For further discussion, lets confine our consideration to "in-rush" current. Take a look at
@Maine Sail article. I have bolded a few key statements.
from Rod's article.
The questions isn't whether the Litium battery has enough "capacity" to handle the load or will be depleted by the load but rather will the "in-rush" current from the motors in the equipment (Anchor Windlass, Lewmar Halyard winch, 5KW generator starter damage the BMS and thus cause premature failure. Now, it is not likely or even feasable that I'll be trying to start/use all of these individual components at the exact same time and I realize that.
Seems to be some misunderstanding of my initial question. Quoting from
@Maine Sail (hope you don't mind Rod) In-rush current for large DC motors can be very high and can result in early BMS failures. It is the In-Rush current that is the killer to the Lithium batteries.
@Stu Jackson
you list the starting current for a 21-44 HP diesel to be 150A for a tiny amount of time. That is not the "in-rush" current though and Main Sail shows the "in-rush" current for a 40 HP Westerbek diesel to be 640A!
The following exerpts are from Rod's primer on Drop-In Lithium batteries and considerations in their proper care and use.
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From:
Drop-In LiFePo4- Be an Educated Consumer
DC Motor In-rush
The reason most drop in batteries cannot be used for starting is the in-rush current. The in-rush of large DC motors looks like a dead short to the FET’s. Imagine sitting there and intentionally shorting your battery multiple times each day…..That is what starting your motor, running a windlass, electric winch or Bow thruster looks like to the FET’s. There are LFP batteries that can be used for starting but they are very expensive at this point in time.
Starting a 40HP Westerkeke takes=640A!!!!
Know your loads before you buy!
The critical load data you need to know is the
in-rush current for all DC Motors .This includes a windlass, electric winches or a bow thruster. You also want know your inverters Pre-charge in-rush. Unfortunately most DC Clamp meters cannot properly capture DC in-rush current. We own three DC clamp meters that claim to do
in-rush but all except the Fluke meters fail miserably. The image below is one of our Fluke 376 meters capturing the in-rush current for a Lewmar V2 Windlass. This customer ruined his FET BMS (seen in an image above in this article) by using his “direct from China” drop-in battery to power his windlass. Warranty? Ha-ha now that’s funny….
The image above is a prime example of how drop-in battery bank went wrong for this customer. he wanted to lighten the load in the bow of his sailboat so he installed a single drop-in battery to power his windlass.What he failed to understand was the BMS’s current handling rating . In just a few short weeks he destroyed his drop-in battery with his windlass when he failed to account for what the peak in-rush current handling of the BMS., Warranty? Not covered!
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I've pretty much convinced myself that I need to wire the starter for the 5KW Generator to the Start Battery. I could get a separate start battery for the generator. The Anchor Windlass is already wired to the Start Battery. It would also be prudent to wire the Main Haylard winch to the Start Battery too. None will be operated at the exact same time nor would I likely be starting the Yanmar at the exact same time I'd be operating any of these other motors.
Any suggestions and/or comments/perspectives are appreciated. Hopefully
@Maine Sail will weigh in soon.
