question

jfcroat avatar image
jfcroat asked

Mppt over set voltage

I have a 24/3000/70 easysolar and have set the absorb voltage set to 28.20v for the 150/70 mppt via ve-direct Bluetooth dongle went to check the system as i’ve only had it running 2 days and the voltage got up to 28.35v yesterday!! My battery specs say not more than 28.2v for a 24v system. Can anyone help please??

MPPT ControllersEasySolar All-in-One
2 |3000

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

3 Answers
Mark avatar image
Mark answered ·

What is the temperature in the morning before the MPPT wakes up?

The MPPT uses its own internal sensor to take a temperature reading at this time & then uses it to correct/compensate the charge voltage for temperature throughout the day.

25°C is the reference temperature and if it's colder the voltage will be automatically increased. If it's hotter the voltage will be decreased.

To confirm if this is the reason temporarily set the temperature coefficient to 0mV/°C or switch the toggle to disable temperature compensation and check the output voltage during absorption charge phase.

You should refer to the battery manufacturers specifications to confirm the correct coefficient to use with your particular batteries.

Also if you want the temperature to be monitored throughout the day & voltage adjusted according, consider adding a Smart Battery Sense device & Bluetooth pairing it with your MPPT.

Alternatively, if this higher voltage is not continuous & only seen as a max daily voltage in Victron connect, then it could have just been a brief spike following a large load being turned off while there was also high charge current output from the MPPT.

6 comments
2 |3000

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

jfcroat avatar image jfcroat commented ·

Will give it a try and see what happens

0 Likes 0 ·
Mark avatar image Mark ♦♦ jfcroat commented ·

Please let us know how it goes.

Also, you may want to consider lowering the nominal charge voltage slightly if it's currently right on the maximum of the allowable range & you still have concerns.

0 Likes 0 ·
Show more comments
JohnC avatar image
JohnC answered ·

Hi J. This can happen from a spike caused by a load change or somesuch. The kit may only take milliseconds to react, but in that time a 'day high' gets recorded. Not for concern.

The main thing though may be temp compensation. The V will be adjusted to allow, unless you've turned it off.

If Pb batts, that's a modest Vabs anyway, and unless the batt maker has also supplied a temp correction factor, perhaps that limit is for the 'masses', a general safe level for all conditions.

I wouldn't be too concerned about it. What I would do though is check Vbat with a multimeter in (say) a stable Absorb condition, and check with the readings of the Victron.

If you haven't had a chance yet to hook your system to the VRM portal (I hope you can), then please do, a lot of this type of seemingly strange behavior is often explained on the graphs once you get the hang of it.

'Easy' does it, ha! Just monitor & measure for now. Adjust if necessary once you get a handle on it all. Nothing urgent to me, but I do sympathize with your concern for your system. Good luck with it too..

Edit/: Posted before I saw Mark's, I've a slow keyboard.. :)

1 comment
2 |3000

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

jfcroat avatar image jfcroat commented ·

My main concern was that i could hear bubling and my batteries are sealed leadcarbon so in my experience thats a bad sign.

0 Likes 0 ·
Paul B avatar image
Paul B answered ·

Dont forget you have two chargers here in this system

ONE being the MPPT unit

the other the Multiplus 3000/70

so you must adjust BOTH UNITS to the correct settings. not just the MPPT solar reg

1 comment
2 |3000

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

jfcroat avatar image jfcroat commented ·

Thanks Paul B that was going to be my next problem to solve if i use the "smart battery sense will that work with the multiplus charger is well?

0 Likes 0 ·