Alternator, Batteries or PCB - Please Help

[joesco]

I searched the forum and believe my Protective Control Box might be toast , but need to lean on the experts again.

I have had directional, abs light, alternator and now a temp gauge issue on my 85 M931. I replaced and repaired all the above and went to a show yesterday and this morning, my batteries dead. Btw, the new alternator is an 80 amp Delco and appeared to have been working fine.

This AM, I put my 24V charger, using my slave plug setup and charged the batteries for about 5 hours. My charger was super hot so I unplugged it and attempted to start the truck and it started right up. I put my volt meter on the slave plug and was getting 25.6 volts.

But my truck's volt meter was barely approaching the green zone.

My questions.... My Hawker batteries are dated 2012, could they be toast? Can they be reconditioned?

Could my PCB be toast? Is there a testing procedure? I've read I should hear a clicking when I turn on the power switch, but I don't hear anything.??

If so, who is there a good goto vendor for a PCB? I've seen prices all over the place!

Thanks very much folks!

 

[jcappeljr]

I have a good used PCB if you need one for sale.

 

[74M35A2]

25.6V is not charging. 12.8V is a fully charged 12V battery, so x2=25.6V. Anything over 25.6V is charging. 3 year old batteries should be fine, and their OCV (open circuit voltage) appears to show fine. Load test is for sure way, but they should last at least 5 years, and maybe even 7-8 years. Using data, your charging system is not working.

 

[joesco]

Thanks, I hope my new alternator is not fried!

 

[Jason O]

A PCB with poor contacts on the batt relay can cause a failure to charge, and the voltage gauge to jump around. I have this going on w/ my 923a2 right now.

I compared the voltage at the alternator output to ground (+27.5) and the battery pack (+25.5). It was either a poor connection or the relay contacts at the PCB. In my case I jumped the PCB at the cannon plug and the truck charges normally with proper voltage (27.5 at the battery pack) and about 12amps DC flowing into the batteries.

 

[joesco]

Thanks very much Jason, are you replacing your PCB? I just received a take-out PCB, but before I do that, I will try your test. I was able to recondition two of my batteries using my NOCO G7200 Smart Battery Charger and I have to say, it saved me a bundle as two of my batteries were junk and two tested fine. Now after 48 hours (24 hours on each battery) this great tool reconditioned the two bad Hawker batteries and tomorrow I will top of the two good batteries so that all four are fully charged.

A PCB with poor contacts on the batt relay can cause a failure to charge, and the voltage gauge to jump around. I have this going on w/ my 923a2 right now.

I compared the voltage at the alternator output to ground (+27.5) and the battery pack (+25.5). It was either a poor connection or the relay contacts at the PCB. In my case I jumped the PCB at the cannon plug and the truck charges normally with proper voltage (27.5 at the battery pack) and about 12amps DC flowing into the batteries.

 

[Jason O]

Yeah, I'll being buying a new PCB. I'll take the old one apart and repair at some point for a spare. Rule out all the easy stuff first before throwing 3-400 bucks at a new part.

 

[joesco]

Installed the take-off PCB (thanks John for the quick shipping), cleaned the connector pins and the 2 wires on the lower outside bolt and the one wire connector on the top bolt, applied dielectric grease and my voltage guage went right to green upon startup. Volt meter on the newly installed alternator showed 27.3 volts. Volt meter on slave plug showed 27.2 volts. So it appears my problems were the PCB as it looked like someone had swap it out at some point because I was missing the two inside steel spacers which caused it to bounce around, probably damaging it.

Thanks folks, so all of the major weak links are now replaced. Sadly, due to my declining health, Zeus will go up for sale soon!