Get rid of the starting battery?????

[john61ct]

And so it would, with a decent size bank right down to 2% above the BMS bottom setpoint.

[ArmyDaveNY]

Originally Posted by skipmac

In a previous discussion on batteries I read a couple of mentions of lithium, portable battery systems for engine starting.

How big is your engine?

I have removed the start battery on two of my boats however both have a Volvo MD6A 10 HP two lung engine. The engines also have a hand crank (I love the old engines!). I've had no issues so far. Both engines take very little effort to start and they start up pretty quickly. About half the time I use the hand crank since they start so easily but roughly half the time I start it electrically.

I love the NOCO GB40 jump starter. It is good for up to a 3 liter Diesel and a 6 Liter gas engine and has 1,000 Amps. The GB700 is good for even larger engins and has 2,000 Amps. Both also have the ability to charge devices using a USB cord and have flashlights.

[FabioC]

Hi,
So as I fully understand this interesting thread...

To summarize what has been said: is the proposed idea the following: have a spare battery around (can be lithium or not) and, in the remote possibility that the starting battery (whatever it is used to start the engine, can be a separate battery or the house bank) does not have sufficient juice, simply jump wire the spare battery and the starting battery?

If that is the proposal, it seems a good idea to me, although it would be good to know in advance whether it works or not (i.e., what's the requirement on the spare battery to be sure that it is going to help to start a large diesel?).

Thanks,
Fabio

[john61ct]

No, fundamental idea is no dedicated starter​ batt at all.

Testing extensively at the dock before heading out of course.

Different detail ideas presented, maybe ask Qs with quote feature on specifics.

[sailjumanji]

Better program. No dedicated starter battery, but both motors are Yamaha high thrust with both electric start and pull start. On one long overnight passage we sudden lost all power, right as we neared Galveston jetty and ship channel. No lights, no instruments, bit lots of commercial traffic! Pull started one engine, and alternator output was enough to run instruments and lights. Turned out windlass switch had shorted, dumped all the chain onto deck, and then blew 80 amp fuse to batteries. We figured it out after dawn, when we went forward and found 150 ft of chain and 50 ft of rode on front net. Another good reason to have anchor secured independent.

[NahanniV]

Thinking about dumping my lead acid start battery and using my 400A LiFePo4 house bank to start my 80Hp Perkins 4.236.

Thinking of getting a smaller, perhaps 100A LiFePo4 battery for an electric outboard and as emergency start for the main engine.

Will keep my little Honda 2Hp around till I see how the electric outboard works out.

[model 10]

You can wire a bunch of dead 12v's in series and get enough juice to start the engine but it would fry your electronics.

[skipmac]

Originally Posted by ArmyDaveNY

How big is your engine?

I have removed the start battery on two of my boats however both have a Volvo MD6A 10 HP two lung engine. The engines also have a hand crank (I love the old engines!). I've had no issues so far. Both engines take very little effort to start and they start up pretty quickly. About half the time I use the hand crank since they start so easily but roughly half the time I start it electrically.

I love the NOCO GB40 jump starter. It is good for up to a 3 liter Diesel and a 6 Liter gas engine and has 1,000 Amps. The GB700 is good for even larger engins and has 2,000 Amps. Both also have the ability to charge devices using a USB cord and have flashlights.

Engine is a Westerbeke W58 (which is a Perkins 4.154 painted red) which is 154 cu in or about 2.5 Liters.

I used to have a Volvo MD17c with compression release levers. If you open the levers even an almost dead battery would spin the engine easily. So get it spinning and pop down the levers and you're running. Loved it.

I've been looking at the NOCO but would go for the GB70 just to have the reserve.

[skipmac]

Originally Posted by Guy

You can wire a bunch of dead 12v's in series and get enough juice to start the engine but it would fry your electronics.

That's exactly what I did when I was stuck with almost dead batteries and no way to charge. The batteries were not totally dead but down to where either or both would not quite spin the engine. Hooked the pair in series and the engine spun like a top. But yes, before doing that disconnect electronics, alternator field, etc.

[skipmac]

Originally Posted by FabioC

Hi,
So as I fully understand this interesting thread...

To summarize what has been said: is the proposed idea the following: have a spare battery around (can be lithium or not) and, in the remote possibility that the starting battery (whatever it is used to start the engine, can be a separate battery or the house bank) does not have sufficient juice, simply jump wire the spare battery and the starting battery?

If that is the proposal, it seems a good idea to me, although it would be good to know in advance whether it works or not (i.e., what's the requirement on the spare battery to be sure that it is going to help to start a large diesel?).

Thanks,
Fabio

Essentially this is it. Use my large bank of house batteries to start the engine BUT if something happens and I can't use the house batteries then have a small, lithium backup battery to start the engine.

Certainly before eliminating my dedicated starting battery I would test the idea but before that I would go to an online forum and ask questions.

[ArmyDaveNY]

Originally Posted by skipmac

Engine is a Westerbeke W58 (which is a Perkins 4.154 painted red) which is 154 cu in or about 2.5 Liters.

I used to have a Volvo MD17c with compression release levers. If you open the levers even an almost dead battery would spin the engine easily. So get it spinning and pop down the levers and you're running. Loved it.

I've been looking at the NOCO but would go for the GB70 just to have the reserve.

I think you'll be just fine with the NOCO GB70. Good luck with it.

[skipmac]

Originally Posted by sailjumanji

Better program. No dedicated starter battery, but both motors are Yamaha high thrust with both electric start and pull start.

OK, problem solved. Sell my boat and buy a cat. Know anyone that will loan me 100-200 boat bucks?

Originally Posted by sailjumanji

Another good reason to have anchor secured independent.

Absolutely. Have anchor well secured BUT also ready to deploy at a moments notice.

[Alberg30Shill]

Originally Posted by a64pilot

The Prius 12V battery is just there to boot the computer and bring the large traction battery online, it doesn’t start anything. A Prius, just like all modern cars does have “dark current” though, small drains on the battery.
There is a replacement Optima Yellow top battery for the Prius, it’s a deep cycle battery as that is what the Prius needs, not a start battery.

Be very, very careful if you ever jump a Prius, you can damage the inverter if your not careful, and that is thousands of dollars. Read the manual. Your only booting the computer, it takes the traction battery to start the engine.

On the Boat, I see a starting battery as silly, why have a separate battery to crank a baby Diesel when you have a monster bank that can do it with much less voltage drop.
I have two banks, one 440 AH the other 220 AH. I leave them combined as one bank. I can’t see the logic of a stand alone battery to start anything.

Because when you inevitably run the house bank to dead thru inattention or exhaustion, you have the ability to start the engine to recharge the house bank.

I think a jump pack is an important piece of gear but there are a lot of junky ones with bells and whistles. I'd recommend the jump pack you see in most mechanics shops, the legendary JNC660. I drive a diesel car and it will start it when the temp is in the single digits DegF. Overkill for my 16hp Yanmar but provides loads of juice for multiple cranks when priming the engine. On sale at $117 currently on Amazon...

Jump-N-Carry JNC660 1700 Peak Amp 12V Jump Starter https://www.amazon.com/dp/B000JFJLP6..._vho-zbQ11GZKP

[Exile]

So with these Li battery packs and in the event of a low or dead battery bank, is it better to hook it up to the battery or directly to the engine starter? Or does it matter?

I ask because I would also like to combine my engine start battery (an 8D!) with my house bank, and use my gen start battery as a start battery for both eng & gen. The potential problem is the gen start battery is a G24 but my engine is a 4-cyl., 3L, 80hp Westerbeke. While the eng specs (400-600 CCA @68º) support using the G24 (870 CCA @68º) for eng starting, I'd probably be better off with a G31 when you consider wire runs, resistance, battery age, etc.

Would be a pita to upsize the G24 based on my existing batt. box configuration. But btwn the Li battery pack and a cross-over relay that combines the house bank if need be for starting, I'd likely be OK. And no, I'm not sure why the batts. were configured for a 8D to be dedicated to nothing but engine starting.

[Bjorn_O]

I am considering using a super capacitor for starting my small diesel. Any comments on this?