12v Battery Bank in Parallel with 6v Bank
Short version I need a quick fix to get thru this summer boondocking. I know what I am considering doing is bad but I don’t know how bad & need input on what will be happening to batteries when...
Forum Discussion
I charge my frankstine bank with a Progressive Industries Intella-power 9180 with charge wizard.. And as I said, battery life is around 8 1/2 years.
Average is 7-9 for the brand of batteries I have. so 8 1/2 is dead bang in the middle of that. No special anything.
I challanged someone to tell me why mixing six volt pairs and 12's would cause them to not charge properly.. I got no answer.. The reason is there is no answer.
The state of charge is determined by the cell voltage, now with six cells in series (What you have if you buy a 12 volt jar or a pair of sixes and put em in series) So long as all the cells are good, you can read state of charge by measuring the resting voltage of the entire battery (Collection of cells).
If one is lower, say .01 volt lower than the rest, then it needs more charge.
And since Electricity, like water, seeks it's own level, THAT ONE IS GONNA GET IT.. The other batteries will not charge till that one comes up that .01 volt,, And from then on they will all be in absolute lock step.
The myth (Which is true in a different configuration) is that "The smaller battery will reach full charge and signal the charger to stop and the larger one will not". In parallel this is IMPOSSIBLE because the battery that is LOWEST on charge will suck all the charge (or as much as it possibly can) Current till it catches up, and from then on they lock.
Here is where it is
BATTERY---battery (two six volt in series say a T105 and a T 125)
In this configuration the smaller one will over charge and the larger one under charge
BUT
BATTERY
BATTERY
They are always IDENTICALLY charged and the bank will reach 100% with a good 3-stage converter/charger like the PDI charge wizard jobs.
Average is 7-9 for the brand of batteries I have. so 8 1/2 is dead bang in the middle of that. No special anything.
I challanged someone to tell me why mixing six volt pairs and 12's would cause them to not charge properly.. I got no answer.. The reason is there is no answer.
The state of charge is determined by the cell voltage, now with six cells in series (What you have if you buy a 12 volt jar or a pair of sixes and put em in series) So long as all the cells are good, you can read state of charge by measuring the resting voltage of the entire battery (Collection of cells).
If one is lower, say .01 volt lower than the rest, then it needs more charge.
And since Electricity, like water, seeks it's own level, THAT ONE IS GONNA GET IT.. The other batteries will not charge till that one comes up that .01 volt,, And from then on they will all be in absolute lock step.
The myth (Which is true in a different configuration) is that "The smaller battery will reach full charge and signal the charger to stop and the larger one will not". In parallel this is IMPOSSIBLE because the battery that is LOWEST on charge will suck all the charge (or as much as it possibly can) Current till it catches up, and from then on they lock.
Here is where it is
BATTERY---battery (two six volt in series say a T105 and a T 125)
In this configuration the smaller one will over charge and the larger one under charge
BUT
BATTERY
BATTERY
They are always IDENTICALLY charged and the bank will reach 100% with a good 3-stage converter/charger like the PDI charge wizard jobs.
