Battery keeps dying- onboard welder charges it?

[Bundy]

Hi All-

I have an onboard arc welder installed by the PO(never used it) and the HO alternator runs straight to the onboard welder. Then there is a red power line/cord running from the welder to the battery.

does this mean the alternator runs through the welder to charge the battery? i though maybe the welder was draining the battery so i unplugged it, but then it died this morning so maybe that was a bad idea?

if i want to remove the onboard welder, do i need to replace the alternator? it looks like a custom mount too. will post pics soon

 

[Socal Tom]

The way the OB welders work is that they add a high amperage alternator. When in normal ( driving) mode, the welder is disabled, and things work as normal. When in welding mode, the welder bypasses the voltage regulator so that the alternator can make more than 12 volts for welding.
It sounds like you disconnected the alternator from the Rig. I hope you didn't damage something. You battery is probably bad. You should hook the welder back up, check the voltage of the battery when off, then check voltage with engine idling fast ( 1000 to 1200 rpm). At high RPM you should see over 13 volts ( up to 14.5) .
Tom

 

[Bundy]

hahaha, thanks Tom- i just hooked it back up and it jumped and stayed running. shut it off and started again.

I guess that is why my last red top didn't last but 5 weeks!

i learn something new everyday... ;D

 

[bigmuddy]

The last onboard welder I had would drain my battery as well. It ended up being a bad diode which was obtained from Premier as they use a high end heavy duty diode. Never had a problem after that.

Ben

 

[Bundy]

Ben, where would i find the diode or who do i know if it is bad?

 

[bigmuddy]

If the diode is killing it? Stick a meter on it and you can literally watch the voltage on the battery go down. If you think of electricity as water, then the diode is the switch that turns the water/electricity off. The only place I know you can get the diode for the welder is at Premier welder. Or if you can take it to a good alternator rebuild shop they can probably find you a match too.

I would charge the battery all the way up. Then turn your headlights on for a minute then check the voltage. Then check it every 10minutes to see if your voltage is dropping rapidly, it won't take very long if it's the diode.

Ben

 

[hdfx81]

Be careful jumping it, that will kill the unilite module real quick mallory recommends disconnecting the dist. then charging the battery.

 

[Bundy]

Be careful jumping it, that will kill the unilite module real quick mallory recommends disconnecting the dist. then charging the battery.

shit, that is great to know- i did not know that. I just blew my second brand new red top because i originally had the welder (and unknowingly the alternator) disconnected and it had died on me.

So now, i have the welder (and alternator) connected with a new red top and it fired fine. i decided to leave it at home and see how it reads after sitting for 24 hours, see if it is something else draining it.

Hopefully it was just me being dumb and not having the alt connected which was killing my batteries because i am driving it to Fabulous Fords this weekend!

 

[Bundy]

is it possible for it to be the ignition switch? i remember that when i put ignition switch back in, there was a thicker brownish wire that was really warm to the touch- i just figured it was because the tumbler was in the acc position.

something is draining on the battery while it's sitting. i only have switches for the fuel pump, fan, and arb locker. only messed with the fuel pump one, but i would think i would hear the fuel pump... it also killed one red top, and drained or killed another one today. charging it tonight and hopefully it isn't dead.

 

[RRRAAAYYY2]

Do you know how to weld? I ask as professional welding unit (if yours is pro) is worth more used than a good new aftermarket alternator is for your truck. Not saying your welder is the cause of your drain, just a liekly candidate. They can get complicated to diagnose, and it might be easier for you to upgrade ot a 3g.

That may or may no solve your problem this time. To check for the draw, turn your truck off and remove the negative cable. Touch it back to the post and how big of spark is there? If there is no spark, take your red top back to the dealer and beat him with it. Then ask for a real battery.

If there is a faint spark, then you have a very small draw. This could be from the memory in a car stereo. If you have a heavy spark, you have something turned on still. Disconnect your alternator's field terminals. If this causes the sparks to go way, you likely have a bad regulator (or wiring to the regulator). If not disconnect the main battery coming from the welder to the battery. If this causes the sparks to stop, then it is either the alternator or welder that is leaking.

If these dont stop the spark then the draw is somewhere else. first thing you can do is pull your fuses one at a time. When you pull one and the spark stops, that is the circuit the draw is in.

Find all that out and we can go from there.

 

[Bundy]

what does the regulator look like? where should the regulator be? I will have to check all these spark tests when i get home today.

Thanks for the suggestions

 

[Socal Tom]

Here is a tip to help track down the drain.
1) disconnect the Postive battery cable.
2) Hook up a light bulb between the positive battery cable, and the positive terminal of the battery.
3) The light bulb should glow if there is a drain on the battery. If its glowing, go to the fuse box and disconnect fuses until the glow stops. Then start tracing what that fuse is hooked to.


Personally, I think you may have fried the diodes in your alternator when you disconnected it. To test this, follow the steps above, then disconnect the big wire from the back of your alternator. If the light goes out, then that is probably your culprit.
Tom

 

[Bundy]

Here is a tip to help track down the drain.
1) disconnect the Postive battery cable.
2) Hook up a light bulb between the positive battery cable, and the positive terminal of the battery.
3) The light bulb should glow if there is a drain on the battery. If its glowing, go to the fuse box and disconnect fuses until the glow stops. Then start tracing what that fuse is hooked to.


Personally, I think you may have fried the diodes in your alternator when you disconnected it. To test this, follow the steps above, then disconnect the big wire from the back of your alternator. If the light goes out, then that is probably your culprit.
Tom

If i had fried the diodes in the alternator, the truck wouldn't run would it? When i jumped started the truck it ran well, it's just when the truck is not running it is going dead.

How do i put a light bulb in between the battery and the positive cable (from the solenoid?)? sounds easy, but i am an electrical novice.

 

[Bundy]

so i am in the process of checking the voltage on the battery every 15 minutes or so for an hour or two, seeing if it's obvious draining. i just checked the truck off and it was 14.5v, and running at idle 14.6v, which is where it should be, i hope.


Edit= 5:14 the voltage is climbing, it's around 14.78 now... is that normal??

 

[Socal Tom]

Voltage can change based on the temp of the battery. If you are starting the engine and letting it idle every 15 minutes, then your test won't work. Staring the engine will drain the battery and then idling the alternator will charge it.

If you do the light bulb test I provided earlier it will tell you if you have a drain. I glowing light bulb means current is flowing from the battery

 

[Socal Tom]

If i had fried the diodes in the alternator, the truck wouldn't run would it? When i jumped started the truck it ran well, it's just when the truck is not running it is going dead.

How do i put a light bulb in between the battery and the positive cable (from the solenoid?)? sounds easy, but i am an electrical novice.

The diodes just keep power from backfeeding into the alternator when the engine is off. diodes are like one way valves, the alternator can still charge perfectly with dead diodes.

The easy way is to pick up a replacement pigtail with a matching bulb from the autoparts store ( get a bulb not an LED) just hold one wire from the pigtail on the postitive post of the battery and the other end to the big clamp that you pulled off.

You can sometimes find "test lights" in the tools section. These are tools built to do this exact job
http://www.stu-offroad.com/electrical/testlight/testlight.htm

Here is a way to do the same test with a multimeter
http://flashoffroad.com/electrical/Batteries/BatteryDrain.html
Tom

 

[RRRAAAYYY2]

The regulator will be part of the welder in your setup.

Using a test light only works on really old systems. if you have a car stereo with memory, an electrocinc regulator, or a one wire regulator, the light will glow even though nothing is wrong.

Diodes in an alternator are for changing the AC electricity created in the stator into DC electrcity that can be stored in your battery. If they are faulty or blown, the alternator will not work.