GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Another generator post (Gen's starting battery not charging)
Re: Another generator post [message #347164 is a reply to message #346809] Sun, 01 September 2019 09:19 Go to previous message
Silvernort is currently offline  Silvernort   United States
Messages: 95
Registered: June 2019
Location: Rock Springs, WI
Karma:
Member
So when a result doesn't make sense, check measuring instrument. It didn't seem likely that that new battery would be bad and I had a hunch my very old charger was not doing its job. I bought a modern 6 amp charger/maintainer and retested - battery is OK.
There was a wire, about 12g, that was connected to positive and going up into the body. On further checking it seemed this just went to the battery checking switch/meter. The problem, it was drawing pretty heavy current constantly. I don't know yet if this wire supplies anything else as the testing had to be interrupted for an appointment with the RV shop for a ball joint replacement and alignment. However, leaving this wire disconnected seemed to solve my discharge problem and other than not being able to check the charge level at the gauge panel, I haven't seen any other issues.
When I get the GMC back, guess I'll have to see what is up with that meter and whether that wire goes to something else also.

Cheers,
Shane

>>Tom Lins wrote on Sat, 24 August 2019 20:47
Silvernort wrote on Sat, 24 August 2019 20:08
>>>Tom Lins wrote on Sat, 24 August 2019 18:53
Silvernort wrote on Sat, 24 August 2019 19:41
On my 73 I've owned since this May, I have a Generac Guardian RV generator that had been working fine. Recently it wouldn't start and seemed to be the battery which looked kinda old. So got a new battery. charged it and gen started fine, but after a few hours died. The battery was discharged, so I jumped it and started right up. Disconnect the jump box and after about a minute the gen stops. Just to be sure I checked the fuel lines, filter and pump - all OK. Tried jumping again, started, this time left the jump box on. The gen stayed running for about 10 minutes so I disconnected the jump box and within a couple minutes the gen stopped. Next, put a trickle charger on the battery overnight. It started right up and kept running so after about half an hour I turned on the AC which worked fine. The fridge was working etc. This was yesterday, I shut it down then went out today and no go.
So it is providing power to the house fine but not charging its own starter battery. How can this be? There my also be some parasitic drain that is probably related, but not sure on that one.
Waddaya think?

Shane
Sounds like your converter is not plugged into an AC outlet or it is not working. If it works like the original Onan it only makes AC and does not make DC to charge the battery.
<<<

I was just going over the schematic and it appears this unit has a winding just to charge the battery. This goes to a rectifier then to battery. I am not an elekchicken but I have a meter, just need to know what (how) to check these components out. ie on the rectifier which has three plugs (case probably ground) what do I look for.
Thanks for the help.
Shane
I believe I found a wireing diagram.
Check and see what the voltage is at the battery with the generator running.
If you are not getting at least 13.5 volts it is not charging.
You need to measure from case ground to the side of the rectifier that goes to the battery.
If that also is low check each of the other two legs of the Rectifier.
If the voltage is low on the input side of the rectifier the charging winding is bad.

JMHO
<<


Shane Harvey 1973 26' "Packer Backer", 1976 Palm Beach, 1965 Dart
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: Rear bearings and races
Next Topic: GMC Gets Some Camera Love In Scorcese's Latest on Netfix
Goto Forum:
  


Current Time: Wed Jul 03 02:55:50 CDT 2024

Total time taken to generate the page: 0.01796 seconds