Lithium for engine start?

[Peregrine1983]

Hi all,

I was considering two of these (https://a.co/d/71Q3Byy) for our house bank, but now I’m wondering whether I should just create one large bank and do away with our separate house and start banks - possibly 3 of these for house and engine start. We have 350w of quality solar with a victron controller and a 70 amp alternator.

Curious to hear whether folks using lithium are still separating their house and start banks and if they’re using different lithium batts for each purpose.

Thanks in advance for any help.

[SailingHarmonie]

Originally Posted by Peregrine1983

Hi all,

I was considering two of these (https://a.co/d/71Q3Byy) for our house bank, but now I’m wondering whether I should just create one large bank and do away with our separate house and start banks - possibly 3 of these for house and engine start. We have 350w of quality solar with a victron controller and a 70 amp alternator.

Curious to hear whether folks using lithium are still separating their house and start banks and if they’re using different lithium batts for each purpose.

Thanks in advance for any help.

There is a currently active thread with hundreds of comments on just this topic… Look for it. We really don’t need another one…

[Tin Tin]

Before wading through a bunch of social media anecdote and opinions - what does your battery user manual have to say about using them as start batteries? To save you some time the Li Time manual on page 3 "Things to know before using" - says "....DO NOT use it as a starting battery"

[s/v Jedi]

Originally Posted by Tin Tin

Before wading through a bunch of social media anecdote and opinions - what does your battery user manual have to say about using them as start batteries? To save you some time the Li Time manual on page 3 "Things to know before using" - says "....DO NOT use it as a starting battery"

Exactly, the battery used must be rated for engine start and most are not. Doing it anyway immediately voids warranty and is just screaming for failure and loss of investment.

[jcapo]

Epoch has a group 27 size battery rated for start but its kinda pricey.

https://www.epochbatteries.com/produ...y-dual-purpose

I just installed two of their 300AH batteries for the house but I'm sticking with SLA or AGM for a starting.

[Ixium]

I can start my 50hp engine with a Gooloo GP4000.

It took about 6% of the packs battery to do it. Just use one of them and run the USB charge cable to any usb port.

Easy peazy

[Hhew]

I’m running 2 x 200AH LiFePo for house and 1 x 135 AH dual purpose (deep cycle + 1000 CCA) for starter and bow thruster. All from Dakota Lithium. Works great.

[Tin Tin]

Originally Posted by Hhew

I’m running 2 x 200AH LiFePo for house and 1 x 135 AH dual purpose (deep cycle + 1000 CCA) for starter and bow thruster. All from Dakota Lithium. Works great.

Is your start battery isolated from the house bank.?

[CaptainRivet]

Originally Posted by s/v Jedi

Exactly, the battery used must be rated for engine start and most are not. Doing it anyway immediately voids warranty and is just screaming for failure and loss of investment.

One maybe not sufficient bot 2 or 3 in parallel are and
yes that is due to the mosfet BMS inside but if your peak current equals to the continuous of the Li-time you can start with them safely and easy. The cells can do that anytime....
Li-time has to secure themselves so they don't take one 100A battery and install it into a semitruck with a big diesel and ask it to start that....but 3 parallel will make it.

But yes thats what a lot forget that you might not been able to start from house when getting these cheap chinese surprise boxes even if the cells can do it but their crapy BMS inside not.

But yes thats why DIY so i have access to the cells, can chose a BMS that can withstand starting surge. Another solution is eg for starter just bypass the BMS (but before shunt so the engergy is counted with) and have a breaker that trips if there is a short or failure of the starter.
And every boater that can maintain their engine can put together a battery from sunfunkits where you can choose which cells and BMS to use.

[CaptainRivet]

Originally Posted by Ixium

I can start my 50hp engine with a Gooloo GP4000.

It took about 6% of the packs battery to do it. Just use one of them and run the USB charge cable to any usb port.

Easy peazy

Thats what i would do on a small daysailor too

[Hhew]

Originally Posted by Tin Tin

Is your start battery isolated from the house bank.?

Yes via a Victron Argofet isolator.