Going Backpack Mobile!

[RESlusher]

Greetings all!

I passed my ham technician test last week so I'm shopping for equipment. I'm looking at the Yeasu 8900R; but before I pull the trigger on it I want to make sure it will be able to do what I want it to do!

First can it be powered from a UPS sized battery? I'm an IT guy and I've got quite a few of those to spare. My plan is to custom build a frame out of lightweight tubing and sheet metal similar to an ammo can, so that everything is together in one unit fitting in my bug-out bag, complete with fold out solar panel(s) and a control.

As I said, I'm an IT guy; but I'm not an electrician. So use little words and short sentences!

Thanks in advance for any suggestions and advice!

 

[gewecke]

Greetings all!

I passed my ham technician test last week so I'm shopping for equipment. I'm looking at the Yeasu 8900R; but before I pull the trigger on it I want to make sure it will be able to do what I want it to do!

First can it be powered from a UPS sized battery? I'm an IT guy and I've got quite a few of those to spare. My plan is to custom build a frame out of lightweight tubing and sheet metal similar to an ammo can, so that everything is together in one unit fitting in my bug-out bag, complete with fold out solar panel(s) and a control.

As I said, I'm an IT guy; but I'm not an electrician. So use little words and short sentences!

Thanks in advance for any suggestions and advice!

I thought IT guys had bigger words, than we do? :lol:
At any rate, it's doable with what you have but I suggest using low power if using UPS batteries, and the more capacity the better, but obviously it's also more weight. 12 AH would work and keep your pack manageable.
18- 24 AH would give you even more op time. If you want to go the solar panel route, then I have a link for you to look at which might be interesting.
I have considered your project as well.

A Mini Power Plant for Your Next Adventure | Biking | OutsideOnline.com

Nice avatar Btw,
73,
n9zas

 

[RESlusher]

18-24 AH, got it! Thanks for the info!

I'm just worried about spending that kinda money on the FT-8900 and not being able to use it the way I want!

I've seen some fold-up solar panels. Even if I had to velcro a couple of them onto the pack (72-hour bag from 5.11 Tactical) at least they'd work. I figure I'll need a charge controller too so I'm not blowing myself up humping through the bush!

Glad ya like the avatar! You can buy it as a patch with velcro backing from Imminent Threat Solutions. A percentage of the sale goes to the Wounded Warrior Project.

73, amigo!!

 

[nanZor]

I would suggest picking up Michael Bryce WB8VGE's book about Emergency Power for Radio Communications.

UPS batteries are not designed for deep-discharge high-cycle life. They have thin plates, and are typically designed to be float charged and used a few times in emergencies.

UPS batteries are also sealed and there are two types - GEL and AGM. They charge at different rates. AGM is recommended, although if you decide to use the gels, make SURE you are setting your charge controller properly. You'll need one that handles gel in that case. If these batteries you are getting are used - avoid the frustration and just get a good new AGM.

If these are gel, then C/20 is the max charge rate and a lower voltage than AGM. AGM can usually withstand a max charge rate of C/4, so this decision alone can make a big difference when choosing the size of your panel. You can see that it will take a LONG time to charge a gel. Personal experience with gel is: forget about it. AGM charges quickly, can be indoors (still MUST be vented), but is a bit more expensive than wet-cells (wet cells have a max C/8 charge rate typically). Sealed AGM is the only way to go if you live in an area that doesn't have a lot of solar-insolation hours (REAL hours of usable solar charging light, not just visible daylight)

There are are a few solar power forums available that might help before you spend your hard earned cash. One of the most common errors is using too small of a panel for too large of a battery, and drawing more than 50% of the battery's capacity on a regular basis.

Quick test for AGM - with at least 4 hours rest (no charge or discharge), 12.8v or more = 100% charged. 12.6v = 75% charged. 12.2v = 50% charged. 11.9v = 25% charged NOT RECOMMENDED.

A 12ah battery might do ok for just receiving for 12 hours (assuming a .5a draw on rx), but if you are going to do any transmitting beyond qrp, I'd be thinking of at LEAST a 50ah battery and properly sized panel and controller to go with it. It all depends on how much power you are running and for how long. In addition, how much available solar insolation hours you have for your location to actually charge. What this means is that even if you get 8 hours or more of visible daylight, it is possible to only get any real benefit from 10am - 2pm.

Essentially, to do this right without frustration, be prepared to spend some $$ on the panel, charge controller, and a TRUE deep-cycle battery. Forget gel and starter batteries.

 

[krokus]

Congrats on passing the test.

AGM batteries are the best, current technology. I use them in my vehicles, since they are rugged and durable.

For solar sources, I saw this company's stuff at Dayton. It is a bit pricey, but looks like good, quality construction.
http://www.powerfilmsolar.com

 

[RESlusher]

If these are gel, then C/20 is the max charge rate and a lower voltage than AGM. AGM can usually withstand a max charge rate of C/4, so this decision alone can make a big difference when choosing the size of your panel. You can see that it will take a LONG time to charge a gel. Personal experience with gel is: forget about it. AGM charges quickly, can be indoors (still MUST be vented), but is a bit more expensive than wet-cells (wet cells have a max C/8 charge rate typically). Sealed AGM is the only way to go if you live in an area that doesn't have a lot of solar-insolation hours (REAL hours of usable solar charging light, not just visible daylight)

...

A 12ah battery might do ok for just receiving for 12 hours (assuming a .5a draw on rx), but if you are going to do any transmitting beyond qrp, I'd be thinking of at LEAST a 50ah battery and properly sized panel and controller to go with it. It all depends on how much power you are running and for how long. In addition, how much available solar insolation hours you have for your location to actually charge. What this means is that even if you get 8 hours or more of visible daylight, it is possible to only get any real benefit from 10am - 2pm.

Essentially, to do this right without frustration, be prepared to spend some $$ on the panel, charge controller, and a TRUE deep-cycle battery. Forget gel and starter batteries.

So I'm assuming that "C/4" means something like "charged in four hours" and "C/20" means 20 hours?

Also, forgive my ignorance but, "QRP"?? I'm still trying to learn the Q codes...

They way I figure, the battery(s) will be my biggest deciding factor on how the frame gets built. Any ideas on materials? I'm thinking aluminum tubing.

Thanks again for all the great info!

 

[nanZor]

Sorry about that - I did kind of go overboard on the whole thing...

So I'm assuming that "C/4" means something like "charged in four hours" and "C/20" means 20 hours?

Actually, it is the amount of current used to charge the battery with. In the case of an agm battery, that max is usually C/4, or around 3amps for a 12ah battery. So, a 60-watt panel puts out nearly 3amps, so this would be about the maximum size of panel for that 12ah battery. And if you are operating while charging, getting as large as you can to the max rating makes sense.

A general rule of thumb is that for wet-cells, you try to keep the current limit between 5 and 13%, or C/20 to C/8. Anything lower than C/20 is not recommended, as the charge current is so low that it takes too long to beat sulfation - not to mention trying to overcome the internal resistance at that point and your dinky panel ends up being a maintainer, and not a charger.

AGM's on the other hand, the rule changes a little from C/20 to C/4. As always, check with the manufacturer specs just in case. Some AGM's can accept charge rates higher than this.

If you can, try to make sure that your charge controller is temperature-compensated. Morningstar makes a nice little 4.5a pwm Sunguard controller that might be nice for this purpose. For camping, I like the PowerFilm products, and one controller they have looks like the morningstar.

There's much more to this, so consider the above just things you'll want to look into.

Also, forgive my ignorance but, "QRP"?? I'm still trying to learn the Q codes...

That means running low power. However, if you were to run a very low power, perhaps a tri-band handheld and a good antenna would be a lighter / better way to spend the money for the backpack.

Have fun - that's what it is all about when all is said and done!

 

[RESlusher]

Thanks for te info!

BTW, I lookec on the FCC website yesterday afternoon before leaving work and saw that my callsign had vbeen issued. I'm KF5RHI.

 

[Rt169Radio]

Thanks for te info!

BTW, I lookec on the FCC website yesterday afternoon before leaving work and saw that my callsign had vbeen issued. I'm KF5RHI.

Cool! Congrats.

 

[K9DAK]

So I'm assuming that "C/4" means something like "charged in four hours" and "C/20" means 20 hours?

Just for clarification . . . C = Capacity of the battery. So for your example 12Ah battery, C=12, therefore a charge rate of C/4 is 3A, C/20 is 600mA, etc.

Also, battery capacities are given at the "20-hour rate," which means that you can expect to draw 600 mA for 20 hours to full discharge, but you will not be able to draw 1A for 12 hours, or 12A for one hour. Of course the definition of full discharge varies by battery type.

Congrats on your new ticket!

 

[RESlusher]

Thanks for the clarification!

73!

 

[nanZor]

Btw, CONGRATS on the ticket!!

KF5LJW explains it MUCH better than I can:

Battery Tutorial and Discussion

And this is only the battery side of things - add a charge controller and a properly-sized panel and off you go!

 

[RESlusher]

OK. One last set of questions.

What's a good, reliable brand of battery for this application? I'm used to stuff like DieHard and Interstate; but I don't think they'd make one that would work for this...that wouldn't weigh a TON I mean!

Aside from putting in-line fuses on the wires between the battery and radio is there anything else I need? Can I hook the battery up to a trickle charger (like this one Battery Charger/Maintainer- DieHard-Automotive-Battery Accessories-Battery Chargers ) until I get the solar panel and controller? What gauge wire should I use between the battery and the leads coming off the back of the radio?

Again, my apologies for what probably sound like knuckle-head questions. I'd rather take the jabs for sounding like a noob than than fry a $600 radio.

 

[gewecke]

OK. One last set of questions.

What's a good, reliable brand of battery for this application? I'm used to stuff like DieHard and Interstate; but I don't think they'd make one that would work for this...that wouldn't weigh a TON I mean!

Aside from putting in-line fuses on the wires between the battery and radio is there anything else I need? Can I hook the battery up to a trickle charger (like this one Battery Charger/Maintainer- DieHard-Automotive-Battery Accessories-Battery Chargers ) until I get the solar panel and controller? What gauge wire should I use between the battery and the leads coming off the back of the radio?

Again, my apologies for what probably sound like knuckle-head questions. I'd rather take the jabs for sounding like a noob than than fry a $600 radio.

Optima Part No. D31M - BlueTop Deep Cycle Marine Batteries

73,
n9zas

 

[RESlusher]

Optima Part No. D31M - BlueTop Deep Cycle Marine Batteries

73,
n9zas

Yikes! They're certainly proud of that one!!

 

[gewecke]

Yikes! They're certainly proud of that one!!

Yeah, cheap they're not but then you DO get a warranty.
That's one of the cheaper one's too, Btw.

73,
n9zas

 

[W2NJS]

For all the questions and problems the large batteries present, you still might wish to consider a 5-watt HT vs. the FT8900R mobile radio where the power available allows you to run only 5 watts. You could run a solar charger for the spare HT batteries you carry and the size of your pack and the weight of it would likely be reduced quite a bit. What you would lose is the 10 meter band coverage.

 

[RESlusher]

That's the other option I'm considering, the Wouxon KG-UVD1P.

 

[wyShack]

If you are going to be backpack mobile, i would guess that you will likly be using 2 meters and 440 most of the tiem . In order to get on ten or six meters you are going to need an antenna that is simply too large to be effective. As you will likly be using repeaters, power is not a huge concern (I have a 5W handheld that covers 70-80 miles in the mountains its antenna height and effectivness much more than power out. another rig great for backpacking is the Yeasu 817. it is a low power all band radio with built in batteries. Get a small tunner and run a wire throough the trees when you get to camp.

most of all enjoy!

73

 

[RESlusher]

Thanks for the info!

A couple hours ago I pulled the trigger on buying a Wouxon KG-UV1DP to mess around with.

I'm planning to get a Yeasu 8900R; but I want to make sure I can crawl before I try walking if you all catch my drift!

Thanks again for all the great info!

73s to you and yours!