I've charged a lot of car/boat 12 volt batteries with my battery charger but
now need to charge a battery off a riding lawn mower/tractor and want to
check on some things first. I guess I'm close enough to "home repair."
First, if there are 6 places to add water to the battery then it's a 12
volt? If 3 places, then a 6 volt? I thought lawn tractor batteries would
be 6 volt, but this one has 6 places (cells?) to add water and yet it is
smaller than the average car/boat 12 volt battery. So, which do I have?
Second, my battery charger will work on either 12 or 6 volt. I've always
just selected the 12 volt setting for what I knew to be 12 volt batteries,
connected the terminals then plugged into the AC and followed the specific
gravity of the solution with one of those floating ball aspirators, when all
4 float, it's charge is OK. If I do have a 6 volt battery, can you use the
floating ball thing to follow the charge or is the specific gravity
different for 6 or 12 volt batteries?
Thirdly, when I set my charger on the 6 volt option, it doesn't come on
until I turn a separate dial which clicks on and allows me to adjust the
output of the charger from 0.2 to 1.2 amps. What amp output should I use to
charge a 6 volt battery?
Why? I believe that all, reasonably modern, gas-powered, self-starting
machines use a 12VDC system.
It's a 12-volt battery. It is probably in the same league as those found on
You don't, so everything else is moot. Charge it at 12-volts.
If your charger is bigger than 10-amps, you would do well to get another,
smaller one just for your lawn tractor's battery. More than 10-amps can
boil-off the electrolyte, warp and crack plates and ensure that you'll soon be
buying another battery - at a lawn tractor or motorcycle parts store.
Even at 10-amps, you should carefully watch the water level during charging.
10-amps may be too much for the size battery you are charging.
I have a solar electric fence charger that puts out 12 volts to an
internel 12 volt gel cell battery. I only use this fencer for
emergencies when the power is out or I want to make a temporary corral
for horses and it's too far from an outlet. The rest of the time, I
ran a few wires out of the device, directly off the solar cell. I
clip it to my mower battery and the battery is always trickle charged,
It dont cost me a cent for electricity. My mower battery is 7 years
old and still works fine.
Darn, I was just goofing, but I was right.
The size doesn't have much relationship to the voltage. Just look at
9-volt batteries for transistor radios etc. They have 6 cells in
them, stacked one on another. (Dry cells are 1 1/2 volts. Lead acid
cells are 2.1 volts.)
One reason lawn mowers could get by on 6 volt batteries is that the
grass doesn't grow when it is below freezing, or even below what, 40?
So the 6-volts stays pretty close to 6 volts. My 6-volt '50 Olds
started fine except one night when it was 0 degrees F, when the 6
volts was probably 3 volts. OTOH, riding lawn mower tractors are also
used in the winter to plow snow and for racing.
That's not the most precise way to measure, but it's probably good
enough, and yes, it's the same for 6 and 12. Because each cell is 2
volts and the chemistry is the same, including the weight of the
BTW, they could make both dry and wet cells out of different
materials, and get different voltages. But it's standardized.
(Except for mercury batteries and who knows what else. I don't think
they have any tractors that use mercury batteries.)
I consider a 1 amp charge slow, and have never heard of anything
slower. but if you have time to wait, I think the slower the better.
For both 6 and 12. IIRC a 12 volt battery takes about a day to
charge with a 1 amp charger. I never measured how many amps a 1 amp
charger puts out, but I'm going to figure it is 1. At .2 amps, it
would take 5 days, although it might be enough to start the car
earlier than that. It takes a lot less to start a lawnmower.
If it has 6 holes, it's 12volt. Just figure 2 volts per cell. 2X6
or 2X3=6. Mower batteries as well as motorcycle ones are still all
2volts per cell the same as a car battery. Just lower amperage. The
size of the cell determines the amps, the number of cells is the
By the way if it has 7 holes it's a 12volt FEMALE battery. :)
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