Run Diesel without batteries? (1 Viewer)

[toadshade]

One of my batteries catastrophically failed yesterday. Or more like I guess I did not know how bad a shape it was in. I need to get to a parts store with no battery. I know my HDJ80 will run without it, and I can roll start the manual, but my question is about the alternator. Is it OK to run the alternator with no load? I figured it might be worse to leave a known dead battery there for the alternator to try and charge, but I have no idea if it is OK if there is no battery at all. And the 12V switch to 24V is in line there, so is any of that mechanism in danger just having one battery in place?

 

[roscoFJ73]

I got told not to do it by a mechanic I used to work with , but that was with no battery at all
But it would be ok if you removed the alternator belts.

It wont hurt to leave a dead battery connected to get to a parts store.

 

[toadshade]

Removing the belt is a good idea. Didn't think of that. Yeah, it just always makes me cringe charging a dead battery with the alternator even though I know it can usually handle it.

 

[Coyomog]

Is there not an on/off solenoid that would have to be energized to allow diesel fuel to flow to the injection pump? How do you energize the solenoid with no batteries installed for starting the vehicle? (I understand that once it is running it would generate power...)

 

[Mr Cimarron]

I had my voltage regulator fail in my Cummins which resulted in boiling both batteries. Once I figured out what happened I then just unplugged the voltage regulator and it stopped charging. This allowed me to get somewhere to replace the batteries and voltage regulator. I guess it depends how your alternator works and how it turns on.

Is there not an on/off solenoid that would have to be energized to allow diesel fuel to flow to the injection pump? How do you energize the solenoid with no batteries installed for starting the vehicle? (I understand that once it is running it would generate power...)

Depending on the pump you should be able to manually turn whatever is needed to get it into the start position. 12v Cummins you can zip tie the arm. On my BJ it didn’t have a EDIC but instead a pull cable to shut down or start.

 

[chapel gate]

One of my batteries catastrophically failed yesterday. Or more like I guess I did not know how bad a shape it was in. I need to get to a parts store with no battery. I know my HDJ80 will run without it, and I can roll start the manual, but my question is about the alternator. Is it OK to run the alternator with no load? I figured it might be worse to leave a known dead battery there for the alternator to try and charge, but I have no idea if it is OK if there is no battery at all. And the 12V switch to 24V is in line there, so is any of that mechanism in danger just having one battery in place?

The fuel cut off solenoid will need a feed. Takes next to nothing, a 9v battery may even do the job..

 

[toadshade]

That makes sense. So the alternator would do the job but possibly burn up. I guess it might be a good reason to get my 1200 amp alternator.

 

[hiluxjeremy]

Should be able to unplug connector from back of alternator i would think. No signal, no charge. Just along for the ride I would think.

 

[toadshade]

Yeah that would be quick. But doesn't solve the fuel pump. I guess I could hook up a 9V to the battery leads

 

[hiluxjeremy]

Can leave both batteries in, unplug alt, bumpstart with key in run, away ya go.

 

[hiluxjeremy]

I've driven waaaaaay too far with failed alternators in both my '92 HDJ81 and '90 LN106.

 

[hiluxjeremy]

Can also use a second vehicle with cables onto dead battery then hit the key, should be enough juice to get minimal crank voltage. I am well aware this is a 24v starting system, second vehicle will act only as larger battery, being in parallel with your dead one. Won't want to leave it hooked up for long just a couple seconds to get truck started.

 

[Squash]

Having no computer to deal with run it. Not sure what your failure of the other battery is.
You can always disconnect the - post.
Btw your 24v starter will start with 12 volts from either battery.
Unplug the ST/E starter relay connector by lifting the TAB up with your thumb and separate white plug. Run a fused wire from good battery + post touch power to E and your starter will spin. Key in run position Remove wire!
You still want power for brakes, signals, clutch in, fuel solenoid.

 

[toadshade]

Cool thanks. I have been curious to know what the clutch feels like with no assist.

 

[Squash]

Clutch may need to be depressed only for starting via batteries.
Keeps folks from starting in gear and then having to chase their unit through the bush or neighborhood.

 

[toadshade]

Nope. Mine will start without the clutch in.

 

[Coyomog]

That makes sense. So the alternator would do the job but possibly burn up. I guess it might be a good reason to get my 1200 amp alternator.

Man, I need one of those 1200 amp alternators....