Wanted: Suggestions for end-to-end solar installation

[Uncle Bob]

Originally Posted by DeeBee

Thanks for all advice from all. I'm still not sold on doing 12v vs 24v but to start my load requirements are light and one 100ah 12v is going to satisfy my needs.

Hi, for what it's worth, my boat is 32 feet and has a house bank of six 6 volt flooded GC2 batteries and has been great going on 7 years now, kept charged with 190 watts of solar and the alternator when run. It lives on a swing mooring.

[waterman46]

Originally Posted by DeeBee

24v is becoming more and more normal and the current (amps) requirements are reduced with 24v.

I won't be sailing around Chicago forever and I have some unusual power requirements (HF Amateur Radio is a power drain, for example)

Do any ham rigs use 24V DC?

Actually the ham or Marine band rigs don't drain that much, unless you send lots of data. SSB transmit is a power miser unless you are unusually long winded! In receive mode, lots less power, though you might spend hours not minutes.

Look instead at refrigeration - that's usually at least 50% of total power requirements.

[jkindredpdx]

I have 2 banks of 2 Trojan SCS150 LA batteries. I generally have A bank as starter and B as cabin. Charged by 2 Solarland SLP045-12U 45 watt module, 12v with Morningstar SS10-12v controller... from Wholesale Solar. A Sure Power: Multi-Battery Isolator - 95 Amp ~ 1 Input; 2 Output keeps the solar from hitting my Alternator. It was economical and works pretty well. I've had great support and service from

https://www.wholesalesolar.com/solar...RoCXs4QAvD_BwE

[Adelie]

Originally Posted by DeeBee

24v is becoming more and more normal and the current (amps) requirements are reduced with 24v.



I won't be sailing around Chicago forever and I have some unusual power requirements (HF Amateur Radio is a power drain, for example)

Ham is not an unusual power requirement. Having 24v for a ham rig would be useful if the rig can use it. Do you have the rig and what voltages can it use?


Yes 24v reduces amperage, but I think 48v will be much more common that 24v in the long run. I haven’t paid attention so I don’t know what is currently available for 24v other than windlasses and trolling motors.

48v is the highest voltage (that is a multiple of 12v) that is not considered “high” voltage (over 60v, 48v charges at about 57v) so the traction folks will cluster at 48v or accept the extra legal liabilities and the go to 96v or higher. So I expect there will be significant development of 48v accessories. Whatever 24v accessories are currently available will continue to be available but not much new.

If I was going to use electric propulsion I would go 48v. If not I would go 12v and have an inverter sited right next to the batteries. Most big loads would run on AC. The only exception might be a windlass and for that I would just pony up the big bucks to have the right sizes cables. Whatever money there is to be saved in cabling by going with 24v is lost in the extra costs for everything else. Maybe I’m wrong but you need to look at the costs of the whole system and the extra head ache involved in doing something unusual.

[markguthrie]

Have you done any battery systems to power an AC? My goal is to have enough battery power to run a single AC overnight. I would like to charge with solar and supplement with the generator.

[waterman46]

Originally Posted by markguthrie

Have you done any battery systems to power an AC? My goal is to have enough battery power to run a single AC overnight. I would like to charge with solar and supplement with the generator.

Interested. I looked up the smallest real AC (compressor/evaporator, not swamp cooler) unit I could find. This one is 1000BTU and quite small, even I, who don't really need AC, might consider this one for marina use: Emerson EAP01. The link to the Home Depot (about $500) web page was 12 lines long so I didn't paste it here.


Anyway it uses 240Watts when running. If it had to run full time to cool the cabin to your comfort, then that would be on an inverter using 12V@20A, plus the invertor losses. Assume 20A average then, if it cycles off sometimes. For an 8 hour run, 160AH. That's roughly equal to the entire daily consumption of our boat in the tropics without any AC. If you want to run this AC away from the marina, plan on doubling your battery bank ($) and charging capacity ($) for this modest or minimal BTU capacity overnight only. If you have space for the batteries.



A lot depends on how much it has to run to make you comfortable, or to make a good improvement in comfort. Guess there is no way to figure that out w/o actually running it in the cabin on a hot night.