Hi guys, I have a Mitsubishi MS230lc-3 excavator and am installing a new stereo. It's a 24 volt system so I bought a 24 radio. My problem is I don't have the negative of the battery unless the key is on or the machine is running. The radio has a memory wire that needs hot 24 at all times but as soon as I turn off the key,the negative side disappears because of the battery relay that switches the battery negative to ground opening up.. I could run a #16 wire from the battery negative to the radio but am wondering if that will adversely affect the machine electrics.The wire will effectively connect the whole machine to the battery negative side. The relay must be there for a reason. Will running the wire carry current for the whole machine with the key off and start a fire being that the wire is a small gauge or will it work ok? Why would the neg. battery side be switched by the relay.With the key off,the battery negative is completely isolated from the frame.Attached is a pic of the wiring diagram. It's from a 240lc-8 machine but basically the same wiring. Any insight would be appreciated. And by the way,We ain't afraid of no Coast.We'll stop on any beach and drink your beer. Coastbuster
It's the same thing as having a battery disconnect switch like CAT and Deere and others used, it's just more convenient since the key switch automatically activates it. Keeps the batteries from being drawn down over time. Some Japanese machines had it in the negative side, most newer ones are in the positive cable. Yes, do not run a small ground wire, it will try to carry a heavy load if anything in the machine is left on and will burn up, unless by chance your radio has an isolated ground wire, that is not connected to the chassis.
Thanks Trax, Thats what I figured,being an electrician for 50 years. The only way to do it I guess is to isolate the radio from the chassis. Thanks again. Dan
...or change how the battery disconnect works..... rewire it to disconnect the hot side. you'd have to look at how the start switch interacts with other terminals if it does and how the relay is wired but at a glance it looks possible. If you go the isolation route make sure the antenna gnd is isolated also.
Oh yea the antenna. Hadn't thought of that yet. Good catch Ronsii. I'll look at the rewiring aspect tomorrow,just got in from deer hunting and I'm bushed. Dan
"and I'm bushed." Great pun, intentional or not. Hope the huning was good.
Got 1 Doe and had a nice buck behind a tree but he just wouldn't take that last step. Smart. Like the undertaker quip. Mine is " I'm using the short form Will." which is " Being of sound mind,I spent it all."