BFL13 wrote:
Don't have my references handy so over to you guys please. If you have a good and bad 6 in series will the bad one ruin the good one? (Where the combo still acts ok as a 12 and is working ok for discharging and recharging)
I know about the parallel situation where one drags down the other etc. But what about in series?
Actual situation-- six-year old pair of 6s. When "full" one has three cells just in the green and the other has the middle cell just in the green but the outer two are in the red on the hydrometer.
Is it just like a single 12 with six cells in series with two low cells?
If the bad one won't ruin the good one, is it safe to add two more old 6s (both good) to have four in series/parallel? Will the pair with the bad one ruin the good pair it is in parallel with?
If so, is this ruination a slow process --months? or fast--weeks?
Thanks
A single bad cell in a 6 VDC to 12 VDC series connection will damage the good battery during charging since the overall battery voltage will be somewhat lower than 12 VDC.
The charging device will try to maintain a nominal charge voltage which means each of the good cells will receive an overcharge which will boil electrolyte and possibly damage plate material.
When you parallel the good string with the bad string, the good string will work hard trying to maintain 12 VDC while acting as a source - lots of circulating currents.
Battery life will be reduced for all batteries...
