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Tue Dec 27, 2011 1:04 pm

I have a 79 vw bus. About every 6-9months i have to replace the battery (under warranty thank God). I have now at least found the problems and would like some help fixing it. I installed my new (3rd.) battery and checked the voltage at the battery cables. It's reading 18Volts. I'm pretty sure 12-14.4volts is the area it should be in. Any idea what it could be? 2 batteries ago I replaced the voltage regulator so i'm thinking it is not that. this time I purchased a new bosh alt. new bosh voltage reg., and new bosh battery. After installing these new units will it (should it) fix the problem? Any idea what else can it be, or any other checks i should do before installing?

Thanks...

Tue Dec 27, 2011 1:13 pm

You'll want to test all the wires between the alternator and voltage regulator, sometimes the terminals push back out of the plug sockets and sometimes the wire breaks inside the insulation, if the reg isn't getting the signal that the alt is overcharging it'll happily keep telling it to make more.

Tue Dec 27, 2011 6:43 pm

Serpent7 wrote: Any idea what it could be?

Normal charging voltage is somewhere between 13.5 and 14V, depending on temperature. 18V is way too high and causing you to boil your battery(s).

Wed Dec 28, 2011 2:20 pm

Vince Waldon wrote: Serpent7 wrote: Any idea what it could be?

Normal charging voltage is somewhere between 13.5 and 14V, depending on temperature. 18V is way too high and causing you to boil your battery(s).

Yeah, kinda figured... gonna take busdaddy's advice and pull the Bus in the garage now for a hour and see what I can find out. too windy and too cold outside right now.

Wed Dec 28, 2011 5:49 pm

Find and test continuity (wiggle the plugs too) of the voltage sensing wire from the regulator to the battery. If it's corroded or dirty it will read too low of a voltage from the battery, and jack the voltage up until it sees 14v coming back.

Sat Jan 07, 2012 7:44 am

Serpent7 wrote: Vince Waldon wrote: Serpent7 wrote: Any idea what it could be?

Normal charging voltage is somewhere between 13.5 and 14V, depending on temperature. 18V is way too high and causing you to boil your battery(s).

Yeah, kinda figured... gonna take busdaddy's advice and pull the Bus in the garage now for a hour and see what I can find out. too windy and too cold outside right now.

Right below the plug that connects to the volt. reg is a pigtail plug, right under that is a whole bunch of lots of wires (8-10) that have been taped together with using ducktape by previous owner, that's about a foot long. I have to unstick and cut all these wires from the ducktape. Already started, and its a huge mess! I'll try and snap a picture today and post. TCleaning up the tape alone is goingto take some time... Thanks previous owner!!!

Sat Jan 07, 2012 1:30 pm

we bought a new harness from the alternator to the VR and electrical system as the old one was hardened and the insulation cracked. The old plugs and connectors on ours were deformed from age and heat. I was going to rebuild it but there is a fellow here on TheSamba who makes them so we just bought his new one. That is absolutlely the solution unless you want to rebuild your own. The new one was the same gauge wire, flexible and new connectors that worked perfect. I threw in a new VR on principal since the car has close to 110,000 miles on it and our charging system has been rock steady.

http://www.thesamba.com/vw/classifieds/detail.php?id=829880

Sat Jan 07, 2012 5:01 pm

SGKent wrote: we bought a new harness from the alternator to the VR and electrical system as the old one was hardened and the insulation cracked. The old plugs and connectors on ours were deformed from age and heat. I was going to rebuild it but there is a fellow here on TheSamba who makes them so we just bought his new one. That is absolutlely the solution unless you want to rebuild your own. The new one was the same gauge wire, flexible and new connectors that worked perfect. I threw in a new VR on principal since the car has close to 110,000 miles on it and our charging system has been rock steady.

http://www.thesamba.com/vw/classifieds/detail.php?id=829880

This sounds like the best ticket!!! I'll purchase this next weekend...

Before I install the new parts, i'll take before and after pics and post them here. The OE wires are all messed up and have been re-taped, and cut and put back together, so with this I won't have those worries. Thanks Kent!

Thu Feb 16, 2012 3:08 pm

SGKent wrote: we bought a new harness from the alternator to the VR and electrical system as the old one was hardened and the insulation cracked. The old plugs and connectors on ours were deformed from age and heat. I was going to rebuild it but there is a fellow here on TheSamba who makes them so we just bought his new one. That is absolutlely the solution unless you want to rebuild your own. The new one was the same gauge wire, flexible and new connectors that worked perfect. I threw in a new VR on principal since the car has close to 110,000 miles on it and our charging system has been rock steady.

http://www.thesamba.com/vw/classifieds/detail.php?id=829880

Just ordered the Harness!!! That's the last piece of the puzzle. New Alt., new VR, new battery, and now new cables... Should be all good here by next week. I'll report back after everything is installed!

Thu Feb 16, 2012 3:20 pm

i've seen wandering and really high voltage readings resulting from lose connections at the starter as well.

Thu Feb 16, 2012 5:42 pm

pb24ss wrote: i've seen wandering and really high voltage readings resulting from lose connections at the starter as well.

Good to know! I'll check all those as well. In the not so distant future I will be running dual batteries so I really want to make sure the electrical system is new, and up to par.

Thu Feb 16, 2012 10:30 pm

99% of the time overcharging will be a bad regulator unless you are seeing AC at the battery from a bad diode in the alternator.

Sat Feb 25, 2012 6:30 am

SGKent wrote: 99% of the time overcharging will be a bad regulator unless you are seeing AC at the battery from a bad diode in the alternator.

Kent, this is exactly what I was thinking... either the VR, or the Alt. I now have all the parts I need to finally rid myself of this problem:

1) Voltage Regulator

2) New Bosh Alternator

3) New Cabling from VR to Alt.

4) New Battery

I'm going to try and start today (wife willing). Then I have one more project to complete before the Spring Show-and-Go car show in NJ. Lowering it 9", and narrowing the front 5"! All parts arrived except rear boomerangs.... BusBoys is still making them.

Also before Bugout I want to have a dual battery setup with a nice inverter!

Sat Feb 25, 2012 9:17 am

Just to add to SG's post. I had this happen to my '79 about 15 years ago. I was boiling my battery. It was the voltage regulator.

A new harness can't hurt either, but even if you get one I like SG's idea of also replacing the voltage regulator even if just on principle.

Tue Feb 28, 2012 6:12 pm

drober23 wrote: Just to add to SG's post. I had this happen to my '79 about 15 years ago. I was boiling my battery. It was the voltage regulator.

A new harness can't hurt either, but even if you get one I like SG's idea of also replacing the voltage regulator even if just on principle.

I'm sure its the VR. I'll test the new VR first, and replace the wires. If its still overcharging I'll replace the alt.

Wed Feb 29, 2012 3:31 pm

My problem was the alternator wasn't charging the battery. I just ordered the harness and a new regulator as well. My harness was falling apart and might as well change the regulator while I'm at it. I bought a sweet combination battery last summer.

Let us know how it goes. fingers crossed.