Cell Tower Batteries- Info

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ak.pedal   1 µW

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Cell Tower Batteries- Info

Post by ak.pedal » Apr 11 2018 1:30pm

I came across these at a friend's shop and wonder if anyone has experience with them they can share. I get about 1.3v per cell but have not load tested or tried charging.

I found the manual for a similar model but these are discontinued. They came out of a backup power system in a cell tower site several years ago and have been sitting since.

data sheet: https://www.p-s-s.com/pdf/GNB-Absoltye-IIP.pdf

looking for:
1. general experience with them. any particulars in using these or are they just normal lead packs (lead calcium according to data sheet)?
2. The lead calcium is supposed to help with cold weather use as I understand. These have unfortunately been stored outdoors so have seen some 100f to 10f temps. Are they likely to be damaged from this?
3. What methods would you use for testing them on site to see if they are worth doing anything with?

image text:
ABSOLYTE IIP, type 100A-23, 1100 Ampere Hours, 8Hr to 1.75 VPC, NON-SPILLABLE BATTERY

ak.pedal   1 µW

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Re: Cell Tower Batteries- Info

Post by ak.pedal » Apr 11 2018 1:31pm

images
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Jon NCal   1 kW

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Re: Cell Tower Batteries- Info

Post by Jon NCal » Apr 11 2018 1:56pm

I do have a lot experience with these. I would charge them up and then take individual cell voltages to see if they hold a charge. They probably are somewhat damaged by not being on a charge for so long. For testing we used adjustable or automatic load banks that can keep a constant amperage and then monitor the voltage over time. You would want to track the individual cell voltages periodically during the load test. Testing is usually done at room temperature, but you can look at the discharge graphs to see what the performance is supposed to be at other temperatures.

craneplaneguy   10 kW

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Re: Cell Tower Batteries- Info

Post by craneplaneguy » Apr 12 2018 9:23am

A few years ago I got a call from an electrician who knew I was "into solar", he had just finished up a job at a cell tower. Long story short, for $100.00 (and he delivered them up the mountain to my shop) I got a large pack of some Italian branded AGM batteries, complete with a steel rack. I promptly sold half the pack for $500.00 (reconfigured as 24 VDC for an off grid customer) then a quarter of the pack to a 12 VDC off gridder, then then donated the last qt. (and got a $500.00 tax deduction) to my local ski area's Ski Patrol, where they continue to perform well at their 8600' patrol shack up top. I never load tested them, but they never spent any time, less then a week, out of service. The cell companies will unload these things well before they show signs of failing, and I would love to get my hands on some more! It's been 4 or 5 years since the Patrol shack install, no signs yet of any problems. Get them cheap or free you can't go wrong.

The big steel rack, was cut up and eventually morphed into several small welding projects as needed, nothing went to waste, I really scored on the deal obviously!

ak.pedal   1 µW

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Re: Cell Tower Batteries- Info

Post by ak.pedal » May 07 2018 6:12pm

Nice score, craneplaneguy! sounds like these are pretty great to have around. Will certainly work them into some projects here.

Jon NCal, I finally got some time to do a little work on these and setup an arduino with voltage dividers to track cell voltages. Working on the serial -> excel part right now and cleaning up the code to accept true resistor values. I will post graphs when I get a charge on them and also will hook up a large heating element or something for a load to look at the discharge. Im guessing the cell voltages should stay rather balanced under charge and discharge cycles. What is an acceptable percent difference? Also, for a given load, the voltage drop should not be beyond some threshold. Can you give me any idea of what healthy packs drop under a few load situations?

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billvon   10 MW

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Re: Cell Tower Batteries- Info

Post by billvon » May 07 2018 10:47pm

ak.pedal wrote:
Apr 11 2018 1:30pm
1. general experience with them. any particulars in using these or are they just normal lead packs (lead calcium according to data sheet)?
Telecom batteries are designed for UPS service (i.e. very long float life, very short cycle life.) They are great as backup batteries, but a poor choice for full time off grid use.
--bill von

ak.pedal   1 µW

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Re: Cell Tower Batteries- Info

Post by ak.pedal » May 08 2018 2:47am

billvon wrote:
May 07 2018 10:47pm
Telecom batteries are designed for UPS service (i.e. very long float life, very short cycle life.) They are great as backup batteries, but a poor choice for full time off grid use.
ah that's super good to know. It makes sense they would be purpose built and then dumped by the telecom companies after they are pulled from service.
Under sizing the load and keeping a high cut off voltage might get a little more use out of them. perhaps

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