Mixing battery sizes and proper system.

[john61ct]

Study this, google or ask Q's until you fully understand it

https://marinehowto.com/how-fast-can...ry-be-charged/

Everything at Maine Sail's site there is gold.

[mitiempo]

Originally Posted by john61ct

875AH bank

Yes that is large.

A serpentine belt will help if you do find it necessary to upgrade the alt.

As well as an external regulator - Balmar MC-614 is ideal - with temp sensors for both the alternator and the batteries. Take advantage of the belt manager as well to dial the alt back to say 70%. Otherwise with that large a battery bank the alternator will have a very short life.

[john61ct]

Less of a problem with a FLA bank than with a high-CAR sealed chemistry.

Especially if able to install a well-ventilated large-frame alt capable of running at 120A output all day long.

But I agree the MC-614 feature set is fantastic, most cases are non-ideal and such fine regulation is required.

A field current disable switch at the helm is also a good idea, when you need to use all your horses for propulsion.

[mitiempo]

Originally Posted by john61ct

Less of a problem with a FLA bank than with a high-CAR sealed chemistry.

A flooded bank of 875 AH @ 50% SOC will accept full alt output for long enough to overheat leading to alt destruction. If the bank was half that size not much problem.

I wouldn't risk it.

[hzcruiser]

Originally Posted by john61ct

Besides the (nit picky) point that 250 amps per hour makes no sense, since amps are already a rate-per-time unit.

AH per hour, day etc more likely meant.

John, I'm afraid we'll never get everyone to understand the differences between power, energy, and the time relationship... it's too nerdy.
Just like it seems impossible to eradicate the mixing, mangling and scare mongering around Lithium-Ion and Lithium-Iron-Phosphate technologies.
We might have to accept it, like the weather and just silently face-palm...