NiMH Battery in an SP50 Motorola 2-way Radio

I ordered a new battery for a model SP50 Motorola radio. I received a NiMH battery of proper size and voltage. The original battery is a NiCad. Will the NiMH battery charge properly in the Motorola charger?
Voltage is 7.2.
Thank you.

Hello jd dave,

Not really. If you really want to use the new ones worry free, a charger made for them is in order. NiMH battery needs a more closely monitored end of charge voltage. You can try charging them while you are there with your present charger,but you need to monitor their temp and voltage. AS SOON voltage starts to drop, and the temperature is so they are warm to the touch,about 105* F. take them off the charger,

Guido.

NiMH battery on a NiCad charger. I had an experiment with that about a year ago, as the old NiCad half D cells in the battery pack of my Air Stream filtered dust helmet were worn out, plus I wanted to try replacing them with the new type NiMH cells that will hold a charge for a year. I fitted a 4AA battery holder in the battery case and filled it with the new slow self discharge AA NiMH cells.

I tried the old Ni CAD slow charger on the new NiMH battery pack as both battery types are 1.2 volts per cell.
I connected the charger through a Kill-o-Watt meter to compare how much power was required for the Ni Cad or NiMH battery packs, the NiMH battery took about 20% less power, so I suspected it would not harm the charger.

Normal recommended recharge time was 14 hours for the old NiCad batteries, the NiMH cells started to heat just a bit at 13-14 hours, so I think they were at full charge at the same 14 hrs. Run time(7 hours) is about them same, so It seems to have worked well and the new cells are claimed to hold 80% charge for a year. Much better than the old NiCad's where I about had to anticipate use a day in advance so I could recharge the battery. With the NiMH cells I recharge the battery packs once per year and it lasts for a season of lawn mowing.

Look on the chargers base/dock. It may have what type of batteries that it can charge with it.

Pretty sure that the Motorola HTN9014 charger can handle both without problems.

Hello Jon Hagen,and

I know it would work. Battery resistance cell for cell is not the same. The NiMH usually have a higher resistance then the NiCads as you found out It's about 20% higher. Knowing the input and monitoring the charging process is the key. I know you would like this. I found out that a lower capacity NiCad cell, will retain more voltage the a higher rates one. I have an old Dewalt18v pack with 1200 Mah cells been two of three years since the pack was charged. Have not checked it lately. I'd bet it still has 18 volts in it. Now I will have to check it!

Guido.

I charged the NiMH battery pak for 14 hours in the Motorola HTN9014C charger. At the end of the charge the pak was warm to touch (105F?) and the voltage was 8.35. I assume the charger will work but that the pak should not be left in the charger for extended periods. Is that correct? Thank you.

Hello Mr Dave,

That is correct! NiMH, should never be left on the charger, they are NOT EVER trickle charged. You can only do, charge them a a very slow rate, if you start from the discharged state, and them monitor the process like you did,

GUIDO.

Guido,
Thank you. I assumed that this was as you've described. I just didn't want to at most burn the place down or at least ruin the battery!
You are our battery guru and I think we all appreciate your comments.

Hello jd dave,

Thanks for the vote of confidence. Glade to help anytime!

Guido.