Replacement batteries for Icom M3EURO h/h

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chrisclin

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At the end of last year the half-dozen NI-CD batteries in my handheld VHF started running down very quickly. I purchased half a dozen NI-MH AA batteries and installed them. The VHF received fine, but when I tried to transmit, all I got was a musical chime.
It looks as though the NI-MH batteries can't take the drain imposed by transmitting. I tried installing ordinary alkalines and they seem to work. I presume this is because they run at 1.5V whereas the NI-MH ones run at 1.2V
I now find that NI-CD batteries can no longer be imported into the EU!
Will I be able to use rechargeable Lithium-ion 1.5V batteries? And would the ICOM charger producing 12V @ 500mA be able to charge them by plugging it into the VHF?

I can carry ordinary non-rechargeable alkalines in the grab bag for use in emergency, but it would be an expensive business to use them permanently.
 
chrisclin said:
It looks as though the NI-MH batteries can't take the drain imposed by transmitting. I tried installing ordinary alkalines and they seem to work. I presume this is because they run at 1.5V whereas the NI-MH ones run at 1.2V
Click to expand...

But Ni-Cd batteries are also 1.2V...
 
Agreed, but Googling implies that NI-CD batteries can cope with the current draw better. My recollections of V=IR etc. Are hazy to say the least, but I would have thought a higher voltage would increase the oomph going through the beast. And transmitting works with alkaline 1.5V batteries.
But maybe I'm confused!
 
Lots of handhelds use Ni-MH batteries and work fine. I'd suspect that either yours are faulty or they're not fully charged.
 
Total voltage for the power pack is 8.4V which seems pretty good for 6X1.2V. I tried transmitting on low power and it seems to work. It implies these batteries can't deliver the required current to transmit the full 5 watts. I don't suppose it could be dirty contacts, could it?
 
One thing i noticed with Ni-Cd batteries was that the held their charge to the last moment, then dead. Ni-Mh batteries would loose power gradually before dying. Li batteries are better than both IMHO.

NB* these finding were form years of using cordless power tools, not radios. Also Ni-Cd batteries are "memory batteries" where Ni-Mh and Li are not.
 
As others have already said, N-iCD and NI-MH AA batts are all 1.2v.
Voltage on rechargeables does tend to collapse pretty quickly as they run out, as anyone who has flown R/C model aircraft will tell you!
I can't help but think your problem must be pretty basic, either the charger is not charging the batts up properly, or you have a bad connection on one of them where it clips into the radio. Or (much less likely) one of the new batteries is a bit of a dud. Measuring the voltage on a meter doesn't tell you much, as there is little load - a bad connection will make itself known when you demand more e.g. by pressing the xmit button.
 
They have dud batteries or they have bad/dirty/weak connections on the spring terminals where they clip in or they are not charged properly. NI-MH batteries work in an M3Euro just as well as Ni-Cad, when the M3Euro was sold 700mAh Ni-Cads were about as good as you got and the charger for the radio would take around 10 hours to charge them. If you replace those batteries with Ni-MH that are 1400 mAh then your charge time will be double to around 20 hours, this is due to the limits of the charge circuit within the radio so a higher rated current on a PSU will make no difference. If you use high capacity 2400 mAh batteries (which are quite common now) your charge time will be very long indeed. I would suggest removing the batteries and charging them in a dedicated AA charger rather than using the supplied Icom charger which will struggle with high capacity batteries.
 
Thanks to all.
Today I purchased half a dozen new NI-MH batteries from Maplin and, without even charing them popped them into the radio. Pressing the PTT button momentarily in both Lo and Hi mode on CH06 resulted in the TX indicator lighting up on the screen and a buzz out of the speakers of my PC. So, I think they are working. It looks as though it was a duff battery after all as I tried charging 4 of them in a standard charger where the light went out after a couple of hours. I then put the other 2 into the same charger and the light didn't go out ovenight, and the batteries and charger are hot to the touch.
Anyway, I've learned a lot about rechargeable batteries over this thread.
 
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