Rolls S6 L16-HC 48 Volt battery bank dead

[qrper]

I went back to the site and took up new batteries. Pulled the old ones and brought them home. I didn’t have time to test the SG (left my hydrometer at the site). But individual battery voltage is 2.75 volts. I plan on testing the SG this weekend when I get home.

When the batteries went out I know it/they were at or below freezing and temps continued to drop.  None of the cells are cracked or bulged. I did have temp comp enabled but I also noticed there is a minimum voltage setting for this!  Mine was at 48 volts.  Not sure if this was an issue. Also I had set my bulk absorbed to 58 volts.  It should have ben 60 volts for the batteries. I didn’t have equalization enabled too. I had concerns about the DC-DC converts for the radios one of them has a voltage input of 44-58 volts. When I installed the new batteries yesterday I set the bulk/absorption voltage to 60 volts. Radios stayed on so the converter must be ok. 

Any suggestions on settings here?  I don’t have equalization enabled. I am a little concerned about excess water use. There are about 5-6 months I can’t drive to the site.  Never had exposed plates on the set that failed.

If I can revive this set of batteries I am thinking about using them as a 12 volt bank for radios/repeaters. I was thinking about getting a KID to charge them with. But instead of solar input I would connect this to the 48volt new battery bank. I want something that will handle all the charging. I would imagine that if I did this the KID would be in float 99% of the time. 

Jim.

Jim,

Lead-Acid batteries live in their own little world. Each brand/manufactuer has slightly different needs when it comes to voltages used for absorption, float, and equalization.

So to shuck it down to the cob, 60V is a tad high for absorptionâ€"you'll go though a lot of water. The equalization voltage I use here is 60.2V. My batteries go into absorb at 58.9V and the Classic holds that voltage for two hours.
I float my 16 US BATTERY L-16HC nominal 48V at 54.2V

I never did like automatic equalization. The stars never align correctly! When the time  comes to auto equalize, it's raining. Or, the batteries are low and can't reach the equalization set point. You do need to equalize this battery at least once per month. Equalization keeps the sulfate from building up on the plates, and of course balances the voltages between cells.

An automatic watering system would take care of the batteries' need however I'd be worried that the whole shebang would freeze during the winter.

Have you determined the cause of failure? At the price of batteries, I'd like to know what happened to kill off several thousand dollars worth of batteries before I replaced them.

Mike

[ClassicCrazy]

I went back to the site and took up new batteries. Pulled the old ones and brought them home. I didn’t have time to test the SG (left my hydrometer at the site). But individual battery voltage is 2.75 volts. I plan on testing the SG this weekend when I get home.

When the batteries went out I know it/they were at or below freezing and temps continued to drop.  None of the cells are cracked or bulged. I did have temp comp enabled but I also noticed there is a minimum voltage setting for this!  Mine was at 48 volts.  Not sure if this was an issue. Also I had set my bulk absorbed to 58 volts.  It should have ben 60 volts for the batteries. I didn’t have equalization enabled too. I had concerns about the DC-DC converts for the radios one of them has a voltage input of 44-58 volts. When I installed the new batteries yesterday I set the bulk/absorption voltage to 60 volts. Radios stayed on so the converter must be ok. 

Any suggestions on settings here?  I don’t have equalization enabled. I am a little concerned about excess water use. There are about 5-6 months I can’t drive to the site.  Never had exposed plates on the set that failed.

If I can revive this set of batteries I am thinking about using them as a 12 volt bank for radios/repeaters. I was thinking about getting a KID to charge them with. But instead of solar input I would connect this to the 48volt new battery bank. I want something that will handle all the charging. I would imagine that if I did this the KID would be in float 99% of the time. 

Jim.

The Classic has a Minimum and Maximum voltage setting.
Perhaps if your Maximum voltage setting was too low, the temperature compensation couldn't raise the voltage high enough when the batteries were cold to charge them all the way.
On my first solar setup I learned how to ruin a deep cycle battery that got cold with a controller that had no temperature compensation. That was a small system in an RV with single battery but taught me a good lesson !
When the batteries are cold and the temp compensated absorb voltage raises , I don't think that translates to using a lot of extra water than normal.
Larry