RV - 600 Watt solar with 2 DIY 280ah LiFeP04 batteries

[HomeTownHockeyFan]

Nice setup. Only concern when using parallel BMSs is, if there is large load and the other decides to cut off power fraction earlier, other might burn. They would need to be designed so they can be used in parallel. Other as a master unit, other as a slave.

Thanks for the feedback.

The only reason I don't think it is a big concern, is that is exactly the setup I would have if I had gone with a commercial solution like Battleborn...each of their batteries has a BMS in them, and would be hooked up in parallel for a 12 volt system.

 

[bdbugbee]

Details on my RV solar configuration

26’ Travel trailer (Rockwood Mini Lite 2509s)

Six 100 Watt roof mounted Polycrystalline Solar panels. (HQST)
Panels are wired in parallel pairs (2P3S)

View attachment 12073

Victron SmartSolar 150/35 charger with BlueTooth battery sensor

2000 watt pure sine wave inverter (Renogy)

View attachment 12075

Inverter is ‘hard wired’ to an Automatic Transfer Switch (Go Power)

Used switches or breakers to isolate the various components.

Replaced the standard RV Converter with one that supports Lithium (Wildkat)

Built two 280ah batteries using EVE cells. (Moved the batteries from the tongue of the trailer to the pass through storage to shift some weight off the tongue)

Using two of the 120ah SmartBMS's wired in parallel

View attachment 12074

Used 8 gauge wire for solar panels

Used 1/0 wire for all battery, charger, and inverter wiring (Even replaced the wires running from the RV power converter)

Was a lot of work…but, very pleased with the results so far.

Nice install. You should love all the energy storage these batteries have. I recently put together a 24V bank for home use using 8-280 ah cells in series and I really like the batteries. Question; how did you mount your solar panels to the roof of your RV? I'm trying to muster the courage to do that and I'm looking for no-drill options if possible except for the hole for the wires going down. Did you use screws and/or VHB/Eternabond? Have you had any issues with the roof mount? I'm looking for ideas and feedback. Thanks.

 

[HomeTownHockeyFan]

Nice install. You should love all the energy storage these batteries have. I recently put together a 24V bank for home use using 8-280 ah cells in series and I really like the batteries. Question; how did you mount your solar panels to the roof of your RV? I'm trying to muster the courage to do that and I'm looking for no-drill options if possible except for the hole for the wires going down. Did you use screws and/or VHB/Eternabond? Have you had any issues with the roof mount? I'm looking for ideas and feedback. Thanks.

Thanks for the the feedback. The roof on my RV is a rubber membrane, so not conducive to no-drill options.

I used traditional Z mounts with Eternabond under them, then used #14 X 1" Stainless Truss Head Phillips Wood Screws, and finally covered it heavily with Lap sealant. I did get the mounts close enough to the edge of the roof so that the screws on the sides went into the roof framing.

I have driven about 600 miles since the mount and they are holding up well.

I ran my wires down the awning mount so that I did not have to put a hole in the roof for the wires.

I hope this makes sense...please let me know if you have other questions.

 

[bdbugbee]

Thanks for the the feedback. The roof on my RV is a rubber membrane, so not conducive to no-drill options.

I used traditional Z mounts with Eternabond under them, then used #14 X 1" Stainless Truss Head Phillips Wood Screws, and finally covered it heavily with Lap sealant. I did get the mounts close enough to the edge of the roof so that the screws on the sides went into the roof framing.

I have driven about 600 miles since the mount and they are holding up well.

I ran my wires down the awning mount so that I did not have to put a hole in the roof for the wires.

I hope this makes sense...please let me know if you have other questions.

Thanks for your reply. I too have a Rockwood (2606WS) and I'm nervous about drilling holes in the roof. I'll get over it. lol

 

[HomeTownHockeyFan]

Thanks for your reply. I too have a Rockwood (2606WS) and I'm nervous about drilling holes in the roof. I'll get over it. lol

Once you have been on the roof of any RV and seen the amount of Lap sealant that is on there, you will realize that more holes and more Lap sealant won't make things any worse.

 

[dashdrum]

Will that inverter run the microwave in all modes?

Side comment about sleep mode: When I put my AIMS inverter in Power Saver mode, the RV microwave will beep every few seconds when the inverter checks for demand. Makes that mode pretty useless.

 

[Electric Personality]

Side comment about sleep mode: When I put my AIMS inverter in Power Saver mode, the RV microwave will beep every few seconds when the inverter checks for demand. Makes that mode pretty useless.

Good to know, didn’t even think of that. With your current setup, is it an issue to just keep the inverter hot, or do you only turn it on as needed?

 

[dashdrum]

Good to know, didn’t even think of that. With your current setup, is it an issue to just keep the inverter hot, or do you only turn it on as needed?

We haven't boondocked yet, but we have it on while driving to run the fridge.

 

[HomeTownHockeyFan]

I am using the Renogy 2000W 12V Pure Sine Wave Battery Converter, which so far seems to do a good job of ramping up when needed, and ramping down when not using much power. I leave it on most of the time, and have seen no issues.

https://www.amazon.com/gp/product/B07H9SXV61/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=

 

[Electric Personality]

I am using the Renogy 2000W 12V Pure Sine Wave Battery Converter, which so far seems to do a good job of ramping up when needed, and ramping down when not using much power. I leave it on most of the time, and have seen no issues.

https://www.amazon.com/gp/product/B07H9SXV61/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=

What happens to the microwave when it cycles up/ down? If it beeps, I may install a switch on it to turn off the mains.....

 

[HomeTownHockeyFan]

What happens to the microwave when it cycles up/ down? If it beeps, I may install a switch on it to turn off the mains.....

With the Renogy Converter, there is not a drop in power as it ramps up to handle increased load, so the microwave behaves as thought it always had full power, and no beeps or blinking lights happen.

 

[Electric Personality]

With the Renogy Converter, there is not a drop in power as it ramps up to handle increased load, so the microwave behaves as thought it always had full power, and no beeps or blinking lights happen.

Incredible, I thought it worked entirely different! Thanks.

 

[hclarkx]

On the wire chafing, my plan is to put sealant of some kind on the pass through hole to keep them from moving...was holding off till I was sure I did not need to run another wire through there. Open to other suggestions as well.

Be sure the sealant is mouse-proof. I left the battery hatch open once with a wire running out of it and along the ground. Mice thought that was their ladder. From there they got into the basement and from there into the living area. Fortunately we had two cats with us.

 

[hclarkx]

A note of caution, how much you can overpanel/oversize your PV array, depends on your specific controller. The most important considerations are keeping your array Voc below and Isc below the controllers max input voltage and current. With Victron those are the only limits that matter, with some other controllers like Epever, and Renogy, you have to pay attention to total power (Watts) as well.

Victron has a good explanation of how it works with their controllers here

Good point; one easily overlooked. As one data point, my Epever 40A Tracer 4015BN is limited to 138V (open circuit) and 1560Watts input (520 W output). I believe the lower rated Tracer models are all 138V and input three times output. I haven't looked at their other lines.

 

[Mike Jordan]

Very nice build. I am trying to picture wires, and opening the awning. Do you have more pictures on how you did the PV wire in the awning?

 

[HomeTownHockeyFan]

Thanks. I don't have pictures, but there are existing wires already in that awning arm (under the black plastic strip that just pops out) and I just ran the wires beside the existing ones...and made a new hole into the camper just under the hole they used for the existing wires.

Fairly straight forward...let me know if you have other questions.

 

[Mike Jordan]

So.... under the fixed vertical arm on the side of the TT? I was picturing an arm that moved out with the awning

 

[HomeTownHockeyFan]

Correct...it runs down the part of the awning arm/support that does not move.

 

[Mike Jordan]

Correct...it runs down the part of the awning arm/support that does not move.

Geniousness. Thats going into my "file" for future use

 

[bdbugbee]

Once you have been on the roof of any RV and seen the amount of Lap sealant that is on there, you will realize that more holes and more Lap sealant won't make things any worse.

FYI, I finally got up enough courage to install 8 x 100 watt solar panels on my RV (4S2P configuration). I anchored 4-10' strut channels to the roof, then attached the panels to the strut channels as shown in the attached photo. I ran the cables down through a gland near the front into a cabinet over the bed, and down the wall to the battery compartment under the bed. The strut channel mounting allows me to remove the panels for roof maintenance without exposing new holes in the roof. I've gone about 2,000 miles down the road and they are solidly secure.