Greetings, I'm a new owner of a 2012 Grady White Marlin 300. This Marlin did not come with the factory generator and air conditioning set up. Does anyone have experience with a lithium battery-air conditioning set up ? Thanks !
Lithium Battery & Airconditioning Setup on a Marlin 300
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Fishtales
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Please don't do this. Lithium batteries have very dangerous chemistries and it is downright deadly in a marine environment. Ever watch a battery powered car go on fire? Can't put them out. Watch the vids of the Tesla cars that were exposed to salt water after the floods. The batteries would catch fire unpredictably in the future. Saltwater or even a salt environment and lithium batteries are a bad combination.
I don’t know much about Airconditions but I’ve been running two ionic lithium batteries on my Grady 232 GulfStream for two years now with no issues with loads of power a lowrance/ hummingbird / UHF VHF Live well without the engine all battery all day long at night all this plus lights with no issues all lithium batteries are not crated the Same and a good understanding of lithium batteries are in order The charger you use must also be compatible. It’s a big expense but the reward is worth the investment
Lithium iron phosphate chemistries do not have the same 'China Syndrone" failure scenario as plane Lithium Ion types.
That said, there are foreign made cheap batteries, even lithium iron that are not the best quality. The quality of the battery management system is very important.
All that aside, system design, both physical and electrical is complex. The AC is probably the most power intensive device and can require significant battery capacity. In addition, the charging system capacity may not be up to snuff also.
Fishtales
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Thanks for the link to Dakota batteries. My limited research so far has been positive on the products they make.
There are definitely folks out there who are successfully running AC's off an inverter system, and many are using lithium batteries for the inverter. The rough math is that for every 1,000 watts of 120V AC power you will need about 100 amps of 12V DC current. So if your air conditioner consumes 1,000 watts (mine is 1,100) then you need 100 Amp Hours of 12 volt battery capacity per hour that you want to run. (This assumes you are running the air conditioner compressor 100% of the time) Don't forget that you shouldn't run lead acid batteries all the way to zero, but you can run lithium batteries pretty much all the way down.
Depending on your set up, you can also provide some of that DC current from your motors. That's how mine is set up, and I get about 60 amps of current at idle so my batteries only need to supply 40 amps to run a 1,000 watt appliance.
The exact math is W ÷ 12 ÷ e = A, where W is the wattage of the appliance, e is the efficiency of the inverter and A is 12 Volt amps needed. For example, I have a Mastervolt Powercombi 2000 watt inverter which has a 90% efficiency so to run my air conditioner the exact amperage is 1,100 ÷ 12 ÷ .9 = 101 amps
Depending on your set up, you can also provide some of that DC current from your motors. That's how mine is set up, and I get about 60 amps of current at idle so my batteries only need to supply 40 amps to run a 1,000 watt appliance.
The exact math is W ÷ 12 ÷ e = A, where W is the wattage of the appliance, e is the efficiency of the inverter and A is 12 Volt amps needed. For example, I have a Mastervolt Powercombi 2000 watt inverter which has a 90% efficiency so to run my air conditioner the exact amperage is 1,100 ÷ 12 ÷ .9 = 101 amps
On my 2021 Marlin, I did not have a generator and installed a 2000 watt Victron inverter/charger and two AGM batteries to power the microwave, coffee machine and stove. It works great and has enough capacity that I didn't connect it to the engines, so I don't charge while on the water. I can make a half dozen coffees and run the microwave for about 5-6 minutes and only used 3-4% of the battery capacity. As suggested above, you definitely want to do the math on the A/C (that I do not have). We have a camper van with a/c and a very large lithium battery system, but the A/C will drain it in about 5-6 hours if we aren't running the van engine to keep charging it as we go and the solar panels aren't enough to offset the A/C consumption. Having the ability to use everything on the shore power side of the electrical system while on the water has been very helpful and the inverters run without any maintenance. We mounted the Victron unit vertically on a custom made aluminum rack that is just in front of the generator platform in the transom and one battery on each side for even weight distribution. If I had to do it again, I would have mounted both batteries on one side as my boat doesn't sit completely level at the dock and this would help correct the slight difference. Also, I feel safer on the battery side of things as I have the option of running my shore power charger if necessary to recharge the batteries for the engines from the Victron battery system. All in all I would highly recommend going this route and I suspect the math will support that it can deliver enough capacity for the A/C if properly sized.
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Absolutely, going with a 12v/24v DC air conditioner unit is more efficient if that is the primary way it will be powered. If you going to use it at the dock primarily and plugged in all the time then go with a more standard 120v AC AC unit and an inverter while running it while off the dock.
I high end inverter charger can provide enough DC current to run a 12v unit while plugged in at the dock. Victron's 2000 watt has a 80 amp charger for the 12v unit, 50 amp charger for a 24v unit. If the lithium is only around to run a AC unit then running a 24v system can improve efficiency and allow small wiring, less current. You will want a good DC to DC charger to charge the batteries off your outboards. If you go to a DC unit you technically dont need an inverter at all, but need a good battery charging system.
Important to understand how much current it will use and size the batteries appropriately. Do not be surprised if your slightly disappointed with how much lithium is takes to get a good long run time.
It can be done, be cautious of installers experience with lithium.