Personally I've found nothing but grief from car batteries in this mode.
Say one battery has a dodgy cell, the other battery then charges the duff
one until neither are very good.
If it were a low power use I'd say isolate them by diodes and charge one at
a time but in this case, either get a battery capable of starting the
vehicle on its own, make sure but batteries are switchable and keep both
charged and use them in rotation.


Incidentally this using cells in parallel goes even more so for other
rechargeable types.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"jim" k wrote in message
o.uk...
old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?

TIA
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/