Solar power won't properly charge

[gnarledwolf]

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.

View attachment 32872

Mine cost $15, and leaves me a little confused. I only know it keeps my battery from overcharging...

 

[frater secessus]

I only know it keeps my battery from overcharging...

That is the primary job of all solar charge controllers.

The one in your pic is a single-stage PWM with three major settings for our purposes:

1. charging voltage
2. load connect voltage
3. load disconect voltage

For offgrid folks like us charging lead at Absorption voltage constantly is probably a good thing; IMO more batteries are killed by insufficient Absorption duration rather than too much. And higher battery voltages mean more available power with PWM. And vice versa: {if nothing else} your harvest is hobbled by low battery voltage. A bit of a vicious cycle.

The only caveat with these controllers is they tend to be built with minimal QC (understandable at the price point), which makes running them anywhere near their rated output a gamble. If the FETs have good contact with the backplate/heatsink they will usually make the full pull. If the FETs are misaligned and don't touch the backplate they may die from overheating when PWM switching is most active.

 

[Zerpersande]

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.

Man, this thread is making me rethink putting in solar. On the other hand,mit seems to have worked for 8 years. i’ll be pushing 80 then and likely to have bigger fish to fry.

 

[bullfrog]

Solar works well and after initial purchase has few problems if you buy quality components but you probably don’t need it if you do not have a refrigerator and probably won’t be able to have enough solar to run an AC for hours. Your vehicle if driven a few hours a day can provide enough for lights, fans and phones via a house battery or things like a Ryobi vehicle charger, their tool batteries and power station. The big question is whether or not you need a refrigerator. If you need AC then you probably need a generator which while running can charge up the house battery making solar optional but useful as it can quietly top off batteries and lessen run time of the generator.

 

[Zerpersande]

…but you probably don’t need it if you do not have a refrigerator and probably won’t be able to have enough solar to run an AC for hours.
The big question is whether or not you need a refrigerator.

Yep, want/need a frig. Although I will be traveling with my van I’m also going to purchase a small bit of land in the mountains. There will be a lot of time spent there with very little driving. If AC it will be a very small unit.

 

[frater secessus]

this thread is making me rethink putting in solar

People post problem threads on forums to crowdsource help, not to report "My solar is working normally".

Anecdote: my solar is working normally. 9:30am local and it's already making 397w, or 53% of rated power. I've lived the last 1,511 days in the camper powered by solar.

 

[VernContra]

Man, this thread is making me rethink putting in solar. On the other hand,mit seems to have worked for 8 years. i’ll be pushing 80 then and likely to have bigger fish to fry.

Don't judge a concept by a single report. I'm sure Gnarledwolf will eventually find the help needed to get the system working. Educating yourself and experiencing the positive uses of solar which when designed and installed properly will perform admirably.

 

[wayne49]

Happy people don't need to vent, or ask questions.

Solar didn't work for me at first, sizing of components was wrong, cabling issues, etc. If it can be done wrong, I did it wrong, from design to implementation.

I was trying to get all I could eat from a Happy Meal.

Now I run a Class C off 600W solar for most of the year, except for the three coldest months, when I am hooked up to shore power, to run electric heat at my home base in an RV park. Traveling to somewhere warm in the Winter would be more expensive than staying in place. Even more so with current fuel prices.

My main bank, 2 100AH AGMs/400W solar, has never dropped below 83% capacity at night with the current setup and usage. The existing house battery now runs lights and vent fans only.