counterbalance
Member
This is a really dumb question, but whatever... My new camper has dual batteries. Can I trickle charge both at the same time by connecting the positive to one and the negative to the other? Thanks in advance.
Trickle Charging Dual Batteries
- Thread starter counterbalance
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Herbie
Rendezvous Conspirator
They look like they're in parallel to me. Not a huge fan of all the ring terminals just stacked up with no apparent fuses for some of them, but as far as I can, that's a parallel connection. Whether the alligator clamps are on one battery as shown or on opposing terminals as indicated by the arrows, it shouldn't really matter.
That said, I do have thoughts about the term "trickle charge" - that's a term that implies a low-current source, which should really be thought of as a battery maintainer, rather than a charger. If you heavily deplete those batteries (say 50%), then just plug them into a "trickle charger", they're going to take a LONG time to get back to full charge. Even with wet cells, undercharging isn't going to do them any favors.
Also worth checking, those do not seem to be deep-cycle batteries, but "dual purpose", which generally indicates a plate design that is not conducive to deep cycling (optimized instead for CCA). I'd be careful about cycling those batteries too deeply, lest they fail quickly.
That said, I do have thoughts about the term "trickle charge" - that's a term that implies a low-current source, which should really be thought of as a battery maintainer, rather than a charger. If you heavily deplete those batteries (say 50%), then just plug them into a "trickle charger", they're going to take a LONG time to get back to full charge. Even with wet cells, undercharging isn't going to do them any favors.
Also worth checking, those do not seem to be deep-cycle batteries, but "dual purpose", which generally indicates a plate design that is not conducive to deep cycling (optimized instead for CCA). I'd be careful about cycling those batteries too deeply, lest they fail quickly.
counterbalance
Member
Well, this is how it came off the lot. I'll have to save reconfiguring the electrical system / replacing the batteries for the future. The dealer told me the batteries were not fully charged when I picked it up and I just wanted to wire it up once and come back to it in a few days, versus checking that one is done and then switching it over to the other.
Is there an easy way to get balanced discharging here? Again, this is how it came from the manufacturer, not a DIY setup.
Is there an easy way to get balanced discharging here? Again, this is how it came from the manufacturer, not a DIY setup.
DiploStrat
Expedition Leader
With only two batteries, it is not a huge mathata, but this will help you understand the issue and shows you the cure.
SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
DaveInDenver
Middle Income Semi-Redneck
The way you've indicated with your arrows is the preferred multiple battery connection for charging. It's incidentally equally or more important during discharging to wire them this way if it's a full time bank.
Although for trickle charging it's not going to be as critical since the assumption is length of time is very long. A battery will eventually charge if left long enough on a source with sufficient voltage and current (perhaps as low as 13.6V at maybe even 100mA) so sometimes you'll see the unbalanced configuration and it'll work to get back to close to 100% if you leave it that way for months (e.g. off season floating).
Although for trickle charging it's not going to be as critical since the assumption is length of time is very long. A battery will eventually charge if left long enough on a source with sufficient voltage and current (perhaps as low as 13.6V at maybe even 100mA) so sometimes you'll see the unbalanced configuration and it'll work to get back to close to 100% if you leave it that way for months (e.g. off season floating).
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counterbalance
Member
Thank you so much. It sounds like moving all the positive cables or all the negative cables over to the other battery would solve that discharge issue?
DiploStrat
Expedition Leader
No! Look at Verstad’s diagram. That is what you want. Master positive lead on one battery and master negative lead on the other.
counterbalance
Member
I think that's what I meant. The two wires here, which I've highlighted with blue arrows, simply connect the two batteries. The suggestion is to relocate the 2 black wires over to the other battery.
