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New house bank in Inverter install questions for newby

Mcgann454

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Feb 19, 2022
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Sorry in advanced if this post is too long.
I am under contract for a 1999 58" Navigator pilothouse that has been on Lake Michigan for most of it's life and not cruised long distance at all.
I am looking at making this into my home and do the loop in her. Lot's more time on the hook and traveling.
I need to upgrade the house electrical system as it is currently in the same state as it was manufactured in.
Navigator makes a great hull that is all fiberglass and no coring is used in any of the the hull or topside, but they seem to have skimped a little on the electrical system.
I have not found a single fuse on any of the 7 8D batteries in the engine room.
The Volvo engines are 24V and the Thruster is 24v. There are two series 8D batteries for the engines start and two 8d Batteries in series for the thruster, one 8d for the Generator and two 8d batteries in parallel for the house. There are two original chargers and no inverter. They also have a GE profile AC refrigerator in the galley and I am told they just ran the generator when out on the lake.
Shore power is 50A 12/240v.

I have been doing as much research on adding an inverter and probably a transformer (there seem to be two galvanic isolators ) as well as lifepo4 battery bank and have some early questions that I can't seem to get good information on.

Question 1) Should I make a 24v house bank of 12v house bank? Thinking 4) 300AH lifepo4 batteries, 2s2p.
Here is my DC panel:
DC Panel.jpg
Most of the electrical upgrades I am making from a chart-plotter,radar perspective are 12v or 24v. The Vesper Cortex I just purchased is also 12v or 24v.
I also read that bildge pumps can take the 24v and not blink, but only one source in a thread mentioned thatand and most of the new dc breakers are 12V or 24V, .

I can put a dc to dc converter at each helm to handle small things like back-up VHF and some of the current instruments that i won't switch out immediately.

Question 2) Will the current panel handle 24v dc current as well as the 12v?
I see multiple answers in many forums and most say it is the amps and not the voltage that is the key, but I will be living on this boat and will not take any unnecessary chances.
Currently budgeting the Victron MultiPlus-II 2x120V 24/3000/70-50 and the Autotransformer 120/240 100A as well as needed dc-dc converters for the 2 helms.

I have 6) 100w 18v flexible solar panels that I am going to start researching next and then look to the engine alternators for upgrades and external regulating and battery isolators.

Any and all comments/ constructive criticisms welcome please.
Thansk,
Mike
 
There are some flexable solar panels that are lasting but for a long time they were all junk...

In your panel i would worry about the rating of the switches... it is a lot harder for a switch to turn off 24 volts then 12...
 
Need more info on your charging system. Some sort of current limiter might be necessary to protect the alternators. As far as fuses at the battery it was common back then to not fuse the house bank. ABYC doesn't recommend fusing a starting battery. With a 24v house bank you could feed the DC panel with a DC-DC converter until further upgrades are ready. I am planning to install a 600 AH bank lifepo4 and a Balmar XT170 alternator with MC614 regulator on our sailboat. My starting battery is a GEL and will be charged with a small DC-DC charger. Look into Solbian panels for flexible, they are the most durable and efficient.
 
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I have been looking for more info on the charging system and the alternator upgrades. Apparently the engines are a bit of a unicorn. Story of my life. Lol They are TAMD 122 EDC. First year of electronic controls. I was hoping to add an alternator or upgrade the existing 24v 60A one to a higher amp externally regulated one, but can’t find any good info. I was able to find a good volvo mechanic that just retired from a large dealership and now does engine surveys. I will be tapping all his knowledge he‘ll let me. If anyone knows any info on these, I’d be great full. Paid for a full membership on boatdiesel.com and still having issues finding good info. Planning on using victron’s battery isolators to split the charge and not blow the alternator if the Lifepo4 bms kills the charging
 
Not exactly sure what that accessory is but a second alternator should be possible.
 

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Best thing to do is to stick with your primary voltage that already exists on your boat. If it’s 24V, then use that, if it’s 12, stick with that. The exception is if you have really heavy duty AC loads (air conditioning, electric galley) that you want to run off an inverter.

On my sailboat, I went all in on the Victron Ecosystem, and it’s really really nice. I did a DIY battery with a REC BMS, and my alternator directly charges my lithium bank via a Wakespeed WS500 regulator. The tight integration of all this gear, along with my inverter/charger and solar chargers, is glorious.

Furthermore, because I’m often on the road for work, I can access the whole thing remotely through Victron’s portal. I can also keep an eye on my bilge, tanks, and similar even from the other side of the planet.

Anyhow it’s a little more expensive than other solutions, but the tight integration and remote control is absolutely worth it in my books.
 
Since it's all original, are you lucky enough to have as built system drawings? They would be very helpful, and you should start with getting them, or drawing them out yourself. I would to this before buying anything.

I would stick with the voltages you currently have. The exception is that if I were to build a single large LiFePO4 battery to replace all of your current batteries, then I would go with 24V, but use DCDC converters to run the 12V side so I didn't have to replace the whole panel and everything else.

600W of solar is really small for the size of LFP you are considering. I have 700W with a 300Ah 12 battery, and it is barely enough keep up with my power usage, about 170Ah per day.

I highly recommend the WS500 regulator if you switch to LFP. The other option is a balmar regulator but it is less advanced and more difficult to program.

Marinesail has several good articles on Lithium batteries. Here is the first one:
 
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