Thread: Ni-Mh battery to replace a Ni-Cd?

Hi Derek,

I went down this path with a Makita last year. Knowing what I know now I should have ditched the originals years ago and started using Ni-Mh replacements earlier. Faaaantastic

I didn't have any issue using my original Makita charger as it was compatible with both battery types to start with.

Cheers, Franklin

My belief is that even if you can find a NiMh battery pack that fits your old Panasonic, you won't be able to recharge NiMh batteries in a charger designed for NiCd.

My belief is that even if you can find a NiMh battery pack that fits your old Panasonic, you won't be able to recharge NiMh batteries in a charger designed for NiCd.

Hi Dave

I think that you are correct. So, I decided to purchase a new charger, one that does Ni-Cd and Ni-Mh batteries: https://www.ebay.com.au/itm/132194796522

I also have placed an order for 2x 12v 300Ah Ni-Mh batteries via Amazon. These were $45 each (including postage).

Regards from Perth

Derek

Hi,
Knurl is correct that Ni-Cd chargers should not be used on NiMh batteries. Ni-Mh chargers normally rely on the fact that when a Ni-Mh battery gets to the point that it is fully charged there is a spike in temperature. A sensor inside the battery pack picks this up and passes it back to the charger control logic so the charger knows to switch off.
Paul

I have had no problem with the original charger supplied with the Makita I have. It was marked as being suitable for both battery types and seems to be working perfectly so far.

On a slightly related issue. I have recently bought a couple of these. I have been guilty of forgetting the occasional item on a charger for longer than is possibly safe. Even my phone doesn't really need to be on charge all night, it charges fully from flat in 3 hours, so I decided I needed something that would turn off automagically.

Originally Posted by paul.cleary

Hi,
Knurl is correct that Ni-Cd chargers should not be used on NiMh batteries. Ni-Mh chargers normally rely on the fact that when a Ni-Mh battery gets to the point that it is fully charged there is a spike in temperature. A sensor inside the battery pack picks this up and passes it back to the charger control logic so the charger knows to switch off.
Paul

Hi Paul

I have purchased a current charger, which does Li-ion, Ni-Cd and Ni-Mh batteries ...



The two Ni-Mh 3000mAh 12v batteries arrived after 2 days!

Regards from Perth

Derek

Originally Posted by Fuzzie

I have had no problem with the original charger supplied with the Makita I have. It was marked as being suitable for both battery types and seems to be working perfectly so far.

On a slightly related issue. I have recently bought a couple of these. I have been guilty of forgetting the occasional item on a charger for longer than is possibly safe. Even my phone doesn't really need to be on charge all night, it charges fully from flat in 3 hours, so I decided I needed something that would turn off automagically.

Fuzzy this is a great idea for any charger especially for lead-acid car batteries that will often reach full charge without reverting to trickle-charge; after about 6 hours. I think mobile phones are safe because they have the circuitry to stop charging when the batteries are full. My MS Surface laptop will continue pushing power all night even after being fully charged - it worries me because I don't know whether it hurts the batteries. BUT I certainly would want a timer for NiCds and NiMhd power tools.

Now for the clincher: I would expect that any electronic charger or chargeable device made after 2010 would have built-in over-charge protection circuitry. So I would not worry overly about it!

Just to update: The NiMh batteries work a treat! My venerable 20-year old Panasonic drill is performing like a spring chicken.

Regards from Perth

Derek

I'd be interested in your experience with the NiMH in relation to self-discharge. I tried NiMH in my Makita 12V drill which gets only sporadic use. The original NiCad battery had very little self-discharge, while the NiMH was flat after about a week. My son-in-law who is a builder has had the same experience with NiMH, but as a heavy user it is not a problem, and he appreciates the extra grunt of the NiMH.

Chas.

I swapped over to NiMH batteries in my Makita 14.4V drill a while ago. My experience is the exact opposite. The original NiCads never held a good charge for long from the first day, I think they were actually worse than my original 9V drill. I haven't had any problem with the replacement NiMH losing charge, often going for weeks between usage and still having power ready to go.

I have two makita drills with NiMH batteries, and they hold charge even if left for a few weeks.

Hooroo.

Originally Posted by Chas

I'd be interested in your experience with the NiMH in relation to self-discharge. I tried NiMH in my Makita 12V drill which gets only sporadic use. The original NiCad battery had very little self-discharge, while the NiMH was flat after about a week. My son-in-law who is a builder has had the same experience with NiMH, but as a heavy user it is not a problem, and he appreciates the extra grunt of the NiMH.

Chas.

Chas, the Ni-Cd batteries I had were about 2 years old and no longer holding a charge. They would run down within 15 minutes of use, and if charged but unused, would run down over the course of a week. Ni-Mh have the reputation of holding a charge for a long time, and being able to be topped up without a memory issue (as Ni-Cd has). Of course it is far too early to tell. I'll report back in a year.

Regards from Perth

Derek