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Fried my charge controller...

ppzzus

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Oct 26, 2021
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So I was on the road and exhausted. Like 10 hours of sleep over a week. Wasn't paying attention for a few minutes and I think I made a couple of errors. It's possible the controller was bad but I'm not sure. I have 3 "SSX-315M-BLK-120-NEW Q-Cells 315W Solar Panels, Black" panels. The charge controller is a triron 4215 rated for 40A. The spec sheet I saw online was that the panels peak was 9a and I have them wired in series so under 30a when the controller was rated for 40? Also my system is 8 280ah lifepo4 cells @24v with current connected BMS. BMS appears to be running great.

Here's where I think I messed up: I just plugged the panels directly into the charge controller. I hadn't grounded them. I check the voltages and it was ready 113 out of the panels. Now the sun was blazing. When I connected the panels in they were already running at full tilt so I assume there was some residual charge in there. Heard a zap then I could smell a little smoke. I had been bench testing the charge controller with a power supply just to get it programmed. It appeared to work find at 10 amps. Then the first time I plugged the panels in ZAP.

The charge controller was a bit screwey to begin with. It would only power up if there was current going in from the panel connections, but not when I hooked it to the battery. I guess it's possible but I'm betting I did it wrong.

So I'm looking for a new controller, preferably on Amazon. I'm on the road full time so I'd like to be able to scoop it from an Amazon locker asap.

Currently charging the batteries with a generator hooked up to a power supply. Works ok just needs heavy babysitting.
 
The 40A rating of the controller is the output current to the battery. It is not related to the panel current. And besides, 3 panels in series has the same current as a single panel. With a 24V system and a 40A output current, it can handle about 1000W of solar.

Most likely you fried the charge controller due to too much input voltage. 3 panels in series has 3 times the voltage of a single panel. What is the Voc of the panels and what is the max input voltage for the charge controller? You must never go over that max input voltage. If you were reading 113V and the controller only supported 100V then that would be why it's fried.

You must also have the charge controller connected to be battery before connecting the solar panels. And lastly, it's a bad idea to connect solar panels in full sun. It's dangerous levels of voltage, especially with three panels in series.

Keep all of this in mind when deciding on the next controller and then getting it hooked up.
 
The 40A rating of the controller is the output current to the battery. It is not related to the panel current. And besides, 3 panels in series has the same current as a single panel. With a 24V system and a 40A output current, it can handle about 1000W of solar.

Most likely you fried the charge controller due to too much input voltage. 3 panels in series has 3 times the voltage of a single panel. What is the Voc of the panels and what is the max input voltage for the charge controller? You must never go over that max input voltage. If you were reading 113V and the controller only supported 100V then that would be why it's fried.

You must also have the charge controller connected to be battery before connecting the solar panels. And lastly, it's a bad idea to connect solar panels in full sun. It's dangerous levels of voltage, especially with three panels in series.

Keep all of this in mind when deciding on the next controller and then getting it hooked up.
So a little more info. Charge controller is rated for 40a in and 150v in unless I'm reading the spec sheet wrong. The batteries were hooked up to the controller as well. Bottom line is my model.
 

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Your controller probably has a fuse, if you are lucky it may have blown with the sudden surge you subjected it to.....but even if blown it may have done damage.
 
So a little more info. Charge controller is rated for 40a in and 150v in unless I'm reading the spec sheet wrong. The batteries were hooked up to the controller as well. Bottom line is my model.
You should still post the specs for the panels. Though I doubt 3 315W panels in series have a Voc over 150V. I have 3 330W panels in series and it would need to get down to about -30ºF for me to get to 150V.

Overall your 3 315W panels should be just right with that charge controller on a 24V system.

Hooking them up in full sun may have caused a surge. Or the charge controller was faulty to begin with. Your comment about the controller not working when connected to the battery is a huge red flag. The controller should be 100% functional once connected to the battery. It should not need any PV input to function. Obviously it's needed to produce an output current but not to turn on and setup.
 
I duckduckgo'd "SSX-315M-BLK-120-NEW Q-Cells 315W Solar Panels, Black"
Looks like VOC of ~40ish per panel (PDF) if I got the right panel
 
I duckduckgo'd "SSX-315M-BLK-120-NEW Q-Cells 315W Solar Panels, Black"
Looks like VOC of ~40ish per panel (PDF) if I got the right panel
Yeah that's around what I gathered. I messaged the seller to verify the amps at 9ish each. Getting 113 at full sun when I tested them.

Now I just need to source a charge controller. I'm a bit hung up on this part as the 150v controllers appear a bit pricey. Tempted to drop down to two panels just to get the ball rolling. I was looking at this controller but I feel a bit dicey about it.
 

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I don't know your budget but the Victron SmartSolar 150/35 is $324. That will handle your three panels in series. If you don't have a shunt yet to monitor your batteries, pair that controller with a Victron SmartShunt and you will have an excellent system with great support.
 
I had that same Epever in my van for years, it did a fantastic job and I'd recommend the same, can't be beat for the price.
 
Perfect. Scooped that up just now. Won't have it until Monday but that's fine. I probably have enough power here to work until then (just a laptop and monitor for work). I'll probably make my way out of town to top it up this weekend with the generator.

I don't particularly like using the generator as it seems to cause the BMS to flip on and off frequently (,I have the generator hooked to a small power supply.
 
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