Help me understand solar controllers

[Halifax Sailor]

I purchased a new mwp renogy wanderer, 10 amp. According to what I read it will suit my needs. The old controller just stopped charging the batteries. Hooked it up according to directions, Reads battery voltage/amps, panel output in volts and amps, and a load volt/amp. Batteries are reading about 11.5 volts. Panel depending on the day are putting out around 13 volts, it is the great white north so I expect that to get much better in another month. The panel only shows .1 amp supply. Here's my question, if the battery voltage is "low" shouldn't the controller be allowing higher amps to charge the battery? or is that muchly controlled by panel voltage? There is no way to adjust the settings on the controller. I have checked both batteries and they seem to check out ok so just don't understand the workings. I have tried contacting Renogy support but no response from two requests. I know some ppl will say mwp should have gone for the other type but I have little needs. Small fridge, lights (all leds), and at a marina with shore power most of the time. Just day sailing at this time. Looking for advice and understanding.

[Spot]

How many watts is the panel?
I am running that same controller on a test rig right now, 44N 93 W 7C almost full sun with a 55W flexible panel.

My panel volts are 21-22 and amps are 0.1 unless I activate the 1 A load then it reads 16V but passing 1A to the battery. Battery is a small AGM from a motorcycle that was neglected and needs fixing...I am still getting used to the controls, I will need to read the manual again too. My original controller is display-free, just indicator lights.

[thomm225]

21 volts is normally what solar panels I am familiar with read when there is no load attached which the plate on the back calls Voltage Open Circuit (VOC)

So if yours is reading that you aren't attached

When you hook up to the battery, the controller will read that voltage and you can watch as it charges from the panel.

Today mine was at 12.6 volts since I have had my panels unhooked from my two 6 volt batteries for a few days.

When I left, the voltage was at 13.6 volts after going up to 14.4 volts during the absorption phase

[Ballsnall]

Originally Posted by Halifax Sailor

Panel depending on the day are putting out around 13 volts,

That's too low, maybe a faulty panel or its a 12v panel?

[MikeHoncho]

If you have direct sunlight then I would expect a faulty panel or cells within the panel. If less than direct sunlight then it could be you are not getting enough sunlight to generate enough volts to allow the controller to pump out amps. My system will show this type of performance at sunset/sunrise or highly shaded events. You didn't give the watts of the panel system you are using. Either they are too small, faulty or not receiving enough direct sunlight.

[Halifax Sailor]

Hi, thx for all the input and I have more info. The panel is a 50 watt, small but I only day cruise at this point. I have 3X 550 amp batteries, 1 starter, 2 house. Right now, on the hard, I have them all disconnected and am charging separately. The panel unconnected will produce over 15-18 volts, it is under a cover (to keep snow and ice off). Not so sunny days it shows 12-13 volts. The highest amp charge I have seen is .4 from the panel. usually its .1. The batteries are at 11-12 volts, I move the leads around to keep them all charged and not dead. My question and I suppose when I take the cover off in a couple of weeks, if the supply voltage goes up with direct sun, will the supply amps go up as well? I am thinking it will, but looking for confirmation. It's a small system but it keeps everything alive when I am sailing and back at the marina I can top off with shore power for the next day if needed. I will wait and update when I get the cover off next week, I am thinking to hang the panel outside the cover for next winter to absorb all the sun it can and maybe not have to go thru this again. Another thought, if I have a dead battery, is there any danger in keeping the panel/controller on it? The controller cuts off at 10 volts on a depleted voltage, doesn't do anything except show the error code. I am going to test them next week as they have all had some charge so should see some improvements. They are flooded but 8 years old so on the downslope for sure. Always have performed well, never any issues but this may be the year for new ones.

[glenn.225]

Halifax
Is your panel in under the boat cover?

And the batteries really at 11 -12 volts?

Any lead acid much below 12.5 V is done for.

Optimal is 13.2 or 2.2 volt per cell.

[sailorboy1]

Originally Posted by Halifax Sailor

I purchased a new mwp renogy wanderer, 10 amp. According to what I read it will suit my needs. The old controller just stopped charging the batteries. Hooked it up according to directions, Reads battery voltage/amps, panel output in volts and amps, and a load volt/amp. Batteries are reading about 11.5 volts. Panel depending on the day are putting out around 13 volts, it is the great white north so I expect that to get much better in another month. The panel only shows .1 amp supply. Here's my question, if the battery voltage is "low" shouldn't the controller be allowing higher amps to charge the battery? or is that muchly controlled by panel voltage? There is no way to adjust the settings on the controller. I have checked both batteries and they seem to check out ok so just don't understand the workings. I have tried contacting Renogy support but no response from two requests. I know some ppl will say mwp should have gone for the other type but I have little needs. Small fridge, lights (all leds), and at a marina with shore power most of the time. Just day sailing at this time. Looking for advice and understanding.

You likely have a bad connection somewhere.

Does your solar panel use MC4 connectors? Did you disconnect and connect them them under load? If so there is a good chance one burned up!

Ask me how I know

[Halifax Sailor]

The panel is still under the cover, clear plastic. I have been carefull to disconnect the panel before the battery. If I leave the batteries on the charger, they will show over 14 volts before the shore power charger shuts off. I will be checking this week to see if the batteries are holding charge or if they are done. They seem to work ok, water levels are good. They do drop quick in voltage when there is any draw so maybe thats a sign. Will know more this week when I test. The panel does not have mc4 connectors, soldered and wired direct thru 15 amp breakers. wondering if wire size may be a little light although it did work well up to this winter so maybe between the batteries and maybe some cells in the panel it's done for.

[Spot]

I tested three multi meters against the controller. One meter was .5v low, the rest agreed, and a different 9v battery in the suspect multi meter decreased the difference by half. I will need to find a new battery and see if that corrects it and maybe take them to work to compare against a calibrated meter.

I hooked the controller to a different battery, making sure to change it from AGM to flooded. PV is 17-18v, amps 1.5, battery 14.4v, load 0.0

I could not get the USB power outlet to work on either battery. Same cord and phone works on the USB outlet of another solar panel. Since I really wanted that feature I am going to return this controller.

You may want to start with a 'known good' meter and battery as part of the process of diagnosing panel and controller.

[OS2Dude]

Do NOT attach any kind of 'real' load to the LOAD connections. It is only for an LED lightbulb or two. It is not meant for a high amperage load like an engine, inverter, 12v cooler, or any kind of mix of similar devices (Multiple cabin lights, 12V TV, Stereo, instruments, etc.). Just disable the LOAD part of the app display.

I started off with a Wanderer PWM controller with my 100W beginner set. I now have a 40A Rover MPPT controller and two 100W rigid panels and two 175W flexible panels.

[CarinaPDX]

A 50W panel should be capable of about 2.5A (very roughly). The approx. 21V max voltage is for open circuit (no load) so if there were little load the voltage would be much higher than 13V (unregulated). Your 0.1A is far too small to drag the voltage down to 13V. Also, if aimed at the sun, a solar panel will put out more power in the winter than in the summer - heat reduces the panel output. (Yes, I have experienced that with my own install.) So something is very wrong. I would start by checking voltage starting at the panel and then at each point of access. Another approach is to check the resistance of the wiring from panel to regulator (the wire is unlikely to be a problem unless physically damaged but connections are always suspect). Check the voltages with the regulator disconnected.

Good luck,

Greg

Edit: if there is a clear cover over the panel that is not part of the panel then try removing it. Most commercial solar panels only use a limited frequency of light and the plastic may be reducing that. It seems unlikely but worth a test.