Warming Batteries

[Neicy]

Was wondering if there would be a safety issue with leaving a lightbulb burning in the battery area. During the cold months I leave a bulb burning in the engine compartment. It makes for a quick start on an old engine.
Thought about doing this for the batteries, but wasn't sure if there is something I am not thinking of that could create a safety issue.

[mitiempo]

If you're worried about the batteries freezing it won't be an issue if they're charged. A lightbulb will give a bit of heat but in extreme cold won't be very effective. I wouldn't put it real close to the batteries.

[Neicy]

I was mainly thinking of the heat as maintaining a temp for the batteries, as I have read they last and perform better when kept around 65 degrees.
Just didn't know if there would be any gas, fume or other issue in connection with the batteries.
The bulb in the engine makes a day/night difference when cranking in the winter. I am in SC so 18-20 degrees is our coldest.

[btrayfors]

Forget it. The batteries will be fine, so long as they're not completely discharged.

Engine's a whole n'other thing. Hope you don't depend on that light bulb to keep the engine from freezing. I saw a big ketch at our dock go down one year -- he'd "winterized" by putting a light bulb in the engine compartment. It burned out (duh).

Bill

[Tempest]

a lighbulb isn't going to make much of a difference in 18-20 degrees..
even 30-40 degrees....it won't get you to 65..

Keeping a good charge on the batteries is more the key..imo

if you're worried, you can always take the batteries off, charge them and keep them at home...

[Neicy]

Thanks, I will forget it. They are too heavy for moving about. Also they are charged.

[roline]

I spent my childhood in the North (Port Radium and Eldorado) , aeh, where we had 3 cords to plug in; lower radiator hose, block heater and a heater around the battery. aeh
Fully charged lead acid batteries can go to about -80F, a 60% charge to -15F. You do get a better amp rating with a warmer battery...

[klem]

A lightbulb is not worth it. Fully charged lead acid batteries cannot have the electrolyte freeze. Your batteries will be fine when it warms up if they are left to be cold now.

The reason that you see a lot of battery heaters on vehicles in really cold places is that battery chemistry works faster at higher temps so you get more cranking current out of batteries. If you had something like a fireboat that needed to be started at a moments notice even in really cold conditions, you could use automotive battery blankets. Otherwise, just charge them and forget about it.

[BubbleheadMd]

As others have said, if you're charged then the battery electrolyte won't freeze and burst the casing. As the batteries discharge, the chemistry turns from more acidic to more like water, and hence more prone to freezing.

As the temperatures drop, the batteries lose capacity. That's what the "CA" and "CCA" ratings are on the battery- one is cranking amps at 32F and the other I think, is at 0F. I forget the actual temperatures.

Anyway, the only reason to heat your batteries is if you are planning on using them- for starting or running some kind of light, or pump. I don't think a 100 watt lightbulb would be useless in an enclosed space if you were planning on placing a load on the batteries.