24 Volt Lithium House Bank Upgrade- Silent Ship

[scottinsydney]

Following the removal of the broken #1 Kohler genset, we now have extra floorspace in the genset room and new wall space on the front bulkhead. There is now only the 20Kva Phasor genset which meets all our power needs. So its time to start planning for next project.... the Silent Ship.

The plan is to:

- Install a 24 volt 300 or 400amp lithium battery bank in genset room,
- Install 3000 watt inverter/charger in genset room
- Install two 24 volt solar panels on flybridge roof
- Reposition the existing 32 volt solar panel to flybridge roof
- Remove the old 32 volt Furuno 6' radar array
- Install compact Furuno Wifi Radar to flybridge roof

I guess there will be interconnectivity between the 32 volt house bank and the lithium battery house bank through DC converters and DC to DC chargers. But the 24 v lithium battery will mostly operate on its own with shore power, genset and solar charging.

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The purpose of the exercise is to reduce to a minimum the use of the genset and to provide the big refrigerator with at least 3 days power without sunshine. Also to power the ultrasonic antifoul system 24/7.

The opportunity exists to take most of the continuous load off the port side lead acid batteries, making them responsible only for bilge pumps and DC LED lighting.

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I'd love to hear your thoughts about this project which should be well underway by September.

[oscarvan]

Assuming the 400A, 80% discharge, 240VAC fridge I get to 32 hours of run time..... guess if it's not too hot and you don't open it much that could work. But nothing else added to that. IOW, I suspect you will be buying more LiFe's..... Like I used to buy expensive Vodka.....

I am contemplating something similar..... Except I am planning to convert the SB engine to 24V. Large bank and inverter attached to it.

[scottinsydney]

Hi Oscar,

Its a big Fisher & Paykel fridge and have monitored it for the past 5 years. It draws through the inverter a continuous 6 amps per hour during summer at 12 volts, except when its cycling and can go up to 70amps for short periods while it defrosts itself.

400amps (say 350amps useable) = 350/6 = 58 hours which is 2.5 days. Sorry my original maths was poor. Anyway, its a big improvement on what we have now. And the battery can be charged at about 50-70amps per hour which is a vast improvement over lead acid.

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So it comes to lithium battery selection and say for 400ah/24 volts .... Victron make nice multiple batteries that talk with one another. Or I can have made a single 400ah 24 volt battery weighing 60kgs (about 130lbs) with 200ah BMS for US$1800 or so.

[Photolomy]

I assume this is for long periods at anchor? As long as you don't need A/C or Heat, then it makes sense. Though, I think you are being overly optimistic regarding two solar panels. But I don't know about your sunshine situation. In my situation, I want to eliminate genset use while cruising (marina to marina) and some anchoring. Solar didn't make sense since while cruising we don't use AC and the alternators would keep the inverter bank charged. And though we would use the genset periodically while anchored, we don't anchor enough to make solar worth it, and we would need AC in the summer.

[dar636]

I ran across this channel, he's a boater local to us when not in Alaska and I found this episode worth the watch if you want to convert to LifePro batteries and reduce genset run time. Great explanation of the before and after results. Might be useful for you.

https://www.youtube.com/watch?v=sLq0faThyaU

[metama]

You are going to want more the 400ah.

I would say at least 800ah or more. Im thinking about much more than that. (currently have 480 AGM, so that's more like 240) and I would say that 1/3 of what we want.

We have (2) 3,800 inverters. Or 3,800 240V.

Look at the Amps off the solar. 2 panel's you should be fine, but most charge controller and most battery setup don't want more than 80-100amp. With the new 320-400 panel's you can get over 100amp in full sun pretty quick.

Also check your alternator to make sure you don't over heat that. Scott on this forum as a recommend on a smart fix to that.