Solar/votronic help required

[Brian123]

Hi all

I recently added another solar array, and am currently down in Spain with a bit of sun (1st time being able to test the new panels out).

My setup
330ah lithium
Array1 2x100w, votronics 250 wired to a bus bar then direct to the battery bank
Array2 (new) 2x160w, votronics 360 wired to same bus bars. Duo connection to EBL for cab battery charging.
Note both mppt’s programmed to lithium charging at 14.4v

Today I noticed that I was getting between 5 & 8 amps in good sunshine, on investigation array1 was showing bulk charging and delivering all of the power. Array2 had all 3 lamps lit on the votronic 360 (bulk, absorption and float) meaning fully charged. At the time the battery’s were circa 80% charged. Array2 was also showing battery voltage as 14.4v

Could the new Array2 be picking the 14.4v from Array1 via the common bus bar? Or is there something else causing Array2 to think that the battery’s are fully charged?

Any thoughts appreciated
Thanks Brian

 

[funflair]

At 80% in your batteries both regulators should be working I think, you might find that disconnecting solar from array 2 will kick the Votronic 360 back into life, I had this as an issue with 2x430mppt Votronic and eventually I just replaced them with one big Victron and never any bother again, I wasn’t the only one to have issues with these Votronic regs.

 

[berni109]

The regulators can only sense what electrical feedback they are getting from the battery/busbar. I suspect that the one showing three lights fully charged is in that state because the other one is banging out full output that makes it look like the battery is full.

 

[funflair]

The regulators can only sense what electrical feedback they are getting from the battery/busbar. I suspect that the one showing three lights fully charged is in that state because the other one is banging out full output that makes it look like the battery is full.

At 80% I would expect both regulators to still be seeing the need for power but maybe we should question how accurate the 80% reading is, either way I suppose the easiest way to test that is to switch on a pretty big load on the battery side and pull the voltage down a bit and if it is as you say the second regulator should kick in.

 

[TrudeandDall]

I have a MP 350 and have no problems whatsoever, although it is set to AGM. However when I start the van and the B2B kicks in at 14.7v the solar immediately stops producing, then immediately starts producing again as soon as the B2B stops.
You could well be on the right track thinking that the two controllers are fighting each other..

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[Raul]

If the battery reached 14.4v its full, and only one controller holding the absorb, the one with better potential.
This assuming both controllers are set equally the same.

 

[Brian123]

Hi Rual

If the battery reached 14.4v its full, and only one controller holding the absorb, the one with better potential.
This assuming both controllers are set equally the same.

hi Raul I am not sure the battery reached 14.4v, according to the BMV the battery was at about 13.26 when I was checking

 

[Raul]

Hi Rual

hi Raul I am not sure the battery reached 14.4v, according to the BMV the battery was at about 13.26 when I was checking

If thats the case, check both controllers are set to charge with same parameters. They should be contributing full chat till about 13.8v, then after that, one with less potential will start to drop slowly.

 

[Brian123]

At 80% I would expect both regulators to still be seeing the need for power but maybe we should question how accurate the 80% reading is, either way I suppose the easiest way to test that is to switch on a pretty big load on the battery side and pull the voltage down a bit and if it is as you say the second regulator should kick in.

Thanks funflair when the sun makes an appearance I will isolate the arrays and check them out individually
I will update later today

 

[Richard n Ann]

I've got 2 votronics.. When I connect the auxiliary panel on cloudy days the charging current doesn't go up, but when the fridge compressor starts the battery doesn't discharge so they are both working

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[StillGoing]

Brian

A BMS is not the most accurate measure of how full a battery is. I recommend fitting a shunt. It should be easy as you’re using bus bars.

I have two Votronic MPPT controllers and they work fine together. They also work when the B2B is running.

 

[Brian123]

If thats the case, check both controllers are set to charge with same parameters. They should be contributing full chat till about 13.8v, then after that, one with less potential will start to drop slowly.

Raul unfortunately there not of charging options, there are only dip switches that can be adjusted, both chargers are set to 14.4v

 

[Brian123]

I've got 2 votronics.. When I connect the auxiliary panel on cloudy days the charging current doesn't go up, but when the fridge compressor starts the battery doesn't discharge so they are both working

Hi Richard n Ann that’s interesting, can you recall, when both chargers are in use do they both show bulk charging on the led’s?

 

[Brian123]

Brian

A BMS is not the most accurate measure of how full a battery is. I recommend fitting a shunt. It should be easy as you’re using bus bars.

I have two Votronic MPPT controllers and they work fine together. They also work when the B2B is running.

Hi StillGoing sorry i should have been move explicit, it is a victron bmv712 with shunt

 

[Richard n Ann]

Hi Richard n Ann that’s interesting, can you recall, when both chargers are in use do they both show bulk charging on the led’s?

No sorry they are both under the the bench seat and very difficult to see. I just see the BM1 battery monitor.

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[berni109]

All chargers should be designed to stop charging when the battery is full. So when any charger senses that the battery has reached the set threshold it should stop charging or go into it's set maintenance phase.
Solar mains or b2b(if running engine) all use similar technologies and monitor output feedback so as not to overcharge. That's why you can have multiple charging devices connected to the same battery or in your case busbar.

 

[funflair]

Hi Richard n Ann that’s interesting, can you recall, when both chargers are in use do they both show bulk charging on the led’s?

I had two Votronic on the last van and they would both be on bulk when the batteries needed it, as the battery voltage rose one would cut back and then ultimately go to float followed by the other eventually.

 

[Raul]

Raul unfortunately there not of charging options, there are only dip switches that can be adjusted, both chargers are set to 14.4v

Thats the settings, each dip switch activates a pre set profile.

 

[the1andonly]

Now I have have 2 votronics duo and a b2b all working happy together but i never look at the leds any more not even my bmv712 cos it all works and i'm never without power. But i am a nerd and read a number of things inc the BMV using an arduino mega and a simple display. Not nerdy enough since i cant display my values onto a nextion touch screen.
I have a question has anyone taken the output from votronics and writen/read to a pi, arduino or the like. What connections/ connectors did you use?

 

[Brian123]

Thanks funflair when the sun makes an appearance I will isolate the arrays and check them out individually
I will update later today

The sun was playing hide and seek today but i managed to get the following readings during a bright spell

Voltages at the solar chargers
Array1 isolated, Array2 All LED’s lit on votronic 360 (no charging), solar in 23.1v, power to batteries 14.4v
Array2 isolated, Array1 LED showing bulk votronic 250, solar in 17.1v power to batteries 13.5v
Battery voltage according to the BMV shunt 13.5v recieving circa 6-7amps

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[funflair]

Looks strange to me but I am no expert, it looks like the 360 is seeing 14.4v so doing no work which would be correct, but your shunt says 13.5v on the batteries and the 250 agrees and is therefore outputting so something not quite right, the difference in the solar voltage 23.1 vs 17.1 will just be because the one down at 17.1 is being dragged down by the MPPT, did you put a big load on the batteries to see if the 360 changed?

 

[Raul]

So, the votronic 360 reads 14.4v and the votronic 250 reads 13.5v. In this instance, what’s the BMV voltage?
Edit just seen it 13.5v
And what wire do you use for he 360 and 250 respectively, from controller to the buss bar.
Looks like one is reading lower than the other, hence the higher reading goes to float.

I would check the wiring to the 360 duo, and make sure they both have a common point battery connection. Make sure you have no washers under cable lug at the buss bar, both feeds to the controllers from bus, as equal as possible.

 

[Raul]

Looks strange to me but I am no expert, it looks like the 360 is seeing 14.4v so doing no work which would be correct, but your shunt says 13.5v on the batteries and the 250 agrees and is therefore outputting so something not quite right, the difference in the solar voltage 23.1 vs 17.1 will just be because the one down at 17.1 is being dragged down by the MPPT, did you put a big load on the batteries to see if the 360 changed?

The 23.1 vs 17.1 it’s just telling you that one is working, and voltage dipped in VMP range, and the other sits at VOC range as it does no work, as instructed by mppt with the 14.4v reading; they are separate mppt’s. All fine there, the mastery is why the 360 is reading higher, needs few tests with the multimeter.

 

[Brian123]

After a couple driving days, I managed to check the mppt to bussbar wiring both moors are using 10mm cable. However the 250 (Aray1) is using a positive cable length of 81cm and a negative of 62cm. The 360 duo (Array2) is using 71cm positive cable and 58cm negative cables lengths
Note: both positive cables include an inline breaker switches
Raul what further checks can I make with my voltmeter

 

[Raul]

You can confirm voltage on the buss bar so bmv, 250 are reading the same or close to the multimeter. If the 360 reads higher ( on the controller terminals battery side), while the others are all equal, then the 360 has a fault.
Try to re set the 360 by disconnecting the solar, then the battery. Re connect the battery and read the voltage on the 360 without the solar. Then turn on the solar and read again.

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[Brian123]

You can confirm voltage on the buss bar so bmv, 250 are reading the same or close to the multimeter. If the 360 reads higher ( on the controller terminals battery side), while the others are all equal, then the 360 has a fault.
Try to re set the 360 by disconnecting the solar, then the battery. Re connect the battery and read the voltage on the 360 without the solar. Then turn on the solar and read again.

Ok thanks Raul, I’ll give it a go tomorrow, do you think the different cable length could be a problem?

 

[Raul]

Ok thanks Raul, I’ll give it a go tomorrow, do you think the different cable length could be a problem?

Very unlikely, your cables sound pretty healthy. The breaker, can you post a picture?

 

[Brian123]

Now I have have 2 votronics duo and a b2b all working happy together but i never look at the leds any more not even my bmv712 cos it all works and i'm never without power. But i am a nerd and read a number of things inc the BMV using an arduino mega and a simple display. Not nerdy enough since i cant display my values onto a nextion touch screen.
I have a question has anyone taken the output from votronics and writen/read to a pi, arduino or the like. What connections/ connectors did you use?

Hi I’m afraid I do not understand the last part of your post( way above my competency level) I have just mastered a voltmeter!!

 

[Brian123]

Very unlikely, your cables sound pretty healthy. The breaker, can you post a picture?

 

[LithiumConvert]

I have found that having mutiple charges for one battery bank does not work as you might hope.

Particulary if you use buss bars or have any shunts in the wiring. *

So much so that I now have a switch in the lead from the solar panel to the regulator so that the B2B works properly whilst dring.

* If you read the documentation for the chargers, they all say that the voltage sense wire should be connected to the battery positive terminal. and this assumes that the negative is connected direct to the battery negative. (i.e. no shunts or buss bars). Fuses don't help either, but we have to have them.