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Just looking for a quick compatibility-confirmation before buying some gear for a rebuilt eMate battery pack


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  • 68kMLA Supporter

Howdy guys!

 

I've got a few eMate 300's around, and (of course) their battery packs are all long dead. I'm fortunate to have a working AC adapter, but that's way less fun than running a portable machine in fully-portable mode. Given this, I'm looking at rebuilding the battery packs (3 packs total, maybe 4-5 if I get ambitious and want to make a couple to offer to other eMate owners). I have minimal soldering skill or electronics knowledge, but the guides I'm finding for this project make it look reasonably straightforward even for an amateur like me.

 

Here's my main question: can someone confirm that these batteries on Amazon would be a good candidate for this project? Also, if anyone here has done the eMate Battery Rebuild project and has any tips, tricks or suggestions for a newbie, I'm all ears :-) 

 

Thanks!

 

Huxley

 

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So I've done a number of battery re-cell projects in the past, and the eMate is indeed not too difficult, you're right! :)

 

These would work fine for the eMate, although being 2500mAh would take a bit longer to charge than the original  - with the benefit of considerably longer runtime of course!!

 

Another option, since you've got quite a lot of space in the battery compartment, is using a 4xAA tray:

 

Check about 60% of the way down this page (search for "Try a Tray")

https://web.archive.org/web/20200214033606/http://planetstephanie.net/2005/10/21/newton-pages/

 

This way you could use regular NiMH AA cells, and you'd only have to solder 2 wires.

 

Whichever method you choose, do make sure that the black thermistor is touching the batteries when you reassemble it, since that's how the eMate knows when to stop charging the batteries (NiMH cells are strange beasts - I recently learnt a lot more about them by buying an old hybrid car, but that's another story...)

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I recently re-celled my eMate 300's battery pack, it wasn't too bad, took lots of before pictures as I was tearing it down and just went slow with with it. I considered the 4xAA tray idea but couldn't find any that would fit without cutting away plastic in the battery bay and I didn't like the idea of that.

 

 

I also found a size of green battery shrink warp that has made the whole thing look somewhat close to original!

 

 

 

 

 

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I have used a pre-assembled 4-pack of cells with leads rated at 2000ma, purchased on eBay. The battery build was trivial: using the original plug and leads from the dead battery, which contains the thermistor, the positive and negative leads are soldered on, the thermistor is located next to the cells, and the deed is done.

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21 hours ago, beachycove said:

I have used a pre-assembled 4-pack of cells with leads rated at 2000ma, purchased on eBay. The battery build was trivial: using the original plug and leads from the dead battery, which contains the thermistor, the positive and negative leads are soldered on, the thermistor is located next to the cells, and the deed is done.

Oh that's interesting - thanks for the tip, sounds like it could be a bit of a time-saver on this project. Since I'm a newbie with this topic, could you link me to one of the eBay items that you've used for this swap/upgrade?

 

Thanks!

 

Huxley

 

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You are looking for a 4.8v NiMh pack arranged like a double barrel shotgun, 4 cells in total (1.2v x 4 cells = 4.8v). Current eBay item number 392758081037 would do the trick nicely.

 

Disassemble the original battery, removing the outer black plastic held by the clips. A battery very like that eBay item lies within. You will re-use that black case, the clips, and the wiring. Take the (green?) sprinkwrap film off the old battery thus exposed. You can then see the whole arrangement. Only clip the + and - wires, leaving the thermistor in the middle intact with the wiring (i.e., of the four wires you deal with on the old pack, you only clip two). You'll likely need to break the thermistor away from the old cells (glue), which will free the wiring, with the plug, for re-use. Assemble the new battery, relocating the thermistor on the new cells similarly with glue or tape, and insulating your solder joints on the two wires (I used heatshrink tubing, but black electrical tape will suffice). I just made a hole in the heatshrink wrapping for the thermistor and poked it in, using superglue to affix it to the cells.

 

It only takes 20 minutes start to finish. It is a very easy job.

 

Install the battery, then charge and cycle the batteries completely. It may require a couple of such cycles before the eMate is completely happy with it new arrangements. I suspect that it learns what the battery is capable of, and certainly the cells get exercised in this way.

 

A NiMh battery needs regular cycling to work properly, and sitting in long term storage or suffering from partial charging repeatedly without full discharges is not good for it, so the system benefits from that initial charge/ drain encounter. And if the cells eventually begin to degrade, they can often be revived by being frozen and thawed. Yup, freezing in combo with the aforementioned cycling will typically give much better performance after a couple of years of use -- something to do with crystals forming in the cells that need breaking down.

 

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