Therm-ic boot heater battery replacement

So my boot heater batteries have been slowing down recently and last week died completely. I figured Dec highs in the 40's can't last and I needed to fix the situation. A quick google search revealed you can buy replacement battery packs for $75, each! Now I knew they were just NiMH batteries so this can't be too hard. The packs at first glance appear to be completely sealed but a little prying with a big flat screwdriver revealed they are really only glued/welded at the corners. It's pretty easy to just pop them open with little damage. Start at the lugs that hold the metal clip. Unsolder the two wires that connect the pack and off to the web for replacements. I used all-battery.com to order 8 AA NiMH flat top with tab batteries. Solder the tabs together to make a new pack of four, insulate with some tape, and use some double stick foam to secure in the pack as the factory did. Voila! As a side bonus the chemistry of these cells has been improving so my old 1700mAh batteries are now 2000mAh ones. All this for the princely sum of about $12 plus shipping.

Wow, a day late for me. I just ordered replacement Li ion batteries for my wife's heaters...$80 each. I though about trying to find a similar battery elsewhere, but was on a dead-line for this weekend. Since the life time of these batteries are too short,I will be doing what you did the next time.

Looks like all-battery has Li rechargables too, though the selection is small for flat top tab and more expensive than NiMH. Still less than $160.

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Originally Posted by stevesmith7

So my boot heater batteries have been slowing down recently and last week died completely. I figured Dec highs in the 40's can't last and I needed to fix the situation. A quick google search revealed you can buy replacement battery packs for $75, each! Now I knew they were just NiMH batteries so this can't be too hard. The packs at first glance appear to be completely sealed but a little prying with a big flat screwdriver revealed they are really only glued/welded at the corners. It's pretty easy to just pop them open with little damage. Start at the lugs that hold the metal clip. Unsolder the two wires that connect the pack and off to the web for replacements. I used all-battery.com to order 8 AA NiMH flat top with tab batteries. Solder the tabs together to make a new pack of four, insulate with some tape, and use some double stick foam to secure in the pack as the factory did. Voila! As a side bonus the chemistry of these cells has been improving so my old 1700mAh batteries are now 2000mAh ones. All this for the princely sum of about $12 plus shipping.

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This is good stuff right here! I will copy this next time my packs turn into duds instead of waiting for the warranty to go through.

I got my replacement Li ion batteries so my wife will have happy feet on Sunday. It is a proprietary battery, so not an easy swap. I will have to do some searching to find the specific battery as I imagine it is not that proprietary, but it not a simple wire in swap either.

thanks for this write up

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Originally Posted by hutash

I got my replacement Li ion batteries so my wife will have happy feet on Sunday. It is a proprietary battery, so not an easy swap. I will have to do some searching to find the specific battery as I imagine it is not that proprietary, but it not a simple wire in swap either.

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Is it made of a bunch of cells or is it one big flat pack? The suppliers have all the odd sized cells 1/2, 2/3, etc. If you know the voltage you can figure how many cells and then see what will fit. Where there's a will, and at the prices they are charging I have a lot of will.

Here's a couple shots of what to expect:

One thing to watch out for. The silver case of the slide switch on the top right is grounded. The battery tab that fits next to it is the positive terminal. Be sure you have enough tape in that area so that they cannot touch. Much havoc if those two ever come together.

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Originally Posted by Fatfish

This is good stuff right here! I will copy this next time my packs turn into duds instead of waiting for the warranty to go through.

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Can I use the same charger with the new 2000 as the old 1700?

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Originally Posted by m627ba

Can I use the same charger with the new 2000 as the old 1700?

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m627ba?!?
that’s not a name, JONG

how long is the life with the new battery?

I am trying to do the same, but can't see how 4 AA batterys fit inn the case. Could you clarify