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

 

[Raul]

View attachment 882072

Bin them and replace with midi fuse in a midi fuse holder. Those breakers have high resistance and are not very accurate on the amps rating. Some generate allot of heat under load.

 

[Raul]

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.

What?

 

[Brian123]

Bin them and replace with midi fuse in a midi fuse holder. Those breakers have high resistance and are not very accurate on the amps rating. Some generate allot of heat under load.

Ok will do, it will have to wait til I am back in the uk though

 

[LithiumConvert]

What?

Basic Electrics. v=iR
Voltage drops in the wrong places.

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[StillGoing]

View attachment 882072

There is no easy way to say this but that breaker is junk. It needs to be replaced.

 

[Richard n Ann]

There is no easy way to say this but that breaker is junk. It needs to be replaced.

Agree, I swapped mine for a midi fuse

 

[Ray-Vic]

In my experience not all charge controllers are necessarily designed to work in parallel configurations without some form of comms between them to synchronise the charging. My Tristar MPPT's were designed specifically to do so, but with some very specific requirements, including separate voltage and temperature sensors. I think if you are running the charge controllers this way, effectively independently and without comms, then you can expect to see some anomalies, and they won't necessarily behave exactly how you would like them to.

With Victron smart controllers I believe you can create a VE Smart network which synchronises the charge status data, but I don't know if the Votronics has a similar facility.

 

[Raul]

The only thing shared on VE network is voltage and temperature between chargers, but each charger measures the battery voltage individually. Only the Inverter has ports for voltage sense, because load drop. On charge controllers is very little volt drop, even a small deviation only happens on max load, then evens out as the current tappers off, no dramas.

Here we have a 13.5 vs 14v reading not under load, so there is no voltage sense benefit.
If the lower reading of 13.5v is in sync with the shunt, I believe the other controller over reads by 0.5v. That’s alllot for small power to be corrected by any voltage sense leads.

 

[wfdTamar]

I have a very similar setup. 2 x 170 watt panels connected in parallel to a Votronic Duo digital 350 and 3 x 130 watt panels in parallel to a Votronic Duo digital 430. Both have their display leads going through the Votronic doo dah that combines readings, then to the display (actually first through the Votronic Bluetooth doo dah that also reads the B2B data, but the bluetooth part of Votronic is a weak point and not worth bothering with).

It all works great. I have potential 60 Amp power source (90 with the B2B) at the height of summer.

BTW - as I recall the LED's on them only show how full the battery is (presumably based on battery voltage which is not much use for lithium). I can't remember it indicating Bulk or Absorption charging.

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[StillGoing]

I have a very similar setup. 2 x 170 watt panels connected in parallel to a Votronic Duo digital 350 and 3 x 130 watt panels in parallel to a Votronic Duo digital 430. Both have their display leads going through the Votronic doo dah that combines readings, then to the display (actually first through the Votronic Bluetooth doo dah that also reads the B2B data, but the bluetooth part of Votronic is a weak point and not worth bothering with).

I agree that the Votronic Bluetooth could be better but I use it all the time. It’s the only way to download the detailed logs so you can see what’s happened with the starter battery, leisure batteries, solar, B2B, mains charger and leisure battery loads.

 

[Ode]

Don't you have issues using different size solar panels ie ,100w and 160w ,I though that mixing different panel wattage
sizes can cause problems .

 

[AdrianChen]

We have 2*100w and 2*175w, each pair on its own MPPT, so full output (if ever there is enough sun).

The issues arise when mixing different panels on one controller. In parallel the controller is limited to use the lowest voltage of the connected panels (wasting any additional from the higher voltage ones), in series the amperage is limited to the lowest output amp panels. If the difference isn't great it may make little difference to the output, but it's easy enough to calculate the effect.

MPPT's also have difficulty working out the max powerpoint in mixed arrays so diluting their advantage over PWM.

At least that's my simple understanding....

 

[Ode]

We have 2*100w and 2*175w, each pair on its own MPPT, so full output (if ever there is enough sun).

The issues arise when mixing different panels on one controller. In parallel the controller is limited to use the lowest voltage of the connected panels (wasting any additional from the higher voltage ones), in series the amperage is limited to the lowest output amp panels. If the difference isn't great it may make little difference to the output, but it's easy enough to calculate the effect.

MPPT's also have difficulty working out the max powerpoint in mixed arrays so diluting their advantage over PWM.

At least that's my simple understanding....

OK thanks ,wasn't quite sure but info helpful

 

[MobyDick57]

I have two arrays (4x100w) & (2x175w) through two Votronic regulators to 600ah. They like 14.6v. I have set one regulator at 14.4v and the other at 14.2v. So both engage when solar power required, then only one tops it up. Saves confusion for the regulators. Been using this configuration for 4 years and all ok

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[the1andonly]

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!!

ok you dont need to understand it, you can get to to good working system with the multimeter and a little bit of help from knowledgable folk like Raul. Me i just play and was hoping to tap into info from others that like to play. it is above and beyond necessary.

 

[Brian123]

Hi all....just to complete the story, i am back in the uk now and have changed the amazon breakers for midi fuses, and both MPPT's are functioning as expected.
Thank you to everyone for offered their views and advice

 

[Raul]

Hi all....just to complete the story, i am back in the uk now and have changed the amazon breakers for midi fuses, and both MPPT's are functioning as expected.
Thank you to everyone for offered their views and advice

Well done, those breakers have high and inconsistent resistance. They are a poor and dangerous copy of original blue sea American made. Ppl fall for the price.