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NI-MH batteries in Minitor 3

Posted: Sun Nov 01, 2009 3:00 pm
by mt1000ff
I have been issued a Minitor 3 SV on VHF Hi to use with the volunteer fire department. I had been using regular disposable batteries. The other day I asked for some rechargables and was given two nickel metal hydride batteries made by Sanyo. IpPlaced the batteries in the pager and pager in non amplified charger. Charge light came on and I left room came back in again and found no light on and batteries not charged. Removed pager and I still have voltage on the charger pins. On replacing pager no light. Was this charger not made for Ni-Mh batteries? I did conduct a search and found nothing on this topic. The online Minitor 3 manual does not say anthing on the type of batteries. I do know of the problems with the Minitor 3 series but I will see if this one is ok.

Thanks
Tim

Re: NI-MH batteries in Minitor 3

Posted: Sun Nov 01, 2009 8:08 pm
by Al
Well, the original batteries supplied by M were NiCD(p/n NYN8345A, NLA) but NiMH should charge OK in your charger. I'd suggest this test to see if the LED 'charging' indicator on your charger went open causing no charge to be delivered to your NiMH batteries: Remove the batteries from the pager and place them in the spare battery charge pockets at the rear of the charger. If the 'battery' light illuminates and the batteries charge normally and operate the pager when reinstalled, you have a charger LED failure. If not, there's likely some other fault with the charger or wallwart.

Re: NI-MH batteries in Minitor 3

Posted: Fri Nov 13, 2009 2:33 pm
by Motoboy
Back when the Minitor III came out, there was no such thing as a NiMH AAA battery, and /\/\ stopped production on the III's before those batteries became commercially available. I have found that they work good in III's and IV's, but since the battery chemistry is different (and therefore the output voltage of the cell is also different), you lose your low battery jingle.

Also, try taking a small instrument to the contacts in the bottom of the pager and just burnishing those contacts a little bit. Might be just enough to make it go again.

Re: NI-MH batteries in Minitor 3

Posted: Sat Nov 14, 2009 6:11 am
by yankeeradio
The LED for the pager socket is open therefore no charge. Replace the LED and you will be back in business.

Re: NI-MH batteries in Minitor 3

Posted: Thu Nov 19, 2009 7:00 pm
by Nand
I was told that NI-MH batteries have a lower internal resistance that Ni-Cad cells when discharged. This will cause them to draw a higher initial current when put in the charger and likely blow open the LED that is in series with the cells.

Nand.

Re: NI-MH batteries in Minitor 3

Posted: Sat Nov 21, 2009 11:57 am
by mt1000ff
Thanks for all of the answers. I just opened the case again and the charging LED appears black, different than the spare battery LED. The contacts for the spare battery are broken, not usable. I dont have the skill nor tools to replace the LED. I will continue using non rechargeables untill I can snag an amplified charger. I will know not to used NI-MH batteries in that one.

Thanks again for the responses

Tim