NiMh charger?

[tomadom]

I want to construct my own NiMh battery charger to charge a bunch of NiMh drill batteries I have (various kinds and all don't have chargers). To buy a charger for each will cost a fortune.

I have in the past bought a module that begins charging and stops charging Lithium Ion batteries between set voltages but from what I understand, I can't use that of NiMh batteries.

My aim is to make something that I can adjust the output voltage on so I can charge all my NiMh batteries. I figured that there may be chargers already on the market that I can use which would need to be coupled with another module to control the output.

Any tips about what I would need to get this going? I'll need to charge up to 30 volts just to be sure.

Thanks

 

[Harald Kapp]

I'll do some Googling for you...

Here's an application note that describes the basics of charging NiMh cells.
Here's an example for a dedicated NiMh charger chip, requiring no µC.
Another versatile chip is the ICS1700A. This is a rather old chip and may be difficult to buy - if available at all.
Here's a project using an Attiny µC, also showing a complete PCB layout.

 

[Bluejets]

I want to construct my own NiMh battery charger to charge a bunch of NiMh drill batteries I have (various kinds and all don't have chargers). To buy a charger for each will cost a fortune.

I have in the past bought a module that begins charging and stops charging Lithium Ion batteries between set voltages but from what I understand, I can't use that of NiMh batteries.

My aim is to make something that I can adjust the output voltage on so I can charge all my NiMh batteries. I figured that there may be chargers already on the market that I can use which would need to be coupled with another module to control the output.

Any tips about what I would need to get this going? I'll need to charge up to 30 volts just to be sure.

Thank

Used one like this for 30 odd years.......mine goes from 1 to 8 cells. 15v dc supply and simply adjust the current, no voltage adjust necessary.

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www.electronicecircuits.com