Solar charging question

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Hmmm, looks like I have a lot to consider, than you for rattling my pea brain . This is our first foray into electric transportation so we have no idea of how much use they will get. I am thinking it will vary depending on where we are. At a BLM campsite along the Colorado in Moab, not much unless we are lucky enough to snag a site before the bike path ends...which can be like hitting the lotto.
Down on the South Rim boondocking just a few miles from the rim, maybe a lot of use. However, I am not a fan of two lane highway riding at less than half the speed of other traffic. There are many parks that do have a low enough speed limit that I would feel comfortable on pavement, or have dedicated bike lanes. On rare occasions we might be in an urban environment like the RV campground in downtown NOLA where the bikes would be a big advantage, but also a full hook-up situation. 

Ok, so I know enough about solar to be dangerous. We do not watch tv, or use the microwave when boodocking. Under those circumstances, it's to charge phones or tablets, run the heater blower, fantastic fan or a 12v aux stand alone fan. I still feel like to properly charge 2 6v's, that I need 2 panels @ a total of 350+ watts-ish due to partial shading that happens in a lot of campgrounds. I don't think (could be wrong) that splitting my 2 roof mounted panels and dedicating one of each to bike/pod  would get the job done in marginal sun for either the Rad or Pod. 

I like the idea of two different charge controllers with a switch, but can y'all tell me how much charge efficiency(or watts wasted if you will) do I lose if I go one charge controller, then to an inverter, then to the Rad battery charger? 

And, if I am charging two Rad batteries at the same time, is anything going to be left to charge the  GC batteries(under good sun)? I am already thinking i need to bump the two roof panels to over 400watts?

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Motor7 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Jan 2019 Location: E. TN Online Status: Offline Posts: 196	Topic: Solar charging question Posted: 13 Feb 2019 at 6:37am
	Hmmm, looks like I have a lot to consider, than you for rattling my pea brain . This is our first foray into electric transportation so we have no idea of how much use they will get. I am thinking it will vary depending on where we are. At a BLM campsite along the Colorado in Moab, not much unless we are lucky enough to snag a site before the bike path ends...which can be like hitting the lotto. Down on the South Rim boondocking just a few miles from the rim, maybe a lot of use. However, I am not a fan of two lane highway riding at less than half the speed of other traffic. There are many parks that do have a low enough speed limit that I would feel comfortable on pavement, or have dedicated bike lanes. On rare occasions we might be in an urban environment like the RV campground in downtown NOLA where the bikes would be a big advantage, but also a full hook-up situation. Ok, so I know enough about solar to be dangerous. We do not watch tv, or use the microwave when boodocking. Under those circumstances, it's to charge phones or tablets, run the heater blower, fantastic fan or a 12v aux stand alone fan. I still feel like to properly charge 2 6v's, that I need 2 panels @ a total of 350+ watts-ish due to partial shading that happens in a lot of campgrounds. I don't think (could be wrong) that splitting my 2 roof mounted panels and dedicating one of each to bike/pod would get the job done in marginal sun for either the Rad or Pod. I like the idea of two different charge controllers with a switch, but can y'all tell me how much charge efficiency(or watts wasted if you will) do I lose if I go one charge controller, then to an inverter, then to the Rad battery charger? And, if I am charging two Rad batteries at the same time, is anything going to be left to charge the GC batteries(under good sun)? I am already thinking i need to bump the two roof panels to over 400watts?
	2016 R-Pod 176T

Motor7 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Jan 2019 Location: E. TN Online Status: Offline Posts: 196	Posted: 13 Feb 2019 at 6:46am
	Oh, and last option is to use a Honda 2000 to charge the bike batteries(gasp)
	2016 R-Pod 176T

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 13 Feb 2019 at 7:49am
	I was going to ask if you already have a genny as backup? If you do that takes the pressure off your solar hardware decisions, you could use that for the ebikes to start with and see how much you actually use them. really, it's Ok to have a genny, I've been a solar guy for going on 40 years and I have one. No way with east coast weather that I can depend on solar all the time boondocking. And if your campsite is in deep shade as is often the case here, your solar array won't do squat. It helps if its portable but if you're really talking about 300-400 watts that's a lot of stuff to store and to lug around. Are you planning on roof mounting your array? its OK to run the genny sometimes, just bring an extension cord and place it far away from your and your neighbor's campsites, and only run it at respectful hours. Re efficiencies, you can assume about 90% for an inverter, and a similar number for dc/dc converters. MPPT charge controllers are about 95%. Battery round trip efficiency for lead acid is about 80%. So worst case scenario is if you charge via an inverter at night you could be about .95.8.9.9=64% charging efficiency. Best case directly charging in the daytime from two separate MPPT's would be about 95%. Sounds like your rPod electrical loads are pretty small. The fantastic fan on high uses 2.8A, on low 1.3, on medium 1.9. The heater uses 2A. So that's maybe 35 amphours a day if you run the fan on high for 12 hours a day in summer. Add a bit for lights, water heater and divide by 95% for the MPPT controller and maybe you're at 40AH/day. Solar modules run at about 80% rated output under full sun so that's about 6.6A at 12V for a 100 watt module, You get roughly 5 sunhours per day (unshaded) so that would be about right to maintain your pod batteries almost indefinitely. By doing this in amphours you can ignore the battery round trip losses. If you say run both bikes down 50% a day that will take 672 watthours2*.5 = 672wh/day into the ebike batteries. 672/.95(MPPT)/.80 (module)/5 (sunhours)=about 176 watts. Add the two and you are around 250-300 watts solar give or take. One thing you could consider is to roof mount a single 300 watt +- large grid tied module. That should fit behind the a/c shroud and run edge to edge on the pod roof, so no holes in the fiberglass. Those modules can be had for as low as around 50 cents a watt so they're really cost effective. That's the direction I'm heading for my solar installation.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

Motor7 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Jan 2019 Location: E. TN Online Status: Offline Posts: 196	Posted: 13 Feb 2019 at 9:49am
	I have a older Boily Pro 3600 Si, which is a Yamaha knock off. But it's too large for this set up( I'm getting lazy about lugging it around). I am considering a Honda 2200, but will it really run a 13.5 actually w/soft start? I like the two panel idea, one in front of a/c, one in rear. Might be able to fit two large ones like you are suggesting..have to measure.
	2016 R-Pod 176T

Motor7 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Jan 2019 Location: E. TN Online Status: Offline Posts: 196	Posted: 13 Feb 2019 at 9:52am
	OG, thanks for breaking it all down in layman's terms...it helps!
	2016 R-Pod 176T

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 13 Feb 2019 at 10:40am
	The device I'm using is the Microair Easy Start. Expensive but it works very well. Some folks use hard start capacitors successfully which are much much cheaper. For others they haven't worked. YMMV. The big grid tie modules are about 39 wide 77 inches long and around 280-350 watts. So you could put one behind and one in front of the a/c shroud if you remove the TV antenna (at least in my 179) and get as high as 600-700 watts, if you ever needed that much. If you don't watch TV anyway that's not a hardship, and you could use the standpipe from the antenna as a chase to get the conductors from the solar modules inside. The big modules weigh about 50 lbs though so adding 2 will be about an extra 100 lbs on the trailer. I want to remove my heavy noisy inefficient roof a/c and mount 3 modules up there, for about 1kW, but then I'm a solar geek.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

Motor7 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Jan 2019 Location: E. TN Online Status: Offline Posts: 196	Posted: 14 Feb 2019 at 5:24am
	Try a Coleman Polar Cub 9200btu. It is much more quiet then the turboprop sounding 13.5..... I was actually shocked the first time it came on...could not even hear myself think. 1450 watts vs 1729. We got rid of TV when I finished our log house in 2011. We still have a tv for dvd or streaming movies, but no "channels"....it's been glorious Edit: I think the Coleman Mach 8 has replaced the Polar Cub...maybe someone here has owned one and can comment on the fan noise level?
	2016 R-Pod 176T

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 14 Feb 2019 at 6:53am
	I heard those are quieter, but my objective will be to clear the entire pod roof area for solar so I don't want any type of roof air. I'm working up a mod for a high SEER inverter minisplit installation, with the condenser on the tongue where the batteries are and the evaporator on the left side wall above the bed in the 179. The current generation of minisplits are about 2x the efficiency of RV roof airs. Then with a salvage 24V 5kwh Tesla battery module and a 24V 2kw inverter, I ought to be able to get through a night of a/c use boondocking without a genny. We've been cable and antenna less since 2008, streaming entertainment, internet news and weather. Cellular data service works fine camping most places, if not we can play a movie. Never going back either.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold