So I started playing with a small solar panel now I have questions!

I bought a small 20 watt panel from Amazon with an external controller. I have it hooked up to two 12V 12AH batteries in parallel for a couple of days now. At first the batteries' charge were too low for the controller to detect so I had to bring it up high enough for the controller to 'see' them. That's all good and working but one thing I'm noticing is that at night when the solar panel disconnects, the battery voltage is always at 12.6v. Will this change over time?
image

What charge controller do you have and what is the battery load?

Not quite sure what you are asking...

12.6V is actually what a 12V battery should read when it is fully charged. It may read higher than 12.6V while it is being charged, but after a few hours, it should settle down to 12.6V. Like all batteries, it will slowly self-discharge over time.

1 Like

It's this kit from Amazon, Topsolar 20W - load is a couple of wyze cam.

@dean - I wasn't sure if it should register more than 12.6V

If this is a true PWM 3-stage charger it should get to >14V during the absorb stage then drop down to >13V in float, assuming that panel is large enough to even get it out of Absorb, which it might not be depending on the battery size, load and hours of sunlight. Try connecting just on 12V battery and the Wyze cams on the Load side of the controller. See it can get just one battery into absorb.

I think my used battery may be the issue here. I have another set of the 12AH ones that I know are still good but not new so I'll set that up after it's pulled from service. I hooked up a Shelly uni to the load without the cameras just so I can do some logging on google sheets.

Almost certainly, since you first said:

It sounds like those batteries sat discharged for a while. They're probably sulfated, which drastically reduces their capacity.

You're right, they were spares that I had sitting on the shelves for more than a year possibly longer that was an exchange from an Amazon purchase. They were probably questionable to begin with and then sat for a long time.

Just updating thread... the new set (older battery) is working much better than my first try. I let the wzye pan cam record continuously last night and still had 12.2V this morning.

Finally got some logging going with two batteries in parallel. I'm curious to see if one battery can handle just one of the wyze pan cam so I'll remove one of the battery over the weekend.

2-battery 12AH setup

I understand that some batteries will have issues if their voltage goes too low too often. I had a setup a while back with AGM batteries (before I had my Shelly Uni to monitor voltage) and I ended up killing them by dropping the voltage too low too often. Not sure how low I brought them though… Something to keep in mind!

Thanks! My setup has been holding up well so far. One battery getting charged during the day and powering my wyze cam pan 24/7 :slight_smile:

1 Like

Download the Hubitat app