Seems a few of you here have worked with big 2V LA cells and since I've scored a set of 6 old ones maybe you can help with some advice.
Not that I have a real plan for these babies other than to attempt to get them back into some sort of usable capacity.
When I got them a couple of weeks back they were mostly ~1V OC and had been neglected/abandoned for some years.
They have a significant capacity of some 1000 AHrs/cell.
Initially I put some charge into each cell just to see that each would take some and as I could see each slowly taking more I figured they might be worth some effort although not much is involved with just clipping on a charger and checking them a couple of times/day.
However I've played with LA cells for decades and used desulphators to improve and lengthen battery life but first I'd like to improve the odds of a successful outcome.
Hunting out how others maintain and service these monstrous 2V cells I came across this Instructable
(yes I know) that seemed very interesting in that Phosphoric acid can be used to renovate and/or prolong life of LA cells:
https://www.instructables.com/id/Lead-Acid-Battery-Care-and-How-to-Restore-Them/Particularly Step 4 is worth a read.
Comments ?
Their current state (please excuse pun) after ~2 weeks charging.
One is damaged with a broken positive connection to the plates. (possible repair later)
The 5 other cells are seriesed up and taking a light charge (unrestricted A) that is growing some 20mA/day.
2 cells appear in reasonable condition in that they are ~2.1V while on charge which suggests they are taking what the series string can supply them. The remaining cells are 2.5, 2.7 and 3.3V in the series string charging @ ~13V. (CV)
The string is only drawing ~2A and up to 8A is available for charging duties when they might be able to withstand it.
All electrolyte levels were low but still above the plates and 2L water added to each to get them into the mid level range. Each cell is specified to hold 20L of electrolyte.
Plans
Get each cell to where it's properly starting to take some charge and below a nominal 2.2V like the 2 better cells.
Buy some Phosphoric acid for cell treatment as described in the article above.
Electronic desulphation of some kind....tests to confirm my 12V homemade 70V 6A 1 KHz pulser will perform on just 5 cells.
Attempt to fix the 6th cell with the broken terminal link. The cell lid can be removed and the electrolyte tipped into a 20L bucket and the plates removed as a package for washing and then repair.
If successful, attempt to recover this cell too.
Lost cause ? Why ?
Possible ? Tips and guidance please.
Thanks for reading.