Charging several 12v batteries at the same time

[GasSavers_Erik]

I have several 12v batteries that I'd like to keep topped off all winter.

Rather than switching the trickle charger between the tractor, the riding lawn mower, the pickup truck etc every week. Car I just hook all of the batteries up in parallel to the same 12v charger and keep them all topped off at the same time?

Would it matter that some batteries are bigger than others (tractor battery vs lawnmower battery)?

[benfrogg]

I worked on a Gentleman's farm for a while. We charged three deep cycle batteries and I think one more regular 12v battery on one "maintainer." It's one of those chargers that only puts out like 1.5 amps and only when the battery needs it. The charger worked just dandy for this task, but it was stressed. Any more than a couple of batteries and you should get another maintainer. Have two banks, you know. The chargers don't care how many batteries there are or the size, but I'm sure they have duty cycles like anything else. The charger will run twice as long if it needs to top off twice the batteries. Three times as long with three and so on. Usually you'll just burn up the charger from having run 24+ hours one day because it isn't made to do that.
I regularly maintain two batteries at a time with no issues.
Oh, make sure you give that maintainer room to breathe. Keep it in a place that will allow maximum air flow to keep it cool.
My 2 cents.
B

[GasSavers_Erik]

Thanks Benfrog. Even charging just two at a time will be better than charging individually.

[kamesama980]

If they are fully charged and just getting a maintenance/trickle charge I don't see any reason it wouldn't be OK. I have 4 or 5 car batteries set up that way.