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JEZ avatar image

150/35 Smart Solar Vs 150/70 Smart Solar Vs 150/70 Smart Solar VE.Can

I currently have 2 x 150/35 Smartsolar regulators charging the same battery bank and not doing a great job and tripping over each other and don't seem to understand what the other one is doing and causing inefficient charging etc.

I have read that i can install Software version 1.4.2 to these two regulators and they will then synchonise via bluetooth and work much better. Can anyone confirm that this is indeed the case and works well.

Alternatively i can purchase 2 x 150/70 with VE.Can and then physically link these together to synchonise. I can then use the other 2 regulators on sites where only one regulator is required.

I don't want to install 2 x new 150/70 with VE.Can if I dont have to and especially if the software 1.4.2 has solved this? Appreciate if anyone knows if this is the case

Also if i am to go for the 2 new regulators which cable do i need to connect the two 150/70 with VE.Can together and what settings should I be doing for AGM Battery Bank so this syncs well and charges batteries efficiently and using both solar banks as much as possible

Thanks to anyone who can provide info on this

smart solar set-up help
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2 Answers
Justin Cook - Bay Marine Supply USA avatar image
Justin Cook - Bay Marine Supply USA answered ·

@JEZ, the latest SmartSolar MPPT firmware is 1.46, and does not support BT synchronization of solar controllers, regardless of what you may have heard. There is a firmware update in the works that will address this, but it has not been released yet, and there is no established rollout date for it.

That being said, the likelihood of your controllers "tripping over" each other is extremely slim... the fact that one will go into float sooner than the other has very little real-world effect on their overall charging efficiency, given that the majority of charging is done during the bulk phase to begin with and is unaffected by the absorption cycle timer which is the cause of the "sooner into float" behavior of multiple controllers paralleled into a single battery bank. You are correct that the two controllers don't know what the other is doing, but they don't need to... during their bulk and absorption phases they're both simply charging as efficiently as they possibly can given the amount of power they're receiving from the PV array that they're connected to. If you are truly experiencing a significant degree of charge efficiency degradation between your controllers, I strongly advise you to thoroughly inspect all components between the controllers and the PV array and the batteries: ie, check all crimps to make sure they're secure, check all connections, check all breakers and fuses and wiring. Since I can say with a very high degree of certainty that any marked degree of inefficiency you're experiencing is not the result of two controllers paralleled into a single battery bank, I can say with an equal degree of certainty that either your array is simply not generating as much as you anticipated or there is a loose connection, off-brand breaker, or some other fault somewhere in the system that isn't going to be solved by replacing the controllers.

With all that in mind, I advise against switching to a pair of VE.Can controllers because the reality of the matter is that their behavior, though more in sync, will not result in a markedly greater degree of charging efficiency.

Even though the current F/W version does not yet support the feature you're asking about, you absolutely should update your devices, because you should always do your best to keep your devices updated - particularly the smaller components like solar controllers and battery monitors and such.

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JEZ avatar image
JEZ answered ·

@Justin Cook really appreciate you coming back to me on this.

Just for info the forum I found the info about 1.4.2 introducing parallel operation across bluetooth was here https://community.victronenergy.com/questions/8178/why-doesnt-the-documentation-warn-that-multiple-mp.html and it seemed to be a Victron representative saying this

I am also confused as to why Victron is introducing this synchonising feature in an upcoming firmware as you have put above - if it doesnt solve anything and they should work fine without it as you have said - i assume it must help in some way?

But i am glad you have cleared that up - cheers

What I am seeing on my 2 150/35's is the first array gets sun earlier than the second. The first array comes on in the morning and bulk charges no worries - when the second array finally gets sun - can be an hour later it starts in bulk but very quickly switches to absorption and float.

Is there perhaps absorption or float timers that need to be setup within the units - i have never really looked at this?

I have individually run the controllers to see if there is anything wrong with each array or wiring etc as you mentioned but they both behave normally on their own and move through to float normally and so feel that cancels out that theory

anything else I can check maybe for this issue?

For sure next time I am at the site i will bring these up to 1.4.6 anyway as well

Thanks again

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@JEZ, yes that is indeed a Victron representative commenting there, but if you scroll down through the thread, particularly note his post to the thread on 6/17, stating

"Hi all, an update:

we are about to release v1.42 for the mppts. If all goes well, next week.

Note that it does not have synchronised charging yet; that will come quickly there after. It does change the lithium default to a fixed absorption time."

Also note further below that he observes that a number of systems won't particularly benefit from synchronized charging, along with the note "systems with lead batteries. most cases it will work OK without synchronising the chargers. During bulk, the chargers will always share the load without any issue. With or without synchronised charging."

Personally I think the update with synchronized charging will serve the largest purpose of stopping the questions about why the chargers aren't synchronized, but then again of course a synchronous system will be overall more efficient... no point having one controller handling most the heavy loads when it can be spread more equally across multiples, though of course when in bulk and absorption the controllers are running a charge rate relative to the sun they're getting and the battery state, irrespective of how many controllers are on the battery.

I would think, if your second controller is quickly going to float, that this is a sign of your bank being charged - if your bank isn't already charged, I would expect the controller to stay in bulk for a significant period of time regardless of how late it woke up. That's a thing to consider - if your battery is charged, your controllers will pass to float rather quickly (as they should) regardless of how much sun they're seeing.

In re to setting fixed absorption times, alas, although you can certainly set the absorption and float voltages (which would certainly affect the time spent in each stage), you cannot yet set a fixed time for the individual stages.

JEZ avatar image JEZ Justin Cook - Bay Marine Supply USA ♦ ·

It is certainly possible that the bank is already charged by the time the second controller wakes up - I will keep an eye on this.

I can use these 150/35's elsewhere across our sites and so I might buy the 2 x VE.Can 150/70 anyway and introduce to this site as that will they will have synchonisation

if i connect the VE.can controllers via cat 5 ethernet will they auto sync - ie I dont need to run these with Colur Control VX or similar to get this synchonising humming?

Thanks again