Need help testing new rv solar set up.

Domromer · July 2017

My wife and I are on a one year road trip in our 23ft rv. We decided to add a small solar set up because we are dry camping a lot more than we imagined. We bought a 200 watt solar kit off Amazon which I installed last week. I hooked up everything and it seemed to work so I installed on onto the rv roof and ran the wires and mounted the charge controller. Everything seemed fine in the garage then I pulled out into the yard to test it. The charge controller is basic with just three led lights, one for the panels, one for the battery, and one for the load. Well the battery led is nice and bright, the load led is nice and bright, but the panel led is so dark that you have to shade it to see that's its actually on. I decided to test it and I know the very basics of using a voltmeter. I checked the voltage on the panels and they were 13 to 18 volts in partly cloudy conditions and 20v in bright sunlight, so it seems the panels are working. Next I went on the roof to check the mc4 connectors, they seemed good and tight and I opened and closed them a few times so they seem good. The only other connection is the in line 20amp fuse that I soldered in. I've never soldered before and made the connections after watching a YouTube video. After soldering the connection I shrink wrapped them so even if If my soldering was ugly i gotta think the connection is good considering the wires are soldered and compressed in the shrink wrap. The next thing I did was plug the solar panels and the battery into a cheap 10amp charger controller that i bought for a different project well in this charge controller all three lights lit up nice and bright. But the solar panel led was flickering. I'm wondering if that's because the charge controller is rated for 100 Watts max and I had two hundred watt panels wired up to it. I'm hoping you guys can help. I looked up the manufacturer is my kit and it seems to come direct from China so tech support does not exist. Sorry about the long first post and any Grammer errors. I'm typing this all out with one finger on my phone in Algonquin provincial Park which is our campground for tonight.

bsolar · July 2017

hmm .. sounds like youre using what i would call 'turd' charge controllers .. for your next move i would splurge on a C35 charger, that will be better for batteries, more exact, and adjustable with a good manual .. in the mean time hook your meter to the batteries and you should be getting a voltage rise over 13v in sun (on a full bat), if you are, the charger and panel is doing its thing ..

Domromer · July 2017

Thanks, I'll try that tomorrow.

Estragon · July 2017

A few things may be going on here, but gotta start somewhere.

The charge controller manual should give some insight on the state of the leds. I assume a (green?) Led would indicate a completed batery circuit, or maybe good voltage (12.8ish) , or maybe polarity. The load led being lit might be similar. The pv might flash to indicate pulsing in pwm charging. If the battery is full, there would be little pulsing as very little current would be needed for charging. If you have a link to the kit, that may help.

In the morning, I would measure the voltage of the battery between + and - terminals. Assuming the battery is discharged some, it should be well under 12.8v. 12.2ish is about 50% discharged. You don't want to go much under that regularly for good battery life. When the sun hits the panels, watch the led, and the voltage on the battery. If the controller is working properly, and you aren't running a lot of loads that prevent the panels from charging the battery, the voltage on the battery should rise to around 14.5v over an hour or two, and stay there for a couple of hours. I'm guessing the led for pv will also be lit better. Also, check the voltage at the terminals on the controller where the pv wires connect. You should see around 18v there.

Soldering a fuse in seems odd to me. Normally you'd want to be able to change it, and would want to wire in a holder that allows for that.

I'm assuming you have a couple of 100 watt panels, and a 12v pwm controller. Normally in that situation, you would wire the two panels in parallel for about 10a at 18v into the controller. It will put out ~10a at charging voltage of around 14.5v. The panels can theoretically put out more, but the controller likely only puts out it's max current no matter (within reason) how much panel it has.

Solray · July 2017

Lol Estragon. I think he soldered in a fuse holder and then placed a fuse in it. I have never seen a fuse that is made to be soldered itself.

Domromer · July 2017

> @Estragon said:
> A few things may be going on here, but gotta start somewhere.
>
> The charge controller manual should give some insight on the state of the leds. I assume a (green?) Led would indicate a completed batery circuit, or maybe good voltage (12.8ish) , or maybe polarity. The load led being lit might be similar. The pv might flash to indicate pulsing in pwm charging. If the battery is full, there would be little pulsing as very little current would be needed for charging. If you have a link to the kit, that may help.
>
> In the morning, I would measure the voltage of the battery between + and - terminals. Assuming the battery is discharged some, it should be well under 12.8v. 12.2ish is about 50% discharged. You don't want to go much under that regularly for good battery life. When the sun hits the panels, watch the led, and the voltage on the battery. If the controller is working properly, and you aren't running a lot of loads that prevent the panels from charging the battery, the voltage on the battery should rise to around 14.5v over an hour or two, and stay there for a couple of hours. I'm guessing the led for pv will also be lit better. Also, check the voltage at the terminals on the controller where the pv wires connect. You should see around 18v there.
>
> Soldering a fuse in seems odd to me. Normally you'd want to be able to change it, and would want to wire in a holder that allows for that.
>
> I'm assuming you have a couple of 100 watt panels, and a 12v pwm controller. Normally in that situation, you would wire the two panels in parallel for about 10a at 18v into the controller. It will put out ~10a at charging voltage of around 14.5v. The panels can theoretically put out more, but the controller likely only puts out it's max current no matter (within reason) how much panel it has.

Here is the link for the kit. Komaes 200 Watts 12 Volts Polycrystalline Solar Starter Kit with 20A PWM Charge Controller + 20ft Tray Cable + 20ft MC4 Connectors + Mounting Z Bracke https://www.amazon.com/dp/B01FD8P3OG/ref=cm_sw_r_cp_apap_54pFDRv7WsJ3X

I didn't explain myself well. I didn't solder the fuse in. I soldered in an inline fuse holder to the positive wire from the panel. When I pull out the 20amp fuse the panel led dims in a few seconds and lights back up a few seconds later when I put the fuse back in. The cc instructions are pretty basic. Explains how to wire the cc and says there is a red led for the panels a green, yellow, and red led for the battery and a single yellow led for the load side. The other thing I noticed is that when the panels are in the sun the battery led is green, when the panels are shaded the battery led turns red, then goes right back to green when the panels are in the sun again. I'll post my battery readings tomorrow. We've been been running solely off the batteries since around 5pm today and before that they would have been charging from the vehicles alternator on a 4 hour drive and the panels. The power draw is pretty limited, a few led cabin lights on and off through the evening and the occasional running of the water pump to flush the toliet or clean the dishes. Here is a link ol to a photo of the charge controller. I tried to upload it to the thread but it kept coming up with an error.
https://photos.app.goo.gl/ZhCL8qBy0KDbbFwt2

mcgivor · July 2017

If the battery is fully charged the CC will be in PWM, the solar LED will flicker on and off at various pulse rates, if a load is applied and the battery voltage is brought down, the solar LED should be on steady, in bright sun, indicating the panels are now passing current to the battery /load. One other point is the CC must first be connected to the battery for voltage recognition, connecting the panels first may prompt it to think 18+ volts is 24V,rather than 12V, this can damage the CC in some cases, please don't ask me how I know this.

mike95490 · July 2017

Domromer said:

.... Next I went on the roof to check the mc4 connectors, they seemed good and tight and I opened and closed them a few times so they seem good. .....

Yep, they likely were good. But not anymore. Opening and closing MC4 is only supposed to be done in the dark, or with breakers off so that there is no current (amps) flowing. The gold plate contacts internally are not rated for make - break operation and will arc the low resistance gold plate, away.

Solray · July 2017

I would think the breakers or fuses would be opened before testing the connectors, naturally.

Domromer · July 2017

> @mike95490 said:
> Domromer said:
>
>
> .... Next I went on the roof to check the mc4 connectors, they seemed good and tight and I opened and closed them a few times so they seem good. .....
>
>
>
>
> Yep, they likely were good. But not anymore. Opening and closing MC4 is only supposed to be done in the dark, or with breakers off so that there is no current (amps) flowing. The gold plate contacts internally are not rated for make - break operation and will arc the low resistance gold plate, away.

The panels were in the dark. When I checked 4he contacts.

Domromer · July 2017

> @mcgivor said:
> If the battery is fully charged the CC will be in PWM, the solar LED will flicker on and off at various pulse rates, if a load is applied and the battery voltage is brought down, the solar LED should be on steady, in bright sun, indicating the panels are now passing current to the battery /load. One other point is the CC must first be connected to the battery for voltage recognition, connecting the panels first may prompt it to think 18+ volts is 24V,rather than 12V, this can damage the CC in some cases, please don't ask me how I know this.

I did plug the charge controller in first to the battery, before I connected the solar panels to the charge controller. So we can rule that out. I'm making pancakes now, after that I'll measure the volts at the battery. We are in pretty heavy shade so the panels aren't doing much.

littleharbor2 · July 2017

Hopefully you aren't using electricity to make your pancakes. Sounds yummy, by the way. Real maple syrup, I hope.

Domromer · July 2017

Real maple syrup (Canadian) is the only way to go, along with blueberries I picked last week. Cooking on propane.

Estragon · July 2017

You mentioned soldering the fuse holder to "the positive wire from the panel". The kit appears to have two panels. Did you just mount one?

If you mounted two panels, and there is a single positive wire coming from the panels to the controller, that implies a serial connection (+ on one to - on the other). Wired in this way, voltage adds and current doesn't, so you would get ~36v and 4-5a at the controller when bulk charging. You would wire it this way for a nominal 24v battery bank and pwm controller.

A parallel connection would be both positives and both negative combined, either in a combiner box with fuses/breakers for each panel (optional with just two panels) or at the controller. Wired in this way, current adds and voltage stays the same, so you'd get ~18v and 8-10a. This would be for a 12v bank.

The included controller seems to do both voltages. It would see the 12v from the battery (assuming you connect the battery first, as you should) and charge accordingly. It probably (but not certainly) wouldn't be damaged getting ~36v if the panels are series connected, but would be wasting 1/2 the potential output from the panels. If the old controller you used is 12v only, it may well be damaged by the higher voltage if panels are series connected.

Domromer · July 2017

I've got both panels installed, two into one mc4 connectors positive from both panels go into one, then negative from both panels go into the other one wire goes from each two onto one connector then wiring into the positive and negative on the panel.

Estragon · July 2017

Okay, so parallel connected - no problem there.

Fusing really should be on each panel + wire before the 'Y' connection, but it's optional with just two panels anyway so no big deal.

Hopefully batteries are charging up now. Pretty nice here in NW Ontario hopefully also in A. Park too.

Domromer · July 2017

OK so it's 10:30am here and the conditions are overcast and we are mostly parked in the shade. The voltage at the battery is 12.70 and the panel voltage tested at the charge controller. Is 12.97 I'm going to post a link to diagram of my wiring set up. Everything is the same except I don't have and inverter wired in. Otherwise I copied this diagram exactly. I'm also attaching a photo of my battery box. I have two 12v batteries wired red to red and black to black.

https://photos.app.goo.gl/E9nbgaAMQYCikFyH2

https://photos.app.goo.gl/36SLzJsIwz1m050z1

Thanks for all the help. It's appreciated.

Estragon · July 2017

The diagram looks okay except; panel fusing mentioned earlier, the load should have fuse/breaker appropriate for wire size, and the wire from Y connection to controller is marked "AWG20", which is hopefully a typo. It should be 12ga minimum, preferably 10ga.

Overcast and shaded, the panels won't put out much. 12.7v is nearly full, but there may be enough coming from the panels to raise battery voltage a bit with no loads. Hard to tell much until there is sun and no shade. Any shade at all (even a wire or small tree branch) will cut output a lot. Lightly overcast can still do some charging.

Red to red and - to - for the batteries is right. Looks like the controller connects to + on one battery and - on the other, which is also right.

Domromer · July 2017

OK quick update, we are still parked in the shade and it's still partly cloudy, the battery is up to 14.43 and the exhaust fan is currently running in the rv, so there is a load on it.

Estragon · July 2017

Good. That means you're getting at least some charging despite the conditions. Depending on the temperature of the batteries, they're likely between 80-100% full.

Domromer · July 2017

So other than my dull led for the panels, it sounds like the set up is working as it should be. Thanks for the help.

Domromer · July 2017

So it's the end of the day. We are parked in the shade again, the extractor fan and ceiling fan are both running. Battery reads 12.87

Estragon · July 2017

The extractor fan and ceiling fan loads should be enough to take any residual surface charge off the batteries, and parked in the shade you shouldn't be getting much charging current, so my guess is the batteries are pretty much full.

Hopefully our nice weather is heading your way so you can be sure, but it sounds like things are working.

Domromer · July 2017

It's been nice and sunny today, we end up parking in the shade a lot to keep our 16 year old husky cool while we go for hikes.

Estragon · July 2017

I guess letting the husky bask in the shade of the panels isn't an option

Domromer · July 2017

Sadly no.

BB. · July 2017

Having a pair of panels (say a pair of 130 watt or so panels) that you can place on the ground and stake in place (to prevent wind blowing over panels and two legged folks wondering off with same) and a 30' extension cord may be nice. For those campgrounds where you can get some sun and still keep the RV cool. Placing the two panels in series (Vmp~36 volts) and using a small MPPT charge controller can make allow the extension cord to be longer and use smaller diameter/cheaper wiring.

Using standard bladed receptacles (vs twist locks) are always nice in a mobile installation (i.e., drive off and leave panels staked to ground).

-Bill

Domromer · July 2017

> @BB. said:
> Having a pair of panels (say a pair of 130 watt or so panels) that you can place on the ground and stake in place (to prevent wind blowing over panels and two legged folks wondering off with same) and a 30' extension cord may be nice. For those campgrounds where you can get some sun and still keep the RV cool. Placing the two panels in series (Vmp~36 volts) and using a small MPPT charge controller can make allow the extension cord to be longer and use smaller diameter/cheaper wiring.
>
> Using standard bladed receptacles (vs twist locks) are always nice in a mobile installation (i.e., drive off and leave panels staked to ground).
>
> -Bill

We actually went that route at first but we are on the move too much to make that set up worthwhile for us. We ordered a renology suitcase that turned out to be defective so we sent it back, then Amazon sent the replacement to our house in Florida instead of our campsite in Maine and we were just about to cross the border into Canada so we couldn't wait for the replacement to come to us, we ended up crossing the border back into NY, and I ordered a two panel kit from Amazon and installed it before heading back across thy border. In the meantime we came to the conclusion that the suitcase style wouldn't work as the only time we are still is when we are sleeping at the campsite, otherwise we are usually parked at trailheads and I wouldn't feel comfortable leaving the solar sitting next to the rv.

BB. · August 2017

Yep--Theft is a big problem.

-Bill

Need help testing new rv solar set up.

Comments

Categories