but often it's an after thought.

And I'd still look at reducing RF power output and investing in a better antenna system. High transmitter power only works in one direction and uses more power. Lower RF power with a better antenna system works in both directions and uses less power.

I REALLY like the idea of splitting into separate projects. Just a person doing an off-grid instillation is a project and a half.

 

[mmckenna]

I'll have to look at the RSS in the quantar to see if it can accept DC without trying to charge. I know it has battery revert and at one time had 24v batteries.

I know the last 2yr with the other inverter charger we had with 120v passthrough is the chinese whatever cloned from something else. Its been ok and done what it was supposed to do other than a hiccup or 2 and the 5kw batterys have been decent just that they don't last as advertized and weve gotten busy when the power goes out. Batteries are good for ehh 20-25hr keyed about 72 standby... They lasted about 12-14 we got super busy and had a structure fire and they got worked really hard and I understand not every time will there be a coincidence like that but it happens.. I think the batteries died at like 6am and the power was back on little before 8 we didn't even know they had died. The stupid remote software is connected but will not read remotely, so idk chinese whatever. IF anything that site at 180w running 12-14hr with 2 5kw batteries lasted that long probably 1 more 5kw battery and we should be decent with the quantar and if the coordinator is correct the 50-75w that just less power we need and less drain on quantar PA and ask the tower owner about a couple solar panels and we shouldn't have to go up there but a couple times a year for PM and mowing. And the site has internet and the Victron will work and we will provide cameras at the site...

OK, sounds like you have your solution. Don't mess with what works. You know your needs, site, support, we don't, so go with that.

When I say remote... It's remote. Goat path to a muddy goat face hill in the middle of nowhere wv where you can literally see the horizon with no obstructions and everything else is way down below... I think it should work fine.

Yeah, I've got some sites very much like that. 100% solar, 10 watts RF out, but 99% of use is from hand held radios, so it's balanced well.

And your right on the antenna.. I posted in the forums about an antenna previously in another section.. When I talked with the frequency coordinator about the site.

He did state that terrain where your antenna is significantly higher average than normal. He stated that this was the highest peak to the west - nw 1700ft the way we need to be and everything else peak is 1100ft or down to 400-500ft that he would be hard pressed to come up with 100w tx that it may be too much and talk all the way into ohio. We did discuss the antennas as well. He mentioned the same deal and then some more electro-phyisics than anything.

He basically said you probably will be hard pressed to need 100w or maybe even get it from the FCC. But put people in the far reaches of your area and adjust the power accordingly you will find the sweet spot and more than likely will not need 100w with a offest 9db gain antenna more like 50w-75w.

Like your other site (the one we are leaving) not being very high above average terrain you got a power of 180w and like 500erp and it barely goes 12-15km.

You are unlikely to get 100 watts transmitter power into a 9dB gain antenna on a site that high. There are FCC imposed limitations that will need to be considered by the frequency coordinator.
But that's a good thing, as it lowers your power needs.

 

[emtunderwood]

OK, sounds like you have your solution. Don't mess with what works. You know your needs, site, support, we don't, so go with that.



Yeah, I've got some sites very much like that. 100% solar, 10 watts RF out, but 99% of use is from hand held radios, so it's balanced well.



You are unlikely to get 100 watts transmitter power into a 9dB gain antenna on a site that high. There are FCC imposed limitations that will need to be considered by the frequency coordinator.
But that's a good thing, as it lowers your power needs.

I'd like to read those FCC limitations.. Just to know whats what..

 

[mmckenna]

I'd like to read those FCC limitations.. Just to know whats what..

90.205

Federal Register :: Request Access

www.ecfr.gov

 

[smithdoor]

Hello,

Our FD is moving to a new site.. No permanent gen access, only in case of grid power failure and batterys depleat then its the SXS up the mountain for a gen to power the system and recharge batterys until grid power is restored.

We are considering purchasing a Kairos with 100w amp which during key-up of the Kairos and amp watt draw woul be 400w on the high side. But we have a quantar thats at 100W that we could use as well. The reason for the kairos was the low draw till the dealer sent specs on the kairos. I like the fact that everything is 13.8v and could have all the same batteries.

I know the quantar is 24v revert but still deciding on batterys and a system and this is where we are at a crossroads. (24v is basically out of the question.)

Do we spend the $x.xx on the Kairos and use 2x640ah batteries for roughly 16kwh power thats 40hr keyed and 106 standby. Using a ICT PS with Charger (87A) to supply the kairos and amp.

Or do we use the Quantar which we have and have it retuned due to new freqs at this site. Use a Victron inverter and say 4 - 48v-100ah batteries and just leave everything on the inverter at 120v ac and use a stepdown coverter from 48v to 13.8v in the event the inverter fails. and having the inverter charger would allow us to use the batteries, pass-through grid power, and if the site owner allowsw a couple solar panels outside.

Difference in the 2 systems estimated

Kairos system with everything (13.8v batteries and grid only) $15,000

Quantar system 120v (48v batteries with inverter charger) $7-8k max.

I mean these are our known options..

What are your opinions and suggestions on how we should mitigate the power situation and future proof for a decent amount of time. Or what have you all done in the past.

This is not a amatuer system or site. Radio shops local are like ughhhh most have generators... I said well, if our county leaders gave a crap we would too.. They don't even pay for our systems, but they make sure the 911 center has whatever it needs to talk to said department.

Hope to hear some options, opinions and suggestions..


Thanks

If live you have a lot power outages you look 12 volt back using lead deep cycle the voltage is 13.5 volts. Then buy a lot on this voltage

Dave

 

[jeepsandradios]

Didn't see it mentioned here but some repeaters allow differtn power levels on battery. Our SAR repeaters are like this. We get an alert to say we are on battery and know its lower power. Its not ideal but fo the site its at it keeps the repeater up for us. May be a way to use less battery and keep the site online vs loosing it completely. YMMV

 

[smithdoor]

Didn't see it mentioned here but some repeaters allow differtn power levels on battery. Our SAR repeaters are like this. We get an alert to say we are on battery and know its lower power. Its not ideal but fo the site its at it keeps the repeater up for us. May be a way to use less battery and keep the site online vs loosing it completely. YMMV

I would not rely on your power outages as works by network of repeaters/nodes and rest the repeaters may not have battery backup or short battery life.

The best is if have HAM license is 28mhz band or no license 27mhz band. Both have a good range with ¼ wave or greater antenna. Both are standalone type system.

Rule Thumb is 1 foot of antenna to 1 mile of range. Over 90 inches takes advantage of ground wave propagation

Dave

 

[smithdoor]

Didn't see it mentioned here but some repeaters allow differtn power levels on battery. Our SAR repeaters are like this. We get an alert to say we are on battery and know its lower power. Its not ideal but fo the site its at it keeps the repeater up for us. May be a way to use less battery and keep the site online vs loosing it completely. YMMV

Here two sizes of antennas I have .
The shorter is on windy days and taller has range over 20 miles .
I posting both antennas photo in same spot but at different angle for best view

In a disaster you may not power ⛮ is out and towers are Down. If towers are up the cellphone would work.
Salesman does tell you part it all nice day

Dave