Battery question and proper way to disconnect from panels

rake1 · October 2016

I have two Surrette 530 6 volt batteries that are 4 years old now and are taking a lot longer to charge with my Gen. I usually equalize every 3 months so I am due again. I assume they are getting weak because of the age of them but they have been good to me so I want to keep them going as long as possible.They seem to equalize better when I disconnect them and charge them one at a time I need to know the proper sequence to disconnect these and reconnect them without harming my solar panels. I normally do it at night when no power is coming into the panels but would like to do it during the day time.These are six volt batteries so when disconnected the panels are sending power to the charge controller but no where for the power to go.Does this hurt the panels? Thanks
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BB. · October 2016

As long as you do not reverse the +/- leads to the solar panels, you will not hurt anything.

The (usual) correct way to disconnect battery power for the panels+charge controller... Turn off (breaker or switch) the solar array first, then turn off the breaker from the + charger output to the + battery bank bus. To reconnect, turn on + to charge controller first, then turn on the + to the solar array. Some charge controllers "get confused" (damage to charge controller is possible in some rare cases) if you connect the solar panels (under sun) before you connect the battery bank.

There is one solar panel technology that is damaged if left unconnected under sun--But those are only used for Grid Tied Solar Power farms, not for home installations.

Are you using a Hydrometer to measure Specific Gravity per cell? Have you used a DMM to measure each battery voltage? (and logging the readings?)

More or less, looking for "differences" (one cell with high or low specific gravity, one battery with high or low voltage under charge, under load, resting 2+ hours).

How do you know the batteries are taking longer to charge?

-Bill

rake1 · October 2016

Thanks BB My Hydrometer reads about 1.260 on all cells but one which reads about 1.20 to 1.22 and does this most of the time.After 3 hours equalization it may get into the green just. but in a month it is back to where it was 1.22. This is at my camp that I usually go to each weekend. I always charge the batteries with my gen before I leave. That is how I know it is taking longer to charge these up. New after the weekend 1/1/2 hour to charge them now 4 years old this weekend it took 4 hours and it has been getting longer for some time now.I do add water probably every two months, I am wondering if after 4 years the electrolyte is getting to weak.The batteries still perform well and still never drop below 12.2 volts in the weekend. But this weekend they did drop to 12.1 volts. Is there anything I can add to bring these batteries back to a new like condition? I read about things you can add to the battery on the net but never really believed that it would work or am I wrong. Thanks

Photowhit · October 2016

You should equalize until all the cells are within .02 of each other.

I don't know what "in the green" means, what does your hydrometer consider in the green?

Do you know the specific gravity when the batteries where new? I think some Rolls are 1.260, but many are 1.280. It might be that the battery bank isn't fully charged when you start your equalizing. I believe the 530 is a tall case 6 volt battery. I would expect the life to be 7 years or so, so it would be worth the effort to equalize as long as needed to get the SG up. I would also switch to equalizing every month, knowing that you have one cell that is consistently low...

rake1 · October 2016

Green is where the Hydrometer says the batts are good about 1.25 what about adding something other than water as mentioned after 4 years the electrolyte must be getting weak.

BB. · October 2016

The electrolyte gets weak because the sulfur is combining "permanently" with the lead plates (sulfation). There is nothing you can do to restore the health of the bank.

You can lessen battery resistance by equalization to knock sulfide crystals from the plates (open the pores). There has been a person or two that found placing the batteries in the back of a truck and drive on a dirt road--The vibration helped too.

-Bill

rake1 · October 2016

So all that info I read about adding to the electrolyte is just crap thanks that is what I thought.

JesusisLord · March 2022

Rake you can overcharge your battery and it will help remove the sulfide buildups. The link below is a video where a man describes the process using an old dumb battery charger that allows overcharging. He also recommends using a 2 ohms resitor, but it not required. He says the resistor helps reduce electrolyte losses in the battery. If this a floored battery that shouldn't be a big issue, because you can just add some distilled water until the plates are covered. If you have a sealed battery the resistor may be a good idea, but if your battery is already dead some risk should be tolerable. Basically you overcharge the battery from 1 days to 2 weeks. The charge that the battery accepts should increase overtime. If it does not increase after 2 weeks it is unrecoverable. Once it will hold a full charge after resting for 24 hours you cycle the battery 5 times to help the plates expand and contract and hopefully knock more of the sulfides off. If everything goes well the battery will be better than before, but never as good as new.

https://youtu.be/6x-JfckAt20

Battery question and proper way to disconnect from panels

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