Jump box for dual battery 7.3 diesel

A jump box big enough to start your 7.3L diesel on its own is going to be a pretty healthy and costly jump box. Probably about 3000+ Amps. Like all devices with their own batteries, the batteries can either last a good long time if you’re conscientious about maintaining them, or they can have a short life if you neglect or abuse them.

For my use, instead of buying a jump box big enough to start the truck engine, and likely not get used for much else, I bought one big enough to start the built-in Generac in my camper even if it’s less than 100% charged.

I’ve got a NOCO GB40, and I use it to recharge USB devices primarily when we’re off-grid. That way it sees some use often enough that I know it’s state of charge. The chances of ever needing it to start the generator are pretty slim, but id never say impossible. I also don’t totally trust all this auto-magic BS on modern vehicles that’s supposed to keep the battery from EVER getting flattened. I occasionally get pretty far away from help, and like to have several backup plans available. Stuff like that always works perfectly for me.......until it doesn’t.

So, my advice would be to think about where you’re likely to be and what other equipment you will have with you, and how you’ll use it to help yourself if the worst happens.

:):)

I’m a big fan of the jump boxes. I have bought several, so they will be available when I need them. They frequently go on sale on Amazon with a lot of competition of different brands and more powerful models can be had for less than $60 pretty often. I prefer the ones that come with cases and end up being 6x6x8 or so. Fwiw, they work better than my older jump box that is 4 times the size. As noted, they can also be used to charge devices like phones etc.

I’m also a fan of power stations. I’ve bought a few of them as well. The prices vary widely. I bought a few on Amazon that are 300 watt size for less than $180. I’ve already used one for a minipower outage. Our power goes out occasionally but usually only an hour or so. They are cool to provide AC where you need it without cords to a generator.

I would recommend a NOCO GB70 or GB150. I have the GB70 and the battery dealer I bought it from said it was big enough to start my Duramax even though that's technically over it's rating of a 6 liter diesel. I've only used it once to start my 6.0L Suburban but it worked great.

Definitely do your research and get one that's up to the task.

Case in point: Couple winters ago my 3500 diesel was parked in a customer's driveway most of the day. That was the day both batteries decided to go south.

Mr. Gadget man brought out a piddly little jump box, insisting it would start my cold diesel. My skepticism was verified when it did absolutely nothing to help. 2 clicks from the solenoid and the box just whined a bit.

I had to get a ride home, get my big stout battery charger and run it a while to get me going.

Would a bigger jump box have done the trick? Not sure, I know little about them.

All I'm saying is be sure it has enough oomph to crank a dead diesel.

This is where two big 12v group 31 AGM's in the camper come into play in an emergency

All the 7.3 Diesels that I have seen, and I have one, carry two 850 + AMP parallel wired batteries for the chassis. It is near impossible for both to die beyond a start up without being neglected in maintenance. I have two of them sitting in my shop due to one morning during a recent cold spell I had to activate the glow plugs twice to get a start up. My next trip was to get two new ones. They are maintenance free except keeping the terminals and cables clean. Six years is a good life for the batteries and they had served well.

Unless the two batteries are both totally dead a 750-850 AMP battery booster should start a good tuned 7.3 with the aid of the weak chassis batteries. I recommend under such time to activate the glow plugs 2-3 times before attempting a start. Preheat the cylinders and do not depend upon the compression solely to do so. If equipped with an engine warmer use it before attempting a start. That 15-40 engine oil gets stiff sitting in cold weather.

Should camper batteries be used for engine starting? I have understood that deep-cycle batteries are not designed to deliver that kind of high amperage. Would engine starting harm camper batteries, or not?

"There are times I almost think
I am not sure of what I absolutely know."
(The King and I)

You'd need #2 cables to jump engine from camper batteries.
The batteries went very long way in last decade.
I was picking up diesel truck from auction and batteries were at 0 due to somebody leaving key in on position.
The yard guy brought jump box in about foot size, so I told him it is not going to work on diesel.
But he had 2 of them and small lithium batteries started big diesel just fine.
I have cigarette pack-sized jumper pack who delivers 300 amp.
Hard to believe, but it did turn my Honda 3000 generator just fine.

The little 800-1000A Lithium jump packs will fire up a cold Chevy 5.3 V8.
I have one for my Snowbike but disconnected battery and tested it on my work truck. It lit off the truck, barely.
They make 2000A ones for around $100. But I’ve never tried to dead start a diesel pickup with them.

RoyF wrote:
Should camper batteries be used for engine starting? I have understood that deep-cycle batteries are not designed to deliver that kind of high amperage. Would engine starting harm camper batteries, or not?

Once, probably not. You don't want to subject them to an extremely long crank time.