Solar Panel to charge battery

[ScottBrownstein]

Paulie1138, No insult intended. If the panel delivered 9.9 amps at 50 volts, they would have sold it to you as 500 watt panel. Perhaps that is just the open circuit voltage and short circuit current. Max current on a really good day with perfect alignment to the sun and a lossless MPPT controller would be 315/14 or 22.5 amps.

No matter, solar works and is a good way to go for silent, long term battery charging.

[babock]

Originally Posted by ScottBrownstein

Paulie1138, No insult intended. If the panel delivered 9.9 amps at 50 volts, they would have sold it to you as 500 watt panel. Perhaps that is just the open circuit voltage and short circuit current. Max current on a really good day with perfect alignment to the sun and a lossless MPPT controller would be 315/14 or 22.5 amps.

No matter, solar works and is a good way to go for silent, long term battery charging.

You are correct. You don't use short circuit current and open circuit voltage. Vmpp and Impp are the specs that determine watts of a panel.

When you calculate how much solar you need, you pretty much need to add 30% if you have fixed non tilting panels on your roof.

[Philkaty]

wife

[tomkatb]

Solar is absolutely useful on a rv.

Under minimal loads it likely will keep the batteries charged most of the time.

However, the question was a Hathaway 5er with a residual refrigerator. They also have electric cooktops and ranges on some.

I doubt there is enough surface area on the roof for enough panels to create 100 watts per hour 24/7. Plus batteries for shady days.

Someone talked about better panels. I am curious. Everything I see is 100 watts 12 volt stuff.

The technology is not there yet. I read about a a guy with $10,000 in batteries plus another fortune in controls and panels, operating A/C on batteries a while. With solar supplemental. With a back up automatic generator.

[babock]

Originally Posted by tomkatb

Solar is absolutely useful on a rv.

Under minimal loads it likely will keep the batteries charged most of the time.

However, the question was a Hathaway 5er with a residual refrigerator. They also have electric cooktops and ranges on some.

I doubt there is enough surface area on the roof for enough panels to create 100 watts per hour 24/7. Plus batteries for shady days.

Someone talked about better panels. I am curious. Everything I see is 100 watts 12 volt stuff.

The technology is not there yet. I read about a a guy with $10,000 in batteries plus another fortune in controls and panels, operating A/C on batteries a while. With solar supplemental. With a back up automatic generator.

There are many panels available over 100w. You don't have to go with Chinese made Renogys either. My US panels were $165 for 175w.

[Philkaty]

Originally Posted by babock

There are many panels available over 100w. You don't have to go with Chinese made Renogys either. My US panels were $165 for 175w.

I have a Windy Nation system 200 watts. Not installed yet ( need time). What about wind power?

[Paulie1138]

Tomkatb, this is what I have found and works for me.

Look into residential or commercial grid-tied panels. A bit larger than some of the 12v stuff. Can be had inexpensively off Craigslist. Downside, you will need an MPPT controller which is more expensive than the PWM. Biggest advantage I have found are fewer panels, less wiring, more current, smaller wire size, better in shade.

Basically, a PWM will only use 13-14v out of the 18-20 volts and current produced by the panel. The high voltage panels 36volts or more, with the MPPT, will take the excess voltage and convert it to 12-14v, and as a result, you get a good boost in current.

In a nutshell, PWM controller on a smaller system, maybe around 200 watts or larger, then consider MPPT. Allow for expansion in your system.


There are many other factors with either system. Research is your friend. There are many threads and opinions out there.

[babock]

Originally Posted by Philkaty

I have a Windy Nation system 200 watts. Not installed yet ( need time). What about wind power?

A kit is ok if you don't really know what to buy. Depends on your budget. You can buy a 200W US made panel here for $185

https://www.continuousresources.com/...panel-5-busbar

You can then decide on the best controller. PWM controllers are pretty cheap. Personally, I think it's worth it to buy a Victron MPPT for a little more money. For a 200W solar panel, you can buy this one or get a larger one with room for exoansion
https://www.continuousresources.com/...er-w-bluetooth

I have no experience with wind power but if I was in a place that had enough wind to make it worth it, I wouldn't want to be in that place in the first place.

[Philkaty]

Originally Posted by babock

A kit is ok if you don't really know what to buy. Depends on your budget. You can buy a 200W US made panel here for $185

https://www.continuousresources.com/...panel-5-busbar

You can then decide on the best controller. PWM controllers are pretty cheap. Personally, I think it's worth it to buy a Victron MPPT for a little more money. For a 200W solar panel, you can buy this one or get a larger one with room for exoansion
https://www.continuousresources.com/...er-w-bluetooth

I have no experience with wind power but if I was in a place that had enough wind to make it worth it, I wouldn't want to be in that place in the first place.

WOW, that is about what I paid for my kit. Thanks

[babock]

Originally Posted by Philkaty

WOW, that is about what I paid for my kit. Thanks

You would have to get your own mounts but I made mine out of 2" aluminum angle and they are WAY better than what comes with the kits.

You would also need your own wire as well.



These are the 175W panels that this same seller used to sell. Now they sell 185W and 200W panels.

[Philkaty]

Originally Posted by babock

You would have to get your own mounts but I made mine out of 2" aluminum angle and they are WAY better than what comes with the kits.

You would also need your own wire as well.



These are the 175W panels that this same seller used to sell. Now they sell 185W and 200W panels.

I went to there website and checked them out thanks

[babock]

Originally Posted by Philkaty

I went to there website and checked them out thanks

I see you are So-cal as well. If you are ever up in the San Fernando Valley, you can check out my install.

[Philkaty]

Originally Posted by babock

I see you are So-cal as well. If you are ever up in the San Fernando Valley, you can check out my install.

I grew up in Sun Valley. I haven't been there in years. Went by my old house and it had bars on the windows, sad.

Thanks for the invite, maybe one of these days. Do you get down to Knott's Berry Farm or Disneyland? We go to Glamis a lot also.

[babock]

Originally Posted by Philkaty

I grew up in Sun Valley. I haven't been there in years. Went by my old house and it had bars on the windows, sad.

Thanks for the invite, maybe one of these days. Do you get down to Knott's Berry Farm or Disneyland? We go to Glamis a lot also.

Not with the trailer!

Yep, sun valley is not the same anymore.

[NV555]

Thanks for all the great info here great place to start my project

[KRedburn]

Might want to check on these panels.

www.itekenergy.com

370 watt panel. made in USA

I have not studied these to see if they would work. Comments from others would help.

[babock]

Originally Posted by KRedburn

Might want to check on these panels.

www.itekenergy.com

370 watt panel. made in USA

I have not studied these to see if they would work. Comments from others would help.

They will work. Just have to add more mounts to make sure they don't flex.

The problem some people have with bigger panels is the real estate on the roof. In some instances, you can get more wattage with slightly smaller panels.

The advantage, of course, is less panels to cable up.

[madsledet]

Originally Posted by johntaylor

Nonsense. I am a full-time boondocker, and I live just fine on a Renogy 100 watt suitcase solar panel. Thousands of others do too. I've only used my generator for 3 hours total this year, on a couple of occasions when I had multiple days of rain.

Can you list what devices you use in from the solar panel to the battery? Including the connections?


Thanks.

[WolfWhistle]

One time, just one time I would like to see a post that isn't highjacked. Or one where two people actually know what they are talking about. Thank you ScottB for the accurate information.
WW

[changing it up a bit]

Go to https://gpelectric.com/go-power-solar-sizing-guide/. You can size your system based on needs. FYI, This is the vendor that my rig was pre-wired for.