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YR YF avatar image
YR YF asked

How to connect victron Lifepo4 batteries to a 3rd party inverter/charger

I want to build a 48v system with my victron Lifepo4 batteries with victron ve bus bms.


How can I use a 3rd party inverter and charge controller?

BMS
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12 Answers
Justin Cook avatar image
Justin Cook answered ·

If you're not using a VE.Bus inverter-charger, no reason to use a VE.Bus BMS - just use a smallBMS and connect the rest of your system appropriately.

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YR YF avatar image
YR YF answered ·

I already have the ve bus BMS. Just wondering how to connect it with a 3rd part BMS. İf not I'll have to get the small BMS. How does the small BMS cut off the inverter to prevent over discharge?

3 comments
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mjs500 avatar image mjs500 commented ·

with Victron battery protector ( 48v 100 amp ) see Victron site product page for more

information

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ mjs500 commented ·

Don't use a BatteryProtect to switch an inverter!

img-20231126-094443.jpg

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mjs500 avatar image mjs500 Matthias Lange - DE ♦ commented ·

ok i stand corrected do not used BP with inverter - charge

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pwfarnell avatar image
pwfarnell answered ·

This is a bit of a problem for 2 reasons.

1. Power

The VE.Bus BMS V2 needs to be connected to a VE Bus inverter or inverter/charger that is connected to the battery because the BMS gets the negative connection to the battery through the VE Bus cable. See section 3.2 in the manual for the VE Bus BMS Mk2. This does not apply to the original version (revised).

If you want to persevere with the VE Bus BMS V2 here is the VE bus pinout so you can see which pin is negative, which I believe is pin 3. Other people have managed to get the VE Bus BMS V2 working without the VE Bus cable connection, see the second link.

https://community.victronenergy.com/questions/64847/rj45-wires-used-by-vebus-pin-out.html

https://community.victronenergy.com/questions/206038/vebus-bms-v2-not-powering-up.html

2. Control

This will depend on your inverter/ charger which will need to be connected up using the ATC (allow to charge) and ATD (allow to discharge) terminals on the Ve Bus BMS. If your inverter/charger only has a single on/off input then this makes it difficult.

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Justin Cook avatar image Justin Cook ♦♦ commented ·
I will note that the original VE.Bus BMS doesn't need the VE.Bus connection, as it has a separate NEG port that is to be connected in this sort of scenario. The VE.Bus BMS V2 does not have the separate NEG port, so does require a VE.Bus connection.
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YR YF avatar image YR YF Justin Cook ♦♦ commented ·
Ok , I have the original. So shouldn't need to connect the ve bus cable. But how can I turn the charger off and the inverter off in the event of over charge and discharge?
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Justin Cook avatar image Justin Cook ♦♦ YR YF commented ·

You'll need to study the user manuals of your 3rd-party inverter and charger to determine how to switch them from your Victron BMS. Since this is a Victron forum, we can't tell you much about non-Victron components or how best to control them - it's on you to read and understand the manuals for your chosen components.

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YR YF avatar image
YR YF answered ·

Can I use two of these to cut off the charge from the charger and load from the inverter?

Would it have to be a 48v or 60v relay?


img-20231126-155940.jpg


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mjs500 avatar image
mjs500 answered ·

DCNEV250 SERIES HIGH CURRENT HIGH VOLTAGE DC CONTACTOR RELAY

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pwfarnell avatar image
pwfarnell answered ·

Do not forget that the ATC and ATD outputs on the VE Bus BMS are low current, they are not designed for driving high power relays or contactors so you will need some form of intermediate relay. The ATC is very low current so you may need a solid state relay. Check the datasheet. You are using this well outside the expected conditions.

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mjs500 avatar image
mjs500 answered ·

Coil Voltage 12 - 24Vdc 72Vdc 48 - 72Vdc

Voltage (Max.) 36Vdc 95Vdc 95Vdc

Pickup voltage (Max.) 9Vdc 48Vdc 32Vdc

Dropout voltage (Min.) 6Vdc 27Vdc 18Vdc

Inrush Current (Max.) 3.8A 0.7A (1.3A @ 48v )

Holding Current (Avg.) 0.13A@12Vdc / 0.07A@24Vdc 0.02A@72Vdc ( 0.03A@48Vdc )

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pwfarnell avatar image
pwfarnell answered ·

The VE Bus BMS ATC and ATD connections could be used to drive a Victron Solid Switch 104 which then drives the contactor / relay, the Solid Switch 104 is rated at 4A switching load.

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YR YF avatar image
YR YF answered ·

Or... I could use a contactor to cut off the AC output on the inverter when the batteries are low. I'll just wire the relay into the load disconnect and have the relay switch the power going to the contactor. When load disconnect goes off then the relay would cut the power going to the contactor and switch off the AC output on the inverter. This would work right?

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YR YF avatar image
YR YF answered ·

Pin layout on the new inverter. Can I make this work?screenshot-2023-11-27-12-51-05-086-edit-comgooglea.jpg


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YR YF avatar image
YR YF answered ·

SRNE HESP48120S200-H

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YR YF avatar image
YR YF answered ·

I see Victron uses cyrix relays to connect Victron BMS to non Victron inverters. İsn't cyrix the same thing as the picture I shared? Can't I just use that?

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