Solar power won't properly charge

[gnarledwolf]

I have been doing solar for 8 years. Usually I get down here to the desert and my batters charge up to 14.4 and their pissing power to excess at least while the sun is up. This year no matter where I am I cannot get above 12 and Usually it's 11.8v. I can't figure out why... and barely generate enough power to run my fan and at 100 degrees, that's an issue.
My setup: I have foldable solar panels from dokio 350 watts. 1 battery from Walmart Maxx 29dc 114w. It is deep cycle and claims it's for rvs. 1 generic solar controller 30a. And every article tells me it should be able to fully charge this battery in about 5 hours.
The panels did the job last year but the battery and solar controller are a few months old. Can someone tell me what is the I problem? I thought it was the batteries and took it back, and they recharged it fine and held the charge but by system bare does much at all.

 

[Camper]

Guessing what is wrong with your solar.... is just a guess.

You need a meter with a shunt to know what it is doing and then you can fix the problem.

This is the one I use:

https://www.amazon.com/Renogy-500A-...mzn1.fos.d977788f-1483-4f76-90a3-786e4cdc8f10

 

[bullfrog]

You need to be able to check the out put of the panels and then what is getting through the controller to the battery post. Normally loose or poor connections or too long of wire runs through too small of wire are the most common problems. If you are not able to find or use the meter check around the area for someone that has one and can. Let us know the general area you are in after checking the above connections and wiring. Maybe one of us is in the area. Since you setup sounds like it is portable maybe even consider taking it to a local vendor and asking them to advise you what’s is wrong.

 

[tx2sturgis]

We can assume the battery is probably OK if it was tested, so you might be having a problem with either the solar charge controller or the solar panels.

But be sure to look over, and check and recheck, all the connections. Sometimes a terminal screw on a solar charge controller can work loose from vibrations on the road, or it might be loose connections on the solar panel connectors or maybe a solar panel has flexed one too many times and it has failed.

What does the display on the charge controller show? Charging? Amps coming in, or not, and does it show incoming PV voltage and battery voltage?

 

[gnarledwolf]

We can assume the battery is probably OK if it was tested, so you might be having a problem with either the solar charge controller or the solar panels.

But be sure to look over, and check and recheck, all the connections. Sometimes a terminal screw on a solar charge controller can work loose from vibrations on the road, or it might be loose connections on the solar panel connectors or maybe a solar panel has flexed one too many times and it has failed.

What does the display on the charge controller show? Charging? Amps coming in, or not, and does it show incoming PV voltage and battery voltage?

 

[gnarledwolf]

The display shows 11.4 at the moment... morning, and 19.9 coming from the panels and I'm currently in Quartzsite in sadden wash.

 

[gnarledwolf]

You need to be able to check the out put of the panels and then what is getting through the controller to the battery post. Normally loose or poor connections or too long of wire runs through too small of wire are the most common problems. If you are not able to find or use the meter check around the area for someone that has one and can. Let us know the general area you are in after checking the above connections and wiring. Maybe one of us is in the area. Since you setup sounds like it is portable maybe even consider taking it to a local vendor and asking them to advise you what’s is wrong.

Connections are tight and I'm in Quartzsite in scadden wash

 

[gnarledwolf]

You need to be able to check the out put of the panels and then what is getting through the controller to the battery post. Normally loose or poor connections or too long of wire runs through too small of wire are the most common problems. If you are not able to find or use the meter check around the area for someone that has one and can. Let us know the general area you are in after checking the above connections and wiring. Maybe one of us is in the area. Since you setup sounds like it is portable maybe even consider taking it to a local vendor and asking them to advise you what’s is wrong.

Connections are tight and I'm in Quartzsite in scadden wash

 

[frater secessus]

I have foldable solar panels from dokio 350 watts.

The only 350w Dokio I see is a nominal 20v panel with a Vmp of 30.0v. If so, a PWM controller on a 12v bank won't be able to make more than ~60% of rated output in any case.

The display shows 11.4 at the moment... morning, and 19.9 coming from the panels

I don't see 19.9v in the photos. If true (and the controller is not borked and the panel really is nominal 12v) this would suggest it thinks the battery is already charged.* This could happen if the charge voltage setting were incorrect.

If battery voltage were 11.4 and panel voltage about the same I'd suspect a physically broken battery (broken plate, shorted cell, etc). A battery voltage reading with the sun down might tell this story.

---

* increasing the OFF period of PWM to reduce incoming power, so the panel side sees higher average voltages

 

[Camper]

I'd start with a new MPPT controller. If you would like, send me a PM and I will send you one free. I have several that I don't need right now.

 

[gnarledwolf]

We can assume the battery is probably OK if it was tested, so you might be having a problem with either the solar charge controller or the solar panels.

But be sure to look over, and check and recheck, all the connections. Sometimes a terminal screw on a solar charge controller can work loose from vibrations on the road, or it might be loose connections on the solar panel connectors or maybe a solar panel has flexed one too many times and it has failed.

What does the display on the charge controller show? Charging? Amps coming in, or not, and does it show incoming PV voltage and battery voltage?

19.9 from the panels, 11.4 currently as it's morning, and I don't really know what some od the other readings mean. I'm in Quartzsite

The only 350w Dokio I see is a nominal 20v panel with a Vmp of 30.0v. If so, a PWM controller on a 12v bank won't be able to make more than ~60% of rated output in any case.



I don't see 19.9v in the photos. If true (and the controller is not borked and the panel really is nominal 12v) this would suggest it thinks the battery is already charged.* This could happen if the charge voltage setting were incorrect.

If battery voltage were 11.4 and panel voltage about the same I'd suspect a physically broken battery (broken plate, shorted cell, etc). A battery voltage reading with the sun down might tell this story.

---

* increasing the OFF period of PWM to reduce incoming power, so the panel side sees higher average voltages

That is what is frustrating. Last years these same panels were producing the 14.4 volts. The 19.9 from the panels comes fron disconnecting the battery so only the solar imput is showing. After the sun goes down and istop using thrower it usually reads 12.3 and I can't find anything physically wrong which is why Walmart tested and recharged the battery and it was fine.

 

[gnarledwolf]

I'd start with a new MPPT controller. If you don't have the $$$ right now, send me a PM and I will send you one free. I have several that I don't need right now.

I'd love to get that from you but o way to recieve it. I had a stroke last year so earned very little money... that's why I can't even do long term camping... just hoping I can pick up and actually do a job and that rangers don't kick me out so I can actually earn the cash for long term. Thefact that my power is not performing makes it all the worse. My brother is with e, has the same set up and the same power problem. I'm wondering if these are a kind of battery that can't be well charged by solar...

 

[Camper]

You could get it general delivery at the nearest post office, but it's up to you.

I also have an extra 200 watt panel and a 100AH lithium battery that I don't need, if we can arrange shipping.

I simply have too much stuff and need to get rid of some.

 

[gnarledwolf]

You could get it general delivery at the nearest post office, but it's up to you.

I also have an extra 200 watt panel and a 100AH lithium battery that I don't need, if we can arrange shipping.

I simply have too much stuff and need to get rid of some.

I won't turn down help... they will allow general delivery for the first month...

 

[Camper]

Send me your name and shipping info and I will work on it.

 

[tx2sturgis]

Is that charge controller always that close to the battery?

FLA batteries (flooded lead acid, in other words, a battery that you add water to it) tend to off-gas and that might be causing corrosion in the charge controller.

Any number of problems can result.

First I would relocate the controller, at least 2 feet away from the battery, and then loosen the screws to the panel, shoot some cleaner like WD-40 in the terminals, and then re-insert the wires, tighten securely.

Loose and/or oxidized connections are the enemy of good electrical performance.

If you see no difference, the controller might be in need of replacement.

 

[jonyjoe303]

From what I can see on the pictures the batteries you are using aren't deep cycle, there more like a start battery. Those batteries need to be fully charged every day to 14.4 volts or they lose potency.

I suspect you have voltage drop from the controller to the battery. The controller is reading 14.4 volts in one of the pictures, that means fully charge for lead acid. When that happens the controller reduces amps to the battery to 1 or 2 amps. You can check for voltage drop by using a multimeter to read the voltage off the battery terminals and bouncing that against what is on the controller display. If the controller display reads 14.4 volts and the terminals read 14 volts or less, you have voltage drop. Lead acid battery terminals need to reach 14.4 volts to fully charge, if they never reach that every night you will be draining a low battery to below 12.1 volts (max cutoff for lead acid) . If the batteries are chronically undercharge everyday, they won't last long. Since they checked good from testing they still havent suffer permanent damage.

One sign that the batteries are undercharged is them reading 12.3 volts after the sun stops shining. A fully charged battery will read 12.7 volts. The 11.4 volts seen in one picture means a severely discharged lead acid. You shouldnt drain the battery under 12.1 volts (50 percent) if you want them to last. Only true deep cycle lead acids can handle draining below 50 percent but those are refer to as golf cart batteries and are very heavy.

If you have voltage you will have to adjust the bulk voltage higher to compensate. For instance if you have .5 volt voltage drop, you need to adjust the bulk voltage to 14.9 volts and then measure the voltage at the terminals to see if your reaching 14.4 volts and keep adjusting as required.

With 350 watts you need an mppt controller to get max performance. I get up to 27 amps of charging power from my 365 watt panel with mppt. With pwm you well be lucky to get 8 amps from your 350 watts. But even 8 amps will charge your small lead acid after a full day of sunlight if you don't drain it under 50 percent.

 

[gnarledwolf]

Is that charge controller always that close to the battery?

FLA batteries (flooded lead acid, in other words, a battery that you add water to it) tend to off-gas and that might be causing corrosion in the charge controller.

Any number of problems can result.

First I would relocate the controller, at least 2 feet away from the battery, and then loosen the screws to the panel, shoot some cleaner like WD-40 in the terminals, and then re-insert the wires, tighten securely.

Loose and/or oxidized connections are the enemy of good electrical performance.

If you see no difference, the controller might be in need of replacement.

no, just for pictures sake. and the solar controller is on a month old

 

[gnarledwolf]

that

From what I can see on the pictures the batteries you are using aren't deep cycle, there more like a start battery. Those batteries need to be fully charged every day to 14.4 volts or they lose potency.

I suspect you have voltage drop from the controller to the battery. The controller is reading 14.4 volts in one of the pictures, that means fully charge for lead acid. When that happens the controller reduces amps to the battery to 1 or 2 amps. You can check for voltage drop by using a multimeter to read the voltage off the battery terminals and bouncing that against what is on the controller display. If the controller display reads 14.4 volts and the terminals read 14 volts or less, you have voltage drop. Lead acid battery terminals need to reach 14.4 volts to fully charge, if they never reach that every night you will be draining a low battery to below 12.1 volts (max cutoff for lead acid) . If the batteries are chronically undercharge everyday, they won't last long. Since they checked good from testing they still havent suffer permanent damage.

One sign that the batteries are undercharged is them reading 12.3 volts after the sun stops shining. A fully charged battery will read 12.7 volts. The 11.4 volts seen in one picture means a severely discharged lead acid. You shouldnt drain the battery under 12.1 volts (50 percent) if you want them to last. Only true deep cycle lead acids can handle draining below 50 percent but those are refer to as golf cart batteries and are very heavy.

If you have voltage you will have to adjust the bulk voltage higher to compensate. For instance if you have .5 volt voltage drop, you need to adjust the bulk voltage to 14.9 volts and then measure the voltage at the terminals to see if your reaching 14.4 volts and keep adjusting as required.

With 350 watts you need an mppt controller to get max performance. I get up to 27 amps of charging power from my 365 watt panel with mppt. With pwm you well be lucky to get 8 amps from your 350 watts. But even 8 amps will charge your small lead acid after a full day of sunlight if you don't drain it under 50 percent.

View attachment 32867

that's what I've been wondering about.... rarely do they ever charge over 12, though they do much better when charged on the car.

 

[jonyjoe303]

all charge controllers I have used pwm and mppt were miscalibrated. The controller were reading higher than the actual battery terminals.
On my ecoworthy 20a mppt I had to get the bulk setting to 15.5 volts just to reach 14.6 volts on the battery terminals. If I kept the bulk setting at 14.6 volts, it wouldnt even charge the battery.



One thing I have always been using are voltage/amp led meters so I can see in realtime if the solar system is actually charging the battery. You need something that can measure amps going to the battery in realtime.

You can get a 90 volt 30 amp combometer for about 20 dollars, these will let you know if the battery is getting charged properly. The LED is bright and easy to read. You install this between the controller and battery. At night time you can monitor the battery voltage so it doesnt go below 12 volts.