Unwanted emergency call activations ? DM4601e/XPR5500e

[VK6NCB]

Hi All,

I am having some issues with Motorola DM4601e radios (XPR5500E in USA) activating an emergency call in a few machines when the vehicle is de-isolated (batteries re-connected) or the engine started.

there is an ignition sense cable connected, spliced into the positive power wire, so the radio fires up the moment it has power, this is working fine on the other machines on site, and in hundreds of installs I have done across many sites. its just the two machines we are having trouble with.

I am thinking it has something to do with a voltage surge or drop, causing unwanted things to happen.
has anyone had a similar issue ? or ideas for a fix ?

turning emergency calls off is not an option, turning ignition sense off is an option, but operators are used to the radios turning on automatically, and is something we would prefer not to do.

 

[buddrousa]

Here are a few questions for starters.
1. How old are the car batteries on the 2 that are causing problems?
2. Is adding a 2nd battery and option?
3. What size wire comes from the car battery to the radio? Yes I use relays connected to the ignition. It is better to use just the ignition sense.
4. What size ground wire is run to the radio and where does it connect to ground?
5. What all else is on this power circuit that powers the radio?

 

[VK6NCB]

Here are a few questions for starters.
1. How old are the car batteries on the 2 that are causing problems?
2. Is adding a 2nd battery and option?
3. What size wire comes from the car battery to the radio? Yes I use relays connected to the ignition. It is better to use just the ignition sense.
4. What size ground wire is run to the radio and where does it connect to ground?
5. What all else is on this power circuit that powers the radio?

they are large earthmoving machines with huge batteries, a Komatsu 600 wheel loader and a Hitachi 3600 excavator.

1. I dont know the age of the batteries, but they do start the machines OK. I will suggest a replacement of the batteries.
2. not an option
3. Im not sure on the loader, but the excavator is connected to the normal power supply we use behind the seat, plugged straight into the 24-12V reducer
4. the supplied 10gauge power cable, runs to the negative on the 24v Reducer on the excavator, I will have to check on the loader (its been a while since I looked at it)
5. nothing on the Excavator, Radio is the only device thats 12V only. theres a UHF CB on the loader on the same circuit.

 

[buddrousa]

3. Is where I would start.
Look at it with a very good VOM and see what the voltage drop is when cranking.
Next I would use a current meter that will read what the current should be during startup.
If possible I would swap out the 24 to 12 inverter with 1 that is working and see if the problem stays or follows the inverter.

 

[VK6NCB]

3. Is where I would start.
Look at it with a very good VOM and see what the voltage drop is when cranking.
Next I would use a current meter that will read what the current should be during startup.
If possible I would swap out the 24 to 12 inverter with 1 that is working and see if the problem stays or follows the inverter.

thanks for the advice ! will start there.
I had a feeling it was a power issue, was wondering if anyone else had seen the same problem before.

 

[buddrousa]

I seen strange things happen on Goodyear Forklifts and Service carts related to power.
Your fastest option may be the last swap inverters.

 

[DeoVindice]

I saw it pretty frequently on off-highway trucks with 24V electrical systems. I recall this primarily occurring on older equipment with a lot of parasitic draws, so an under-voltage condition might be involved.

Maybe try a ChargeGuard?