Solar Issue?

gypsmjim · 06-05-2017, 07:12 AM

I have a 100w Renogy "RV Kit". It is permanently mounted.

My usual procedure is to disconnect the battery from the RV when we leave, and then turn on the solar panel to keep the battery charged. The Shore power cord is also disconnected.

When we return next weekend I plug the shore power back in, turn on the battery switch and turn off the solar.

Recently, when we arrived and I turned the trailer back on (before I connect the shore power) I have noticed that I'm getting 18 volts on my panel (I have a digital volt meter plugged into the TV 12v receptacle). As soon as I disconnect the solar it drops to about 13 volts. When i connect the shore power it usually runs about 13.4 all the time.

My SpG is right on and my battery acid level is constant.

Do I have a problem?

marbles · 06-05-2017, 08:17 AM

My Epever MPPT charge controller shows power coming from the solar panel in volts and amps. It also shows power for the battery in volts and amps. They are different.
The power from the solar is not passed to the battery if the battery is full. The power from solar will be zero at night but the battery will show volts and amps being drawn.
I do not connect to shore power except for AC and have not done that yet. I do not disconnect the solar panel. It keeps the battery charged as needed and only as needed.
I am running one house style 275w solar panel on the roof plus a 20amp Epever MPPT charge controller. This is all connected to two Trojan T-105 6v golf cart batteries.

M&A · 06-05-2017, 08:32 AM

Quote:

Originally Posted by gypsmjim

I have noticed that I'm getting 18 volts on my panel (I have a digital volt meter plugged into the TV 12v receptacle).

I would worry about this. I don't think your TV amp (often left on), stereo (still uses power for memory when off), and detectors(s) would like that much over voltage. If I'm reading what you are saying correctly.

Subaru297 · 06-05-2017, 08:39 AM

Sounds like you are reading 18 volts from the battery if you are reading it from a 12v receptacle. This should not be happening normally. You can get up to 15 volts or so during an equalization cycle but 18 is too high.

Sounds like your charge controller is defective or has been damaged. Depending on your sequence of events you may have damaged it. As far as I know all charge controllers need to have solar power cut first and then battery power cut. If you cut battery power and then solar you can damage the charge controller.

To trouble shoot I would draw down your battery a little bit and let the solar charge it back up without shore power and keep an eye on the voltage. If you see it rise above the specified voltage from the manual then I would say you have a defective controller and email Renogy about getting a replacement.

In the future I would not worry about turning your solar on and off. Just leave it on 100% of the time. Nothing bad will happen if your solar and your converter are trying to charge the battery at the same time.

Cheers

X213_2015 · 06-05-2017, 08:46 AM

Renogy documentation says to always disconnect the solar panels before disconnecting the battery and that the battery should be connected to the charge controller prior to the solar panels.

I put big tags on my battery reminding me to do this and a tag on the inline fuse of my solar panel that's installed near my charge controller that I use as a panel disconnect. PV Voltage can get pretty high (20V in some cases) and without the battery there for the charge controller to monitor it will just dump whatever is available. The over voltage could cause a problem.

When you connect shore-power the converter in your camper will start supplying power (regulated) to the camper and effectively "knock off" the solar charger (it sees a voltage and senses "I'm all charged up" then goes into a float mode). FWIW I leave my battery in all summer connected to my solar and haven't had a problem. That's what the solar setup is designed for.

The larger off-grid controllers and smaller ones like this one I have in mine (Renogy 200W w/ Wanderer charge controller and the Renogy Adventurer Charge controller had similar instructions.

Subaru297 · 06-05-2017, 08:56 AM

That is a good idea. I should add some labels to my battery as well so I don't forget!

**Mustang65** · 06-05-2017, 09:54 AM

It sounds like your SOLAR charge controller is passing your panel voltage (18VDC) directly to the batteries without reducing it. As asked before, do you disconnect the SOLAR panels from the SOLAR charge controller before you disconnect the battery. If not, sooner or later the controller will be damaged. The voltage from the SOLAR charge controller to the batteries, should never be 18 volts. When a deep cycle battery is being equalized, it should only have a 15.x voltage to the battery. The inexpensive PWM SOLAR charge controllers do not have this option. I would hate to see you fry your TT's electronics (fridge, CO sensor, radio...)

Does the voltage stay at 18 volts, or does it drop down after a few minutes or so?

I put my labels right on the SOLAR breaker box... takes the guessing out of the cut-off.

Don

My Registry

RVing with SOLAR

gypsmjim · 06-05-2017, 10:04 AM

Thanks for all the comments and let me clarify my setup.

I have a switch between the battery and the trailer. That's the one I turn off when I'm not there. The second "switch" is the shore power cord - it's either connected or not. The third switch is between the solar controller and the solar panel.

The solar controller is permanently wired to the battery. That is never disconnected.

Example - when I got to camp this weekend the battery connection to the trailer was off, the shore power was off and the solar panel was on. I first checked the solar controller and saw the 18v. Then I turned the trailer switch on and verified the 18V at the TV 12v receptacle. Then I turned the solar panel off and the TV 12v receptacle dropped to 13v. Then I plugged the shore power cord in and the 12v receptacle went to 13.4v.

I'll follow the suggestion of drawing the battery down a little and then try the solar again. But based on comments so far it sounds like the controller may need to be replaced. In the future I'll just leave the solar on.

Thanks to all...

Subaru297 · 06-05-2017, 10:14 AM

Sounds like what you are doing shouldn't have damaged the controller and it is just defective. Hopefully Renogy has a good warranty. Or Amazon if it was a recent purchase they might exchange it for you.

Cheers

gypsmjim · 06-05-2017, 10:59 AM

Its just past 2 years and their warranty is only 1 year. I don't have the model no. handy, but it looks like they carry a different one now.

**Mustang65** · 06-05-2017, 11:19 AM

I would still contact Renogy support and discuss the problem with them. They may replace your controller if you tell them that the forum you belong to (27K members) is waiting to hear what they have to say about the controller.

Don

My Registry

RVing with SOLAR

X213_2015 · 06-05-2017, 11:22 AM

Quote:

Originally Posted by gypsmjim

Its just past 2 years and their warranty is only 1 year. I don't have the model no. handy, but it looks like they carry a different one now.

You may want to give Renogy an e-mail. They have excellent customer service in my dealing with them. It never hurts to ask. The Adventure controller is nice in that it has a display but I don't think it's any more "advanced" than the wanderer or the one prior to that.

[edit]Don beat me to the punch - and for what it's worth he inspired me to do my solar install[/edit]

gypsmjim · 06-05-2017, 11:43 AM

My experience with Renogy has been good as well.

We'll be down this weekend and then i'll get the model numbers. I have all the documentation in the trailer. I'll e-mail them Monday.

I'll also turn off the solar panel if its still at 18V. I don't want to fry the battery either.

Thanks to all fore the usual good help...

**Mustang65** · 06-05-2017, 05:36 PM

Quote:

Originally Posted by gypsmjim

I'll also turn off the solar panel if its still at 18V. I don't want to fry the battery either....

The sooner the better. Take voltage readings before disconnecting the panels. Oh, and check the battery water level also.

Don

My Registry

RVing with SOLAR

gypsmjim · 06-07-2017, 07:39 PM

OK, here's today's update...

Got to camp and the voltage in the solar controller "monitor screen" was 17.9. Turned off the panel and turned on the trailer and inside the voltage was 13.2. After about an hour it had dropped to about 12.4.

Checked the Controller's "system monitor screen" and all indicated "normal". Checked the settings and the highest voltage allowed was about 15 (equalizing).

The battery fluid level was perfect. However the SpG was over the top on my meter.

I sent an e-mail to Renogy. I'll post their reply.

PS - the controller is a "PWM-Type"

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