Legion Solar?

[cbr046]

I have an opporturnity to purchase a solar system a buddy bought for his RV.  2 panels (2x150W), 25V 100Ah LiFePO battery, Grid Controller, Inverter.  Two problems I see are 1.) It's a 25V system and 2.) There's no AC charging for the battery.  I could buy a charger, but the battery . . . .

https://legionsolar.com/index.html  or https://www.plxdevices.com/Legion-Solar-Do-it-Yourself-Solar-s/123.htm

It's clearly focused on residential roof mounting and solar charging only.  My buddy is no longer available so I can't ask what he was thinking.  I'm thinking pass because of incompatibility with the coach's 12V system.  It would have to be a completely separated system. 

Am I missing something?

- bob

Edited June 15, 2023 by cbr046

[jacwjames]

I guess you could buy a 24 volt charger to be able to charge the batteries.  The system could be installed an used as is but not sure how you'd integrate it with your current system. 

If the system is being sold at a really good price to make up the difference/aggravation of adapting the system it might be worth it

Edited June 15, 2023 by jacwjames

[CAT Stephen]

4 hours ago, cbr046 said:

I have an opporturnity to purchase a solar system a buddy bought for his RV.  2 panels (2x150W), 25V 100Ah LiFePO battery, Grid Controller, Inverter.  Two problems I see are 1.) It's a 25V system and 2.) There's no AC charging for the battery.  I could buy a charger, but the battery . . . .

https://legionsolar.com/index.html  or https://www.plxdevices.com/Legion-Solar-Do-it-Yourself-Solar-s/123.htm

It's clearly focused on residential roof mounting and solar charging only.  My buddy is no longer available so I can't ask what he was thinking.  I'm thinking pass because of incompatibility with the coach's 12V system.  It would have to be a completely separated system. 

Am I missing something?

- bob

Bob,

 

I'll walk you through the process:

- Do you have pre-existing wiring from your roof to the compartment or room where you will keep your inverter?  If you do, what is the gage of the wire?

- What type of batteries are you trying to charge (Lead Acid, Lithium, ect.)

- What is the make and model number of your existing inverter? 

 

[Rocketman3]

To me this would be a pass… (to add to a MotorHome).

1. The lithiums are only 100ah @ 24v.  That’s equivalent to a 200ah 12v battery- not a very big battery. 

2. This would just be “additional equipment” on your MotorHome- you probably could not remove anything. 
 

3. it would take more stuff to make it work seem less in the RV. 
 

4. to add solar to your rig, it would probably be better to pick out the panels for the perfect size for your roof. 

Now it this is for a shed, etc… maybe…

[cbr046]

@CAT Stephen The LiFePO battery is included, but it's 25V.  I think our inverter is a Xantrex.  This inverter wouldn't be compatible.  The whole system would be independent of the current system.

@Rocketman3 I can't envision integrating this into the coach . . . . which is why I'm asking if I was missing something.  Too many trees at the house, and too many generators to cover an outage.  Definitely seems like a "pass". 

- bob

[CAT Stephen]

17 hours ago, cbr046 said:

@CAT Stephen The LiFePO battery is included, but it's 25V.  I think our inverter is a Xantrex.  This inverter wouldn't be compatible.  The whole system would be independent of the current system.

@Rocketman3 I can't envision integrating this into the coach . . . . which is why I'm asking if I was missing something.  Too many trees at the house, and too many generators to cover an outage.  Definitely seems like a "pass". 

- bob

Thanks Bob,

 

If you are not using the system with your inverter, then you can't use it with your batteries since your batteries are connected to your inverter except for the 24V Lithium you mentioned.  And Lithium can't be used on your chassis side as Lithium chemistry is not compatible for starting and you chassis side is not 24V compatible.  Here are my revised questions for you:

- What is your use case for the new solar system since your lead acid house batteries are connected to your inverter which is 12V, is not lithium compatible, and is not 24V compatible, and also can't be used with your chassis batteries?

- Do you have pre-existing wiring from your roof to the compartment or room where you will keep your inverter?  If you do, what is the gage of the wire?

[cbr046]

38 minutes ago, CAT Stephen said:

Here are my revised questions for you:

- What is your use case for the new solar system since your lead acid house batteries are connected to your inverter which is 12V, is not lithium compatible, and is not 24V compatible, and also can't be used with your chassis batteries?

- Do you have pre-existing wiring from your roof to the compartment or room where you will keep your inverter?  If you do, what is the gage of the wire?

Because of these incompatibilities of 12V / 25V system it's not going to work as an integrated unit.  I won't be buying it, no matter the price.

And yes, there's pre-existing wiring for one roof panel.  The gauge is so small any additional panels would need new wiring pulled.

- bob

[CAT Stephen]

12 hours ago, cbr046 said:

Because of these incompatibilities of 12V / 25V system it's not going to work as an integrated unit.  I won't be buying it, no matter the price.

And yes, there's pre-existing wiring for one roof panel.  The gauge is so small any additional panels would need new wiring pulled.

- bob

Bob,

 

Good call to pass on the Lithium batteries, but your existing wiring will be suitable, depending on the gage of the existing wiring. As an example, 14 gage wire was used on most Monaco Coaches in the early to late 2000s for the factory 60 watt solar panel.  So, at 24 VDC (VOC of a 12V panel), this wiring had some spare amp capacity. As 12V solar panels are rated at 24V VOC Volts output, here is the detail: 

- The capacity of 14 Gage stranded wire with 60C rated insulation, a 10 feet total wire loop with a 4% voltage drop specification typically used for Monaco factory solar panel wire runs from the roof are rated at 11 Amps

So, if you wire your solar panels in a combo parallel & series array, and use a high voltage MPPT solar controller, the existing factory wiring is entirely suitable.

 

Here is the configuration I used to install a substantial 1.2Kw solar panel array on my roof using that Monoco factory thin 14 gage stranded copper wire:

- Total of 12 Renogy 100 Watt Solar panels.

- Each Renogy 12V solar panel is rated at 24VDC VOC and a rated maximum output at 5.21 Amps

- Panels are wired as two (2) arrays wired in parallel with each array consisting of six (6) panels each wired in series

- Each array runs at 144 Volts DC at 5.21 Amps @ 77 Degrees Fahrenheit

- The arrays are paralleled in a combiner box for an aggregate output of 144 VDC @ 10.42 Amps (i.e. close to fully utilizing the 11 amp capacity of the 14 gage stranded copper wire if I were parked on the equator at noon on a perfectly clear day.)

To compensate for extreme high voltage induced by very cold morning weather (this condition is referred to as HyperVOC), I am using a Midnight Solar Classic 200 solar controller so that my solar controller doesn't experience over-voltage destruction.  So, if I was winter RVing in Canada on a very cold morning at -40 degrees Fahrenheit, the VOC (Voltage Open Circuit) correction factor for my solar voltage output would be 1.25 thus:

- Each array runs at 144 VOC *1.25 = 180 VDC  at 5.21 Amps @ -40 Degrees Fahrenheit.

- My Midnight Solar Classic 200 Controller will handle a maximum of 200VDC, so I am safely within this solar controller maximum voltage of 200 VDC

 

Bob, I hope that the detail above provides you with insight as to how useful your existing 14 AWG factory solar panel wiring is so that you can potentially move forward with your solar project.  If you can attain lightly used solar panels for less that 50 cents per watt, you are getting a bargain.  But the solar panels must be a size that allows you to still access your roof.  Most standard residential solar panel don't work well in RV applications because they are just too large.  

 

 

 

Edited June 17, 2023 by CAT Stephen

[wamcneil]

Installing a solar system is a lot of work either way. If I were doing it again I would go 24v (and if a smokin’ deal comes along on a 24v inverter I still might).

In my case, going 24v would be easier than rearchitecting the system to properly deal with 200 amps @ 12v. Aside from the inverter, all of the other 12v loads are pretty small and could be handled with a 24-12v converter and maybe one small 12v battery. (assuming you’ve already replaced all the halogen ceiling heaters with LED lights).

That being said… Regardless of the system voltage… If you’re not already strongly motivated to go solar you’re probably right not messing with it and trying to adapt a system that wasn’t designed for your purpose. 
Cheers

Walter