Typical battery charge time with 200w or 400w solar

[treemaze]

My 2020 UMB came without factory solar panels, and I found 8 AWG solar prewire behind both these panels:



The wire terminated in the back of the battery compartment but did not go to the roof. I didn't see a good way to drill up to the roof from either location (they're close to the roof edge). It would be easier to drill up to the roof from the cabinet between the arrows, and it's possible to connect to the prewire from there (probably with a bit of exposed wire in the top of the cabinet). Depends on your floorplan of course.

I decided the best way to hide the solar install was to drill up to the roof from above the pantry and run new wire. In the UMB it's easy to route wire from battery or inverter to the pantry. The solar charge controller wouldn't fit in the battery compartment but it did fit next to the inverter.

 

[SSTraveler]

Short answer is Yes, you have to run a wire pair from the roof to the Leisure solar prewire location which in turn runs to the house battery box. When I did my install I didn't drill any new holes in the roof. I used an existing hole that Leisure used to run the radio GPS and Sirius antennas. Others have drilled a single hole for their installations. The good thing is that it doesn't have to be very big for a #10 wire pair (minimum size of roof down wire) to fit. There are lots of solar install threads if you do a one word thread title search you'll get lots of info for your own install. I totally agree with you that you can do a solar installation yourself and it will be seriously less expensive and superior to anything Leisure is offering. Plus you have this group to help you every step along the way. Based on my experience I know you'll be glad you installed your own high quality system!

 

[Vantastic.pa]

I believe you're asking a difficult question to get actual experiences because when someone is running solar it is usually keeping their system topped off. And they always have some draw like their fridge. In my mind if you have a solar panel (200w) that allows for you batteries to be depleted to 50% while I'm the sun then you don't have enough solar. If you can fit more add more. Personally I have a 300w panel that actually performs the 300w I have seen up to 320w coming in, not often. But that keeps my 300ah battery bank topped off at 98-99% while running my dometic fridge freezer combo on 120v so the inverter is running on that as well, and I don't have any issues. When I find my self camping in the woods with little to no light on the panel i loose about 10% battery a day under normal use of lights, water pump, diesel heater if needed. So it's hard to say but I would go with the 400w. It will be much better in the long run if you want to spend any time in the north during winter when the sun is not up very long.

 

[michaelh]

Michael,

Thank you for sharing your data. The heaviest use case of the batteries for my case will be when attending astronomy star parties where I will run my astronomy equipment at night of the batteries. In most cases I will be out in the middle of a field without any trees for obvious reasons and plenty of sun. These take place during the months of April through Sept. so, again, a fair amount of sun exposure. So I will have a better than average 'solar day" compared to camping in the winter and under shade. Charging on the road doesn't help this use case since I will be parked for 5 or more days.

Right now I have 400w of the factory flex panels on order and have to decide if I want to cancel it and do my own after market upgrade with rigid panels and Li batteries, or reduce the order to 200w of flex panels with the standard AGM batteries to see what my needs really are and then do the upgrade in a year. But there are lots of threads on that topic and I don't want to turn this into another one of those.

Would love to hear a few more actual experiences just to be clear.

I love that you're doing astronomy - me too! I have a little 127mm Mak-Cas. If you're referring to a Go-To scope, they don't use much power. I drive mine off a Celestron Power Tank. For the situation you're describing, I reckon 400W should do you fine. All the best!

 

[curtismacc]

Michael

That's great.

Yes, mounts can draw surprisingly little when just tracking the stars. Smaller mounts draw as little as a few watts but my MyT uses 9-10watts tracking and more slewing. Add to that cameras, cooling fans, a heater, powered USB hub and I am using anywhere from 25 - 30watts. So an 8 - 10 hour night would require around 200 - 300watts. Now that doesn't include a laptop which can drive this up much higher.

 

[Klipstr]

Michael,

Thank you for sharing your data. The heaviest use case of the batteries for my case will be when attending astronomy star parties where I will run my astronomy equipment at night of the batteries. In most cases I will be out in the middle of a field without any trees for obvious reasons and plenty of sun. These take place during the months of April through Sept. so, again, a fair amount of sun exposure. So I will have a better than average 'solar day" compared to camping in the winter and under shade. Charging on the road doesn't help this use case since I will be parked for 5 or more days.

Right now I have 400w of the factory flex panels on order and have to decide if I want to cancel it and do my own after market upgrade with rigid panels and Li batteries, or reduce the order to 200w of flex panels with the standard AGM batteries to see what my needs really are and then do the upgrade in a year. But there are lots of threads on that topic and I don't want to turn this into another one of those.

Would love to hear a few more actual experiences just to be clear.

Yes, you want to cancel your factory panels and do this on your own. You will be able to have more efficient rigid panels, a better charge controller and the Li batteries for what the four panels from LTV would cost.

I have four 100W Renogy panels. I see between 280W and 400W depending on time of year/day. In July when we were out I routinely saw 380W at noon. That had fallen to around 320W by the last trip a couple of weeks ago. Sun angle plays a definite role! That said, we charged our 30% depleted 220AH battery bank in several hours. At high summer sun you will see around 7A per panel.

 

[curtismacc]

As I said I plan to eventually have 400w of solar one way or another. Are the glass panels (I know there are many different ones out there) compatible with the flex panels. If I get 200w of the factory flex and later want to install 200w with glass panels can I add them into the circuit the same as if they were all 4 flex or all 4 glass panels?

 

[Klipstr]

Yes you can. You will want to replace the charge controller they provide with a better MPPT controller. The forum consensus seems to be the Victron 100/30 or 100/50. You'll then wire the four panels in a series parallel combination to improve performance...

If you look at the price of this charge controller and four Renogy 100W panels, add $200 for miscellaneous stuff you will see just how much extra the LTV option is costing you. That might help you alter your plans!

 

[curtismacc]

Thanks Klipstr. For sure I would save a lot of money even assuming I use upgraded components. The only reason I would get the factory 200w is that I don't have to drill any holes in the roof and I have at least minimal solar immediately. I might not have time to get to the installation for a while.

 

[Klipstr]

There is that but with Covid you have plenty of time. And you can ask LTV to do the prewire for you. I did that in my rig and they ran the roof wire to the spot where the charge controller would normally be and then wire from there down to the battery. So it's all there. Generally folks have found the best way into any of the Unity floorplans so drilling that hole, while a bit disconcerting, is not difficult. I just have a hard time spending $$$ on something I can do better myself. But I get your point.

 

[sprint2freedom]

FWIW. I started with 400W of solar and upgraded to 600W. It would have been easier if I had just started out with the amount I knew I wanted eventually. The difference in terms of cost and effort were actually fairly small.

I suspect you won't learn much from having a 200W system first except the feeling of "free" power raining down from the heavens and that you could have collected double the amount by choosing double the panels.

At what latitude(s) and what time(s) of year are you expecting to generate power? Winter can be very different than summer for solar. Depending on latitiude, days are (much) shorter, weather is (much) cloudier, solar angle is (much) lower, and panels tend to get obscured by snow or leaves. I have seen as little as 10 watts produced from my 600 watt array at noon near the winter solstice, and in excess of 700 watts in the summer in the sunny Southwest. Tilting panels may provide a significant improvement in winter at high latitudes, but I didn't want the hassle.. too dark and too cold to be up on the roof for a meager harvest anyway.

 

[sprint2freedom]

Solar Resource Data, Tools, and Maps

www.nrel.gov

Scroll down to Global Horizontal Irradiance (GHI) section and have a look at the maps of Monthly Averages. Compare summer months with winter months for a little taste of what I'm talking about..

 

[curtismacc]

Sprint2freedon - My RV will get the vast majority of use between April and Oct. No plans to do any winter traveling unless it is to warmer southern states. As I said, I will be out in the middle of a field, usually with no trees to obscure the views of the night sky. All different latitudes from Maine to Florida, Washing to southern Cal and in between. Lots of sun raining down for solar, but also lots of heat to deal with.

Klipstr - thanks for the input. Still mulling over my final decision which I need to make very soon since the build starts in Dec.

 

[DiverBob]

I am located in Michigan and now with the sun being firmly in the southern skies, my 600 watts of solar panels is pulling in a peak of 320 watts or 1.33 kw as for yesterdays daily total. Of course I start getting useful output around 0745 AM until 5 PM at night, so much reduced input from the sun. Now you could use this to extrapolate how much useful energy will a 200 watt array give you this time of the year. I really like the having the extra power (next weekend will be 4 days of primitive camping so whatever sun I can get will be appreciated) and wish I had done this much earlier. I got my LTV with 400w and just lived with the limitations of the system LTV installed. If I hadn’t gotten it like that from the factory I would have added the better setup much sooner!

 

[sprint2freedom]

Lots of sun raining down for solar, but also lots of heat to deal with.

Then you may wish to opt for non-flexible panels as the flexible type tend to get very hot. That contributes to a short lifetime as well as decreased output (colder panels perform better). Rigid panels are typically mounted with a small air gap underneath.

 

[curtismacc]

Since it gets awfully hot out in a treeless field in the spring and summer, we astronomers typically use aluminet cloth to shade our tents, shelters, etc. It comes in 40% to 80% reflectivity cloth sheets which can be cut to order. It is extremely light weight but bulky. I was thinking that with glass panels it would be easy to cover the roof and the sunny side of the RV with this and and still let the suns rays illuminate the panels but keep the RV much cooler. It works best when there is a dead air space between it and the tent, shelter, RV, etc. Another reason to avoid the flex panels.

I am going to confirm that I can get LTV to run the wires up to the roof which I think they would do a lot better than I. If so I think I will do my own 400w of glass panels.

Here is an example of the shade cloth: https://www.greenhousemegastore.com...in?returnurl=/coverings/shade-cloth/?count=60

 

[autostaretx]

Decisions, decisions ... what species is a Sprinter?



--dick

 

[sprint2freedom]

Not sure if that was a serious inquiry, but I would recommend a higher density on the theory that if it's sunny enough to put up an awning, you'll want the "best" shade possible.

 

[Gamma1966]

Solar Resource Data, Tools, and Maps

www.nrel.gov

Scroll down to Global Horizontal Irradiance (GHI) section and have a look at the maps of Monthly Averages. Compare summer months with winter months for a little taste of what I'm talking about..

Another valuable tool is on the web and if you plug in your street address or position co-ordinates it will show you what the sun irradiance is on that spot for ever minute of everyday of any year! https://www.suncalc.org
I use it at home to monitor solar input on my solar panel array on my house.

 

[curtismacc]

Agreed, if it is a serious question I use 70 or 80% shade cloth to reflect the maximum sunlight. It becomes a trade off between reflectivity and how much wind can pass through without causing the shade to sail.