Open-Source NiMh Battery Charger/Analyzer

For all NiMh fans, seems pretty interesting project! Still 9 days to go…

Open-Source NiMh Battery Charger/Analyzer

More info also here:

I’m pretty sure that was already posted on here as well as CPF, it is an interesting project.

Now thats a nice charger!!
Color LCD 128x160, data logging to SD card, adjustable charge rate, break-in & refresh modes, actual capacity, temp monitor / log, rgb led status.
Open source, open hardware.

ooh, i’d like to see the open source stuff later on!
i started making my own nimh-tester with my arduino earlier this year, but somewhere something went wrong, and i haven’t been in the mood for troubleshooting the project yet :X

This would be a brilliant device if it was for lithium ion batteries.

I’d love to see an open-source Li-ion charger project! There are already so many good Ni-MH chargers to choose from, this almost feels redundant.

The project manager noted that this charger had far greater accuracy and resolution than commercial hobby chargers, but for real life scenarios, I think hobby chargers, offer decent resolution and many more capabilities, including the ability to charge many chemistries. .

I don't see a great need for nimh batteries to have a device this advanced. At least compared to lithium ion they're much less finicky and risky, and unlike lithium ion it's easiest to buy the best.

I suppose it's a nice device if you don't have an advanced charger yet.

I agree. It’s nice to get the most out of your Ni-MH’s, but even if you don’t, the average user won’t notice it. Eneloops especially are very lenient. :slight_smile:

I've tried to search here and couldn't find it, sorry for double post if it had been posted already.


There are good chargers for NiMh already but I don't know of any open-source and with data logging :)

It would certainly be great to have this kind of project for LiIon batteries, I'll drop the author a note about this!

Please do! I would think this would be very popular. It could greatly lower the risk with lithium ion batteries, especially the cheap *fire batteries, would get rid of the mAh guessing game, and provide advanced features with less weight, bulk and hassle than hobby chargers. I could see it being in the shopping cart or wish list of every member here, CFP, LPF and the foreign language forums too. Where his nimh is kind of neat, a lithium ion version would be something most lithium ion battery users should have.

Maybe ask for two more things too.

Make it 26650 sized. And that doesn't count the kind that's really 18650 size, but the contacts barely make contact with 26650's. If he can't do that, then add a connector (JST?) along with the 18650 size slots. The connector means we can build our own magnetic wires or battery holder to charge any size battery with his charger.

Adjustable current like his current charger. Something like 300mA for 16340's and 1.5A for 26650's, but I'm not set on these numbers, just wanting a good safe spread for different types of batteries.

EDIT: A high charging current isn't critical, but it'll help sell more.

I wonder though actually how long before you can actually purchase of these for real?

They are estimated for delivery in August 2013 according info on kickstarter. All seems to work good so they should be ready in time.

I don't see the need for a Lithium charger the moment that the market is full of great digital chargers (Hobby Chargers for RC). I use an iCharger and I have absolute control on my Lithiums. I can measure, charge, discharge, log on the PC, cycle etc etc. Yet, I can go up to 10amps charge or discharge, balance charge separate cells, set precisely the rates I want on every chemistry I need, set the termination voltages......Hell, I can charge up to 12 18650 Cells at the same time and there higher end models that can do multiple times that with the proper power supply......they just cost $$$$$.

No need to reinvent the wheel for's already there for years unless I am missing something critical here???

The power supply is a biggie in terms of cost and complication. Then there's the cables.

This thing should be as simple as plugging in. It's a great tool for lithium ion users from rank beginners to the most advanced users.

You're only looking at it in terms of charging. A hobby charger isn't going to tell you the health of your cells, and isn't going to log temperature, and I don't think it can log resistance either.

Yes, it is a charger, and it can be worth it only for that, but it's a great deal if it's used for its ability to log with more sensors and analyze the data. Sure, you can analyze your cells to the same degree manually with multiple tools, but this thing would make it so much easier.

It also provides support. That's something that just can't or won't happen with hobby charger clones, and I don't think happens with the real deal either. When you want something changed in the firmware, you're SOL with a hobby charger. That's where this thing is better. You can do it yourself or rely on the community to do it for you. The changes are actually possible.

The SD card is a nice treat. It means you can log without being attached to a computer, like if you're charging an especially suspicious cell outside.

Hobby chargers like iCharger are great, no doubt about it.

But like leaftye is saying, the main advatage of li-ion charger with features like hobby charger would be in it's compact size, features and easy to plug&use.

I can imagine using hobby charger for charging batteries for flashlights, but if I would knew the compact is accurate charger I would always prefer compact for charging 18650 and the like batteries.

Now there is the option to get a laser cut acrylic case.

I would also love to see a compact li-ion charger with these features. Plus balancing perhaps.

I’m not interested in using a iCharger that I have to rig-up with cables, magnets, craddles etc; an accident waiting to happen. I too would really like to see this project evole into a model for Li-Ions too, not a combo one though; I don’t like the swiss army knife approach, jack of all things - master of nothing. A really nice Hi-Tech Li-Ion charger with built in craddle, full info LCD, all the logging goodies, and follows the precise Li-ion charging specs.

[quote=leaftye] ... You're only looking at it in terms of charging. A hobby charger isn't going to tell you the health of your cells, and isn't going to log temperature, and I don't think it can log resistance either. ... [/quote]

Just an FYI, the iCharger 208b does log temperature, and I think other iChargers that have the data logging feature probably do too. I'm not sure why you would want to log internal resistance as it would not change significantly during a charge cycle.

While hobby chargers are very capable, I think they are aimed at users who require the high power or who want the precise control they provide. I like my 208b's ability to let me adjust the charge rate according to the capacity, age and condition of my cells. But then, I also enjoy fiddling with magnets and cables.

That said, if a LiCo/LiPo/LiFe capable cradle charger with LCD, data logging, and the adjustability and quality of a hobby charger became available, I would stand in line to get one.

Thanks for telling me that about the 208b. You're right indeed. It only fits one sensor, but at least it offers it.

Logging internal resistance continuously throughout the charging cycle may not be useful, but since it's presumably automatically logged, taking a single data point per charging cycle can be used to track the degradation of the cell over time and charging cycles.

I'd be very interested in seeing how much the internal resistance, capacity and temperature changes over the course of a couple years. Even though I have the tools to do the first, I don't do it because of the extra hassle. With a device like this, I'd only have to keep a log of the order in which cells are charged.

We have to keep in mind that this is his first charger he's selling. He may ultimately end up building something like an open source hobby charger. It's not too fetched considering he's already dreaming up a 4 port nimh version that can handle different types of cells simultaneously and with greater current. I would prefer something with a built-in power supply though, even if it limits the maximum charging current.

This device doesn't exist yet. We shouldn't set limits for a device that has yet to be designed. If there are features we want in a future charger/analyzer device that is open source, then we should be giving him feedback. We can rightly complain if he refuses to implement those features. For now I'll just complain that he's not working on this device...yet.