Jumper switch - AGM starting battery with Lithium TM batteries

[P413]

Got a 2019 520L boat, currently running all AGM batteries for starting and TM. My TM batteries are on it's last legs and thinking about converting to three 12v deep cycle lithium batteries. If I did this, I was wondering if it would have any impact on the jumper switch feature that I have on the boat. In the event of a dead AGM starting battery, could I still flip the switch and jump off the new lithium batteries that are not made as starter batteries? TIA

[mactlman]

when I got mine I was told the jumper switch is not used if you go with lifepo4 batteries must remove the jump feature but others have done it also I have read?

[caddelma]

Should only use the jump switch if your lithium's are rated for cranking, if they are not the BMS should shut them down.

[goodman_fishing]

What size are the 3 lithium batteries?

[Jbass123]

when I got mine I was told the jumper switch is not used if you go with lifepo4 batteries must remove the jump feature but others have done it also I have read?

Yes, there was a similar thread on this forum recently. On that thread, I replied that lithium trolling batteries *can* be used to jump start a dead cranking battery—using the Ranger jump start switch—if the lithium trolling battery is engineered for such usage. The key is in the BMS, or battery management system, built into the lithium battery in question. I have successfully used my MillerTech 100ah trolling battery to jump the AGM cranking battery in my boat. MillerTech confirms that their lithium batteries are adaptable for using the Ranger jump start. On a previous boat, I tried jump starting an AGM cranking battery with Bass Pro Shops lithium trolling battery, and that was a fail. The BPS lithium battery popped the BMS as soon as I turned the key, using the jump start position on the switch, and that in turn made all the trolling batteries non-usable until the BMS cooled off and reset. So the short answer is: contact the lithium battery manufacturer and ask them whether their trolling batteries are usable to jump start your AGM cranking battery.

[jstbass]

Get a jump pack to carry with you

[Jbass123]

Jump pack is good, too. I carry a Noco GB40 in the boat. But a properly designed lithium trolling battery like the one I outlined above will allow you to continue fishing and running the accessories on your boat for hours if/when your cranking battery fails. Imagine your cranking battery dies and needs a jump start with 3-4 hours left in your fishing day. Unless you’re in a situation where you can run the gas engine for a very long time, necessary to restore sufficient charge in the cranking battery, you’d be forced to do several more jump starts if you want to continue running graphs, live well, etc. And even then it’s doubtful you’d have enough extra charge in the cranking battery to run accessories. But with a lithium trolling battery connected to your cranking battery via the jump switch, you can select the “battery 2” position and run everything from that trolling battery for as long as you want. Start the big engine, run all accessories, etc. Since lithium trolling batteries of 80-100 amp hours usually have a lot of charge left at the end of the day, “battery 2” would probably last the remainder of your day without running down. And with a Bluetooth charge app, you’d be able to keep an eye on remaining charge as well. Win-win.

[dean c]

If you install a cranking capable lithium in the position of the jump switch, it will work as normal.

[mikeky]

Hold the button in for a couple of minutes, maybe more. Release the button before starting.

[BassinLA13]

Well I know it's not the best way to do it ... but at a recent Derby I drained my original AGM in my 2022 520R Cup boat after scoping all day - we were about 10 miles from the ramp so we Jumped off the TM batteries and didn't look back - that said only in an emergency would I have done that. In the meantime I upgraded to a 12v125ah Ionic Lithium Marine Cranking Battery and it's pretty awesome - both 12" Lives, active target & live wells all day = 75% left on the battery - Bluetooth app easy to read as well. I also have a portable NOCO charger that came with the boat but sometimes it just doesn't seem to work ?? Probably user error.

[howieranger]

I have a buddy that just added Li trolling and cranking batteries and purchased a NOCO GB40 jump battery and the instructions said that it was only for lead acid batteries and NOCO's website says not to use it for LI batteries.

[JohnnyGZ21]

I have a 2021 521L with AGM cranking battery and Lithium trolling motor batteries with jump switch from factory and it works. I've used the feature. My understanding is the jump battery has to be rated High Output.

[erickennedy1]

I've used my ionic 50ah trolling motor batteries to jump start my interstate 31 agm cranking battery using the factory switch on my 2019

[jstbass]

Allow me to chime in with this scenario. If I have 2-125amp Ionic batteries in parallel for starting and house. and 3- 50amp for the trolling and the 2 mains go down to a point were the big motor wont crank over would you flip the jump switch to try and start. Can you even do it? Just asking

[Jbass123]

To answer your question, the 50ah lithium trolling batteries might be too far under-amped to work in that scenario. Big engines take at least 1000 CCA, and when a lithium battery [your cranker] is dead, it’s dead. If you tried to jump start with an underpowered troller and popped the BMS, you would then be completely dead in the water until the BMS reset. In your case, unless you’re thinking of upgrading to more powerful trollers, I’d get a good strong jump pack like a GB70 Noco. That said, there’s a lot we don’t know about your style of fishing. If you are completely killing 125ah lithiums inside a single day of fishing, you probably need more than just a jump start, because otherwise you’d simply have to go home after starting the big engine. With a big, dual-purpose lithium in trolling position #1, you could continue to fish and even run graphs [for a reasonable amount of time] in battery position 2 on the jump switch.

Allow me to chime in with this scenario. If I have 2-125amp Ionic batteries in parallel for starting and house. and 3- 50amp for the trolling and the 2 mains go down to a point were the big motor wont crank over would you flip the jump switch to try and start. Can you even do it? Just asking

[Mike Stevens]

Yes, there was a similar thread on this forum recently. On that thread, I replied that lithium trolling batteries *can* be used to jump start a dead cranking battery—using the Ranger jump start switch—if the lithium trolling battery is engineered for such usage. The key is in the BMS, or battery management system, built into the lithium battery in question. I have successfully used my MillerTech 100ah trolling battery to jump the AGM cranking battery in my boat. MillerTech confirms that their lithium batteries are adaptable for using the Ranger jump start. On a previous boat, I tried jump starting an AGM cranking battery with Bass Pro Shops lithium trolling battery, and that was a fail. The BPS lithium battery popped the BMS as soon as I turned the key, using the jump start position on the switch, and that in turn made all the trolling batteries non-usable until the BMS cooled off and reset. So the short answer is: contact the lithium battery manufacturer and ask them whether their trolling batteries are usable to jump start your AGM cranking battery.

I used my BPS lithiums to jump the AGM cranking battery with no problems in my ‘21 Ranger. I will add that if you put a power pole charge in you must remove the jump feature for the charger to work. Found that out the hard way.

[rangered]

We were fishing in Florida last year and the breaker tripped that I had plugged
my battery charger into. They didn’t get charged for 3 days and when I checked
the cranking said like 12%. I have 4 Ionics and the trollers were at 45%. So
I flipped the switch to jump and ran all day. I have since done it once
more. I don’t see an issue if they are all the same type of battery.