panel not charging

shepcal · April 2019

try to make this short. Bought new Forest River Stealth Toyhauler w/ factory installed GoPower 200w solar system w/ Carnanah panel. Has worked fine up till a couple of months ago then it quit charging. The controller shows a moon and arrow to battery but no amps. I have disconnected the wires and have 12.2 vdc from battery and from a clean solar panel I show 19.6 vdc with full sun. Controller seemed to be problem after doing both hard and soft resets. Got a new controller, same results. Dealer for GoPower is almost 2 hours away. Any suggestions before I make the trip?

BB. · April 2019

Measure the Vpanel input to the charge controller in the middle of a sunny day... Yout want to see anywhere from >~19 volts (battery charged, no current draw from charge controller to ~Vbatt+a little bit voltage (i.e., if battery is 13.2 volts, then Vpanel should be ~13.2 to 14.0 volts or so for a PWM type charge controller) and you should be reading >50% * Imp rating of panel (full noon time sun, panel facing sun).

If you see Vpanel at 15 volts or lower, with very little charging current, then either the panel is bad, or the wiring between the panel and the charge controller has a poor electrical connection.

Do you have any sort of DMM (digital multimeter) with current measurement (AMPS) capability? The "easy test" is to disconnect the Vpanel connections from the charge controller, and with your meter set to 10 Amps full scale, connect the meter to the solar panel and see what sort of current you read (hopefully >0.50*Isc in full sun). If you read very little current, then you have to work your way back up the wiring and look for loose/overheated/corroded connections, and possibly do the short circuit current test directly on the panel output itself.

If the solar panel wiring looks good, then you have to start looking at the charge controller and battery wiring itself. The confusing thing is that charge controllers make their own decision(s) on how much current and voltage to send to the battery bank (and DC loads). If the charge controller thinks the battery bank is full, it will send little current to the battery bank. If the controller is "broken", it will also send little current to the battery bank.

By looking at the Vpanel input and Vbatt outputs of the charge controller with a DMM, If the voltages look OK (good voltage at the Vpanel input and Vbatt equals the voltage at the battery terminals), then you have to figure out if the controller is working correctly.

Nominally, if the Battery is at 12.2 volts, the charge controller should be sending as much current as possible to the battery bank (whatever the solar panel can supply). Until the Vbatt is somewhere around 14.2 to 14.8 volts (maximum battery charging voltage, held for a period of time--Absorb mode charging). After an hour or 4, then the charge controller should drop the Vbatt down to something like 13.2 to 13.8 volts -- That is Float voltage and should be held there until the sun sets (and/or your start drawing DC current for your loads).\

-Bill

Estragon · April 2019

One other thing to note; always connect the controller to the battery first, and only make the pv connection after the controller has fully booted. If it sees pv voltage first, it can put it in a weird state. I'd also throw a blanket or something over the panel to minimize sparkiness when making the pv connection.

shepcal · April 2019

Appreciate the comments. As said voltage measurements were taken close to noon full sun and clean and at controller. I talked to tech at gpelectric (who I had talked to prior on controller) told him situation was the same even with new controller. Gave him voltages recorded but for warranty they also need amps from panel. I have a Fluke 111 multimeter that can measure up to 10 amps, but it's reading 0.00. Checked for draw at battery with light on, still read 0.00 (I did check fuse, it's okay) so believe that portion of meter is defunct. Anyway ordered a clamp on dc amp meter. Should be here in a week or so. I'm pretty sure it will show 0.00 as does the controller. For a short circuit amp reading disconnect from controller, clamp one of the wires and then short them together for reading? As said, appreciate the replies. Been in HVAC trade for last 45 years, dealt with AC current, no problems; DC current seems to have more gremlins to me! Thanks, Shep

Estragon · April 2019

One big difference between AC and DC is DC will sustain an arc, even at fairly low voltage, whereas AC generally won't.

To test for Isc, I'd highly recommend covering the panels when making the connection to avoid arc damage to MC4 connectors. It may not be necessary at the controller input wires, but the connector contacts at the panel can be more sensitive to damage. If the controller side shows no/low short circuit current, testing Isc at the panel connectors would be the next step. As the name suggests, the test is done by reading current across the +and - wires, effectively shorted through the meter in (DC) current reading mode.

If a "200w system" means 2 x 100w panels in parallel, I'd double check the Isc rating on the panels to be certain the meter can handle Isc x 2 for testing the combined current at the controller end.

mcgivor · April 2019

One thing I've had problems with is MC4 connectors going bad, open circuit the voltage looks good, under load it's near zero, have had to remove them to restore current flow. Some panels use cheap connectors, this may or may not be the case but worth checking.

panel not charging

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