Kristof G. avatar image

Battery Voltage problem for Float / absorption


after asking a lot of persons , no one can give me a good answer so iam gone ask it here ;)

i've seen wierd thing going on with my system...

float is 55.20v , but the quattro doesnt stay on that voltage always some volts below it , 54.7v or 54.4v (in the beginning the 55.20v was good, but i dont remember the version of the firmware)

i have tested firmware 2.30 and all the beta's (now running Venus OS v2.30~51 )

i have tested with or without DVCC = same ( i need the "max. charge current" , because i have 10kw on the battery and only 95A can go to them )

i have the same problem for absorption voltage , it doesnt stay on 60v , always some volts below.

Here i have an other problem , the current does not go below 32A and stays putting 32A (or even ramps up the Current again) in the battery for the max. absorption time (6h)

i've been testing this for a long time and my battery is not broking for what the tests reveal, maybe its the way the battery works...?!?

absorption example :

All my mppts are like this ( also the values are the same for quattro ve.config)

i have 2x 150/70 and 1x 150/35

here you see the mppts try to go to the 55.20v :

My installation :

color gx - voltage of Shunt and quattro:

batteryExtra voltage meter:

above pics are for Float status

tests :

if i put value for absortion voltage to 60v (ve.config app) = quattro goes to 59.?v (does not stay at 60v)

if i put value for absortion voltage to 62v (ve.config app) = quattro goes to 61.?v

for that test iam sure my battery goes or can go to 62v

quattro values are always diff. from what the shunt tells me


quattro 8000-110A and mppts are the last firmware , color is last beta

battery 48v - 840ah


if you have some more questions i will give or will try to give you an answer , i must / will find my problem here :D

the one test i"ve not done, is reverse back to an older firmware for the quattro... (older than downloadable version)

thanks for reading this ;)


edit : added a screenshot from colorgx, so you can see there is enought pv power.. its feeding into grid a little

Venus OSvoltageabsorptionfloat
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i am thinking of something....

could it be a voltage sense sensor that be " broken" in the quattro or theyou shunt? ( or a litle off scale?)

or something in that way?

OR there is indeed a temp compensation ,but how can i undo that? just unplug the sensors outen of the shunt and quattro?( since there is no temp sensor in my mppts , "i think")

i can not test it with an other quattro... so...its a crap situation here...


Meuahhaha...i think i found my problem!!! The temp sensors in quattro and shunt removed =

Lets hope that solves my problem!?!?!?!

Will test tomorrow

Woehoe :-)

Ok..test is done...

And succes with the voltage! ( all the temp. Sensors out) ( thx paul and john!)

But my "old" problem is still there... ones he goes in absorption, all goes good, the voltage stays 60v, the current does down and at some point the current stops doing down!(around 30 a 40Amps), stays at that current for max. Absorption time and sometimes goes back up ( then the voltage goes up and down..and up and down)

An other thing , the shunt always shows less voltage than the quattro and voltagemeter and mppts .

Any ideas for my problem?

4 Answers
JohnC avatar image
JohnC answered ·

Hi Kristof. Have you considered Temperature Compensation.

A Quattro will normally come with a temp sensor which is attached to a battery terminal post and will adjust charge V in real time to suit.

The mppt's, unless fed a signal from other external kit, will use their internal sensor. In that case it is determined around when they fire up in the morning, and set for the day. Sounds crude, but avoids the internally generated heat as it loads up in full sun. In practice I find it quite adequate for my Pb's.

So it's possible that the target V's of the units can vary between each other. It can be tidied up with extra kit, but I've not bothered - close enough for me. From summer to winter I see perhaps 0.8V variance in the applied V, and would be a worry if I wasn't aware of the cause.

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Joi john,

Thx for answer, ive connected the tempsensor...but how can i see if its working ( connected also the temp an shunt and is in same place at the battery)... in the color the temp. Sensor to be looked ( share temp. Thing) at is also the shunt selected.

Any more ideas?

Krissoff a way to test this is to remove the temp sender out of the quattro connections for a day or to and then see if all the charging figures are correct then put the temp sender back on.

just do this so that you can compare

Lol when i disconnect tempsensor, direct error on thats good

So i can say it works? Dont think that is my problem...

Something else:

I see in the pictures, it looks like the heat-shrink around your battery terminals is in between the connection, (it might be cut away, I cannot see that). if so, please make sure it is cut away to ensure a good connections.

On the voltage: Probably the temp-compensation, you can measure the temperature of your batteries with a separate temperature meter if you're not sure.

Hoi boekel,

Question...they are not real connected to a terminal ( is that needed???) Because its a temp sensor..i thought if they just lie on the battery it is good...? If they must be connected..what is the diff. Than?

Edit : just for you i connected them to terminal

Of that really solves my problem, i gone give ya a kiss (hahahaha)

My apologies :)

I meant the battery connection terminals in the Multi, but if the other one helps ;)

battery terminals (of the battery itself) is also the best place to measure the temperature, but I sometimes put the temperature probe between the batteries in the middle (those get the highest temperature)


On my quattro they are connected ok , there is a copperring under and above the clamp... so they are connected good, for the temp on my battery, no succes / diff ( so no kiss :p )

We / i have to look for something other that can be wrong ...

Never use washers between cable and terminals! these are extra points where resistance occurs.

all washers should be above the cable eye.

No nothing to do with your initial question, but that is almost certainly to do with the battery temperature, what is the ambient temperature there?


I ve also changed the terminals, without spacers...dont think that will do..but maybe its a beter contact...

Kristof G. avatar image
Kristof G. answered ·

Ok, ive tested with only the mppts on ( so no quattro, no ess,...) and the voltage is MUCH stable than with quattro. Will test like that more when i have a free day.

So iam almost sure its not the battery and the mppts...its the ESS or the quattro that does the "wierd" control...

Ofcourse on this above test there is not enought sunpower will post same test later this week...

Thx again for the help everyone :)

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Kristof G. avatar image
Kristof G. answered ·

Ok , i give up on my problem.

ive tested the MPPTs individualy and they go to Float (in a second) + the voltage goes to 60.01v (like i put in the mppt settings) , the voltage is the same on the Battery extra , the only thing that is not right is voltage meter 0.12v off.

so thats good news for the mppts , BUT de minute. i go with the color (dvcc voltage share on) or go with the quattro ,thats the wurse, the mppt voltages drop and the voltage doesnt at up + doesnt go to 60v anymore . goes in float at 57.9v (quattro is 60v ve.config)

i"ve added some picture during the test, of the mppts (not the quattro)

voltage of the batteryExtra meter when the mppts are @ 60v

here you can see the absorption of all the mppts colorgx = always wrong values , not from batteryExtra , not from the mppts even not like my voltage meter: (no mppts connected to the color)mppt connected in the color voltage ok:(dvcc voltage share off)Voltage meter on the battery:

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1 comment
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(because of 10 attachments . in one post)

and some pics of the victron connect (GSM):

for now iam unclear what my problem is to charge my battery proper , when the quattro is on , the amps ramp up after a time , always max absorption time of 6h (ve-config) .in the pic. you can see my battery holds the voltage overnight.

Paul B avatar image
Paul B answered ·

Hi Kristof

just a double check

I have just reread the whole post and in that whole post I cannot see a mention of what Firmware the Quattro is on

it should be on FW 459

please check this and if not please upgrade it

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quattro = 459

all mppts = 1.39

color = rc2.30