Battery Backup

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lrcrabtree

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With so many types of batteries on the market now (AGM, LIo, lead acid, etc.) I'm at a loss as to what is best to use as a battery backup for my ham radio transceivers. I want to set up a battery back-up, maybe a small bank of batteries, that will be outdoors with the power lines run through the wall into my shack area; charged / maintained by 110V and/or solar. Transceiver use is average less than a couple hours per day. Any ideas on the type of batteries, advantages and disadvantages is very welcome.

Larry
KJ6QVI
 

mmckenna

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Gel Cell Lead Acid. Make sure you are getting ones called "VRLA". These are Valve Regulated Lead Acid. The "valve" part lets the vent when the pressure rises, usually when abused, to keep them from cracking. When under normal use, the valve stays closed to keep the good stuff inside.

I'm running tons (actual tons) of VRLA's in large telephone and radio system applications. Properly maintained and float charged they should last 10 years or more, depending on the designs. I'm in the middle of swapping out our battery plant for our phone system and I'm replacing them with GNB 20 year batteries.

If treated well and not overcharged, over heated, they don't vent anything. If you charge them too fast, charge them with too much current, or too much voltage, they will outgas hydrogen. Part of our project includes hydrogen detectors at all my sites that send in an alarm if they start outgassing.

Outside can be a good thing, but batteries like this do not like wide temperature swings. Ideally you want to keep them in the 60-80˚ F. range. For every 10 degrees you go above 80 you are taking life off the battery. Get them too cold and they won't perform.

Ideally you'd want them inside, enclosed and vented to the outside.

Your charge controller needs to be designed for "float charging", which is a constant steady voltage applied to the batteries. Temperature compensation is necessary, also. It is often used to automatically adjust charge voltage to compensate for temperature fluctuations.

The battery manufacturer will be able to supply the float voltage settings, temperature compensation settings, maximum charge current (Usually C/20, or the current capacity of the battery divided by 20).

Stainless steel hardware used on and around all your batteries is also necessary.
Frequent inspection and preventative maintenance will get you the most life out of your batteries.

A good brand to check into is C&D Technologies. Look at the TEL 12-105 batteries, or something in the TEL 12 family. They are suitable for what you want to do.

I've surplussed a whole lot of the C&D's over the years, many have gone to amateur radio clubs, some have been recycled. It's not uncommon to be able to pick them up used from the telephone, cable TV or other similar companies. We usually replaced them well before they were completely worn out and they usually had 5 years of life left in them, at least.

Fuse -everything- Big batteries like this don't take kindly to short circuits. It gets messy really fast.

Here's two battery systems that were delivered a couple of weeks ago at work. 600AH 48V systems, there are two in the photo, each split in half, 4 pallets. About 6000 pounds worth. Each one is made up of 24 each 2 volt cells.

 
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KC4RAF

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^^^ As 'mmckenna' suggested.

Even plain ol' standard lead acid car battery. They can take a beating and still produce. With trickle charger, you'd be just fine. That's what I use and haven't had any problems. (I do vent with a fan because of the hydrogen and oxygen thou.)
 

BlueDevil

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Any suggestions for a battery that will be used as a primary power supply for a portable repeater setup that will be deployed outdoor and possibly in any weather conditions? It will be in an enclosure but could still be out in 100+ degree temperatures or in sub freezing conditions. I plan to use a 100watt solar panel to charge the system during the day. However would want the system to be able to run for a couple days without having to be charged. I have been looking at batteries in the 100Ah capacity range.
 

Rred

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A car battery can be a bad idea. If it is actually NEEDED and you need to run it down to a deep discharge, car batteries can often be killed by as few as 4-6 deep discharges. They are actually designed for no more than a 10% discharge, as compared to a true deep cycle battery which is designed for 30-50% discharges hundreds of times, and able to withstand often 50-100 really deep discharges, i.e. to 80%.

In order to do better than that, your next step up is a big one, to lithium technology, where 2000 deep cycles to 90% discharge are often promised. Of course the price is also going to be dramatic, and all of the "lithium" technologies except LiFePO4 use a flammable electrolyte and (think Boeing Dreamliner) need special fire extinguishers and cautions.
 

BlueDevil

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Understood. I haven't been looking at utilizing a car battery. I have been looking at 100Ah AGM SLA Batteries.
 

slicerwizard

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Even plain ol' standard lead acid car battery. They can take a beating and still produce. With trickle charger, you'd be just fine. That's what I use and haven't had any problems. (I do vent with a fan because of the hydrogen and oxygen thou.)
As noted, car batteries are a very bad idea. They're designed to supply brief bursts of high current and that's it. After running them down a few times, you end up with close to 0 Ah capacity. Better quality batteries may handle it better, but why not spend that extra cash on a deep cycle instead?


Understood. I haven't been looking at utilizing a car battery. I have been looking at 100Ah AGM SLA Batteries.
When you run them down for a few days in freezing conditions, the electrolyte will turn into water and freeze. That usually splits the plastic case.
 

mmckenna

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Any suggestions for a battery that will be used as a primary power supply for a portable repeater setup that will be deployed outdoor and possibly in any weather conditions? It will be in an enclosure but could still be out in 100+ degree temperatures or in sub freezing conditions. I plan to use a 100watt solar panel to charge the system during the day. However would want the system to be able to run for a couple days without having to be charged. I have been looking at batteries in the 100Ah capacity range.

They do make batteries that will tolerate wider temperature ranges, but freezing to 100+ is getting a bit extreme. They'll work, but you'd spend a lot of money and still have reduced life span.

Usually the way this is done commercially is to have the batteries inside an enclosure with the equipment where temperature extremes are not quite as wide. Sometimes they'll even bury the batteries in a waterproof vault underground to stabilize temperatures.
I've also seen a number of locations that use thermo-electric generators. These will utilize propane/CNG and using non-moving parts will generate some electricity. TEG's are not a good idea for high load systems, but they will work well for small/occasional load systems. Propane/CNG use is pretty low so it isn't hard to get enough fuel on site to keep the system running for months to a year at a time.

Wind power is sometimes used to supply power when the solar panels are unable to generate enough, overcast/stormy conditions or solar panels covered with snow. Problem with wind power is that high gust winds on mountain tops can often destroy a wind generator that isn't up to the task

Often a combination of systems are used to supply the power needs. Also, keeping electrical loads to the absolute minimum helps a whole lot. A high site with good coverage can often do well with a 5 watt repeater and good antenna systems.

Smaller battery systems with a good solar power system might be a good choice since the battery life span won't be as long.
I'd figure out what you need for the equipment, then decide how much power you really need on site. Design a battery/charging system based on that, then size your enclosure to make sure the batteries will fit inside. Usually the electronics will generate enough heat to keep the temperatures above freezing inside the enclosure. When it gets hot, finding a way to ventilate might be helpful.

Not a lot of really good choices for low budget hobby/amateur use. These sorts of environments take some money to make work well.

It can be done though. Here's a large radio site that is well off the grid. No commercial power, no commercial telephone service. Everything is either generated on site or brought in annually by propane truck. Backhaul is all microwave:

 
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Rred

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AGM batteries, just like wet lead, come in both SLI (starter) and deep cycle types. And "50-50" types.
If you look at JCI's Optima brand, there are red, yellow, blue cases to distinguish them. But flat plate AGM's will give you more power for less money than cylindrical ones like Optima.

AGM are great for indoor use, where minor acid spills can be costly problems. But generally they are at least 30% more expensive than the same capacity as wet lead. Golf cart (aka "traction") batteries can be a very good bet because they are so common and competitive, although you may find they are 6v batteries and you'll need to bolt them up in pairs. Wal-Mart and Sam's Club often have the best prices on these if you have no distributor.

Chrysler used to offer thermal protection for the battery in their police/fleet vehicles. It looked like a Styrofoam cooler. So if you can't afford more exotic climate control, either a masonry enclosure (for high thermal mass) or Styrofoam (to prevent the worst of the heat cycling) may be some help at a much lower price.

The charging system really needs to have a temperature sensor and compensate for that, as all commercial grade systems will. And if there's any chance of deeply discharged batteries freezing in the cold--then you need to reconsider and move the installation indoors.
 

mmckenna

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\And if there's any chance of deeply discharged batteries freezing in the cold--then you need to reconsider and move the installation indoors.

Excellent point. All my systems have low voltage disconnects on them. When the system looses AC mains and goes on battery, the system will watch the battery voltage. When the battery voltage reaches a set point, a contactor opens up and disconnects the battery from the system. This protects the battery from getting drained too far. When the power recovers, the system will reconnect the battery and charge it back up.

Really important to have this if you have a large battery system. Discharging cells beyond a certain point can permanently damage the battery.

Temperature compensation on your charging system really is required in these sorts of installs if you want your investment in batteries to pay off. Just blindly dumping power into the battery isn't the way to do it.

I use almost entirely Alpha power systems. Some of my radios sites are using Newmar. There are other manufacturers.
Newmar makes a lot of 12 volt systems, although some of their designs are kind of poor. I haven't had any failures with their systems. They do have some small systems and charge controllers. Might be a good idea to surf on over to their site and take a look at what they offer. It'll at least give you an idea of the options.
Alpha makes a lot of 48 volt and 24 volt systems for telecom/cellular, but they do have some 12 volt systems. Alpha is an excellent company to deal with.
 

KI7HYI

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A car battery can be a bad idea. If it is actually NEEDED and you need to run it down to a deep discharge, car batteries can often be killed by as few as 4-6 deep discharges. They are actually designed for no more than a 10% discharge, as compared to a true deep cycle battery which is designed for 30-50% discharges hundreds of times, and able to withstand often 50-100 really deep discharges, i.e. to 80%.

In order to do better than that, your next step up is a big one, to lithium technology, where 2000 deep cycles to 90% discharge are often promised. Of course the price is also going to be dramatic, and all of the "lithium" technologies except LiFePO4 use a flammable electrolyte and (think Boeing Dreamliner) need special fire extinguishers and cautions.

There is always the new deep cycle batteries which are designed for cranking as well.
 

Rred

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Nothing new there. A "starting" battery is simply any battery that has enough impulse power to keep the starter happy. I've used a 17Ah "gel" (AGM) alarm battery to start a marine diesel engine.

Almost any deep cycle battery with a decent capacity can generate enough impulse power to start a reasonably sized engine. (Shh! Don't tell anyone!) Most of the "dual purpose" batteries are actually slightly more robust SLI batteries, and not deep cycle batteries in any way at all. The real way to find out is to ask the manufacturer how thick the plates are. Thick plates = true deep cycle. Thin plates = SLI. Anything in between? Is just a beefier SLI, not really deep cycle at all.

The battery guys are like the tire and mattress guys, for the most part. Or Forest Gump's box of chocolates: You never know what's going to be inside.
 

KI7HYI

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Nothing new there. A "starting" battery is simply any battery that has enough impulse power to keep the starter happy. I've used a 17Ah "gel" (AGM) alarm battery to start a marine diesel engine.

Almost any deep cycle battery with a decent capacity can generate enough impulse power to start a reasonably sized engine. (Shh! Don't tell anyone!) Most of the "dual purpose" batteries are actually slightly more robust SLI batteries, and not deep cycle batteries in any way at all. The real way to find out is to ask the manufacturer how thick the plates are. Thick plates = true deep cycle. Thin plates = SLI. Anything in between? Is just a beefier SLI, not really deep cycle at all.

The battery guys are like the tire and mattress guys, for the most part. Or Forest Gump's box of chocolates: You never know what's going to be inside.

Unless one has used "cranking deep cycle" batteries for several years and know that they can do both jobs equally well as non-deep cycles and non-cranking deep cycles, as I do.
 

Rred

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I said:
"Almost any deep cycle battery with a decent capacity can generate enough impulse power to start a reasonably sized engine. ***(Shh! Don't tell anyone!) ***"

And now you had to go and tell everyone?
 

Rred

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Larry-
Not knowing your real energy budget or intended use...some of it is hard to guess. If the repeater is intended to provide EMCOMM support, you might want 3-5 days of battery power on it. You' have to figure out how many amps for how many hours of TX/RX it will need, and ho reliable that 100A solar panel will be. And typically a solar panel will give you, in one summer day, five hours worth of the maximum rated capacity, no more. So you add it all up and see what the budget will allow. Group31 or other 100Ah batteries are about all one person can lug, so I can appreciate that limit.

But than when you've done all the math, add this in. A 100Ah battery is really just a 30Ah battery. That's because it may have 2000 charge cycles at a 70 SOC, but that may drop to 200 cycles at an 80% SOC, or 1000 cycles at 50% SOC. Pulling them down below 30% discharge really impacts their long-term performance, so plan conservatively. AGMs also like to get back to a full charge, not just "almost" full, and keeping them topped up every day can also take their typical life from 4 years to 6-8 years, a very good investment.

FWIW.
 

rbm

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I have three different emergency power systems.
They're listed below.

However, the one I use most often is one of the Wen 56200i's at the link below.
It's 1600 Watts is sufficient for most things.

You can carry it around like a 'heavy' suitcase. Even pick it up, and put it in the trunk of your car.
My wife can even carry it. (Not that she likes to. ;) )
You wouldn't want to walk a mile with it, but for short distances, it's great.

I use it far more often than I thought I ever would.
I have an electric pole pruner, hedge trimmer, etc. and the Wen (at about half the price of a Honda) was a great investment.
I liked it enough that I got a second one to double the power.

If I had no worries about getting gasoline during widespread power outages, I wouldn't even bother with the batteries and solar panels.

The big generator and the batteries, inverters, and solar panels just get tested a few times a year to make sure everything is in good shape.

I have several long extension cords on reels.
They're connected in the center of their lengths to the reels so it only takes half as long to wind them up.
https://www.lowes.com/pd/Bayco-100-ft-4-Outlet-Plastic-Cord-Organizer/1214695

Rich


I have three different levels of emergency power.

A Generac 7500 watt generator that will run the water heater with 240 volt output and a lot more


Two of these: (around $420 each)
WEN 56200i, 1600 Running Watts/2000 Starting Watts, 4-Stroke Gas Powered Portable Inverter Generator
https://www.amazon.com/gp/product/B00SMNLF4M/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Along with one of these to connect the two WEN 56200i Inverter Generators to give 3200 running watts:
WEN 56421 Parallel Connection Kit for Inverter Generators
https://www.amazon.com/WEN-56421-Pa...rd_wg=NnKZx&psc=1&refRID=KJ21T826GTXD8FTCND04

And last, I have six golf car batteries with 6 x 100 Watt Renogy 12 Volts Monocrystalline solar panels.
Four of them feed a Xantrex 2000 Watt pure sinewave inverter.
Two feed a Xantrex 1000 Watt pure sinewave inverter.

The golf car batteries are 6 Volts so you need to use them in PAIRS.
I have them continuously connected to a Battery Tender charger.
But, you MUST check the electrolyte level frequently because it will dissipate over time.

The golf car batteries are Duracell ECG2 and available at Sam’s Club etc. for around $115 x 2 = $230
Their 20 amp hour rate is 230 amps.
If kept in good condition, they’ll deliver 25 amps for a little more than seven hours and also 110 VAC with an inverter of your choice.
Duracell® Golf Car Battery - Group Size 230 - Sam's Club
 
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rbm

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I should have mentioned this in my first post.

My 4th and 5th emergency power options.



I didn't think of them at the time because I don't consider them to be serious options for most uses.
However, if you just want to run a scanner, VHF/UHF transceiver, or small 120Volt appliance, they can do the job for a short time.

I use them while antenna & amplifier testing before I mount everything permanently.

The jump start box on the right contains an AGM 12V 18AH battery. (UB12180)
The trolling motor box on the left will hold a good quality 12Volt, group 24- and 27-size battery.

I keep one of each in both vehicles and also another pair of the Min-Kota boxes in the garage.

One of each in the vehicles because the jump start box can be depleted after just a few starts.

In the past, when I've been called to help friends with battery problems, I'll get their car started using the big box, and then let them take the jump start box to make sure they don't get stuck before they can get a replacement battery.

Rich
 
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KI7HYI

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I should have mentioned this in my first post.

My 4th and 5th emergency power options.



I didn't think of them at the time because I don't consider them to be serious options for most uses.
However, if you just want to run a scanner, VHF/UHF transceiver, or small 120Volt appliance, they can do the job for a short time.

I use them while antenna & amplifier testing before I mount everything permanently.

The jump start box on the right contains an AGM 12V 18AH battery. (UB12180)
The trolling motor box on the left will hold a good quality 12Volt, group 24- and 27-size battery.

I keep one of each in both vehicles and also another pair of the Min-Kota boxes in the garage.

One of each in the vehicles because the jump start box can be depleted after just a few starts.

In the past, when I've been called to help friends with battery problems, I'll get their car started using the big box, and then let them take the jump start box to make sure they don't get stuck before they can get a replacement battery.

Rich

Since most starting problems are related to the bad connection from corroded terminals preventing the battery from having a good enough connection to either charge or start, I use my experience in both electronics and mechanics to fix the connection problems before replacing components. Most jumpstarts bypass the bad connection and fail to restore the charging potential of the battery.
 

rbm

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Most jumpstarts bypass the bad connection and fail to restore the charging potential of the battery.

Where I come from, that's called 'Common Sense'. ;)

My daughters had their own set of tools and a battery brush by the time they were 16.

Rich
 
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