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Old 05-07-2022, 09:07 AM   #1
markpj23
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City: Bradenton FL
Vessel Name: Deja Blu
Vessel Model: Marine Trader 62
Join Date: Mar 2021
Posts: 158
Decision Time - House Bank Is Toast

After our 2nd extended time away from the dock since purchase I feel safe in saying that our house bank is toast. There are 6 - 8d batteries less than 4 years old. Hard to believe they have such a short life but I have no clue as to how they have been treated. The right components seem to all be here: Balmar alternator controls, Xantrex inverter/chargers, BlueSeas ACRs and all seems to be functioning.

Assuming 200ah for each 8d, I should have 1200ah @50% discharge = 600ah or pretty close if I've got the math right. My Victron battery monitor showed a whopping 168ah consumed when the inverters shut down for low battery voltage (11.6 volts if I remember correctly).

My load averages 48 amps (measured by the Victron). We run a big residential refrigerator, plus a dorm sized fridge, plus some engine room blowers on 120v. Add to that my 12v loads for nav gear, etc and we are the definition of why trawlers love to travel from one dockside power connection to the next

I could go the cheaper and quick route and just swap out the 8d AGMs. I want to be able to get through the night w/o the generator and new AGMs would probably allow that. Not much reserve though.

Sure is tempting to go the LiFePO route and get at least twice that capacity, although still at nearly twice the cost for the UL listed Kilovaults. Throw in the external BMS, Wakespeed, etc and the cost difference is not trivial. Throw in the ABYC standards evolution and possible insurance issue and the decision gets 'complicated.'

Two questions for the group:
- Am I correct that my current batteries are shot or am I just expecting too much of them?
- Is the current cost & complexity of the LiFePO solution worth the additional capacity? (I know that's subjective....)
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