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48v solar/electrical system


hemsteadc

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Just yesterday I finished up my 48vdc system. You don't see that every day!

 

8-12v Lifeline AGMs in series/parallel, 6 -135w panels in series, Outback 60 charger, Cotek 4000w/48v inverter, Orion 48->12.5 converter, and Schauer 48v 15a charger. The only casualty was a couple little digital voltage readouts - they died trying to display 50v.

 

The solar capture seems to be pretty good.. in Quartzsite with tilted panels at 11.30am I'm harvesting 52.3v x13.7a= 716watts from 810 watts of panels.

 

I have no trouble running my air conditioner (not from solar) with this inverter, and that's with #6 wire to the inverter.

 

So far I'm liking this a lot.

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COOL (pun intended) if you're actually harvesting 716 net watts from 810 panel watts (88%), you done good. Of course, the time of day, suns intensity, and angle need to be right on to achieve what you're experiencing. As long as "shading" isnt a problem, the series configuration higher operating voltage equals less current flow and potentially less voltage drop (subject to wire size and length) from panels to your controller.

 

CONGRATULATIONS if I come to Quartzsite can I park next to you?? Maybe lend me an extension cord lol

 

John T (A measly four 12 volt panels in series)

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Wow, that sounds like a great harvest. I haven't had a good try with mine yet. The one day it was sunny it said 550 out of approx 800. This was Mich so I didn't know what I should expect. Right now we have been on the road and had sites in shade so I have not been checking. I used quite heavy gauge so I am wondering why my numbers were low.

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A Dometic energy hog a/c draws around 1750 W from our battery/solar setup. A split-level may only draw 750 W. We have considered removing Dometic from roof above living roomto get rid of its high profile and replacing with a split level. Might look into 500 W split level in bed room as well.

 

Replacing Dometic would free up space for two more 235 to 250 W panels. The Dometic's profile is so high that it would put further panels in shade.

 

We have been very happy with 90 V from panels and 48 V (nominal) battery suite. Folks have just been stuck in the 12 V paradigm for what they feel to be good reasons.

1. DC system is 12 V

2. Batteries are 12 V or doublets of 6 V

3. Most folks use fairly small 12 V solar panels.

 

Oldman is aware of the advantages of higher voltage:

1. smaller cabling for power

2. Smaller MPPT: 1400 W at 90 V is only 15.5 amps, it is 117 amps. Have to consider that controller changes voltage to 48 V (nominal) or 29 amps.

 

You do require a DC to DC power converter and we have a 508 W Mean Well 48 V to 12 V converter.

 

Reed and Elaine

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I can't picture an A/C that will run on 716 watts. What is make and output/

Sorry.. I didn't mean to say that my solar will run it 100%. My previous system (@24v with a Samlex 2kw inverter ) would not start my air, no matter how big the cables were. And my old Prosine @12v would run it, but things got hot, and eventually burned up the undersized 120v pigtails - twice. My goal is to be able to run air from inverter without things heating up, while charging at the same time to help out.

I assume you are using the Orion 17 amp converter? Is that going to be enough power for your systems? My hydraulic pump uses WAY more than 17 amps.

It's the Victron Orion 360w DC-DC converter. The slides are my biggest draw, and that's plenty of wattage.

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We have been very happy with 90 V from panels and 48 V (nominal) battery suite. Folks have just been stuck in the 12 V paradigm for what they feel to be good reasons.

 

Oldman is aware of the advantages of higher voltage:

1. smaller cabling for power

 

 

Excellent.. sounds like my system. 90v is about right as an average from the PV array. We have to be careful of shading!

 

I love the smaller cabling. So much easier to work with.

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We have run the Dometic several times at up to 3.5 hours as combination of solar/battery suite in mid-summer. More often we have run the Dometic for half an hour or so at dusk just off the batteries. This cools cabin down to 80's and 12 V fans moving air about are sufficient. The 12 V fans are one amp or about 10-12 W. We have four 12 V receptacles (aka cigarette lighters) in main cabin and two in bedroom for fans, Iphones etc, and two in the main luggage compartment. We do have fairly large battery capacity.

 

The split-level air conditioners run off 120 V AC (240 AC according the the folks in Oz), 24 V and 48 V DC. Question is whether to accept power loses going through inverter or run 48 V lines to split-level.

 

Reed and Elaine (getting 5th wheel ready for trip to Yucatan and Belize - or so it is planned)

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Have read this (500 to 750 W power requirement) on threads on two Aussie fora. The following is from Expedition Portals http://www.expeditionportal.com/forum/threads/126273-Anyone-actually-install-mini-split-heat-pump-on-camper

with one posting

quote_icon.png Originally Posted by LeishaShannon viewpost-right.png
We're using the Mitsubishi SRK20ZJX-S 2.0KW on our camper, it draws just 350W on high and because its a variable compressor can run as low as 190W. In a well insulated camper it will have quite short cycle times so its possible to run off solar with an appropriate inverter / battery bank. We have 1500W of solar, 360Ah @ 24v of Lithium batteries and 2 x 1600VA Victron Multiplus in parallel and have no problem running it.

 

I googled this system and the power requirements for the Mitsubishi was higher than posted by LeishaShannon. LeishaShannon does have a quite impressive setup. Noted that a number of the posters had Kimberly Kruisers (probably the best boondocking trailer I have read about) so this is probably also an Aussie forum.

 

A friend of our son's installs mini-splits on houses in Las Cruces, NM and we may have this done someday. We have spent some time googling this but scarcely consider this researching as yet. Minisplits are a lot quieter as well. Best bet for us is to avoid high temperatures.

 

Reed and Elaine

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I've had some experience with mini-splits in trucks. They work well until the vibration destroys them. In one application a bank of 12 volt batteries, along with solar, was designed to run the minisplit (12,000 btu) for 10 hours. And it did. But that is a SMALL space relative to an RV.

 

I'm still searching for a DC/DC converter that will handle my 80 amp peak DC load. I can find one for 24/12 but not 48/12. I have not yet investigated if I can reduce that peaking....but I'm thinking I might be able to.

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