Lithium Battery for Tender Motor Starting?

Ahoy,

So last week I had the opportunity to use a very compact lithium battery to start a very (completely) dead Ford Explorer. The young lad that provided me with the "jumper" said it had not been charged in some time, and wished me luck. It didn't exactly throw the motor out of the Explorer, but it started fine on the first try.

Question - has this compact lithium battery technology made it to tender outboards for a starting battery? I think it would be a great solution for a 15hp tiller motor with electric start.

Thanks in advance!

These lithium jump packs are very cool. They however are very unreliable. They were designed to operate very weight sensitive devices like RC planes. Mechanics love them because a jump box now fits in their tool box and can be safely locked up. Failure to follow their specialized instruction can end in (fire, meltdown, explosion). They all come with warnings to not stay connected to an alternator for more than 20 seconds and to only charge using an approved charger.

I have been looking into the same thing. Lehr uses an internal lithium battery on their electric start motors and motorcycles have been using lithium batteries for a few years. I just need to find a source locally since shipping to where I need it poses a problem.

Tom

I have a 15 hp Lehr Outboard with a lithium battery under the cover. It’s about the size of two packs of cards. It is amazing how well it spins the engine and holds its charge for months without being charged.

If I were trying to go for a small dinghy battery that was maint free, I would simply buy one of the power sports AGM batteries. Readily available, not too expensive, works with existing charging systems, self discharge rate is very low.

Lithium technology has definitely made it to outboards, although in this case not for the starting motor.

https://www.torqeedo.com/en/products/outboards/cruise

tiltrider1 said:

These lithium jump packs are very cool. They however are very unreliable. They were designed to operate very weight sensitive devices like RC planes. Mechanics love them because a jump box now fits in their tool box and can be safely locked up. Failure to follow their specialized instruction can end in (fire, meltdown, explosion). They all come with warnings to not stay connected to an alternator for more than 20 seconds and to only charge using an approved charger.

Click to expand...

Not the one I have. It just plugs into a standard 110v wall plug. As far as reliability, I've only had it bouncing around in the back of the truck for 4 or 5 years so who knows? Maybe it will last or maybe not.... So far so good, at least I'm not on fire! Yet!

I have 52v lithium batteries for my ebikes that have had hundreds of charges without any issues and later this summer I intend to hook one up to a trolling motor to convert my Whitehall skiff into an electric tender. IMHO, hobbyists from the RC world have given lithium a bad name by promoting the use of battery packs with no BMS (battery management system) to control charge and discharge. A proper battery pack from Luna or EM3EV is just as reliable as a wet cell lead acid battery, and a lot more powerful!

There are numerous vendors for lithium motorcycle start batteries, almost any of which would work on a small outboard. Everybody should please note that there are MANY different kinds of lithium batteries. The lithium polymer and lithium cobalt chemistries are the ones you read about in the newpaper as having started fires etc. The lithium chemistry used in motorcycle start batteries is lithium iron phosphate, LiFePo4 or LFP for short. This chemistry is far more resistant to thermal runaway which is the mechanism by which a Samsung cell phone catches fire. An LFP is a little heavier than the lithium polymer used in cell phones and RC planes, but far lighter than a lead acid.

A properly made LFP with built in battery management system is as safe or safer than a lead acid, while weighing 1/4 - 1/3 as much in an engine start application. Cost is 3x or so higher - but it will last perhaps 3 times as long too.

Interesting coincidence. I'm in a battery lab currently getting a product vib tested. FoMoCo has a quite a number of li-ion EV packs around, getting vib, crash/crush, and penetration tested.
The major car companies do a LOT of li-ion battery tests.
Yeah, some steel test rooms are black inside with soot.