jump starting your boat engine?

[rboat]

In an emergency can you jump start your engine if the starter battery is a flooded lead acid and you want to jump it using your trolling battery which is a lithium Lifep04 battery?

I did this years ago when my battery died, but my trolling battery back then was a regular deep cycle lead acid.

I was just wondering if it would be possible with a lithium battery without doing harm to anything. Thanks.

[Fishingmickey]

Hi Rboat,

     I wouldn't try jumping it. I'd be very scared of blowing something up or letting "the smoke" out. I think you'd stand a good chance at frying your lithium battery if you tried jumping it and maybe even cause a explosion of the lead acid battery, or battery fire/fry your lithium battery. It would also depend on the size of the motor and battery rating.

     A trolling battery in lithium Ion wouldn't be rated for the amp draw needed to turn over your starter.  Depending on the size of your trolling motor full load amperage rating verses your motor starter.

Regards,

FM

[MN Fisher]

Nope - as Mickey said, the lithium deep-cycle batteries aren't rated to expel enough amps to crank a motor...not even my little 25hp. Invest in an 'Emergency Battery Pack' as those ARE designed to fill in for cranking batteries.

 

31 minutes ago, Fishingmickey said:

A trolling battery in lithium Ion

If someone is still running a Lithium-Ion Deep Cycle on their boat, I'd suggest they get rid of it NOW. Those things are a hazard. Modern Lithium Deep Cycles are all LiFePo4, which are MUCH safer than the old Ion batteries.

[J Francho]

I've pulled the battery from my truck to get a boat started, lol. 

[Tennessee Boy]

If you do something that a manufacturer says not to do you accept the risk.  What will actually happen if you do it?   It depends on how many amp are needed to start your motor.   It depends on the specs of the  lifepo4 cells in your battery.  It depends on the quality of your BMS and how it’s configured.   A quality BMS should be able to protect your battery.  You should be able to directly short the battery without damaging it.   Can you trust the BMS in a cheap battery you bought on Amazon?   I don’t know.  You can check the battery’s manual to see what its short term current limits are.   My BMS  will shut down at 500 amps after 1/2 a second.   It will shut down at 200 amps after 30 seconds.  I think that would start my 90 hp Merc but I’m not sure.
 

I carry an emergency battery pack.  It can be recharged with my LifePo4 battery if necessary.   If it failed I would use my LifePo4 to start the motor and take the risk if I was stranded without any other options. I have a Battleborn battery and I trust the BMS.
 

 

[gim]

2 hours ago, MN Fisher said:

Invest in an 'Emergency Battery Pack' as those ARE designed to fill in for cranking batteries.

I agree, something like a noco jump pack is a wise investment. They can be found at a steep discount on Black Friday later this month.

 

I got two last year, one for the boat and one for the truck. Haven’t used either one yet for a jump but I have used them for the flashlight and the USB port to charge up a phone.

[casts_by_fly]

8 minutes ago, gimruis said:

I agree, something like a noco jump pack is a wise investment. They can be found at a steep discount on Black Friday later this month.

 

I got two last year, one for the boat and one for the truck. Haven’t used either one yet for a jump but I have used them for the flashlight and the USB port to charge up a phone.

the one I have is a 10,000 mAh charging bank which is a TON of portable battery for phones, computers, etc. Well worth having at least one. Mine stays in the truck. Jus have to remember to charge them every now and then. 

[MickD]

11 hours ago, MN Fisher said:

Invest in an 'Emergency Battery Pack' as those ARE designed to fill in for cranking batteries.

Greatest little things since slice bread.  Not that expensive, holds charge all season, takes up little space (about like a moderate sized book) , can start any marine engine + your truck engine.

[PourMyOwn]

9 hours ago, casts_by_fly said:

the one I have is a 10,000 mAh charging bank which is a TON of portable battery for phones, computers, etc. Well worth having at least one. Mine stays in the truck. Jus have to remember to charge them every now and then. 

I charge mine using the 12v in my truck as I drive. 

[MN Fisher]

10 hours ago, casts_by_fly said:

the one I have is a 10,000 mAh charging bank which is a TON of portable battery for phones, computers, etc. Well worth having at least one. Mine stays in the truck. Jus have to remember to charge them every now and then. 

I have one of those too...if I'm wearing the camera shoulder rig or chest rig, it's connected to power the camera.

[GaryH]

Emergency start is definitely the way to go. I run 3 lithiums for the TM and a AGM for the cranking with an Ionic emergency start wired  to it. If the starting battery gets to low just push the button on the unit or from your phone. Peace of mind.

[dwtaylor]

I recommend getting a Noco GB40 (or similar), which has 1000A or larger jump pack for this instead of using your trolling motor lifepo4 batteries.  I have had to jump my engine several times due to my group 31 not having enough juice to crank the engine.

 

I also recommend having a power switch isolating your graphs from the battery when jumping it to avoid damage to the graphs.

 

I run livescope, a garmin 93 at the bow, a garmin 106 at the console, dual power poles, and the livewell pumps on a single group 31 lead acid battery due to my engine requirements.  I have on multiple times had my battery too low over 6 hrs of fishing to start my outboard.  Thus, I am going to buy a "budget" lifepo4 battery for electronics only to get my graphs off the main battery to improve reliability and also allow for me to add another graph and livescope for full time forward and perspective modes.

[TnRiver46]

Depends on your definition of emergency. I’d try it if it was snowing in the middle of Lake Superior after dark with no cell service, warranty would not be my concern at that moment 

[J Francho]