voltage at startup for 24 v system (1 Viewer)

[Snuiser]

Hi,
Just wondering what voltage I should be showing on my volt meter on the dash when I first turn the key. It's showing less than 24v. Does that mean one of my batteries is going? After startup it's higher than 24v.
Also... if you have to jump it, how do you do it? Can you jump it somehow from a 12v system?
(Just bought the HJ60 a few weeks ago and coming to terms with 24v systems)
Thanks

 

[A2B in a TLC]

Hi Snuiser,

From my own experience and the posts on MUD, it seems to be a chartacteristic of some TLCs whereby it takes a few minutes after start up for the charge system to kick in. Even Western Starters, who rebuilt my alternator, were surprised by the lag.

Regarding jumps starting a 24V from 12V, once again, there are posts on MUD. I have done this a few times. Pick one battery (hopefully the one with the lowest charge) to connect the jumper cables. Do not connect to both batteries.

I have had "failures" in my attempts. That is, even with a boost, the vehicle will not start. I assume this is because the charge in the batteries was just too low. OK after a charge. For me, this becomes a problem as I have an automatic tranny and cannot simple roll start on a hill.

Take care,

Bruce
A2B

 

[Snuiser]

more...

thanks a2b... To clarify, I meant what voltage should you be getting BEFORE the engine turns over... with the ignition switch on but before starting.

 

[sandcruiser]

I've never used a 24 system, but it seems that if you are having trouble starting, you could disconect the batteries, then run a jumper to one for a while, then to the other for a while. This way you would increase the voltage in each by at least a little bit.
If you pay careful attention to the voltmeter in the donor vehicle, you might be able to tell which of your 2 batteries is lower, then leave the jumpers on that battery (after charging each) and try to start....
I've never tried this, it just seems like it could work

 

[lowenbrau]

The low volts is likey due to the glowplugs running. They run for up to two minutes even after the light goes out. Next time you start it turn the key on and wait... you'll hear a click from the footwell eventially and the guage will jump up some.

As for boosting. Most often the 0-12v battery is dead. A boost to it from a 12v rig will generally do the trick. If not, then charge one battery for a while ( five min) from the running rig and then boost to the other battery.

Don't run any 12v accessories unless you have a 24-12v converter.

 

[arutgers]

two healthy batteries in series should deliver between 25.2 and 25.6 Volt before starting. You'd better measure that with an accurate voltmeter directly at the batteries; the voltmeter at the dashboard may not be accurate enough. Perhaps more important: both batteries should read about 12.6 ... 12.8 Volt each. If they differ more than 0.2 Volt then I would worry about imbalance.

Ton

 

[skoki]

On my 86 HJ60, with 2 good batteries, I typically get 18 volts when I first turn on the key, after my 1st glow plug click it jumps to 20 volts. After the 2nd glowplug click (20 seconds after the 1st click) it jumps to 24volts. After running for a few minutes and when driving, the alternator kicks in and the gauge reads 30 volts. My HJ60 with dual batteries has a "high side" battery and a "low side" battery. The high side is on the passenger side and runs at 24volts. The low side is on the drivers side and is your 12volt battery. Whenever you are jumping from a 12volt vehicle connect to your low side battery. Never try to run 12 volt accessories straight off your low side battery. It will drain your battery. Purchase a quality 24 to 12 volt converter, install as per instructions and tap your 12volt accessories off that. I purchased 2 aftermarket fuse blocks wired one after my 12volt converter and the other off my high side battery. Now it's really easy to hook up either 12 or 24 volt accessories. By the way I have never had any trouble with my high side battery, any issues where always on my low side battey.

Rab

 

[Beast]

On my 86 HJ60, with 2 good batteries, I typically get 18 volts when I first turn on the key, after my 1st glow plug click it jumps to 20 volts. After the 2nd glowplug click (20 seconds after the 1st click) it jumps to 24volts. After running for a few minutes and when driving, the alternator kicks in and the gauge reads 30 volts. My HJ60 with dual batteries has a "high side" battery and a "low side" battery. The high side is on the passenger side and runs at 24volts. The low side is on the drivers side and is your 12volt battery. Whenever you are jumping from a 12volt vehicle connect to your low side battery. Never try to run 12 volt accessories straight off your low side battery. It will drain your battery. Purchase a quality 24 to 12 volt converter, install as per instructions and tap your 12volt accessories off that. I purchased 2 aftermarket fuse blocks wired one after my 12volt converter and the other off my high side battery. Now it's really easy to hook up either 12 or 24 volt accessories. By the way I have never had any trouble with my high side battery, any issues where always on my low side battey.

Rab

Same here. I run 2 24>12 reducers one for my switched power and the other for my constant. This way my radio will keep the clock.