Recently I asked the question, how to stop external MPPT150/35 charging battery equipped with "2 signal BMS" connected to MP-II, when "external control" of said MPPT fails.
Got the answer but I also have EasySolar-II GX with internal MPPT 250/70.
How to solve the same problem with this internal MPPT?
How to stop its charging the battery when "external control" fails?
There is no way to connect to it ATC signal from BMS
In that case, adjust the MPPT Voltage settings in the MPPT it's self to a lower value.
If there is a communications failure then the MPPT will revert to its internal settings. Lower value setting will then prevent continued charging at the upper Voltages of the charge cycle.
I have not seen inside one of those Easysolar-II units to know how accessible the solar charger is, but it should just be a regular 250/70-Tr solar charger and that model has remote on/off terminals that you can simply wire into your BMS ATC signal for backup control.
In the other topic I was told that that on/off terminal is used by internal GX device.
What is Victron solution for the situation when GX device fails and there is noting stopping MPPT from charging battery when BMS is telling the system no to.
Hi Marek,
Again I have not looked inside a Easysolar-II unit, but even if that is the case you should still be able to wire the BMS ATC signal in series with the existing wiring to achieve what you want.
Once there is an open circuit between the solar charger remote on/off terminals (or alternatively, if there is no HIGH or LOW signal), charging will stop, regardless of which device has triggered it.
A you sure this is OK with Victron?
I would not want to find out later that I do not have warranty anymore.
Is there some kind of whitepaper, made by Victron, describing this connection?
Hi Marek,
I think you will find that is the only way to achieve what you want.
If you want to be certain about any warranty implications, you might want to ask that question through the official channels (through your dealer) and await a formal response from Victron.
Providing the solar charger remote on/off terminals are easily accessible, I see this as fairly straightforward, but of course this is your unit, and you need to be comfortable and confident.
I don't know of any documentation describing this specifically for the Easysolar-II unit, but you can look at the the solar charger manual for information on how the remote on/off terminals function. In summary you can open/close the circuit between the two terminals or provide a HIGH or LOW signal direct to the respective terminal. See https://www.victronenergy.com/media/pg/Manual_SmartSolar_MPPT_150-60_up_to_250-70/en/features.html#UUID-20ac1af2-7925-4279-27cc-d14249d09217
Thank you for the info. If it is so easy, as you say, I will try to implement this.
My BMS provides two dry contact signaling the ATC and ATD states.
And a general comment to Victron designers.
Shouldn't that connection be implemented by you in the EasySolar-II from the start?
No problem Marek.
I think the first step is just to take a look to see how accessible everything is and what the current wiring arrangement is.
If there is already Easysolar specific wiring connected to the solar charger remote on/off terminal it might just be a single wire providing a HIGH signal (as opposed to a loop between L & H); in that case just make sure that voltage is compatible with your BMS ATC contacts and anything else you may have connected to the same BMS ATC contacts. Otherwise you may need to add another small relay or similar to provide isolation.
Current draw will be almost zero from the solar charger remote on/off terminals and those relays look to be good for at least 60VDC based off those specs, so even if you find that battery voltage is being provided to the solar charger H terminal, that relay looks fine.
In case the same BMS ATC contacts will also be connected to another device simultaneously, you might still need isolation between devices, otherwise you should be able to simply tap into the existing remote on/off circuit and run it through the BMS ATC contacts.
Once you take a look inside your Easysolar-II unit you should be able to tell quite quickly what is going on with any existing wiring and you can also probe with a multimeter to confirm.
This is getting complicated by the minute. :)
Those rekays contacts are now used to tell MP-II what my BMS wants.
EasySolar-II's AUX-1 input is used for ATC and AUX-2 is used for ATD.
I do not think AUX-1 and ON/OFF terminal in MPPT can be connected in parallel.
External relay with 2 sets of contacts would have to be used.
To use it I would need external power source for its coil.
and problems pile up.
