Looking at the MNT Pocket Reform components in the The MNT Pocket Reform Operator Handbook, I found a single replacement option listed in the compatible battery cells, namely the EREMIT 606090, 3.7V, 4000mAh, LiPo. According the handbook, these battery cells can be acquired directly from a single vendor:
Reading the specifications of both battery cells, both has the number 606090, and the same specifications of volts and amperes. However, they differ in the size, 6×60×90mm and 12×60×90mm, respectively. So, I guess one fits on the Pocket Reform, and the other doesn’t. Also, one is available and the other isn’t.
Since I don’t know much about battery models, I wonder about the risk of having no replacements after 5 years. I imagine that I will still find batteries in the AAA format, but I don’t know if there will be batteries in these less common formats. Please let me know about this risk.
Hi, I’m working on this exact issue at the moment. You can theoretically use any protected LiPo 3.7V cell that fits in the case (and ideally has 2 pin JST-PH connector). The holders are designed for 606090 format, but it can also be thicker, like 706090 which I found on Amazon with 5000mAh. The only issue is that often the JST-PH connector has the polarity flipped vs our cells, but you can swap the crimped ends of the connector relatively easily with a sharp plastic tool (and be extremely careful not to touch anything with the red wire’s end).
Apart from these DIY solutions, I’ve started talks with a battery manufacturer so that we can sell replacement batteries ourselves next year.
i’ve been rocking a pair of these ones on amazon for about $50 post tax n such since June 4th of this year and they’ve been great for me. little over double the MaH of stock and i get ~8 hours out of them on a full charge consistently using low power mode in gnome. took a few cycles of like 5% to full for the Pocket to properly work with them and get the battery life i expected, which is testament to the BMS board’s design (shout out to MNT!). i made some basic 3D printed spacer bars as seen in my post about turning my Pocket Reform into a cellphone replacement, which i can upload the CAD files to dropbox later today if you want.
with the batteries, spacers, and some JST connectors with the metal inserts (with careful note of polarity!), and thin double sided tape on my 3D printed inserts later, and i was good to go. you can also do without spacers, just make sure the batteries are placed as close to the BMS board’s temp sensors as possible (i haven’t had issues, likely because mine are as close as possible, same distance as original stock batteries give or take a mm), and then put the double sided tape on the top, so they stick to the lid. they barely fit but it’s just big enough, and with a capacity upgrade like that, hard to complain. also if you stick them to the lid, keep in mind not to tuck your wires insanely, and mind how you open it so you don’t tug on things and break it
can’t recommend the upgrade enough, and huge props to MNT for making this so insanely easy.
Thank @minute for your answer! Thank @Nebula-System for reporting your experience! It seems that batteries will not be an issue, because it is question of time that they will be sold by MNT. And anyway, it would not be so difficult to find and install an alternative replacement.
Any word on factory-approved batteries? I’m already finding that I would like better battery life in my Pocket, and that’s before receiving my RCore upgrade, which I understand eats batteries faster than the iMX8M+ I have.
Hi, I’m recovering this post, hope asking something useful for any future reader as me.
This is a dumb question but this frightens me a bit. If I buy new batteries for my Pocket, can I cut the JST PH connectors from the old batteries with some remaining cable, and solder them to the new batteries?
I am aiming at this HXJNLDC brand on Amazon from Europe, took the reference from Josch post about his batteries upgrade.
Should I trust red/black colour polarity on the battery cables? Else, is it safe to use a voltimeter directly on the battery cables? I guess it is, but this makes me feel a lot of respect.
I don’t think your question is dumb. Nobody is born with this knowledge and we have to ask so that we can learn. Please don’t feel bad when asking for advice.
Good. Li-ion cells can be very dangerous.
Yes, you can. But JST-PH connectors, even those which are already crimped are very easy to come by. If you cut the connector off the old batteries, you safe on the purchase now but then you have to solder a connector again once you want to make use of the old cells. When I swapped my cells, I just got a bunch of 10 pre-crimped JST-PH cables and now I have some spares for future projects.
I would personally never trust it and always check. Checking takes a few seconds and in the worst case just confirms what the colors are already telling you. In the best case, you avoid desaster in case the colors do not match what is usually chosen to indicate polarity.
Yes. You must make sure that the ends of the cables never touch. I usually have a piece of tape around at least one of the bare cable ends at all times so that they can never accidentally short-circuit. But you can safely touch both ends with each tip of a voltmeter to see which one is the positive and which one the negative cable end. If you are using a multimeter, make sure that the red/black cables you attach to the multimeter are attached to the correct plugs for measuring voltage.
Ask anything you are uncertain about. Li-ion cells are dangerous!
