[RE-wrenches] 2 volt Trojan RE series L16 Batteries

[Brian Teitelbaum]

Funny story: we once had a brand new L-16 that came back to us from a customer who said that it was bad. We checked the voltage and it was 6.2VDC. We tried to run a small 6V motor with it to no avail. Checked the voltage again at 6.2VDC. Then we did the unthinkable: we shorted across the terminals with a short piece of #10 wire. Only a very faint spark was noticed, and the voltage dropped to zero. Took the wire off and read the voltage at 6.2VDC.

Upon calling the manufacturer we got the expected response of "that's not possible". It took forever to get the manufacturer to replace it.

We never cut it open to take a look, but I suspect that it was a micro-fracture in one of the internal buss bars, with enough continuity to provide voltage but not enough for current flow. We didn't measure the SG either, but I doubt that it was anything other than normal.

Brian Teitelbaum
AEE Solar



From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bob-O Schultze
Sent: Wednesday, April 20, 2011 12:16 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] 2 volt Trojan RE series L16 Batteries

Rich,
It sounds like you've got a rotter or two. Given the short age of the pack, that's my suspicion. Try checking the individual battery voltages when under load and fairly well discharged. I've seen a new battery bank all show good SG and individual voltages while resting but one or more batteries tank badly under load. Poor manufacturing QC is the cause.
good luck, Bob-O

On Apr 20, 2011, at 12:03 PM, Rich Nicol wrote:


RE Wrenches
My question regards a system (installed by homeowner / friend) where they recently upgraded their t105 battery bank to Trojan RE series L16 2 volt cells.  The battery bank consists of 6 batteries in series for a 12 volt system.  The interconnects are 12" long 4/0 cables with crimped and soldered lugs.  Main cables are 6' long 4/0 cables.
The first issue is high terminal temperature during periods of heavy draw (~100 amps @ 12v when water pump is on).  Due to the issue the owner has been only running the water pump when charging the batteries with his generator since the transfer switch on the Outback inverter has transferred his household circuits from the battery bank to the generator.  Obviously this is an inconvenience. Before the end of life on his T105's he had no issues with the 6 volt cells in series/parallel using only #2 AWG interconnects.
Most recently he's experienced an issue where the inverter will not come on at all and when attempted to come by switching on his main DC breaker  the voltage at the batteries sags from 12.5 to ~5V!  This issue is not with the inverter since I loaned him a back up Trace DR I keep around as a loaner but it too would not come on and voltage sagged as well.  This sag is with no demand since it sags immediately when the DC breaker is switched on when connected to the inverter even though the inverter has not been switched on.
I stopped by this AM to check out the situation, specific gravity of all cells is good, open circuit voltage on each cell is matched at 2.12  volts.  The battery bank is only about 4 months old.
Any insight would be greatly appreciated.

Battery specs:
2 volt, Rated Capacity @ 5 Hr rate=909 AH, 20 hr rate = 1110 AH, 100 hr rate = 1235.

Thanks for your help!
Rich



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