Can Lithium and NiMH/Alkaline batteries be mixed?

[rcnuk]

Can lithium and NiMH or Alkalines be mixed in series to make a certain voltage? Is it safe?
Example: 2xlithium (7.4v) + 1xAlkaline (1.5) = 8.9v

 

[Sable]

I'm pretty sure internal resistance at least would make that a bad idea - not to mention mismatching battery capacities and sizes (I don't know of any alkaline 123A sized cells, nor any 3v AA-sized lithium batteries - and this would be a terrible idea with Li-Ions).

If you're looking for specific voltages from a pack, you might try building or ordering custom NiMH or Li-Ion packs, or using a regulator circuit of some kind.

Mixing battery charges is a bad idea. Mixing battery chemistries (NiMH AA and alkaline AA) is a worse idea. I think that mixing battery chemistries, sizes, and capacites would be a very bad idea indeed, I'm afraid.

 

[2xTrinity]

I expect that in that setup, the LiIons would case a cell reversal on the alkaline, that is, they would start to "Charge it up", which it is not meant to do. One of the cells would have a big chance of simply acting like a resistor, heating up, and bursting. Mixing cells of different kind, even cells of the same kind with different state of charge is a bad idea. When you're dealing with LiIon, be very careful using multiple cells -- mismatching unprotected cells (cells that lack a circuit that will prevent cell reversal, or overheating) can lead to a very nasty fire (all sorts of toxic residue etc left over), even an explosion if the cells are inside a sealed light.

 

[rcnuk]

Thanks,
Not worth the risk.