Dueling MPPT Solar Controllers

[Yoda]

Yep it is an old wild west saga

I have 2 MPPT solar controllers hooked to two sets of panel's. Both are Victron smart units (Bluetooth and connected to the Cerbo GX). One is a 100/20 and the other a 100/30 Wren first installed the were both programed the same and appeared to be in sink as far as charging modes. - bot contributed to the charge

Over the past week I have found only one charging - the 100/20 the 10030 is not contributing and it is attached to the larger panel array. However the 100/30 is showing float and the 100/20 is showing bulk. I have flooded batterys (4-6V in series parallel.

In the past they have both equally contributed to charging the batterys. Could somehow they have fallen out of sink - if that is even possible?

Now I know there is someway to look at the charge history, but for the life of me I cant find that on the touch 50

Is there something I can check and change with Victron connect and my phone?

BTW I am hooked up to shore power if that matters, so the batterys should be 100% all the time

Its time for spring maintenance where I do and equalization run, and then refill the batterys as needed (Crown battery instructions to equalize first before filling) I do this twice a year in the spring and fall.

I'm guessing as I am on shore power the MPPT 100/30 is seeing full charge and knows not to contribute, but the 100/20 almost always is showing something, hiowever I have not noted the charge mode every time I have checked - my bad.

Any thoughts? Trying to learn here

Keith

[Scott'n'Wendy]

I don't have any solar or know how the controllers determine state, but I think a poor connection in the 100/20 controller/panel cct could fool the controller into thinking the batteries are below full charge. My first step would be to examine all the connections primarily in the 100/20 cct. Get that new torque screwdriver out and check them all....lol. What?!? you didn't buy one yet?!?

[howson]

Any thoughts?

Here's how I'd approach troubleshooting, Keith.

1) Disconnect from shore power or turn off the converter using the circuit breaker.
2) Disconnect both MPPTs from their respective array. (You do have disconnects between the arrays and MPPT inputs, right?)
3) Run the furnace or other high amperage device for a bit to ensure the battery bank is <100%.
4) Assuming there is PV (sunshine) on the arrays, reconnect one of the MPPTs. Does the battery charge? If yes--it's fine. If not, troubleshoot.
5) Repeat step 4 for the other MPPT (with the first one that presumably is good disconnected).

Post what you find.

Howard

[TucsonJim]

Yoda -

Keith. I second Howard's recommendations. But I also have a question for you.

Do you have the two charge controllers sync'd together in VE Smart Networking? If not, you can see how to do so in the video below. Skip to 6:15 in the video.

https://youtu.be/N0UB7LZVduk?si=1UJxg1xguv_f6qLN

Jim

[Yoda]

Yoda -

Keith. I second Howard's recommendations. But I also have a question for you.

Do you have the two charge controllers sync'd together in VE Smart Networking? If not, you can see how to do so in the video below. Skip to 6:15 in the video.

https://youtu.be/N0UB7LZVduk?si=1UJxg1xguv_f6qLN

Jim

Say What?.....................VE Connect and networking.......What are you thinking....or dreaming?

You want me to use my Smart Phone, which I am a dummy operating and actually follow directions........................................ remember I am an Engineer I don't use directions - I create them in engineerese..... yes it is a secrete Engineer Knights Templar origination organized to take over the world tonight... Yes too much Oak Island watching. and Narf! I really liked that one...... my Daughter sent me the entire series for Christmas.

However in this case I just might try this....what could go wrong

Jim - Thanks for the link - it looks simple (gulp - did I say that). Give me a week to try this out. It is starting to get warm enough I just might thaw out.- will be fun - I hope.

BTW I did find the video interesting and informative - never knew this was possible

howson I have disconnected shore power and am watching the behavior as I rip out (salvage) the chase lounge . Its funny I found a few loose bolts and nuts below it - from the frame above. Good thing I did not want to sleep on it would have folded up.

I think I will turn the Multiplus on (currently on charge only) and do a bit of microwave use and possibly brew a cup of coffee. That should put a good dent in the battery status. Then I can run your tests. Will also be a good test of how the battery bank is doing after 4 years. I need to know this for boon docking a week after the Colorado Rally. Also need to make sure my generators run.

Jim - Thanks again for the link - I will probably cruse through his other videos too.

Keith

Please stay safe everyone.

[TucsonJim]

Jim - Thanks again for the link - I will probably cruse through his other videos too.

Nate and Will Prowse are two of the best on the internet. Nate is a Victron guru and he explains complex concepts in easy to understand language.

Jim

[ajg617]

Firmware glitch. Howard's correct. I don't have the same controllers you do, but had to run my batteries down to 12.8V with fans/furnace/etc. after 11 days of not being able to get my batteries over 70% SOC even when connected to shore power or running the genset. My solar controller put out sufficient charge (actually it was a little too high) that the 120V charge controller SW said OK, never mind - the other charge source has it covered and it remained in idle mode for 11 days. I was told it was an engineering feature. This was in the manual for my 120V charge controller: Nicely written eh?



Why didn’t my battery charge?
Like any computerized device, data in affects the data out. Influences from outside the converter may cause the SW to operate in an unexpected mode.
A large battery bank, a high current demand from the RV or additional charging sources such as an alternator or solar will influence the operation of the SW.
If the battery bank isn’t full after 8 hours of charging,the SW won’t know this. Your bank may be too big for your charger or some of the charging current is taken up by the RV and is not allowing enough current to fully charge the bank.
Voltage from the alternator or your solar controller will also influence the SW and appear to indicate a fully charged bank. When you supply AC power to the converter, the SW will stay in idle mode.
Well that just stinks, what’s a person supposed to do?
Buy an accessory to manually put the controller in bulk mode.