Slave Cables and Battery Charging

[52 M-42]

I've been wondering if it is possible to charge the batteries in the M-37 trucks through the slave port connection on the left side of the truck. Looking at the wiring of this port, it seems to bypass the electrical system and only provide power to the starter. Is this correct? If you plugged a 28VDC generator into this port would it charge the batteries?

Has anyone installed a slave receptacle on the right side of the truck with a direct connection to the batteries for charging purposes? If you installed a cutoff switch for this receptacle so that it wasn't hot all the time, it might be a handy addition.

Thanks!

52 M-42

[k8icu]

Your Slave connector should hook into the batteries even if it hooks to the starter as the wires should be connected. So yes you should be able to charge the batteries using the slave connector. Unless someone wired it up in some weird fashion.

[Carter]

Yes, I have a lab. quality filtered dc power supply that I bought at a sale at Aberdeen Proving ground that I have used in the way you describe. I do not leave it un-attended and just charge at 25 amps max for only short periods of time, usually charge about 5 amps after the first burst of 25 for a couple of min. Never had any problems charging that way and had rigged up a large rubber 2" thick plug with holes drilled in it to hold short lengths of copper tube that had the pos & neg. leads soldered to them to plug into the slave connector. Worked great, saved removing the pass. seat and battery box lid when charging, plug and go.

[majorhitt]

Yes you could jump start or charge using the slave receptacle. There is no need for a cut out switch, other than for your peace of mind. Keep in mind while charging you will build up some unwanted gases in the battery box .

[52 M-42]

Thanks, you guys! I didn't know if pumping power into the system from the slave port would get to the batteries and if it would; would it burn up the points or other parts of the ignition.

So the slave port is hot all the time? Or only when the ignition is on?

Thanks again for clarifying this for me. Naked little electrons running around loose in copper wires leave me confused. I'm a nut, washer and bolt kinda' guy.

52 M-42

[majorhitt]

The slave receptacle on your M is just like the ones in your house(more or less) it is hot all the time. The power can't get to the points until you flip the ignition switch on. Those naked little electrons are waiting for the order to go somewhere, either to a vehicle that you're jump starting or to the vehicle their in waiting for extra help to start their vehicle.

[Cal_Gary]

Agreed-always hot unless you have a kill switch on your batteries like I do.
Gary

[52 M-42]

Yes, I do have the kill switch on the batteries. Mine is hidden under my seat however, as an additional security feature.

Thanks again for all the help guys. This will help with a couple projects I've got in mind.

52 M-42.