Jump start with lithium house battery?

[WhitH]

This may seem like a silly question but…..can I, in the event of an emergency, jump my van using my house lithium battery…..with my jumper cables? I have no immediate needs or concerns other than always wanting to know my options. I’ve considered a lithium jumper pack but those are pretty big and not cheap to jump a diesel and so I got to wondering….

[kbeefy]

Lithium battery BMS systems usually have a maximuim load current they are able to discharge.


A common rating is 100 amps. Some are higher, some are lower. Jumper cables can only carry so much current.


A starting battery with good connections might discharge as much as 400 amps or more with good connections and cables if the need arises.



Your Duramax likely draws 200+ amps during crank. Much more if discharged or cold.



Depending upon your house battery bank, it should be able to greatly assist your starting battery.


All the above factors will determine how much assistance it can give. Maybe plenty, maybe not enough.

[marret]

Originally Posted by WhitH

This may seem like a silly question but…..can I, in the event of an emergency, jump my van using my house lithium battery…..with my jumper cables? I have no immediate needs or concerns other than always wanting to know my options. I’ve considered a lithium jumper pack but those are pretty big and not cheap to jump a diesel and so I got to wondering….

You might carry a lithium jump starter pack something like this (you have the 2.8?, can’t remember):
https://www.amazon.com/NOCO-GB70-Ult...s%2C72&sr=8-40

I don’t have this one, but have carried a lithium jump starter pack for years and used it multiple times for others. Started a dead Lowe’s rental truck too.

[boywonder]

You can always connect the jumper cables and get a cup of coffee......wait 20 minutes or so....allowing the the Lithiums to partially charge the starting battery......which can easily provide more than 200 amps when charged enough to start the van.

[Twoxentrix]

Originally Posted by marret

You might carry a lithium jump starter pack something like this (you have the 2.8?, can’t remember):
https://www.amazon.com/NOCO-GB70-Ult...s%2C72&sr=8-40

I'll second the NOCO, but would recommend something a little more powerful for a Diesel - may be faced with trying to 'jump' more than once. They also come in handy to repower Laptops & Cell phones.
Periodically NOCO offers them for a really good 'Sale' price.
https://www.amazon.com/dp/B08WZFPXFM...1zcF9kZXRhaWwy

[WhitH]

Thanks all. Mine is the 6.6 Duramax so it would take the largest unit NOCO has to offer and I’m trying to avoid just carrying around something else if I don’t have to.

Boywonder, your suggestion is an interesting one and the kind of thing I’m working dering about. So maybe not a jump start per se but connecting them and allowing them to normalize as one bank somewhat is safe? To be clear the starter batteries are not lithium. May be assumed but making sure.

[kbeefy]

Yes, that works fine. If you have alternator based charging you can even wire in a method to 'override' your combiner, isolator, or dc-dc charger to charge your starter batteries. Just don't attempt to start while your in this 'override' mode unless all the wires and components are adequate.

Often times, if lead acid batteries aren't too badly discharged, just removing the draw and letting them rest for a while will allow them to 'recover' enough to start a smaller gasoline engine.

[WhitH]

Got it. If I were desperate enough to try this I’d just use alligator clip jumper cables. Would it be smart to disconnect the DCDC charger before connecting?

[1der]

kbeefy brings up a major consideration to look into re: the battery BMS cutoff for discharge protection. So, starting with cables connected is probably not happening as the BMS will shutoff. boywonder's approach would hopefully help to keep the current flowing to the starter battery under the BMS current cutoff threshold.

A fun little chore is to reset a BMS which has shutoff due to discharge - which can be done with the lithium jumper pack, which is what you would have used to jump start the engine

Which Lithiums do you have?

[kbeefy]

Originally Posted by WhitH

Got it. If I were desperate enough to try this I’d just use alligator clip jumper cables. Would it be smart to disconnect the DCDC charger before connecting?

If your dc-dc charger is only active while your alternator is charging, it's not necessary. If it is drawing power while the key is in the 'run' position, then it would be beneficial to disable when you have a low starting battery situation.

I dont believe there is any other necessity to disconnect or disable the dc-dc charger for the purpose of jump starting.