Hi All.

I'll appreciate some help with a basic 12v setup for a water pump.

Starting from the bottom:  12/24v submersible DC pump , drawing about 2.5amp @ 12.2v.

                                             : Connected to a 75/15 Victron Smart solar charger.

                                             :Battery 75ah

                                             :Panel 200w  , 17.64vmp ,21.6voc and 11.34Imp. (Chinese.................)

 

The problem lies with my solar panel. Even in full sun shine at 12o'clock the highest amp rating I get is 5.5Amp's ,half what it should be. The volts would be at 17 or even a bit higher. I confirmed these readings (on phone...Victron connect on phone)  with a multimeter.

 

Might this be another buy cheap pay more later , Chinese product, or can it be diodes or something else?

I've added a picture of the solar panel and the diodes.

Thank you.

Morne'

Welcome MB1.

Are you measuring the actual panel only, or with the MPPT connected to the battery?

Panel will only give what the systems requires, i.e. if the battery is low and pump operates, it will give the controller is set to and / or what sunlight there is

If battery is full and pump runs, it will just give enough to run the pump.

Hi TTT.

I did both.Measured with panel connected to charger and load on and just panel. Current never higher than 5.5amp..

MB1

1 hour ago, MB1 said:

... drawing about 2.5amp @ 12.2v ...

Perfect. But the load is small?

Out if interest, can you read the Controllers settings? Have the cable and software?

The smart solar charger (Victron) is bluetooth enabled. Download the software from Playstore. (Andriod) .

See attached screenshot.

I can see and change just about every setting. I left it on the pre set" battery life" setting.

For reference:The screen shots was taken early in morning with heavy cloud cover. 

Nice!

History looks perfect for a 200w panel and a very small load.

I must say that I don't see a problem, the pump draws about 30W and the panel supplying about 100W which is enough to run the pump and keep the battery topped off.

If you would like to test the panel capabilities then try this:

1. Disconnect panel from the system so not charging,
2. Run the pump from 7am to midday (about 150Wh),
3. Then connect the panel which will now have a battery to charge and a pump to run.

If you do the above then I am sure you will see much higher power output from the panel, dropping as the battery SOC increases.

P max over 3 days did not even reach 100w is this normal for a 200w panel?

With a full battery and a small load yes, pretty normal.

Thank you Pilot Fish.

 

I will give that a try. Just need to wait for a sunny day. (Never thought I would say that in Alldays , Limpopo..LOL)

Out of interest, what controls the pump, when does it run/stop.

That is more of a weather restriction there. previous day was in bulk the whole time, i.e battery isn't full. if there was a spat of sunshine on the panel Pmax should have at least gone over 100W.. something else going on here. how bad is the weather really?

Before I had the mppt I had a pwm charger with a seperate 12v Dc timer.

The reason I ask is because I was typing my first response before you posted your reports - there us definitely a problem!

A lead acid battery should never be allowed to drop to 10.5V, if I look at 2 days ago your battery went from 14.3V to 10.5V while the panel was supplying charge. So either your pump runs all night or the battery is shot - but something is a bit off.

Hi Weasel.

2 and 3 days ago , the weather was not that bad.Broken clouds. 

 

1 minute ago, MB1 said:

2 and 3 days ago , the weather was not that bad.Broken clouds. 

pmax should have gone over 100W, its in open air as well.. with some cloud edge over 200W would not be surprising.  How long is the panels cable and what thickness of wire. 

 

4 minutes ago, pilotfish said:

So either your pump runs all night or the battery is shot - but something is a bit off.

yes load isnt more than what that panel should generate, i agree somethings up. 

2 days ago the battery went from 14.3V (fully charged) to 10.5V (SOC=0=damage).

A 75Ah battery can theoretically supply 900Wh between SOC=100 and SOC=0, your consumption was 560Wh of which 280Wh was from the panel so 280Wh should be from the battery.

The battery should never have dropped from 100 to 0 under those conditions - so my opinion is battery kaput!

 

It is very difficult to judge performance of a panel/mppt with a dud battery - replace the battery (I suggest 200Ah to allow for some cloudy days) and try again.

I think what I must do is give it a few more sun shine days. Get the data from charger and get back to you.

20 minutes ago, Weasel said:

.

 

14 minutes ago, pilotfish said:

...

Sorry....Im having some problem working with quotes etc..

 The battery is not that new so that might be the problem...

 

I dont doubt it.

Your system requires a battery protector that will cut off the pump before battery gets damaged - too late for this battery I'm afraid to say.

I missed the 10.4v on the batt. Well spottetted guys!

I thank all of you for your input.

I will get back to you as soon as I have more data from the mppt.

Im not sure why the voltage went that low. The load should have been disconnected by the "battery life "  algorithm wich was preset.

 

 

14 minutes ago, pilotfish said:

A 75Ah battery can theoretically supply 900Wh between SOC=100 and SOC=0, your consumption was 560Wh of which 280Wh was from the panel so 280Wh should be from the battery.

oh yes its not happy that one... @MB1 looks like the best thing you have there is the 75/15.  i still think somethings up with that panel :/

Weasel, Im with you on that one......

I have a brand new 120 watt panel that I will stick up tomorrow....

 

Thanks guys.