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paddyglenny avatar image
paddyglenny asked

How to change "state of charge when bulk finished" value in the smart solar mppt?

I have a tubular plate traction battery so to get the "state of charge when bulk finished" value in the smart solar mppt higher than 60 volts (to avoid the default 85%), I need to change the absorbtion voltage setting in the mppt to more than 60 volts. But Victron Connect cannot find the mppts so how else can I get into the mppts to alter that setting. I have 2x smart solar mppts connected via ve direct cables to a ccgx, which in turn is connected to the 15000 Quattro inverter using a ve bus cable. The mppts do not have bluetooth capability.

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2 Answers
JohnC avatar image
JohnC answered ·

Hi @PaddyGlenny

The setting you're looking for isn't in the mppts, it's in the Quattro. Normally accessible via VEConfig, which you may be familiar with..

Come back if you need help with that.

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paddyglenny answered ·

JohnC, thanks for replying. Yes, I know how to change that value in the inverter using VE Config but as I understand it, the absorbtion voltage value in the mppt must be set a little higher than in the inverter, otherwise the soc % goes to default, which is 85%.

When I select "tubular plate traction battery" as my battery type when configuring the Quattro, it automatically selects 60 V as the absorbtion voltage, but then the "soc when bulk finished" reverts to 85%...

The accepted answer to a similar question posed was this:

There is information about this in Section 2.4 Battery State of Charge (SOC) of the CCGX manual.


2.4.4 Details on VE.Bus SOC


While the Inverter/Charger is in bulk, the SOC will not rise above the value as set in VEConfigure3 for the “State of charge when Bulk finished“ parameter on the General tab; default 85%.


In a system with Solar chargers, make sure that the Absorption voltage as configured in the MPPT is slightly above the same setting in the inverter/charger. The latter needs to recognize that the battery voltage has reached the absorption level. If it doesn’t, the SOC will be stuck at the earlier mentioned End-of-bulk percentage, default 85%."


Thus I assume I need to go into the mppt to change that value to slightly higher than 60V, no?

Sorry if this is a bit rambling, but it's a bit hard to describe quickly!

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JohnC avatar image JohnC ♦ commented ·

@PaddyGlenny

Ah, ok. That 2.4.4 reference has been removed from the CCGX manual, so I'd assumed no longer relevant. But it seems that functionality still exists..

I'm not sure why your VictronConnect won't work with the mppts, but you could select the preset you want in the Quattro and change/tweak the defaults it sets. That may change the name of the preset to something like 'User Defined', but you can set what you want. Maybe a little lower than that set in the mppt.

Consider (if you haven't already) applying DVCC's SVS and STS functions, so that both chargers are reading from the same page picking up their baseline V and temp-compensation data.

I don't hold much faith in that 85% thing anyway. Solar comes on slow and ac-charge much faster, so it won't give the same results over a day. Eg., my own VEBus SOC stuck on 85% today for almost 3 hours and only 'let loose' when the mppt reached Absorb. By then my batts would have been better than 85%, and if I had applied ac to charge instead, would have hit 85% early and likely overestimated SOC.

So maybe set it all up for one charger type and make concessions when you bring in the other.




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paddyglenny avatar image paddyglenny JohnC ♦ commented ·

Hi John, I was assuming that when you select tubular plate traction battery (as mine is) that it automatically inserts 60V because that is the appropriate voltage to be reached before bulk charging finishes. Atm, to be lower than the 57.6 default setting inside the mppt, I have had to set that value inside the Quattro at 57.5V as I haven't figured out yet how to get into the mppt to change that default to 60.1V. I want to get this right because atm the battery reaches 57.5, triggering the change from bulk to adsorbtion, but the soc at that point has only got up to about 68%. When that trigger happens, the mppts reduce from giving approx 6kW down to about 2kW, even though I am still a long way off fully charged. This is the issue. Btw there is no charger, the system is 100% solar, off grid, with no generator. Do you have any idea where I can find the info about how I can get into the mppts if they don't appear on the VicConnect list?

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JohnC avatar image JohnC ♦ paddyglenny commented ·

@PaddyGlenny

Don't fall into the trap of believing (turn your head away) an SOC when you know it's incorrect. Your 6 > 2 kW charge reduction won't be caused by SOC, it's likely just plain-ole V doing that. Ie. your batt bank's ability to accept a charge.

Re VictronConnect. It should work. Look through this: https://www.victronenergy.com/live/victronconnect:start

I think it uses VRM if you come in via ethernet, so have that up. I use a Win10 laptop, what are you trying with? As of today VC 5.27 firmware is current. And maybe the GX firmware might need a topup. 2.57 the latest there.


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paddyglenny avatar image paddyglenny JohnC ♦ commented ·

John, ok, so now I'm up at the client's house where the system is installed. The Smart bmv712 (which is not connected to the ccgx btw due to the fact that all the ve direct ports are occupied and I haven't yet received the ve direct to usb conversion cable) is showing 100% (I am more inclined to trust the bmv as it measures charge coming in from mppts and charge going out via inverter) but the battery monitor on the Quattro is only showing 74%. This 74% figure is new and used to go up to 100% but now only seems to reach 74 no matter how long the battery has been charging. Trouble is I've been messing around with the batt voltage setting via victron connect and I don't know which one I changed that might have caused this 74%. Do you have any idea how I can get the two monitors to give at least a reasonably similar reading? The client is asking why the difference and I don't know how to answer him!

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JohnC avatar image JohnC ♦ paddyglenny commented ·

@PaddyGlenny

Tell him the truth. I've done some more testing of mine today to try to sort a useful reply to you, and have come to the conclusion that VEBus SOC isn't very good handling solar input.

To explain - I raised the batt efficiency setting to make the SOC push harder, and it did that. Good winter sun, but I never quite made Absorb over the shortish day, and the SOC stuck at 85%. Yet the 'tail' current reached about 1.5% @ Float V, indicating nearly full batts (for my batts 100% is ~1% tail). For me to have got that showing on the SOC I would've needed to set the VEBus Absorb level way low, and I don't need it down there when I use my generator.

Client, eh. Lucky he doesn't also have a batt bms giving a third option. Victron don't recommend installers provide clients with multiple choices for SOC, as it's almost impossible to make them match. At least without much trial'n'error. Many installers seem to set them up to show an 'optimistic' figure to keep the client happy. (Edit/: Just to be clear, Victron don't recommend that, just an industry-wide observation of mine.) :)

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