H2S Coming from battery bank.

[goodoleme]

Hello everyone,

I have 8 Trojan L16H-AC wired in series (435ah @48v). Last week while performing battery maintenance everything was good with water levels and SG, each cell was around 1.277.
I started equalizing and within about 20min could smell a very high concentration of h2s, I know that smell very well living on a well for 20+ years. So my 1st thought was over charging from internal resistance, I let the eq run for an hour and checked each battery for high temps, each battery was the same temp, none of them got to hot. I disconnected them from the system and waited 24 hours and checked the OCV, was 51.5v. I know OCV is not for checking SOC. I reconnected them and put around a c/20 load (around 19a) on them for 3 hours, voltage dropped slowly to 49.5. When load was removed voltage went back to 50.5. Then did a recharge and could smell the h2s again. Once done with the recharge I rechecked the SG and each cell was around 1.27/1.26.

The bank was installed 1 year ago and has never been discharged below 90% soc. It does get a little of micro cycling. I have 2760w 57.5a (c/7.5) of solar power connected to the CC for charging. Bulk\Abs is set to 59.28v and float is 54v and eq is done at 64v.

I am not sure what to do from this point other then a high load test that brings each cell down to around 1.99v.

Any help would be great, thanks.
Neil

[Sunking]

Are you using water? Having to top off every week or two?

Make dang sure your hydrometer is accurate and you are adjusting for Temperature.What you are describing is over charging. FWIW you only EQ charge when required, NOT REGULARLY.

You do not EQ until 1 of 2 conditions exist.

1. When batteries have a low specific gravity after being topped off with water and a full charge cycle (<1.235).
2. When the range of specific gravity between highest and lowest cells is > 0.030 points.

Rotten Egg smell is not only really bad for the batteries, but extremely toxic to humans. The smell means one of two things. Failing batteries, or Over Charging the heck out of the batteries.

For now lower Bulk/Absorb to 58.4 volts and if you can adjust Absorb Time lower it to 2 hours. Float is fine at 54 volts. Leave EQ OFF and monitor SG.

Come tomorrow get up early if you are a late sleeper with Hydrometer by your side, and monitor SG every 30 minutes starting in the morning. Just one cell, the Pilot Cell near center mass. The moment you see SG flirts with with 100% SOC, Do not wait until it gets 100% but Flirts with say approaching .002 to .003 points before. Note what system is doing. If it is still in Bulk Mode, incrementally lower voltage until system is in Absorb Mode. You can tel Absorb when charge current goes down say 40% off full current. Absorb and Float should be more then enough to finish charging the last point or two.

[goodoleme]

Should I change the cc charging to c/10 43.5a vs c/7.5 57.5a?

Adding around 64oz (2.6oz per cell) per month, temperature where the bats are is high now, around 85+, hot now in south Fla. My hydrometer is not a temperature correcting one, that one went walkies on me! I did order a new one.

Thanks.

[Sunking]

Should I change the cc charging to c/10 43.5a vs c/7.5 57.5a?

No you have a over voltage or bad cell issue, not current. C/7 is just fine on Trojans. Does any one cell grab your attention for any reason?

[goodoleme]

Only within the last month did I change the bulk/absorption voltage from the inv/cc default after reading, are you killing your bats, and also reading the Trojan data sheet. Trojan also says to use 2.47v. The default on the inv/cc was 57.6v for bulk/absorption. I also left the default for the float @ 54v.

I do have the battery monitor I never installed, I am going to install it tonight just to see how much current is going in and out.
I also am going to put on some no-ox-id when installing the bat mon., thanks for the tip and brand on that!

This cell did grab my attention, and was 1 deg. higher when it was under the equalize charge.

all the terminal post look like the pic on the left and then there is this one.

20180815_180015.jpg2.jpg

My wife just told me my where my tc Hydrometer was, said I left it on the floor in the garage, doh!

20180815_193424.jpg

[Sunking]

Nothing catching my eye, point it out please.

FWIW I like the cable, and looks like they are terminated OK, at least you have real battery terminals because there is no Inspection Holes. Only thing that I see or missing is use of an Anti-Oxidant.