Reply With QuoteGo for it & get rid of the wingnuts.
Is it ok to charge batteries in parallel ?
Both batteries are the same age, same condition and same Amp hr size.
The batteries are 45Ah AGM deep cycles.
If I connect them in parralel like the pic below, leave them for a while to balance the charge between them, is it ok to charge them connected like that? The way I look at it, the charger will just see the two batteries as a larger capacity battery.
Or is there a chance of over cooking a battery doing it like this?
.......Ash
Go for it & get rid of the wingnuts.
....why?Originally Posted by Fed
they screw into the battery terminal and have been charging fine for the last year or so....
.......Ash
Because they can't be tightened properly, they also have a small footprint are are known to give problems.
Keep them if you want to it's your boat, just a suggestion.
The only time you may have issues Ash is if one of the batteries is getting a bit suspect. Other than that won't be a drama. Fed's remark on wing nuts, I assume, is more based around a "standard" wingnut that screws onto a stud. Evinrude at least (not sure about other manufacturers) have identified their use as a potential cause of EMM spiking and specify they must not be used. If you are simply running your electric on these they shouldn't be a drama - just make sure they are tight
The charger current will divide according to the individual batteries resistance . Think of resistances in parallel, the lower resistance will take a proportionally larger share of the circuit current. IE, if you have 50 amps supplied by the charger, if the batteries are identical resistance, they will have 25 amps charge current each. I'm running a larger start battery than house battery, just charging in parallel, never an issue. But, as a PP said, if one battery is dying/dead, it will give the whole system problems.
cheers, the batteries are used in an electric only 3m punt and both get a good run each outing so I will know if a battery is not performing like it should. The wingnuts don't come loose as they bite down into the ring terminals quite firmly. Was told to connect the positive Charger clamp to the positive on first battery and the negative charger clamp to the second batteries neg terminal to avoid voltage drop...
.......Ash
It shouldn't make any difference electrically. You are only really looking at the resistance of the actual leads between the batteries --if they are in good shape, there won't be any voltage drop. Voltage drop is a product of resistance and current flow,the higher the current flow for a given resistance, the more the voltage drop. Voltage drop may not exist on a connection until you actually up the demand, ie, have more current flowing through it. leads that short, in good condition, would need to have a very high current indeed, beyond it's rating , to get any chance of drop.
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