M2 leaving in charger

Jay G. · Post by **Jay G.** » Sun Oct 09, 2005 4:42 pm

Here's my situation.

I have a minitor 2 which I leave in the amplified charger 24/7. It functions as an in-building alert unit with the external speaker. ABout once a week or so, I swap batteries so it doesnt burn them out.

What I am looking to do is eliminate the battery - Is there a way i can "jump" the battery so I dont need to leave it in???

Thanks!

nmfire10 · Post by **nmfire10** » Sun Oct 09, 2005 8:37 pm

The charger's + pin goes through a 47ohm resister and directly into the battery's + tip. The charger's ground pin is obviously ground on the pager.

I'm not sure how it manages to charge the battery but not power the pager with it in this fashion. I would think if the charger's + pin was in parallel with the battery's + tip, it would keep the pager on without a battery in it. But it doesn't so I'm not sure.

Al · Post by Al » Mon Oct 10, 2005 3:35 am

If you look closely at the battery's + contacts inside the M2, you'll see that there are two contacts...one contacts the very tip of the battery, and the other contacts the shoulder on the + end of the battery. I think if you jumper these two contacts, that'll do what you want without the battery being inserted.

nmfire10 · Post by **nmfire10** » Mon Oct 10, 2005 4:19 am

Ah ha. And for the power to flow from the charger contact to the pager contact, the top of the battery is touching both, continuity, power. I'm going to do this when I get home as well and see what happens. It makes perfect sense now.

Al · Post by Al » Mon Oct 10, 2005 7:55 am

I think that I would reduce the charger's voltage to about 3.6VDC to avoid letting the magic smoke out of the M2. If I remember correctly, the charger's voltage(unloaded) is around 7 VDC.

nmfire10 · Post by **nmfire10** » Mon Oct 10, 2005 10:35 am

Why wouldn't it smoke it with the battery in there? It's in parallel.

jcpd9720 · Post by **jcpd9720** » Tue Oct 11, 2005 12:07 am

OH MY GOD IT WORKS!!! i simply put a half inch un-covered piece of speaker wire, doubled over, between the two pieces that are ultimately connected when the battery is put in, and it works. I carry a min III on my belt, and needed a backup pager to wake me up if that one was dead, the ol' min II is back in service. I can't even find the batteries for min II's, this is a life saver! Thanks for the idea guys!

Al · Post by Al » Tue Oct 11, 2005 5:12 am

Batteries for the M2s are still readily available, both from Motorola and from second-source suppliers....in fact, I ordered and received two dozen of them just last week(M2s are still in use in this area).

tvsjr · Post by **tvsjr** » Tue Oct 11, 2005 6:05 am

Al wrote:Batteries for the M2s are still readily available, both from Motorola and from second-source suppliers....in fact, I ordered and received two dozen of them just last week(M2s are still in use in this area).

Yep, they're just fairly pricey from Mother M. I pay about $4/ea. for good-quality Multiplier units from Tessco.

jim · Post by **jim** » Fri Oct 14, 2005 4:51 am

Do you really want to run a 3V pager on 6.5V?

The battery is the "regulator". The wall wart's limited current in conjunction with the resistor and the load of the battery for a generic "regulator" to create the slightly over 3V to float the battery.

Eliminating the battery will allow the full wall wart voltage to the pager.

jcpd9720 · Post by **jcpd9720** » Wed Nov 09, 2005 12:16 am

I have had mine redneck engineered for a couple weeks now, and no problems with smoke! the only thing I have noticed though is that it seems to drain the power tremendously to squelch it closed, but it does work. it also has extremely low volume on the voice side of things. Mine is a min III with repeat... it does not have enough power to store the audio. It seems to be just enough to wake me up!

aaknitt · Post by **aaknitt** » Sat Feb 04, 2006 1:14 pm

How do you do this on Minitor III? I only see one solder pad on the + battery side.

Andy