charging batteries

[andy230]

Hello all,

Can anyone tell me if I can charge a 12v (small, kickstart only bike) battery from the large 12v 110Ah battery I use to power the solar garage?  This is used to store the charge from the solar panel.  And how would I go about this??  Would it work just to connect in parallel???

I was just wondering if it can be done on a 12v system as I wanted to avoid plugging in a (240v) charger.  I know the output from this is 12v, but dunno what the electrical basis is of the charger’s supply at the croc-clips.

Cheers, andy

[guest146]

In a way it would work but when you charge a battery it pushes in about 14v for a 12v battery so with just 12v it may just get a little more charge in it but not a lot

Ken

[Steve H]

Can you not charge it with the solar charger ?. The big battery would charge a battery which is dis-charged, but not as well as a proper mains charger.

[andy230]

Can you not charge it with the solar charger ?.

Yes but not overnight   

I use the bike during the day, which would mean running without a battery.  And the short days/low light mean that it would probably take a good few days to charge just now.

In a way it would work but when you charge a battery it pushes in about 14v for a 12v battery

Ken

Right.... I'm with you, effectively its "forcing" electrons in against a gradient....  In that case I'll not bother and just charge it overnight.  Id does mean dirty hands in the mornign tho!

cheers anyway

a

[guest27]

A pair of marigolds - clean hands.  Another that I always forget is just how good barrier cream is.

R

[guest295]

NO! A big battery provides like 300 Amps. Your bike battery is supposed to be charged at maybe 3 Amps, basically no more than a tenth of its rated capacity. Any more and you warp the plates. Treat a battery well and it will last an amazing time; abuse it and it's dead.

[Steve H]

NO! A big battery provides like 300 Amps. Your bike battery is supposed to be charged at maybe 3 Amps, basically no more than a tenth of its rated capacity. Any more and you warp the plates. Treat a battery well and it will last an amazing time; abuse it and it's dead.

Point taken, but it would depend on how discharged the smaller battery is. The larger battery can probably supply 300 amps to a very low resistance circuit. However with the smaller battery in parallel, it would only be the differential between the two voltages that would result in a current flow from one battery to the other. 
If the smaller battery was very discharged than I would agree with you, the current would be too high and it would probably knacker the battery.
When I was a younger I used to help out a guy with a Cheney B50 scrambler (they were called scramblers back then, none of the MX nonsense). His ignition ran total loss from a battery, which he charged after each race from a car battery.

[andy230]

will probably do the same with the racer... 

total loss anyway, but will need to fuind out if this will actually charge it,

a

ps.  And yes, the DR battery was *completely* flat.  As an epilogue, I have sourced a new kill switch.  Plus, it has an integtral headlights on-off switch.  Mine currently doesn't, US import, so lights on all the time.  This kills the battery unless you start first time.  Which mine certainly doesn't!  So that will be a bonus, being able to switch lights off until running.

[guest146]

Andy

Not quiet sure what you need Is it a mobile charger? Why not rig a connection from your lighter socket in your van or car and then while you drive it will charge. Then it will get the 14v. Providing you vans not overcharging it should be ok.

Ken