Heated battery tray/compartment?

[Ned Kelly]

It seems that batteries operate at best efficiency around 27c/80f temp. Most power, and fast recovery rate for charging. Graph here:
http://www.aa1car.com/library/2003/us20310.htm


I was contemplating on fabbing up some heated battery compartment to try and keep my battery near this optimal temp during cold winter months. Might be extra useful for winter use of the electric winch.

...or is this a goofy thought?
I see 404 Unimogs had a battery warming tray that used rerouted hot exhaust gas under the battery tray. I was thinking using engine coolant rather than exhaust.

 

[paratrooper307]

Interesting idea. I guess it depends how cold it gets where you are, and how much you are really stressing the battery during operation. Battery voltage/amps are most critical when starting the engine, and a warming system as you describe wouldn't be helpful there. Plus, engine coolant requires time to get to temperature, and by that time your exhaust manifolds and engine are probably throwing off enough heat to warm things up under the hood somewhat. The complexity of plumbing not be worth it to offset the gain in efficiency, which isn't of greatest concern since you have a constant charging source. If you're doing any serious winching, you'll probably want a dual battery system in place anyway, and potentially a larger capacity alternator, which makes the system less relevant.

Now, with electric cars that find their range severly tapped by cold weather, a heating system is almost mandatory, and you find it on applicable models.

It's a toss up based on how much efficiency you will gain for the additional complexity and cost, as well as weighing the options for more conventional methods of increasing battery capacity.

 

[ryoken]

seems to me an AC 110, plug in at night deal would be best... warm for that morning startup.. once running, not nearly as important...

 

[diesel4me]

I've seen guys with big rigs use a propane powered engine heater to get the engine warmed up before starting,if you had one of those, you could wrap some heater hose around the battery to warm it up before the engine is started "cold",where no electricity is available......
An AC powered battery heater is great at home for the first start of the day--but if you go somewhere and park the truck for several hours ,like at work for 8 hours,the cold start to go home is the one you'll have trouble with!..unless you can "plug in" at work too..this applies to block heaters on diesels too...

 

[MrSchaeferPants]

Interesting idea. I guess it depends how cold it gets where you are, and how much you are really stressing the battery during operation. Battery voltage/amps are most critical when starting the engine, and a warming system as you describe wouldn't be helpful there. Plus, engine coolant requires time to get to temperature, and by that time your exhaust manifolds and engine are probably throwing off enough heat to warm things up under the hood somewhat. The complexity of plumbing not be worth it to offset the gain in efficiency, which isn't of greatest concern since you have a constant charging source. If you're doing any serious winching, you'll probably want a dual battery system in place anyway, and potentially a larger capacity alternator, which makes the system less relevant.

Now, with electric cars that find their range severly tapped by cold weather, a heating system is almost mandatory, and you find it on applicable models.

It's a toss up based on how much efficiency you will gain for the additional complexity and cost, as well as weighing the options for more conventional methods of increasing battery capacity.

Makes most sense to me. I don't think you'd even notice a change once normal engine temp was reached. Unless you do a whole lot of "start cold engine, winch immediately" type work.

Solar trickle charger w/warming pad? Or just plain trickle charger on battery to make sure you're always up to snuff.

 

[Ned Kelly]

Yeah, I've had trickle charger on there for super cold nights. Synthetic oil, high-torque mini starter, and block heater make those cold starts a lot easier. Starting isn't usually an issue.

I was just thinking of optimum battery temp when the vehicle is operating for hours at a time in the cold - wheeling and winching. Meh, maybe I'm looking for a solution to a problem that doesn't exist.

I plan on mounting two Group 31 batteries, and was probably over thinking things when I upgrade the batteries. Thanks for putting me in my place and tempering my thoughts.