Mixing Batteries on Float-- Mex Test Update 2
UPDATE 1 on 23 Dec post UPDATE 2 on 25 Dec post ---------- Mex is driving me crazy! He said do not mix my used 12s (Scrubber batteries, he calls them--humph! They are respectable golf car batte...
Forum Discussion
Decided to try out Mex's tests on my two "previously enjoyed" T-1275s where I have noted before that one seems to be in better shape than the other based on higher average SGs, although each has variations among its cells for SG.
This should tell whether they can be left in parallel safely for a long term float on one charger, or need individual floating with two chargers.
So to get started, where they have been on individual floats for a while at different voltages (13.5, 13.4) been watered a little in some cells after last overcharge(affecting SGs), I put them in parallel, gave them a quick overcharge at 15v for an hour, and got , while still being charged, 14.94v each.
I watched as they started to show bubbles, but did not see anything obvious which cells started to bubble first. Not boiling anyway, just small bubbles coming up in strings.
So next step is disconnect everything and let them sit for four or five days and check voltages and SGs. Meanwhile, after an hour I took an initial set as a benchmark sort of with surface charge still present:
Battery A (the good one?) 13.43v
Battery B (the also ran) 13.40v
Battery A 1.275, 75, 70, 90, 75, 75
Battery B 75, 75, 1.300, 75, 75, 75
So now must wait a few days and see what happens.
Mex says a low cell draws from the others. Battery A has that lower cell at 70 there, which is always the low cell when taking SGs. Battery B has that crazy high SG cell, which is always high like that.
Not a clue what that might mean, can't fix it, it just is!
If Mex is reading, is this a proper start? Do I check daily or just wait four days? (I doubt all the surface charge will be gone in only four or five days, but we'll see)
This should tell whether they can be left in parallel safely for a long term float on one charger, or need individual floating with two chargers.
MEXICOWANDERER wrote:
...........
Here's a tip to understand the reality of same type of battery has different chemical attributes according to its state of charge or age.
Fully charge all batteries
Wait 4 or 5 days, then measure the voltage potential of each battery
Take a hydrometer reading then reconcile it to voltage of each battery.
A tenth of a volt is significant, two tenths is worrysome when you are trying to balance batteries.
To amplify the test, apply 14.8 volts after fully charging the batteries. Note that the cells with the lowest gravity and lowest initial voltage boil first.
Cells that droop after charging, actually CONSUME power. Roaches check in but they don't check out, time. The worse the cell the hungrier they get. Some are the eqvt of a 20 watt load on the other cells in the bank.
............
.
So to get started, where they have been on individual floats for a while at different voltages (13.5, 13.4) been watered a little in some cells after last overcharge(affecting SGs), I put them in parallel, gave them a quick overcharge at 15v for an hour, and got , while still being charged, 14.94v each.
I watched as they started to show bubbles, but did not see anything obvious which cells started to bubble first. Not boiling anyway, just small bubbles coming up in strings.
So next step is disconnect everything and let them sit for four or five days and check voltages and SGs. Meanwhile, after an hour I took an initial set as a benchmark sort of with surface charge still present:
Battery A (the good one?) 13.43v
Battery B (the also ran) 13.40v
Battery A 1.275, 75, 70, 90, 75, 75
Battery B 75, 75, 1.300, 75, 75, 75
So now must wait a few days and see what happens.
Mex says a low cell draws from the others. Battery A has that lower cell at 70 there, which is always the low cell when taking SGs. Battery B has that crazy high SG cell, which is always high like that.
Not a clue what that might mean, can't fix it, it just is!
If Mex is reading, is this a proper start? Do I check daily or just wait four days? (I doubt all the surface charge will be gone in only four or five days, but we'll see)
