battery charging

On trickle charging, if it doesn't make the bat to hot then probably ok but you need to monitor them and not needed daily or constantly over the winter unless you are having a discharge problem. I've had bats stay up all winter with no use and no problem. But there are too many things that can short or cause a minor discharge that will run the bat down over the winter along with just being cold can run them down and I've had those problems too. For bats not run over the winter, I'd just disconnect the cables and if worried just charge them once a month or so. Seems like dead bats and freezing weather makes it difficult for bats to come back to life again.

Also don't put a bat on concrete or the ground. Somehow makes them go deader than a doornail. For loose bats, set them on an insulator.

And as we all know heat is the major cause of bat failure and particularly during the summer and those 100 degree days. Sometimes twisting the post while romoving and cleaning the clamp on a hot battery damage the internal connections. However, the symptons of bat damage usually don't show up until the winter when you try to use the extra amps that are no longer there.

If the charger is current limited (internal circuitry limits output to about 270 ma regardless of terminal voltage) you could simply hook it and it'll work. But be careful if you do this: If left charging too long (ie. weeks) it could slowly boil the battery dry.

OTOH if the charger is NOT current limited it'll supply more than it's rated current when connected to a 6 volt battery. Consequently it'll overheat in very short order.

If this is the case you could again add a series resistance to limit charging current to a little over the self-discharge rate of the 6 volt battery. Without doing any calculations I guess a #194 lamp (12 volt side marker/instrument panel bulb) would be about right - but this is just a quick guess.

If you feel the need to charge the battery, my recommendation would be to charge it at the low rate for 24 hours once every 1-2 months.

Incidentally I own a couple 6 volt tractors. They sit unstarted/uncharged from mid-December until late April/early May. But unless one has a battery that's about worn out they always start up unassisted every spring. Seems there's no harm from just letting them sit.

1 - The 12 volt bulb limits max charging current to a lower level - about 3 amps or so. Thus less chance of harming the battery as it reaches full charge.

2 - If the battery fails short or there's otherwise a short in the charging circuit, a 12 volt lamp will simply light up normally. OTOH a 6 volt lamp will burn out almost instantly - it becomes essentially a rather expensive fuse.

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BTW your advice to not leave a 6 volt battery charging in the manner unattended is very good indeed!

12V Charger - -6v batt1+ -6vbatt2+ + charger