Batboard

Hello. I have a set of 3 P1225 16f VHF, and all work great except one.

No matter which battery is on the radio (all moto original batt's), it thinks the battery is low. IE, when I TX, it gives the low battery beep at the end and blinks the LED on TX. When I power up the radio, I get the standard 2 Beeps which means the battery is fully charged. The radio does this with known good batteries. It appears to TX at full power, and even gives the regular power up tone indicating good battery. It just TX's like the batt is low, when it is not. Again, all batteries are motorola original, good date codes, and this is the only radio that does this, even to fully charged batteries.


Any ideas on what's wrong or what I can do to fix this?

Since it gives a low battery indication on tx - i.e. when the battery circuit is loaded to about 2 amps, I would begin by checking everything in the positive and negative battery circuit between the battery contacts and the PC board. Most likely there is excessive voltage drop due to higher than normal resistance somewhere between the battery voltage sensing point on the PC board and the battery terminals.
As an example, I have found that on GP300s there are small butterfly clips soldered at 6 or 7 places along the edges of the PC board. These clips complete the negative circuit to the radio's chassis(which is tied to battery negative). When two or three of these clips break off the PC board, the total negative circuit resistance increases. When the radio transmits and draws about 2 amps, the actual voltage measured by the onboard MPU on the PC board is lower than it should be, so you get an early low battery tone from the MPU.

Thanks for the reply, Al.

I will try tomorrow afternoon when I get home and see what I can do with it.