Jump-start a Yanmar 6LP diesel engine?

[Mike Monte]

Hello:
Is it possible to jump-start an (above-listed) engine that has a dead battery?

(Using one of the remote battery jump-start units that are used in the auto industry?)

[Tree]

Can’t see any reason why not.

I’ve been looking at these small units that you charge once a year and fit in the palm of your hand to keep aboard in case of emergency.

Something like this.

https://amzn.eu/d/2jhYojI

[Mike Monte]

The reason for my query:
I plan to spend a few overnights on a mooring this upcoming summer.......and with the 'fridge/lights being a constant draw......
I plan to set the 'fridge at its warmest setting but want to bring a jump-start pack just-in-case.
I will set the battery selector to house while the engine is off.

I plan to run the engine for a while each day to let the alternator charge the batteries.

I'm just looking to see if anyone has done this before.

[Jkraft]

You could jump it in an emergency but if you are switching to your house battery when the engine is off, I see little reason to worry about it. What does concern me about your plan is what you are doing to your batteries. You shouldn’t be pulling them down past 50%

[Tree]

I Agree with that - why not fit a solar panel?

I've left my boat for three days before batteries need charging with the fridge running and inverter powered up, i once even left it with the battery charger on but forgot to switch over to shore power when i turned the battery charger on so technically the batteries were charging themselves

If you are using the fridge, the key is to get it cold on shore power and that way it wont be running so often. I still have the original Norcold in mine which never gets turned off and if anything, its too cold even on the lowest setting.

[WillieC]

If your fridge is too cold on the lowest setting...hmmm

But boss, I keep cutting the board and it's still too short!

JK, Tree. Love your engine refresh tales. I refresh mine by rubbing the oil leaks around, with a FRESH rag.

And some real good advice here on the jump start situation. Make sure you know and understand how the switches actually operate and how your batteries get charged and used. Don't assume your boat is the same as some yahoo's here, not that there are any yahoos on AOG. Read here:

https://marinehowto.com/1-2-both-batter ... derations/

[Tree]

Maybe my fridge is knackered lol - if I put any drinks in it for a long time they freeze!

Maybe the number 1 is as cold as it goes and 5 is the warmest it can be?

[WillieC]

Don't leave them in there for so long! Duh!

[Nancy]

Mike, depending on your alternator output, it could take a long time to charge the batteries. Have you considered carrying a portable generator like a Honda? Be sure to only run it on the swim platform, though, and tie it off.

With a modern fridge (as opposed to an ancient Norcold that must be the only one in the world that gets too cold) you should be fine on the hook for 2-3 days assuming you have reasonable capacity. I like to calculate amp-hour usage and check it against battery capacity, never going below 50% and hopefully not anywhere near that. Running batteries too low shortens their life.

The article Willie links to is excellent.