question

carolin sorbier avatar image
carolin sorbier asked

No watts, no amps but batteries are ok

Hi all,

I have 4x 140W solar panels connected to 2 charge controllers wired separately, each fed by a pair of solar panels. They charge 2x6v Trojan T105 batteried (deep flooded). I have changed the battery preset to match the batteries specifications.

Here is the problem: the reading on the batterie directly seems good and accurate. But on the app I read 0 amps and 0watts. Sometime it goes to 10w but that's it. Strangely the history shows something else.

Any ideas what could be the problem? Thanks

Here are some pics:

MPPT Controllers
screenshot-2019-05-18-15-20-24-123-comvictronenerg.png (120.4 KiB)
screenshot-2019-05-18-15-20-02-682-comvictronenerg.png (166.7 KiB)
screenshot-2019-05-18-15-59-58-007-comvictronenerg.png (166.8 KiB)
screenshot-2019-05-18-17-01-10-600-comvictronenerg.png (163.4 KiB)
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3 Answers
JohnC avatar image
JohnC answered ·

Hi Carolin. You say you have 2 cc's. The one you've showed us is in Float slightly above it's target, so will back off to zero watts. The other must still be producing. This can happen for a few reasons, nothing to be concerned about if you're sure (& happy) about the batt V being at that level.

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solgato avatar image
solgato answered ·

The only time you will see a Watt and Amp value using the App is if the batteries are in need of charging and being charged, or you have a load on the system.

Those values are not a reading of the battery, but the solar power that is being converted by the chargers to charge the batteries.

Since your batteries are charged and there is no place for the power to go, when you launch the App you will see zero. The small amount you might see as you mentioned is the small amount needed to keep the batteries at their float level much like a trickle charger.

If you put a load on the batteries, you will see the Watts and Amps increase as the charger converts more solar power to cover the load while maintaining your bank voltage.

Your history shows that the batteries are being charged when the chargers “wake up” and that they are then going into float. This is probably occurring earlier in the day before you are monitoring with the App. By the time you use the App, the batteries are already charged and floating so you don’t see any Watts or Amps in the App, just a minimal amount if your bank falls below your target float value of 13.50V.

As JohnC said, your bank was above your target at 13.55V so either your other charger was doing some work, or your bank was full and neither were converting power because there was no place for it to go because your batteries are full.

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james-eaddy avatar image james-eaddy commented ·

I'm having a similar issue where I'm seeing voltage for pv and battery, but no amps on either and solar reads 0 watts.


Reading through this thread, am I right in assuming the amps and solar watts will only show when the charger is using the pv power?

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ james-eaddy commented ·

Yes, the MPPT can only show you the actually used PV power, not the theoretical available power.

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carolin sorbier avatar image
carolin sorbier answered ·

Thanks a lot, that is very helpful for me who inherited this whole solar system without knowing much about it before.


I'm still a little confused about the reading. I have 4x130W panels but the readings are very different everyday. Of course the weather change but for instance today is very sunny and I only get 30W, although the batteries are full are 10am. I have a multimeter but it doesn't read the amps so I get read it directly from the panels.


Here are some pics


Thanks


screenshot-2019-05-21-17-30-54-957-comvictronenerg.png (77.4 KiB)
screenshot-2019-05-21-17-30-37-637-comvictronenerg.png (297.9 KiB)
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solgato avatar image solgato commented ·

You will only see what the chargers are using to maintain the batteries, not the full output of your panels or the maximum output at a given time depending on how much sun there is.

So it’s not a measurement of your panels output, but the amount of energy being used by the charger -the amount of energy going into your batteries.

Think of it like this. The power your panels make has to have somewhere to go, if your batteries are charged they can not take the power, so the chargers basically turn off the flow of energy like a water faucet and the App measures how much is flowing through the faucet when it’s open, not how much water you have.

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