question

mirubi avatar image
mirubi asked

Problem with 2 new MPPT 75/15 - both freeze at night

Hi, I already have 5 of the MPPT 75/15 mit Bluetooth. The first 3 still work perfect without any problems.

But the latest 2 I bought are not ok... every 2-3 nights one of them freezes, so the next day:


- still shown in Bluetooth summary, but no connection possible (loop from 0-100% and again and again)

- battery not loading

- solar 0 Volt

- daily summary in overview is from the day before


Solution: Disconnect both Battery + PV and it's working again.

Both serial number begin with HQ2236* und have the latest firmware installed.


Is there any solution I can try so solve this issue?

MPPT SmartSolar
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

12 Answers
Paul B avatar image
Paul B answered ·

check to make sure that the PV voltage is getting to 5 volts above battery voltage , once started they will run with as little as 2 volt difference.

your indicating that the voltage is zero so this means its a dead short on the PV side, are the POs and Neg correct (check with a volt meter)

make sure FW is updated

check for a bad connection in the PV aray wiring (ie under High start current ithe pv connection maybe going open circuit) so check that there is also a zero voltage reading at EACH panel when the PV is showing zero volts - as if its zero then so should all the panels voltage reading also be zero.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mirubi avatar image
mirubi answered ·

Hi, the only reason can be a problem on victron mppt side because all other of my 3 victron 75/15 mppts works fine with the same batteries, cables and PVs. Already switched them.

And as I wrote it is a matter of seconds to solve it when i am at home - just disconnect all cables so the mppt does a restart. Everything is fine after it.

But when I am not at home all pv-power from that day is lost.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image
seb71 answered ·

If you can't connect to them via Bluetooth, how do you know the voltage, power, etc?

Do you also have a GX device and you connect to them using that?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mirubi avatar image
mirubi answered ·

ov.jpg


Both are still visible in the overview but no detailed connection possible if I click on them (0-100% loop).


2-DP went down 2 days ago, 3-AC this night and I am home not before Saturday to fix it. I would have to buy 4 wifi relays to disconnect pv and batterie remotely so they can restart. :-/

The others ones never had those problems and are months older.


ov.jpg (57.1 KiB)
2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image seb71 commented ·

If you can't connect via Bluetooth, I would not trust the overview data for those MPPTs. Do not take those values as the current ones.


Each MPPT is charging a different battery?


Test in other ways if only Bluetooth connectivity is not working or the entire MPPT charger is not working. For instance measure the current with a clamp meter.


I dont use Gx - just bluetooth with a mobile phone and the victron app. I connect to this phone per teamviewer to see whats going on.

Is that phone close to all MPPTs?

0 Likes 0 ·
mirubi avatar image mirubi seb71 commented ·
I think you are right - this night I used all the battery power until it was empty and the battery volt in the overview did not change. So bluetooth seems to still send a signal but everything is from the point of freezing which always happens in the night when there is no pv power - and as I wrote not every night, sometimes it works for 5-7 days until it happens.


The phone is close to the mppts - but that is only for my vacation now, the same problem happens when am i am at home using my main iphone in front of the mppts.

And yes, every mppt has its own batteries - but I can switch batteries, pvs and mppts... its always the same 2 mppts which are causing this problem.

0 Likes 0 ·
mirubi avatar image
mirubi answered ·

I dont use Gx - just bluetooth with a mobile phone and the victron app. I connect to this phone per teamviewer to see whats going on.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

kevgermany avatar image
kevgermany answered ·

The two problem units have status 'Aus', off in English. Normal reason for this is too little, or no voltage coming from the panels. It would help if you could get the input (panel) voltage readings. And check wiring, switches, fuses for breaks.

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mirubi avatar image mirubi commented ·
That "off" is from the point of freezing which always happens at night every 2-5th day of using. After that freeze its not coming back to load the battery - even if there is enough pv power. Batteries and pvs and wiring is ok because my other 3 75/15 mppts works fine with the same configuration (already switched the cables)
0 Likes 0 ·
seb71 avatar image
seb71 answered ·

After that freeze its not coming back to load the battery - even if there is enough pv power.

Did you check that with a clampmeter?

Or measured the battery voltage with a multimeter at intervals, to see if it is not charging?

What is the MPPT LED status at that point?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mirubi avatar image mirubi commented ·
I have to check when i am back at home but as I remember the bulk led was not on before restart.
0 Likes 0 ·
seb71 avatar image
seb71 answered ·

Do you have a USB-VE.Direct interface?

You could connect with a Windows PC/Laptop to the MPPT and check its status this way for troubleshooting.

3 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mirubi avatar image mirubi commented ·
No, I only use the bluetooth connection.


I think the problem is software or hardware related and only only appears with mppts from this production lot as both were produced on the same day I think.

0 Likes 0 ·
seb71 avatar image seb71 mirubi commented ·

With a VE.Direct-USB interface hopefully you could determine if the MPPT itself got stuck or just the Bluetooth is frozen.

0 Likes 0 ·
mirubi avatar image mirubi seb71 commented ·
I am still no back at home but i am sure now that the mppt is not loading the battery any more until it is restarted. It was a sunny day today and the battery still cant run the tie grid inverter. My other Victrons made almost each 1 kwh today with the same configuration.
0 Likes 0 ·
mirubi avatar image
mirubi answered ·



8a4a0d89-9e7c-44a4-8dde-3a893dad5dc7.jpeg



Im am back at home - both MPPTs had no led light on and did not charge the batteries at all in the last days.


As always it took 5 seconds to solve - Just turn off batterie+pv and some moments later on again and they load the batteries within seconds.


c6c7da26-31ab-4ff0-9e0a-41e10d071f40.jpeg (3.3 MiB)
4 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image seb71 commented ·

Not the cause of your issue, but those battery wires look very thin.


Also, for battery wires, fuses are more reliable than MCBs.


When the MPPTs are "frozen", if you only disconnect the PV, do you have voltage on battery terminals of those MPPTs?

0 Likes 0 ·
mirubi avatar image mirubi seb71 commented ·
The only reason for the MCBs is that I can easy disconnect them :)

And I already ordered better cables.

0 Likes 0 ·
seb71 avatar image seb71 mirubi commented ·

How do you disconnect the PV wires? Just remove the wires?

There is no switch, nor fuse/MCB for PV wires in your picture.

0 Likes 0 ·
mirubi avatar image mirubi seb71 commented ·

Here they are ;)

c471b713-5079-49a4-b86d-a6385483d934.jpeg

0 Likes 0 ·
c471b713-5079-49a4-b86d-a6385483d934.jpeg (406.0 KiB)
mirubi avatar image
mirubi answered ·

5e976161-1c0d-4dc3-baa4-205b60c68486.jpeg


And before you ask - the batteries got empty AFTER they freezed because I turned on my grid tie inverter - thougt that it would be a way to restart them but they still got enough power to keep the freeze.


5e976161-1c0d-4dc3-baa4-205b60c68486.jpeg (140.7 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image
seb71 answered ·

One thing to try:

Swap one of the "good" MPPTs (such as #1) with one of the "bad" MPPTs (such as #3).

Reprogram them if necessary.


If the freezing problem follows the "bad" MPPT, it probably mean it's a production batch with some issues (since you have 2 "bad" MPPTs from that same batch).

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mirubi avatar image mirubi commented ·
I already did this - both mppts were connected to #1 +#4 batteries and pvs where they had the same problem 1-2 times a week.
0 Likes 0 ·
seb71 avatar image seb71 mirubi commented ·
Right, you wrote about that. Now that you mentioned it again, I remember reading it.


What more can I say: time to contact your dealer?

0 Likes 0 ·
mkvanl avatar image
mkvanl answered ·

Hi merubi,


Currently i’m facing exactly the same issue.


How did you solve your problem?

Awaiting your reply,

Macht thanks, Mike

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mkvanl avatar image mkvanl commented ·
Just for info. Mppt renewed and problem solved. Was clearly a production/hardware issue.
0 Likes 0 ·