NoDirectionHome Posted January 30, 2016 Report Share Posted January 30, 2016 Just thinking out loud. What are some of the issues of 48 VDC solar? Do the conversion losses outweigh the benefits? Cost of equipment? Also how about the same idea of 230 VAC inverter input/output, or generator? Link to comment Share on other sites More sharing options...
Yarome Posted January 30, 2016 Report Share Posted January 30, 2016 Just thinking out loud. What are some of the issues of 48 VDC solar? Do the conversion losses outweigh the benefits? Cost of equipment? Also how about the same idea of 230 VAC inverter input/output, or generator? Absolutely! Providing the use of quasi decent gear the cost factors will be the same and highly more efficient to the upteenth factor. Especially in the case of an MPPT controller with an appropriately sized array, you'll see cost benefits over wire gauge as well as overall efficiency for the same/less cash outlay. On the other hand.. inverter and/or generator hi-voltage units will not see the same type of return in most RV applications once a transformer is implemented to convert to usable voltages. I'm not as nearly "versed" with those units and Reed, Jack or others might be able to answer that question with more accurate information. Link to comment Share on other sites More sharing options...
NoDirectionHome Posted January 30, 2016 Author Report Share Posted January 30, 2016 Thanks Yarome, hopefully others perhaps with even some actual experience will jump in. I'm thinking in terms of RV air conditioning (split unit) @ 230 VAC and a 48 VDC battery bank w/ high voltage PV array. Link to comment Share on other sites More sharing options...
StarDreamers.us Posted January 30, 2016 Report Share Posted January 30, 2016 Also, you may want to look at the newest generation of solar panels, i.e. the new LG neon panels are 300+ watts and very good performance specs. Good luck. Safe Travels! Link to comment Share on other sites More sharing options...
Dranoel Posted January 30, 2016 Report Share Posted January 30, 2016 RV A/C generally is not practical to power via the battery bank unless it is extremely large. The amperage is just too great. Link to comment Share on other sites More sharing options...
NoDirectionHome Posted January 30, 2016 Author Report Share Posted January 30, 2016 Thx StarDreamers, I had missed those. I had tentatively planned 4 Astronergy ASM6612P-315 for panels but the weight of the LG's is attractive. One of my other concerns is, can you generate enough current when charging at 48V? Link to comment Share on other sites More sharing options...
NoDirectionHome Posted January 30, 2016 Author Report Share Posted January 30, 2016 Dranoel, Not quite yet, but between Tesla's Powerwall and efficiency improvements, I think that in 2 years it will be a reality. Link to comment Share on other sites More sharing options...
Jack Mayer Posted January 30, 2016 Report Share Posted January 30, 2016 When you say 48 volt solar I assume you actually mean a 48 volt nominal battery bank. Because the panels themselves do not necessarily have a Vmp of 48 volts. (I say this to clarify for others - I assume you know that.) For a large array and large battery bank it is very efficient - as Yarome said. You have to use the appropriate inverter, obviously. The biggest issue is finding a dc/dc converter that will output 12 volts from the 48 volt nominal bank. There are not many of them out there for this combination, and if you have hydraulic slides the pump will likely be your biggest 12-volt load. You may have trouble supporting that with most of the CD converts you find. My pump runs at 70 amps, sometimes. I may try to find a pump that runs at higher voltage so the step-down is not so large. House lighting is simple - it is not much of a load. I'm starting a design for a large mobile system and if you find something that outputs 100 amps let me know. That is what I will need. 100 amps @ 12 volts from a 48 volt bank. I have some stuff that will do it - but it is VERY expensive. BTW, I like THESE panels better than the ones you chose. But either will work. The LG panels are more efficient and lighter, but cost more. If weight is a factor then that would be what would bias me to them. Or, if space is limited then the smaller LGs might be a better choice. The 2% efficiency difference would not be a factor for me. Link to comment Share on other sites More sharing options...
NoDirectionHome Posted January 30, 2016 Author Report Share Posted January 30, 2016 Thanks Jack, Yes the only high amperage 48>12 V converters are very expensive. I'm not sure why. 4 of these http://www.powerstream.com/DC3a.htm would cover you I suppose but I'm thinking big picture from scratch which you could also do using 48 VDC motors and appliances where appropriate. Nice panels! Weight is not an issue as I am planning on a custom build. Link to comment Share on other sites More sharing options...
Jack Mayer Posted January 30, 2016 Report Share Posted January 30, 2016 As far as possible I like to be able to use standard manufacturers products without modifying them. Thus the "issue" with Quadra Bigfoot leveling system and Lippert slide motor ratings. But I may discuss that with them or substitute something else. I just hate to void the warranty on a new product by changing the motors. And the controls will be affected too....you quickly get sucked into a Pandoras box of changes. HERE is a 60 amp converter 48/12. But it is $1700. Link to comment Share on other sites More sharing options...
NoDirectionHome Posted January 30, 2016 Author Report Share Posted January 30, 2016 Yes, I saw that one & immediately dismissed it as ludicrously expensive & not very efficient. As far as warranties go, I've always been the one to "make it better" (not always successfully) from the get go so if they wouldn't do that for me, I'd just be the pioneer. "We" may have to be the ones to drag these companies kicking and screaming into the 21st century. BTW Jack, because my company specializes in high pressure pneumatics, I've also toyed with the idea of air motors for intermittent loads such as the slides or levelers. Link to comment Share on other sites More sharing options...
Scrap Posted January 30, 2016 Report Share Posted January 30, 2016 Slides and jacks seem to be a big draw, but one-time cycle thing to me that doesn't really the LV side sized just for them. The LV side of trucks has been the bain of my existence so keep it simple on your first shot right out of the gate. But if they do need to be in the system, would they complete a cycle off of one of the little 31/900 Ultracaps? You'd knock yourself down to a continuous 25A going that way while they are running. 48V isn't really my realm, but I keep seeing the year 2018 in articles about "hybrid lite" that is 48V stuff like golf carts, big mowers, etc, so it'll get there eventually. I'd also be willing to bet it'll be water cooled when it hits mainstream as well. So there is that WEG loop again..... Know it, love it, and might as well plan for it if you are going to use automotive/IP67 components. Absopulse has been my place for the big DC converters. HVI is what we used last but that is for 300-600V stuff. They do have others and you can call Techsols if you need some post sale customizing for it. I'm sure no matter what it'll be over $1K though. The Power One BMC is another option that you might be able to get custom in 48V. BelPower I think is their name nowadays,. Link to comment Share on other sites More sharing options...
Shadow Catcher Posted March 1, 2016 Report Share Posted March 1, 2016 We have a 66 cell high voltage panel that in shade puts out 36V. The Moringstar MPPT SunSaver can handle 70V. There are advantages. Link to comment Share on other sites More sharing options...
reed and elaine Posted March 10, 2016 Report Share Posted March 10, 2016 As noted in previous posts, we have a 48 V nominal battery suite of LFP. The voltage from panels is 90 V and a maximum of over 1400 W on very clear summer days. The power goes to the 12 V AC via a Mean Well 508 W 48 V to 12 V transformer. The advantages have been touched on by some of the previous posters: the most evident are using much smaller cabling and controller. 1400 W is onlly about 16 amps at 90 V. We are currently at Isla Aguada between Campeche and Villhermosa and it was 103 F on the road yesterday (hottest day of the year apparently), so we are taking it easy for a day in the shade, where we are running AC off battery/solar/and 750 W from the supposedly 15 amp plug in. We have met only 5 US RV'ers in our two and a half months in Yucatan - and one heck of a lot of Germans, Swiss, and Canadians. Link to comment Share on other sites More sharing options...
NoDirectionHome Posted March 13, 2016 Author Report Share Posted March 13, 2016 I have a question about inverters. Some inverter shore / generator inputs are 240VAC, some are 120VAC and some are 120/240VAC. Wouldn't it make sense use a 240VAC unit and split phases at the trailer? In the case of 30A 120V only being available, you would just have the one leg available, but that seems very manageable. So now some "sparky" tell me what I'm overlooking Link to comment Share on other sites More sharing options...
BoonHauler Posted March 16, 2016 Report Share Posted March 16, 2016 As far as possible I like to be able to use standard manufacturers products without modifying them. Thus the "issue" with Quadra Bigfoot leveling system and Lippert slide motor ratings. But I may discuss that with them or substitute something else. I just hate to void the warranty on a new product by changing the motors. And the controls will be affected too....you quickly get sucked into a Pandoras box of changes. HERE is a 60 amp converter 48/12. But it is $1700. I'm a little late coming to this conversation but what the heck...... I know Quadra Mfg. has 24 VDC systems. Maybe not in a six point system but I am sure thay have 24 VDC pumps for their 'QE' systems. Have you talked with them? I'd have to think 48 VDC would be doable. Now as the the Lippert stuff, good luck on that one. Link to comment Share on other sites More sharing options...
Dale P Posted March 16, 2016 Report Share Posted March 16, 2016 960 watts - Open Voltage = 45 Vdc MPPT controller =Midnight Classic 150. Can handle up to 150 Vdc input Output = 6, 6Vdc batteries. Series, Parallel Recently playing around with my solar, I achieved 750 watts @ 55amps. This was not optimize for sun to panel. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.