Thinking about installing the Renogy 20 amp DC to DC charger

[Wavery]

What a coincidence. We live in Fallbrook (N County, SD).

I checked with the guy that I bought my 320W panels from and he is out.

[Rob Culver]

Originally Posted by Wavery

Rob,

I buy a lot of solar panels off craigslist. I've never gotten a bad one. Here's a 375W panel that should fit nicely on the rear shell of your TM. It's 78" x 40".

If I got it right, you live in Orange County.

Do a search on CL for "solar panels". There's a ton of them, even brand new ones for around $0.50 per watt. I found mine ( in Menefee (brand new) for $0.45 per watt and they are bifacial.

The 1st thing that you need to consider is your battery storage. That's where it starts getting costly. A 280ah LiFeP04 battery will cost you around $550 (with coupon). Then you need an MPPT solar controller and misc hardware..... ~ $150-$200.



https://orangecounty.craigslist.org/...767753654.html

https://www.amazon.com/CHINS-LiFePO4...1zcF9hdGY&th=1

https://www.amazon.com/Victron-Smart...s%2C170&sr=8-2

Thanks Wayne,
I saw this ad on craigslist for new 370 watt panels. It's not bifacial but the price per watt seems very good at only $120. But don't know anything about the brand name, reliability, or accuracy of the 370 watt rating. Would the same watt rating on a non bifacial panel like this be just as good?

https://sandiego.craigslist.org/esd/...769558724.html

[Wavery]

Originally Posted by Rob Culver

Thanks Wayne,
I saw this ad on craigslist for new 370 watt panels. It's not bifacial but the price per watt seems very good at only $120. But don't know anything about the brand name, reliability, or accuracy of the 370 watt rating. Would the same watt rating on a non bifacial panel like this be just as good?

https://sandiego.craigslist.org/esd/...769558724.html

Just take a multimeter with you. It should put out 38.2V open circuit in full, direct sunlight. If it does, you should be good. Looks like a perfect size for what you want to do. I think that you would be quite happy with it.

[ShrimpBurrito]

Don't know if it matters, but that 370W panel is made in Cambodia.....

Dave

[Rob Culver]

Originally Posted by Wavery

Rob,

I buy a lot of solar panels off craigslist. I've never gotten a bad one. Here's a 375W panel that should fit nicely on the rear shell of your TM. It's 78" x 40".

If I got it right, you live in Orange County.

Do a search on CL for "solar panels". There's a ton of them, even brand new ones for around $0.50 per watt. I found mine ( in Menefee (brand new) for $0.45 per watt and they are bifacial.

The 1st thing that you need to consider is your battery storage. That's where it starts getting costly. A 280ah LiFeP04 battery will cost you around $550 (with coupon). Then you need an MPPT solar controller and misc hardware..... ~ $150-$200.



https://orangecounty.craigslist.org/...767753654.html

https://www.amazon.com/CHINS-LiFePO4...1zcF9hdGY&th=1

https://www.amazon.com/Victron-Smart...s%2C170&sr=8-2

Another question for you Wayne:

You suggested the Victron MPPT 75/15 charge controller, but I'm thinking that would not be big enough for a 300 watt solar panel that I'm looking at considering that the output amperage could theoretically go as high as 25 amps.
Which model would you recommend for a 300 watt panel? The 100/30 one?
One thing I noticed about that model is that unlike the 75/15 it requires a grounding wire. Since I would be looking to drop in replace the current PWM controller from the factory which is located near the sink, where is the closest place to hook up a ground wire under the sink? I see that there is a large metallic water heater close by but does that metal connect to the chassis ground? If not, any ideas where the best place to attach a ground wire is? Thanks to you or anyone else reading this for your advice.

[Wavery]

Originally Posted by Rob Culver

Another question for you Wayne:

You suggested the Victron MPPT 75/15 charge controller, but I'm thinking that would not be big enough for a 300 watt solar panel that I'm looking at considering that the output amperage could theoretically go as high as 25 amps.
Which model would you recommend for a 300 watt panel? The 100/30 one?
One thing I noticed about that model is that unlike the 75/15 it requires a grounding wire. Since I would be looking to drop in replace the current PWM controller from the factory which is located near the sink, where is the closest place to hook up a ground wire under the sink? I see that there is a large metallic water heater close by but does that metal connect to the chassis ground? If not, any ideas where the best place to attach a ground wire is? Thanks to you or anyone else reading this for your advice.

Maximum output for that panel is <11A and 34.2V. The controller that I listed will handle 15A and 75V. It should be fine for 1, 370W panel. If you ever wanted to add a second 370W panel, just wire it in parallel. That would be a max output of 69V and 11A. Within the tolerance of that 75/15 Victron controller.

[Rob Culver]

Originally Posted by Wavery

Maximum output for that panel is <11A and 34.2V. The controller that I listed will handle 15A and 75V. It should be fine for 1, 370W panel. If you ever wanted to add a second 370W panel, just wire it in parallel. That would be a max output of 69V and 11A. Within the tolerance of that 75/15 Victron controller.

Thanks for the quick reply Wayne. I'm a little confused though because it looks to me like the 15 in 75/15 refers to the output current to the battery and not the current coming from the Panel. Have you ever seen one of these 75/15 controllers deliver more than 15 amps sustained to the battery?

See this chart from the Victron site in which they show a maximum of 15 amps battery current for the 75/15

https://www.victronenergy.com/media/...fications.html

[Wavery]

Originally Posted by Rob Culver

Thanks for the quick reply Wayne. I'm a little confused though because it looks to me like the 15 in 75/15 refers to the output current to the battery and not the current coming from the Panel. Have you ever seen one of these 75/15 controllers deliver more than 15 amps sustained to the battery?

See this chart from the Victron site in which they show a maximum of 15 amps battery current for the 75/15

https://www.victronenergy.com/media/...fications.html

The "75" refers to the maximum allowable voltage coming from the solar panel array. The "15" refers to the maximum allowable amps coming from the solar panel array and the maximum amps that the controller will handle.

The job of an MPPT charge controller is to take whatever V and A that it is given (within the 75/15 limit) and convert that current into the maximum amps that the battery will take @ 14.4V (for lithium). If the battery is low, the solar controller will increase the amperage going into the battery by decreasing the input voltage from the solar panel, from (say) 30V to 14.4V. That will dramatically increase the controller output amperage from (say) 9A to 15A. Your 200ah LiFeP04 battery will accept up to 100A from your solar controller (although it will never output that much). That is the beauty of lithium.

[Rob Culver]

Originally Posted by Wavery

The "75" refers to the maximum allowable voltage coming from the solar panel array. The "15" refers to the maximum allowable amps coming from the solar panel array and the maximum amps that the controller will handle.

The job of an MPPT charge controller is to take whatever V and A that it is given (within the 75/15 limit) and convert that current into the maximum amps that the battery will take @ 14.4V (for lithium). If the battery is low, the solar controller will increase the amperage going into the battery by decreasing the input voltage from the solar panel, from (say) 30V to 14.4V. That will dramatically increase the controller output amperage from (say) 9A to 15A. Your 200ah LiFeP04 battery will accept up to 100A from your solar controller (although it will never output that much). That is the beauty of lithium.

Thanks Wayne,
I went ahead and ordered the 75/15. Shouldn't be too difficult to install as it's not much bigger than the existing PWM controller and doesn't require a separate ground wire. Thanks again!

[Wavery]

Originally Posted by Rob Culver

Thanks Wayne,
I went ahead and ordered the 75/15. Shouldn't be too difficult to install as it's not much bigger than the existing PWM controller and doesn't require a separate ground wire. Thanks again!

Just be sure to hook up the battery first, then the solar panel.

Did you get that solar panel?