Making "Godly" Ni-MH / Ni-Cd charger

[FireFlower]

Hello,

After I finish setting up my laboratory computer I am going to start designing a better NiMH / NiCd battery charger.

Reasons: Currently the biggest consumer available chargers are for 8 cells, sadly I have over 30 cells and amount increases with every time I toss away alkalines away from remotes etc.
Also when my friends come over and wireless controllers suck up those batteries dry pretty fast so I like to have a nice amount of charged cells already.

Capabilities: Deep-charging, Quick-Charging, Capacity test cycle, Drain and charge, Battery resurrection (dark magic?), upkeep, Over current & Over charge protections, temperature protection, dead cell notification, Single cell charging, Charges AA/AAA batteries
Design: Stack-able (modular) up to 8 charge units with 1 power unit, won't deliver power to over stack (beyond charger capability).

Do you guys have any further ideas to put into this? Suggestions are welcome, I have been just brainstorming about this myself about a month soon.

Edit: When basic charger 'module' is ready I might design a Li-ion charger module also for it.

[System Error Message]

First step is designing the PSU for AC to DC, you will have to make this well or get a premade one. This is quite important.

Than you have to design the DC to DC convertors, this is because NiMH and NiCD have different charging profiles. Also not sure if you want to add a controller and fancy screen.

Technically if you were only to charge 1 type of battery all you need is a good AC-DC PSU that outputs the charge voltage of the battery. You will need a limited to make sure only a certain amount of amps go through. I've seen an interesting multi battery charger on instructables that you can build yourself really cheap but thats only for a small number of batteries. It has a small screen and the ability to pick a profile or adjust a voltage. If you're interested look it up and build a version of it to handle much more current.

The main limiting factor in charging a battery is the maximum safe current a battery can handle. If you have 30 batteries to charge at a time this in turn means you need a good PSU, one that can output the amps you need while staying cool.

[FireFlower]

Yeah, part of the project is to design nice good DC-DC converter/s.  Of course I could just order 4 Varta quick charger units but hey where is the fun in that?

I have a very interesting and a very efficient converter in mind which doesn't cost too much either.

Edit: Yes I know the main limiting factor is current, I was thinking max. quick charge rate would be 1C and it would drop down if battery heats up too much. If that current becomes too much to handle for all batteries at once maybe I will put a software limit for it where you can address some cells to be quick charged and others will be queued.

[linux-works]

I'm working on a lipo (1S, for now) charger, multi port.

maybe there's some overlap in the projects, or maybe later, if not now.  I plan to open source mine.

it will be arduino based and have local+remote UI ability.

teaser shot:





my motivation is the piss-poor state of commercial lipo chargers and how dangerous and uncalibrate-able they (now) are.