Battery shield

I changed the battery in our 19 yr old Chrysler this weekend and was reminded that there is a battery shield that has lasted all these years. The battery is in the front on the driver’s side and in front of (and to the side of) the transverse engine.
The shield is like a sheath or sleeve that slips onto the battery and surrounds it on four sides, leaving the top and bottom uncovered. The shield is probably best described as black bubble wrap, although the black plastic is thicker/stiffer than regular clear bubble wrap.

Our 13 yr old Toyota’s battery doesn’t have a shield (or if it did, it is long gone) and I’m wondering about making one for it based on the Chrysler one. The Toyota’s battery is also in the front on the driver’s side but in front of the transverse engine.

And a little more history is that batteries last longer in the Chrysler than in the Toyota.
I’ve thought that due to the Toyota having more electronics, but maybe it is a difference in heating and a shield would help.

Any thoughts, experiences or suggestions out there?
(BTW, I suspect climate considerations are not significant because the ‘shield’ only slows heat transfer to/from the battery.)

If you really want a shield, try the link below.


This is what you need…much better than a regular shield

Capturebattery heater

Thanks. I know various products exist.

My question is more about whether they are worthwhile. It costs nothing (and probably doesn’t hurt) for me to keep using the Chrysler shield.

But it would cost something for me to either make or buy something for the Toyota and so whether it’s a good idea matters.

Thanks, but given my location in a relatively warm state, warming the battery is not a concern.

The shield is to protect the battery from underhood heat, not to keep it warm.


I wouldn’t bother. There are lots of factors that go into a battery’s longevity, including brand. Does your Toyota use the exact same brand/model as your Chrysler? If not, then you haven’t reduced your longevity experiment to only one variable and therefore do not know which variable is impacting longevity.

It’s fairly unlikely that a little sheet of plastic is going to have any appreciable effect on the temperature the battery case sees, because as soon as you start moving the airflow under the hood will cool it down anyway. Unless you spend a lot of time just sitting still with the engine running, a battery shield would be of limited thermal regulation utility.

There’s no way to control down to only one variable (different engines, different battery sizes, etc). But I did the best I could: both have only used Costco/Kirkland batteries once the OEM ones died. And on that score, the Chrysler used 3 in about the same time that the Toyota used 4.

I agree with the idea that there’s likely little effect while airflow dominates (even if battery charging during that time creates some heat).
I suspect the main difference is after the engine is turned off and residual heat from the engine can reach the battery. That might be the main point of difference.

Maybe. But I bet if you were to aim an infrared thermometer at the battery it wouldn’t get much hotter after you shut down than it gets if you park it outside all day in July.

And that’s just the outer wall of the battery, which itself is shielding the interior of the battery from a lot of the heat.

If you really want to try it, don’t get too fancy. Just go to Home Depot and get a sheet of Lexan, then cut it down with a jigsaw. You can even semi-permanently mount it if you make yourself a bracket that will hook into existing bolts. Run with that for awhile and see if it makes a difference, and if it does, make something prettier. :wink:

You are probably correct. Yet the idea isn’t that the battery would get hotter after shutdown, but rather stays warmer for longer after shutdown. So a shield might reduce the number of times (and/or duration) that are like parked outside all day in July.

If you just get on a normal 3-4 year replacement schedule, a shield is kind of academic. I’ve got one battery boxed in and another pretty open. Both are in the same location. For $130 I don’t hesitate to replace them at the first sign of failure.

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I guess I’m a little stuck with the ‘waste not, want not’ mantra.
The last two batteries in the Chrysler lasted over 8 and over 5 years. That’s about 14 years total and more than 4 if on a 3 year schedule.

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Maybe I should get one. My car batteries always die after about four years of Florida heat, whether I get a cheap battery or an expensive battery.

Have you seen how much a sheet of Lexan plexiglass goes for these days? I wouldn’t call it cheap.

You don’t need much of it.


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Yep. You can buy the shields preformed or in roll form.
Here’s an example-

The Checker cabs had the battery in under the trunk compartment away from the heat of the engine. They did this to make the battery last longer. On my dad’s 1939 Chevrolet, the battery was under the passenger side floor. You pulled back the floormat and lifted a plate to service the battery. The original battery lasted 7 years and the replacement was still going strong when he traded the car in 1950.

Several of the battery heat shields had a low absorptance coating to reflect the heat. That would tend to keep the battery cooler.

My 59 VW bug and my Olds had the batteries under the back seat. If you relocate it though you need to have the vented one and vent it outside.

You could probably make something yourself using some sheet metal and a pair of sheet metal shears. Start by cutting w/a strip the appropriate width and long enough for the circumference. You’d have to come up with a way to make the 3 bends, and rivet/glue/etc the two ends together to form a rectangle. Just make sure it is positioned so it doesn’t touch any wires or connectors of course.