Renogy - thanks Bob

[Seraphim]

Thanks Bob for pointing out the Renogy solar kits. I was having trouble finding solar panels to fit in the available space on top of the truck camper. Renogy has a four panel 400 watt kit, and the panel's aren't as wide as most. I could probably fit 6, if I wanted.

Haven't ordered it yet, because I want to call Renogy first. It seems the included PMW charge controller is positive ground, but the RV system is negative ground. There are apparently options. I also want an LCD display on the controller.

In addition, I'm wondering if I want to go with an an MPPT controller. The panel's are 12 volt, but I run them in series for 48v, or run pairs in series for 24v. Not sure if there are really any advantages, since I don't care about running thinner wire. I'd pay the extra money for MPPT if it were more effective, for temperature or other reasons.

What do you experts think?

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While I've got people's attention, does anyone see any problem with using the roof vent for the fridge as access point for the cables down to the controller? It would perfect in my case, as I want to mount the controller and LCD just beneath the fridge...

 

[akrvbob]

I'm satisfied a quality MPPT controller will pay for itself in the extra power it gives you and in superior construction. I think the only reason to use a cheap PWM controller like the Renology is because they are so cheap they are disposable. If it breaks you throw it away and get another one.

Vents are a standard method of bringing in wires on RVs.
Bob

 

[66788]

Most experts agree that if your solar system is less than 400 watts, there is not sufficient benefit to the MPPT over PWM to justify the cost. Larger systems, yes. My step van will be 480 watts and I chose the MorningStar TriStar 45 PWM as the charger of choice. The adjustable charge point settings is essential to achieve the 14.8 charging voltage for Trojan flooded batteries.

As to wiring the 4 panels in series, the disadvantage to that is if one panel gets shaded then your whole charging system is down. Individual panels in parallel will give quad redundancy. If one panel is shaded, the other 3 still produce full power.

 

[Seraphim]

Thanks for the input, all.

I think I'll go ahead with the kit 'as is' for convenience sake, and run them in parallel. It should do what I want, which is extend my time out without shore power.

I can upgrade later, if necessary. But right now, a 400 watt system for under $670 and free shipping - we decided that will be our Xmas gift to each other.

Reviews pretty much agree the system gives owners 20 amps, and since we only use about 25 amps a day, that should pretty much cover us.

 

[Seraphim]

Quick update:

If anyone else is interested - do not order the 400watt kit on Amzon for $670. The PCM controller is set up for positive ground, and in our Units we need negative ground. Negative ground is available, but you probably have to call Renogy to order it. I'm guessing it may add $20 to the cost, but maybe not.

Renogy has a 400 watt RV kit - $818 - which includes an upgraded negative ground PMW controller with LCD (about $100 more than a basic), but has 40' adaptor cables (about $70) and 16' battery cables (about $28).

I don't need those long cables, but like the better PMW charge controller ($129 alone). Going to call when they open and see if I can get a price break on shorter cables. They have a good customer service reputation. For the extra money, I'll also ask about an mppt controller.

Will update.

 

[Seraphim]

Here's the kit I ordered:


http://www.renogy-store.com/400W-RV-Kit-ViewStar-p/kit-rv400d-vs.htm

I looked at the mppt controllers, and - for the additional cost and our minimal needs - I stayed with the PMW. If I add panels later - and I really can't think of any reason we should - I can upgrade the controller.

I probably could have done it a bit cheaper, but with all the vents and the AC on the roof, the dimensions of these panels made them fit the jigsaw puzzle of available space quite easily. It's easy to fit two more of these panels on top, and I could possibly squeeze a total of 8 on. Then I could power the amp for my electric guitar lol. Maybe...

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Photos when I'm done. Should arrive next week.

 

[akrvbob]

That looks really good! It should serve you well!

Renology is quickly getting a reputation as the low cost leader in solar!

If your interested, I'd like to do a post of your install. It shouldn't be too hard or take too long. They key is lots of pictures. The text wouldn't have to be much more than a few paragraphs and captions explaining each picture. Number the captions to the pictures and I'll put it all together.

If you'd rather not, I totally understand.
Bob

 

[Bela's Mom]

Ok, I have a dumb question. I have the controller that is positive ground connected to my house battery. Why does it work? Is it because my house battery is not connected to my chassis battery which is negative ground? Is it because the panels are portable and not connected to my roof? I've read stuff but still can't wrap my brain around it.

My little set-up is simple. Controller to battery...fused of course. Solar panels to controller. The battery is connected to a converter/charger and an on board generator but not to an isolator or chassis battery.

 

[VanLifeCrisis]

i have the cheapo renology kit. i dont even know what a positive ground is lol i just wired them to my battery, pos to positive post and neg to negative post. it said in the manual the controller handles 400 watts i assumed it was the same one as the 400 kit. nothing melted at least...

 

[Seraphim]

That looks really good! It should serve you well!

Renology is quickly getting a reputation as the low cost leader in solar!

If your interested, I'd like to do a post of your install. It shouldn't be too hard or take too long. They key is lots of pictures. The text wouldn't have to be much more than a few paragraphs and captions explaining each picture. Number the captions to the pictures and I'll put it all together.

If you'd rather not, I totally understand.
Bob

Not a problem. My only concern is attaching the panel's without fasteners showing through on the inside. Have to take a look at the interior.

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Ok, I have a dumb question. I have the controller that is positive ground connected to my house battery. Why does it work? Is it because my house battery is not connected to my chassis battery which is negative ground? Is it because the panels are portable and not connected to my roof? I've read stuff but still can't wrap my brain around it.

My little set-up is simple. Controller to battery...fused of course. Solar panels to controller. The battery is connected to a converter/charger and an on board generator but not to an isolator or chassis battery.

I can only take a guess - I'll bet you have both positive and negative hooked up directly to the battery, and you're not using the frame as a ground. I'm not savvy enough to know for sure if it would work. If it does, one can order the cheaper 400 watt kit and not worry about it.

Maybe someone with more electrical know how would confirm my guess...

 

[Bela's Mom]

Thanks, Seraphim. Yes, I have both positive and negative from the controller hooked to the battery; it has worked fine since I installed it. I don't plan on changing my little set-up anytime soon but was just curious about it. I had read that one could use a positive controller on a negative ground chassis as long as the "load" was not electrically connected to the chassis. I didn't understand what load they were talking about. Need a picture, LOL.

I'm glad that you are able to get so many panels on your roof. You are going to really enjoy having it, I'm sure.

I would be interested in a write-up also if you decide to do one. I have a class B with all of the AC, vents, etc on the roof and may want to upgrade one of these years. I would be interested in seeing what you do.

 

[Seraphim]

Thanks, Seraphim. Yes, I have both positive and negative from the controller hooked to the battery; it has worked fine since I installed it. I don't plan on changing my little set-up anytime soon but was just curious about it. I had read that one could use a positive controller on a negative ground chassis as long as the "load" was not electrically connected to the chassis. I didn't understand what load they were talking about. Need a picture, LOL.

I'm glad that you are able to get so many panels on your roof. You are going to really enjoy having it, I'm sure.

I would be interested in a write-up also if you decide to do one. I have a class B with all of the AC, vents, etc on the roof and may want to upgrade one of these years. I would be interested in seeing what you do.

A car uses the frame like a return (negative) cable. The negative pole of the battery connects to the frame. Al devices (radios, brake lights, etc) also have their negative side attached to the frame. That way, you only have to run one wire - the postive wire - out to the device. Electricity runs from the postive side of the battery, to the device, but return to the negative side of the battery via the frame itself. The negative side of the battery is called the ground, so your car is a negative ground system. You're not using the frame on your vehicle to hook up the controller, so I guess it doesn't matter that the controller is not a negative ground device.

That's my guess.
If that's true, I COULD have used the cheaper 400 watt system - but I wanted the LCD controller, anyway...

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I'll start the write up with what I PLAN to do lol. That should make what I ACTALLY do more interesting. Probably more humorous, as well.

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Heres a link to all their kits, from 100 watt to 400 watt.


http://www.renogy-store.com/marine-rv-solar-panels-s/1838.htm

 

[highdesertranger]

not that it really makes a difference for our discussion, but dc power actually flows from negative to positive opposite of what most people think. here's a link that explains it. http://www.school-for-champions.com/science/dc.htm#.VGahg890zIU . highdesertranger

 

[Seraphim]

Then my junior high school teacher taught me wrong lol...

 

[MikeRuth]

Just a side note many of today's late model cars are now using dedicated ground wires for things like running lights, brake lights etc. I believe that's due to so many plastic parts they are mounted to.

And YES Electrons flow from the Negative terminal to the Positive terminal!

 

[Seraphim]

Just a side note many of today's late model cars are now using dedicated ground wires for things like running lights, brake lights etc. I believe that's due to so many plastic parts they are mounted to.

And YES Electrons flow from the Negative terminal to the Positive terminal!

I had actually heard about the electron flow being reverse from what was originally thought. But remember, my last science classes learning about batteries was in the late 60s *grin*. They still taught then that 'current' flowed from pos to neg, as best I remember. As long as I remeber red to red and black to black, I'm GENERALLY on the right track lol.

 

[highdesertranger]

way back when I was taught pos to neg also, learned different latter. highdesertranger

 

[Seraphim]

Hmmmmph...

Just noticed Renogy dropped the price on their 400 watt (nonRV) kit by about $50
to $619. This has the entry PMW controller, 4 panels, connectors and mounts, and 10' of 10AWG cable that runs from the panel's to the controller. You provide your own cable.

Didn't notice if other prices on kits were reduced, but they had some nice 'daily savings' on items - and those savings weren't on the site Friday. Just in case anyone's interested.

Perhaps this should be announced in its own thread...

 

[Seraphim]

Looks like I may have waited a bit late in the year to install solar panels outside on the camper lol.