DVCC - Battery Temperature Sensor

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Mark asked Oct 18, '18

DVCC - Battery Temperature Sensor

Hello,

I am setting up an off grid setup with a 24v 3000VA MultiPlus, 150V/85A Smart Solar MPPT, BMV-712 & CCGX.

I am using the battery mid-point voltage as the Aux input on the BMV (so can't also use the BMV to monitor battery temperature).

I plan to enabe DVCC and wanted to know/confirm if the data from the battery temperature sensor connected to the MultiPlus will be 'shared' with the MPPT via the DVCC feature?

I really want the MPPT to receive/use accurate & up to date battery temperature data for the charge voltage compensation.

Thanks in advance.

Best regards, Mark C.

Temperature Sensor DVCC

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Guy Stewart (Victron Community Manager) answered · Oct 18, 2018 at 11:32 AM

Unfortunately not. This is a known limitation we would like to address in the future, but at this stage shared temperature in offgrid is limited to the BMV-712 temp probe, and ESS systems.

Another option would be the Smart Battery Sense to give the MPPT precise temperature awareness.

Perhaps consider the smart battery sense so you can keep your midpoint voltage reading.

This presumes a smart Bluetooth enabled MPPT on the compatibility list.

https://www.victronenergy.com/accessories/smart-battery-sense

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Mark ♦♦ commented · Oct 18, 2018 at 12:01 PM

Thank you for the fast response Guy.

Do you have any rough timing for when the DVCC shared temperature sense feature will be expanded to also use the MultiPlus temperature sensor? (As that would be my prefered arrangement)

I also think that 2 separate wired temperature sensors is a bit messy.

Reading the smart battery sense manual I was also under the impression that it is not recommended or allowed to be used together with a CCGX?

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Elimac Mark ♦♦ commented · Mar 15, 2019 at 09:49 PM

As far as I understood, the conflict is there only if you enable DVCC and Voltage + temperature sensing. If you enable DVCC but disable Temp and voltage sense, I think the smart sense can be used with CCGX. But I might be wrong... I also would like some clarification.

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Guy Stewart (Victron Community Manager) answered · Oct 18, 2018 at 12:53 PM

The Smart Battery Sense is intended to be paired with the MPPT, not the CCGX (which has no bluetooth). I would disable the Shared Voltage Sense feature in DVCC on the CCGX - I have personally found this feature to cause more issues than it solves.

The Smart Battery Sense is intended to be mounted directly to the battery, and can be made quite elegant.

I have no information on when full shared temperature data from the Multi would be available; nor why it isn't available now that might be preventing that functionality. But even shared temperature data from the BMV is a relatively new feature, so there is hope.

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mvader (Victron Energy) ♦♦ commented · Oct 23, 2018 at 05:48 PM

Hi, you wrote:

> I have no Information on when full shared temperature data from the Multi would be available; nor why it isn't available now that might be preventing that functionality.

It will take quite a while for the battery temperature as measured by the Multi is shared to other devices. Requires firmware updates in multiple products. And other priorities.

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porcini mvader (Victron Energy) ♦♦ commented · Mar 15, 2019 at 12:07 PM

Hi, are there any news about this? I would also like the MPPTs to take the Multi's temperature measurement.

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mvader (Victron Energy) ♦♦ porcini commented · Mar 15, 2019 at 12:31 PM

Yes this is part of the underway v2.30 release.

No dates though. Could be one month; could be several.

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 15, 2019 at 08:18 PM

Hi @mvader,

Even though it is still a month or so away that's great news!

Over the past few months I have been regularly following the progress through the Github ticket #374 & saw that the initial implementation was complete about a month ago.

What about DISPLAY of the temperature reading - has there been a decision made about that?

I understand the possible 'display' accuracy concerns you had (since it was never intended for this purpose, with small increment steps), but if you can get the temperarure display (based on the Multi temp sensor) to function at an acceptable level then that would be my strong preference.

I like information / data, rather than running blind...

Regards, Mark.

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mvader (Victron Energy) ♦♦ Mark ♦♦ commented · Mar 15, 2019 at 11:32 PM

It will probably be shown. On venus gui, vrm, modbustcp, etc.

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 15, 2019 at 11:39 PM

Great, thank you! :-)

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 15, 2019 at 10:32 PM

2nd question - I assume that the temperature reading from the Multiplus temp sensor will still be sent/shared, even when the Multiplus is turned off? (turned off via the CCGX only)

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mvader (Victron Energy) ♦♦ Mark ♦♦ commented · Mar 15, 2019 at 11:31 PM

Hi Mark, when its properly turned off, standby current draw as low as possible, then the microprocessor in the Multi will be off too: no more data. I expect to not see any battery temperature data when its off.

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 15, 2019 at 11:51 PM

That's a shame & will be an issue/disadvantage for me (as the site is unoccupied for days at a time, so the inverter is turned off via CCGX), but I do understand the challenge...

I was under the impression that some parts of the microprocessor were still active in the background when turned off by a Venus device (with main switch swill on).

Isn't it the 'inverter component' that draws the majority of the standby current?

If there is any chance to obtain some kind of 'in-between' off state where the microprocessor is still active (but the inverter is off) - that would be highly advantageous/desired in this situation.

I do know that the 'search' mode already exists & partly achieves this... maybe that's in interim solution...

Would what i am suggesting be at all possible?

(Not necessarily an immediate update)

Thanks again, Mark.

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mvader (Victron Energy) ♦♦ Mark ♦♦ commented · Mar 16, 2019 at 12:05 AM

Hi Mark, There are various situations where you really want as little standby current as possible.

I dont know how deep its switched off at the moment by heart; but I expect real deep; and in that case I don’t see the battery temperature as a good reason to start increasing the standby current / and or add complexity by making different states or options. Sorry.

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 16, 2019 at 12:17 AM

No problem, thank you.

Could you please confirm if it will work with the Multi in 'search' mode then?

(If that's my best option currently available)

PS. No problem if you want to come back with the answer(s) after confirming with your R&D team.

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mvader (Victron Energy) ♦♦ Mark ♦♦ commented · Mar 16, 2019 at 12:18 AM

I think so; yes. You’ll have to try to be 100% sure

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 16, 2019 at 12:32 AM

Thank you - once the feature is released I will try.

I also just came up with the idea/option of leaving the Multi in 'charger only' mode/state, but with no AC IN available.

That may work even better?

(As far as I know/expect the microprocessor should be active & the inverter should be TOTALLY off)

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mvader (Victron Energy) ♦♦ Mark ♦♦ commented · Mar 16, 2019 at 07:08 AM

Sorry, but also that I don’t know by heart. Lowesr consumption in that case would also be microprocessor off, and wake-up / powered from AC-in. But if its like that in reality is something I’m not sure

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Mark ♦♦ mvader (Victron Energy) ♦♦ commented · Mar 16, 2019 at 09:10 AM

I just done some basic test's & think it 'should' work in 'charger only' mode.

In 'charger only' mode (with NO AC In) the Multi DC bus voltage IS still sent to the CCGX. So I would expect the same for temperature.

When the Multi is OFF the Multi DC bus voltage is NOT sent to the CCGX.

In terms of power consumption;

BMV-712 =0W

BMV + CCGX (screen on) =5W

BMV + CCGX + Multi ON / Inverting (no load) =29W

BMV + CCGX + Multi in 'Charger Only' mode = 8W

So it seems that the microprocessor running in the background while in 'Charger Only' mode is only drawing 3W! (which is very good)

So based on this information, I would dare say that it should work... would you agree?

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Modifications Space

Node Red Space

Answer 1 · 2018-10-24T06:05:31Z

Mark answered · Oct 24, 2018 at 06:05 AM

Thank you very much for the additional information Matthijs.

So by the sound of things it is not that simple but will be an option available at some stage in the future.

Hopfully it is sooner rather than later & I will eagerly await this update.

I already have a MK3 to USB interface to update the Multiplus firmware, so no issue with that aspect.

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