Yet another charging Lithium/Lead hybrid setup thread

[Goodxcharly]

Very complex with a few twists and turns and not to mention what ifs. That is why I stick with lead acid 6 volt Costco golf cart batteries at a $100 a pop each, 2 banks and 300 watts Solar which Keeps my fridge and freezer going indefinitely as long as the sun is out. Otherwise it is the Universal or Honda.

[SailingHarmonie]

I don't have any specific recommendations about the house batteries, but way to simplify your system a lot.

Normally a separate windlass battery is installed simply to avoid the long run of large cable from a house bank to the bow. But your windlass battery is located near the house bank, so you already have the large cables run. The reason for the separate battery is negated. Ditch it, and power the windlass directly from the house battery.

Windlasses use a lot less energy than people imagine. While they can draw a lot of amps when at or near stall when the anchor is stuck, that rarely happens and only for a few seconds. Even lifting the anchor and chain vertically in deep water it is really just above idling.

A lot of your questions are trying to solve complexities around the separate windlass battery. You just do not need it. With properly sized cables having a separate windlass battery right next to the house bank makes no sense.

Just as an example, my boat runs a bow thruster from the house bank. That bow thruster draws nearly 500 Amps. The round trip cable run is nearly 60 feet. It has worked for over 25 years. The windlass is also powered from the house bank, but its draw is trivial compared to the bow thruster.

[WE9V]

Originally Posted by SailingHarmonie

A lot of your questions are trying to solve complexities around the separate windlass battery.

No, the complexity is really 1) maximum alternator charging current to the Lithium house bank, AND 2) preventing damage to the alternator diodes when (not if) there is a lithium disconnect, causing a load dump, causing overvoltage.

Complexity is reduced by getting rid of the windlass battery, but that alone doesn't solve both of the above requirements. That said, your points are very valid about the relatively low current requirements of the windlass, limited benefits of a separate windlass battery mounted way aft / near the house, and the 100A draw (max, average WAY less) not being much for a 460Ah lithium house with two paralleled 200A BMSs.

I may consider not replacing the windlass battery, but an ArgoFET or ACR to the start battery would still be needed to prevent alternator damage from a load dump.

[newhaul]

Originally Posted by WE9V

No, the complexity is really 1) maximum alternator charging current to the Lithium house bank, AND 2) preventing damage to the alternator diodes when (not if) there is a lithium disconnect, causing a load dump, causing overvoltage.

Complexity is reduced by getting rid of the windlass battery, but that alone doesn't solve both of the above requirements. That said, your points are very valid about the relatively low current requirements of the windlass, limited benefits of a separate windlass battery mounted way aft / near the house, and the 100A draw (max, average WAY less) not being much for a 460Ah lithium house with two paralleled 200A BMSs.

I may consider not replacing the windlass battery, but an ArgoFET or ACR to the start battery would still be needed to prevent alternator damage from a load dump.

Why complicate it . Set your charging sources to charge to 13.8v And call it a day.

At that setting if you have a nanosecond spike (which your controllers can easily handle)
From a LVC OR HVC the 1 in a thousand chance of alternator damage is miniscule compared to the problems that caused the issue . Aside is the alternator actually your primary charge source?