abs@ukc.ac.uk (A.B.Smith) (02/22/91)
I just bought two six volt car batteries for my car (they are connected in series to give a 12 volt system). They needed charging and this took quite some time, having to do it for each battery. The question is, can I charge them in parallel or series to cut down on the time/effort ? I did try charging them in series, but got a very low amp reading (was this because the charger couldn't cope?). Many thanks, Andrew
burkley@cod.NOSC.MIL (Joe Burkley) (02/22/91)
Warning!! This is speculation, I don't know for sure. It appears to me that you should be able to charge the batteries in either configuration. In series is the way you have them installed in your car. Your car's charging system is in fact charging them (in the series configuration) while you drive. Why should a battery charger have a problem in charging them then? Semi's use this configuration. In parallel, the charger is just seeing a battery (6 volt) with twice the capacity. Often pickup trucks and RVs are fitted with two batteries in parallel so that they have extra capacity for running access., cold starts, etc. Again, the car's charging system handles it, so why wouldn't a conventional plug in charger. The only problem I can see is that if one battery is bad, it may affect how the other is charged. -Joe -- =-=-=-=-=-=-=-=-=-=-=-=-= \ \_ _/ / =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= | Joe Burkley | O_O | "It's not enough that I succeed, | | burkley@cod.nosc.mil \/_\/ everyone else must fail." | =-=-=-=-=-=-=-=-=-=-=-=-=-=- \_/ -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
jeq@i88.isc.com (Jonathan E. Quist) (02/23/91)
In article <74@owl.ukc.ac.uk> abs@ukc.ac.uk (A.B.Smith) writes: > >I just bought two six volt car batteries for my car (they are connected >in series to give a 12 volt system). Oh, you own an MGB, then? >The question is, can I charge them in parallel or series to cut down on >the time/effort ? I did try charging them in series, but got a very low >amp reading (was this because the charger couldn't cope?). I'm assuming you used a 12 volt charger to charge them in series. Since the batteries are new, the current draw from the charger will be relatively small, since a battery fresh from the box is generally about 65% charged already, possibly more. You could charge them in parallel with a 6 volt charger, but this will take twice as long since each battery is only getting half the current. (E.g., if you have a charger that produces 6V @ 2A or 12V @ 2A, charging in series gives 2A through both batteries; in parallel would give each only a 1A charging current.) As someone else mentioned, if one battery is bad, you're better off charging seperately. With new batteries (or batteries with no serious problems that have been wired in series) charging in series should give good results. -- Jonathan E. Quist INTERACTIVE Systems Corporation jeq@i88.isc.com Naperville, IL DoD #094/ '71 CL450-K4 "Gleep"
choll@telesoft.com (Chris Holl @adonna) (02/23/91)
In article <74@owl.ukc.ac.uk>, abs@ukc.ac.uk (A.B.Smith) writes: > > I just bought two six volt car batteries for my car (they are connected > in series to give a 12 volt system). They needed charging and this took > quite some time, having to do it for each battery. > > The question is, can I charge them in parallel or series to cut down on > the time/effort ? I did try charging them in series, but got a very low > amp reading (was this because the charger couldn't cope?). Do you have an MGB? Just guessing. I have two, and they have twin six volt batteries. I have recharged them in series, as if they were a single 12-volt battery, many times. (I've had one of them since '75, and they have Lucas electrics.) I agree with Joe Burkley's comment that if one battery is bad it could affect charging the other. Just take all the typical battery-charging precations. Chris Holl TeleSoft San Diego, CA