Batboard

Can anyone enlighten me on rechargeable battery choices for Minitor III & IV's. I know the factory are NiCd 1.25v 250 mAh AAA. Is this all that should be used, or can Ni Metal Hydride be safely used also. I guess I'm looking for a lesson in rechargeable batteries. Our FD is poorly funded, so I don't want to damage any equipment. Thanx!

The pager itself won't really care about battery type, but the charger might. The charging curve is different between the two chemistries & I don't know if the factory Minitor chargers are built to handle both. Someone else might chime in with more info.

Todd

If you look under your charger, you should see a sticker that says Ni-Cad only. I have seen a couple of wall transformers fail due to this.

Thanks! I see where a sticker once was on all the chargers but nothing is left anymore. I'll play it safe. Thanks again for the help!!!

I have been running MiMH batteries in my Minitor 3 for the past five years, and a Minitor 4 for the past 2 years, all without any problems. Also, our department bought 30 M4s a year ago and we have been using 850 maH NiMH batteries in them, with no problems... at least any that could be attributed to batteries.

I had the same concerns before I switched from NiCd batteries but the chargers - one a charger/amp, the other a standard desktop charger - never seemed to mind a bit.

One caution - do not use Radio Shack batteries, they will not last and they may leak. We have been using either Ever-ready or Sanyo batteries and they are great.

Joe

WB2IID wrote:I have been running MiMH batteries in my Minitor 3 for the past five years, and a Minitor 4 for the past 2 years, all without any problems. Also, our department bought 30 M4s a year ago and we have been using 850 maH NiMH batteries in them, with no problems... at least any that could be attributed to batteries.

I was considering using NiMH batteries in my Minitor 4. What has been your experience with the length of charge? Right now I am using the motorola spec Sanyo 1.25v NiCads which I think are 250 maH. I am also assuming you do not use the motorola chargers and use a NiMH charger instead... correct?

Length of charge depends of course on the level of activity, operating mode, etc. I invariably run in tone alert mode, about 2-3 pages a week, so for me the length of charge is typically about 4 days with NiMH batteries. This is with 650 mAH cells. There are 850 mAH cells made by Eveready which will last even longer.

Your mileage will be less if you get more pages and operate in CSQ mode.

No special charger - I have been using both the standard M charger/amp and the desktop charger with no problems. I routinely have batteries on charge for weeks at a time - months in fact - with no damage to the chargers or batteries. I can't comment as to the battery capacity or any long-term effects of overcharge, however since I have not measured them.

As I said before, I started with RS batteries and they only last a few months before coming apart. The cells I use now I actually bought from a Minitor dealer (not M batteries, of course) and have been going strong for a couple of years.

I too have been using Eveready (I think) the same set of AAA NiMHs in mine for a long time now with no problems. Actually I never really found how long it would last on the original NiCds, the run time is so much longer than my II. I could tell when it was time to go to bed because my II would run out of battery about the same time I would

I think the major issue with trickle chargers and NiMHs is, the capacity is so much larger, that the trickle charger will not put enough amp hours into the battery overnight to replenish it completely in one night.

FWIW I use one charger at home, and another one in my bedroom at the station, and if I happen to pull overtime I use the one wherever I sleep. No failures but we do not have too many NiMHs other than mine in service.

Birken

You bring up a good point, which I forgot to mention: the higher capacity cells require longer charge times with the standard chargers. So, you want to run ALL NiMH so that the batteries being charged have a chance to completely recharge.

If you run one pair NiMH and 1 pair standard NiCd batteries, the NiMH batteries cannot be recharged fully when the NiCds are in the pager, because the battery life is so much less.

Also FWIW, what I do and have always done, even with a II, is to keep one battery (or pair) in the pager and one in my pocket for backup. Leaving the one set/pair in the pager at all times and only rotating the backup in only every couple of weeks. With the II it was often necessary to switch these out when you were out for a long time but with my IV I have never found it necessary to switch to the backup even with the NiCds. I don't even know why I carry them any more except out of habit, I should put some alkalines in my glove box and be done with it.

Birken