Battery discharging over night WITH charge controller

[S1M0N]

Hello, hope someone can shed some light on my problem.

I have a simple solar powered gate opener setup at home. I am having trouble with the battery seemingly discharging over night.

I have 2 x 20w panels wired in series making 24v. These are then wired to a charge controller, which is then wired to 2x 12v 7ah batteries also in series.

Panels : BlueFusion Mono Solar Panels 10W - 100W. For grid-tie commercial system builders and off-grid Caravan, Yacht applications. - https://midmarine.com/product/bluefusion-mono-solar-panel/

Charge Controller : LCD Solar Panel Battery Regulator Charge Controller Dual USB 10A/20A/30A 12V/24V | eBay - https://www.ebay.co.uk/itm/LCD-Solar-Panel-Battery-Regulator-Charge-Controller-Dual-USB-10A-20A-30A-12V-24V/123133341839?ssPageName=STRK%3AMEBIDX%3AIT&var=423545070868&_trksid=p2057872.m2749.l2649

When sun hits the panels the charge controller shows it is charging and the volts go up to 24-26v and the battery level shows full/mostly full. In the morning when I check, the charge controller shows 19-20 something volts and the battery level is empty.

I cant figure out if the charge controller doesn't have a blocking diode or it isn't working, or if the charge controller battery level /volts indicator are just wrong. Or if I am missing something altogether!

At the moment I don't have anything wired to the load of the charge controller as I am just trying to figure out the charge situation.

I thought about putting a schottky/blocking diode on the + side of the wire going to the controller to test if the controller actually does have a function blocking diode or not. But not sure if that is the correct thing to do.

Any help would be greatly appreciated.

 

[Andy-1960]

I would check to see if any current is being drawn by the charge controller at night that is causing the drain?

 

[S1M0N]

I would check to see if any current is being drawn by the charge controller at night that is causing the drain?

That's a good idea! I just watched a video on how to check for a parasitic draw on a battery. I guess that's how I would check this.

Thanks for your reply, going to give that a go!

 

[buzzlightyear]

some times the cells go down on the batteries in cold weather.

 

[Wilko]

Hi - as Buzz has said, it's likely the solar panels are not doing much and cold is tough on the battery. How old is the battery?

 

[S1M0N]

The batteries are only a month old, and as of yet have had very little use.

I wondered about the cold weather, but the batteries have gone down to 9.6v! Thats the 2x 12v batteries in series! just thought that much of a drain seemed a bit much for just cold weather??? Especially as the batteries were not used for anything, they were just wired up to the charge controller and the solar panels.

I'm starting to wonder if the batteries are just duds. Correct me if im wrong but 9.6v on the batteries seems like they are probably dead? They do charge up to just over 13v each when i bring them inside and use mains charger. They also hold that voltage fine when just sat inside for a few days.

I have messaged the seller of the charge controller to see if they can confirm that the controller has discharge protection. I maybe wrongly assumed that was one of the standard features of charge controllers.

Thanks for the help so far, i just seem like i have hit a wall of things to try

 

[Jim_e_Jib]

The batteries are only a month old, and as of yet have had very little use.

I wondered about the cold weather, but the batteries have gone down to 9.6v! Thats the 2x 12v batteries in series! just thought that much of a drain seemed a bit much for just cold weather??? Especially as the batteries were not used for anything, they were just wired up to the charge controller and the solar panels.

I'm starting to wonder if the batteries are just duds. Correct me if im wrong but 9.6v on the batteries seems like they are probably dead? They do charge up to just over 13v each when i bring them inside and use mains charger. They also hold that voltage fine when just sat inside for a few days.

I have messaged the seller of the charge controller to see if they can confirm that the controller has discharge protection. I maybe wrongly assumed that was one of the standard features of charge controllers.

Thanks for the help so far, i just seem like i have hit a wall of things to try

If the batteries have been regularly discharged to around 5V each, it is likely they will have been damaged.

It would be interesting to find out what the seller says - the charge controller does seem to be very 'keenly priced' - perhaps it is not the best one for this job?

It looks like your batteries are being discharged by something - it could be the charge controller as @Andy-1960 says. Does the gate opener have a continual standby current draw? It could be that your batteries are just too small to cope with this and that of the charge controller overnight.

 

[S1M0N]

If the batteries have been regularly discharged to around 5V each, it is likely they will have been damaged.

It would be interesting to find out what the seller says - the charge controller does seem to be very 'keenly priced' - perhaps it is not the best one for this job?

It looks like your batteries are being discharged by something - it could be the charge controller as @Andy-1960 says. Does the gate opener have a continual standby current draw? It could be that your batteries are just too small to cope with this and that of the charge controller overnight.

Thanks for the reply.

The charge controller is keenly priced (that's a nice way to put it). I am happy to replace it, if that is the cause of the problem, but I would prefer to know for sure if possible.

The batteries have only ever been that low once, but I am still not sure that they are not kaput.

It is possible that the batteries are too small, but they are not actually being used. All this is happening with the gate system completely disconnected. The only things connected are the solar panels, charge controller and batteries.

I guess that would mean either the controller is draining the batteries. The panels are draining them over night because the controller doesn't have a blocking diode, or the batteries have had it. Or some combination.

Maybe I should put a blocking diode on the + of the panel connection before the charge controller?

Also as Andy said I should "check to see if any current is being drawn by the charge controller at night that is causing the drain"

Thanks again.

 

[ss1289]

Did you ever figure out the issue? I'm having the same problem.
Thanks!

 

[john doe]

use diod switch.

 

[john doe]

install a one way diode