Outboard engine charging from regulator/rectifier?

[audiobill5]

Hello,
I see so many people that mention charging batteries with an older style outboard motor charging system without an alternator.
What do you think?
Who has done it successfully?
Who has had problems and what were the problems?
Great forum!
Up here in New England the weather is finally a little bit warmer, so may the boating begin!

 

[Skypower]

You will need a properly sized “DC to DC” converter if you are thinking of charging a lithium battery. Lithium charges much faster than lead acid and needs a way to limit the current draw. For simplicity I’d stick to size and type of battery the outboard motor manufacturer recommends. Blowing up that stater can get expensive and stranding.

 

[audiobill5]

I'm told the 'drop in' Chargex lithium iron 12.8v 75aH (Tampa, FL) would do it.
I plan to run one each to my two 150hp OMC FFI's
Designed as a drop in about 15 years ago. Now they power satellites for the Navy and a few others.
I'm in the boat parts business and want to bring my Whaler into the 21st century, gots to have a crazy set-up.
Did you see the new SeaRay SLX-R 400E boat?
a 40 footer with 3 Merc. Racing 450HP's, something like high 50's for top end speed!
They say the lithium iron battery bank for this crazy new SeaRay is 10x the size of a Tesla battery bank!
Safe voyages!

 

[Skypower]

Yes it will do it, BUT if you deplete it, the current that it WILL draw to replenish itself is massive and most likely destroy the stater charging coils or rectifier. Example; You start, go out and have a good time but you don’t stop anywhere and run the sound system or leave something on, the only time anything’s on, the engine is also on. Nothing bad happens, everything’s good. Next time you go out, you stop and fish, the big amp is on making tunes, depths sounder is on, VHF is on. Now you’ve been there for hours. You start, no problem. You head home and it’s an hour away and you think everything’s fine and you make it home. Unfortunately on the way back the charging circuit is working overtime at full capacity because the lithium battery will demand everything it can until it’s charged. Unfortunately most alternators are not rated for CONTINUOUS duty and about a half hour into the ride home the charging circuit fries.
Then you try to find another stator or rectifier for an OMC and if you can find a good one you may have sticker shock. To do a lithium conversion right you need charge controllers to go along with the lithium and the knowledge to wire them in. Keep life simple and easy and just use the factory recommended batteries. When not in use, use a battery disconnect. If you have an older charger, replace it because they kill batteries. Battery Tender is the best smart, small, inexpensive charger, this was bought at Costco. The people that say you can do it will stand by their claims and fix it?……. Talk to people on the boating /fishing forums.

 

[audiobill5]

thanks, got a Victron Energy 30a 3 leg charger
Nothing to drain much, just a vhf radio and a disc player.
No amps/radar
great read, thanks