Tom avatar image
Tom asked

Smart MPPT 100/30 remote switch

The smaller Smart MPPTs like the 100/30 or 50 do not include remote shut down switches needed to connect to a BMS. They do have VE direct ports that you can connect an optional VE cable that allows for remote shut down, but when you use this you can not connect a Bm712, ccgx, or Venus GX. How do you get around this road block to have both a remote shut down in a BMS over charge alarm and also connect a Bm712? The lowest cost Smart MPPT with a remote switch is Smart 150/45 at $200 more than the 100/30 unit. Does the BM712, CCGX, and Venus GX have a port to connect the BMS lead to to switch off the MPPT?

The other option is to use a BP65 between the MPPT out to battery. So my question here is it save to use the BP65 as a shut down to the battery with the PV still charging the Smart MPPT 100/30 or will it damage it?

This is for a RV installation.

MPPT Controllers
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klim8skeptic avatar image klim8skeptic ♦ commented ·

Hi Tom,

The bmv712 will connect to the smart mppt with Bluetooth, not the ve direct port.

Could you use the relay in the bmv for what you need?

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Tom avatar image Tom klim8skeptic ♦ commented ·

I have no idea, this is what the question is in the post? The BM712 has BT but that is to provide information at your phone. The BM712 still needed to plug in to the VE port on the Smart MPPT 100/30 to get the information.

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nebulight avatar image nebulight commented ·

I ended up doing the BP100 between my 100/50 and the battery as I also have a Venus but there is no solution for BMS control. I have a healthy pack and haven't triggered the BMS, but I did test it half a dozen times and the MPPT seems to still be working fine.

Victron's own VAN Build project has the same setup so I assume it's okay to do?

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1 Answer
Justin Cook avatar image
Justin Cook answered ·

@Tom, the BT on these devices is for much more than just seeing data on your phone; you can use the BT to set up a VE.Smart Network across your Victron Smart devices, and they will share data as necessary. That's what Klim is referring to. Set up a VE.Smart Network on your BMV712, then "join" that network on the MPPT, and the two devices are now connected without using the VE.Direct port.

Then you can use either the VE.Direct cable from your MPPT to shut down your BMS, or you can use either of the two relay-out ports at the back of your BMV to trigger it as well, just depending on your desired shut-down values.

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Tom avatar image Tom commented ·

I guess I just don't understand why the smaller Victron Smart MPPTs do not include a simple remote switch. The new Smart Orion TR 12/24-15 chargers have remote switches, but do not have a VE direct ports. Go figure.

I am aware of using the BP65 as the remote switch for the smaller Victron MPPTs so I have to assume disconnecting the MPPT from the battery while the PV is still sending current into the MPPT is fine.

I am just trying to improve on my Battery Safety and BMS system.

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Justin Cook avatar image Justin Cook ♦♦ Tom commented ·

I will say that switching off the output while charging is not recommended for MPPTs. It's likely fine under most circumstances, but of course it's always recommended to turn off PV side first if at all possible. My thought is mostly that if you have your MPPT's battery type and charge profile appropriately set for your batteries, then there would be no possible need to manually turn off charging. In general, if your device settings are appropriate to your system, you should have no need to be manually turning things off and on.

Again, I would use the VE.Smart BT network to let your MPPT communicate with your BMV, then use the relay outs from the BMV to switch your BMS rather than relying on a BatteryProtect.

As for the fact that the Smart Orions don't have a VE.Direct port, that's not surprising because all the necessary communication can be achieved over a VE.Smart network. The Bluetooth connectivity is not just for seeing data on your phone; that's a very important point that I think many people miss at first glance.

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nebulight avatar image nebulight Justin Cook ♦♦ commented ·

Hey Justin,

Just curious how you'd use the BMV relay to control your the charge via a BMS? Most BMS units will have an Allow to charge Allow to discharge outputs. I'm using the Allow to charge signal to control the BP, just not sure how it will shut off the charger going through the BMV?

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Justin Cook avatar image Justin Cook ♦♦ nebulight commented ·

@nebulight, the easiest way would be to run a VE.Direct non-inverting remote cable from the MPPT to the BMS, thus the BMS shuts off the charger when needed. @Tom seemed to be under the impression that the BMV needed to be connected to the MPPT via VE.Direct cable for communication, which is incorrect; they can communicate via BT over VE.Smart network.

My proposed solution -as an alternative- would be to use a Cyrix between the battery bank and the MPPT; the Cyrix would be triggered open/closed by one of the relay-outs of the BMV, as determined by whatever parameters were set. IE, the NC relay out would connect to the Cyrix and permit charging unless, say, batt SOC >95%, then the BMV NC relay would open, triggering the Cyrix open, which would disconnect the MPPT from the battery.

I still maintain, however, that so long as the MPPT's charging profile and voltages are set appropriately, and a temperature sensor is connected to the BMV and the BMV and MPPT are communicating over VE.Smart network, that it should never be necessary to externally disconnect the MPPT from the battery.

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Tom avatar image Tom Justin Cook ♦♦ commented ·

Justin, I am not using Victron Batteries so I can't use the Victron BMS for Victron Li Ion. I am using a Electrodacus SBMS0 that can functionaly shut off charging from the Multiplus, Smart or Blue MPPT, and Smart Orion TR during an over voltage event alarm. So this is a secondary safety device BMS. Since my solar battery inverter system is installed in my RV the complete battery is shut down during storage so yes it is common to disconnect the MPPT from the battery. Before I do shut the battery down I do shut my PV breaker off first before the battery. However in an over voltage event the alarm will send a signal turning off charging from the Orion, MPPT (at the battery with the BP65, and Inverter Charger.

If I wanted to use the Cyrix as a relay shut down between the PV and MPPT instead of using the BP65 between the battery, would that be acceptable? I assume the highest voltage from the PV would be 36-40vdc since I am wired for 24 volt charging.

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