12, 24 or 48v
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ianganderton
Auckland, NZ
What size inverter? This is the key question
The logic is mainly to do with keeping cables a sensible size
Up to 2000W inverter 12V with mostly 12V DC loads and occasional 120v power requirements
Up to 4000W inverter - 24V mainly inverter with some key dc loads on 24v like fridge
Up to 8000W inverter - 48V all AC
The logic is mainly to do with keeping cables a sensible size
Up to 2000W inverter 12V with mostly 12V DC loads and occasional 120v power requirements
Up to 4000W inverter - 24V mainly inverter with some key dc loads on 24v like fridge
Up to 8000W inverter - 48V all AC
Charleswgibbs
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What kind of loads are you powering with this system? The bigger the load the more sense it makes to go with a 24v or 48v system.
First goal would be to be able to power the AC (120V, 14A) for a day trip. Maybe 4-6 hours on the boat, and a 70% duty cycle.
Secondary goal would be able to run the AC overnight. Maybe able to heat water and take a shower, although I would be okay if that required turning off the AC while the water was heating.
Awesome goal would be able to throw the generator in the ocean and mark it as my own fishing reef.
Secondary goal would be able to run the AC overnight. Maybe able to heat water and take a shower, although I would be okay if that required turning off the AC while the water was heating.
Awesome goal would be able to throw the generator in the ocean and mark it as my own fishing reef.
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The bigger question might be, how large is your battery and how will you charge it? 120V/14A for 6 hours @ 70% duty cycle is about 600Ah at 12V. For overnight about 2x that.
120V/14A could be handled by a 2kw Inverter, but given the starting currents and the length of time it will run, 3-4kw is probably better, so 24V is a good choice. Use DC-DC converters to power the 12V stuff.
120V/14A could be handled by a 2kw Inverter, but given the starting currents and the length of time it will run, 3-4kw is probably better, so 24V is a good choice. Use DC-DC converters to power the 12V stuff.
32 volt boater
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Putting batteries in series adds problems and complexity. One bad battery with one bad cell in series ruins the whole string.
Go with 12 volts. Little doubt you already have 12 volt alternators so why not charge and run stuff wile motoring?
Even though I had to do some studying to manipulate and solar charge outside multiples of 12 I stayed with 32 volts cause that's what the boat was set up for. A/C will run off the alternators.
I got the outback 32 volt inverter starts that anchor windless fat AC motor no problem, I am sure the 12v version kicks butt too www.google.com/search?q=OutBack+FX2012
Its also a charger and has that automatic AC transfer function.
Go with 12 volts. Little doubt you already have 12 volt alternators so why not charge and run stuff wile motoring?
Even though I had to do some studying to manipulate and solar charge outside multiples of 12 I stayed with 32 volts cause that's what the boat was set up for. A/C will run off the alternators.
I got the outback 32 volt inverter starts that anchor windless fat AC motor no problem, I am sure the 12v version kicks butt too www.google.com/search?q=OutBack+FX2012
Its also a charger and has that automatic AC transfer function.
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I would likely build my own batteries, but I agree with you that a 12V system would be simple and easier to implement.
But also, I wouldn't charge these batteries directly from my alternator(s). I would use a 12V - ##V converter just to limit the charge current. So I could charge 12 or 24 volt from my alternators using 12->12 or 12->24v converters.
These are just some of my thoughts. I would love any feedback/criticism.
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schmism
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If your considering lithium then this is a non issue because even 12v is 4 cells in series. At which point loads are my biggest concern. 2000w on 12v is ~170a that's a very large expensive wire in the boat world. vs 41a (@48v) which is a very easy wire to source and run.
For anything above 2kw I'd go 48v and provide DC-DC converters for 12v devices. (starting battery for the engine excluded)
To meet your goal of AC overnight, you're looking at 1200-2000Ah at 12v. Consider how you will parallel cells or batteries.
At 12v, you will be pulling upwards up 150A for 8-12 hours. But a 3000W inverter will need to be wired for 300A. If you decide to go larger than 3000W, i don't think they are available in 12V. Cut those numbers in half for 24v.
Best to buy a 24V alternator. A big one. A 100A 24V alternator will take 5 hours to charge a 1000Ah 24v battery. A stock 12v that's current limited will take 10-12 hours to charge, assuming the A/C is left off.
At 12v, you will be pulling upwards up 150A for 8-12 hours. But a 3000W inverter will need to be wired for 300A. If you decide to go larger than 3000W, i don't think they are available in 12V. Cut those numbers in half for 24v.
Best to buy a 24V alternator. A big one. A 100A 24V alternator will take 5 hours to charge a 1000Ah 24v battery. A stock 12v that's current limited will take 10-12 hours to charge, assuming the A/C is left off.
32 volt boater
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www.google.com/search?q=marine+hot+water+heater+with+heat+exchanger&tbm=isch
Hot engine coolant is routed through the coiled tube to heat the water in the tank when the engine is running. Currently, up to 65% of the heat energy produced by internal combustion engines is wasted.
Marine air conditioners bring in cool water from the sea and heat it with the energy from the compression process before returning it to the sea but I think recovering that heat for showers is a DIY science project.
I thought about using the air conditioner waste heat to pre heat the entire main water tank but never built anything.
32 volt boater
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And then 24 volt starters too ? And bilge pumps and everything else
They make lots of big 12 volt inverters and they are still the cheapest
Wagan EL3748 12V 10000 Watt Power Inverter with Remote Control, 20000 Watt Surge Peak, Proline 12 Volt Power Converter for Home RV Camping Van Life Off Grid https://www.amazon.com/Wagan-3748-Black-PROLINE-WATT/dp/B01DPB7F6M
Whats a van going to do with 10000 watts ?
Anyway Megalophobia is a type of anxiety disorder in which a person experiences intense fear of large objects. Around here it always seems to focus on wire.
I don't see the big deal running a few feet of big fat wire. Compared to the price of this hobby overall an extra $100 on wire isn't much.
32 volt boater
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All I know is my discontinued 32 volt system is a pain because I walk into any boat store and almost all the toys on the shelf are 12v.
Oh look on sale a spot light with half a zillion candle power ! 12v. Its always like that.
Oh look on sale a spot light with half a zillion candle power ! 12v. Its always like that.
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Not afraid of big wire. But afraid of a 10kW inverter that is s brand I've not heard of, costs only $1300, and weighs only 25lbs. That doesn't add up.
10,000W is 900A at 12V. 900A fuses cost more than a dcdc converter, and you will need several.
Plus the need for an alternator that supplies 2x the amperage. Price a 200A large frame alternator?
I assume a 12v starting battery will be retained, and arguably you should use a dcdc supply even for 12v to isolate and protect your electronics. So not really any more complicated. And 24v is *much* cheaper.
32V is weird, 24V is common. And 24v-12v dcdc converters are cheap.
32 volt boater
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32 volts was the standard on big boats till about 1980. I think it started with trains. Locomotives still using it.
16 caps = 32 volts
16 caps = 32 volts
| Reserve Capacity (RC @ 75A) | 398 Minutes |
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JustinG
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You may have not heard of us, but we've been building inverters since 1991 and have been in business since 1993 here in Hayward, CA!
There are several ways to fuse a 10Kw inverter; of course you can get a 1000A fuse which is going to be pricey, or you can run multiple power wires (equaling or surpassing the correct size single cable) and fuse those sections individually.
Goboatingnow
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On an a boat don’t create alternative voltages unless there’s a huge overriding requirement. If it’s a 12V boat keep it so
I can see the advantage of having a separate 24v house system with a caveat as to certain load scenarios. Say you want to convert over to induction cooking and ditch the propane or alcohol stove. Seems most induction use up to 1500 - 1800 watts, on high at least. Add in a few items like a computer charging and tablet, a few fans and a refrigerator and seems like a 2000 watt inverter could be stressed fairly quickly.
All of this would depend on how much solar you could add, or on shore power a lot, or additional genny onboard.
I would leave all engine functions, radar and navigation separate on the 12v batteries charged by the engine. Add small B2B 12v to 24v to the house but would not rely on that to supply much; just to top off the house.
Basically its all about load size as others have said.
All of this would depend on how much solar you could add, or on shore power a lot, or additional genny onboard.
I would leave all engine functions, radar and navigation separate on the 12v batteries charged by the engine. Add small B2B 12v to 24v to the house but would not rely on that to supply much; just to top off the house.
Basically its all about load size as others have said.
JustinG from Wagan Tech. Likely your post violates forum policy but that is not my call.
However since you sell (supposedly build) inverters (and they are not cheap!) I have to ask why they have non adjustable low voltage cutoffs. The level in your specs is so low as to damage batteries due to full discharge. Yes your competitors in the mobile inverter market also do this but it really should change.
