question

strop avatar image
strop asked

Battery Discharge Protection - Inverter

I have a mobile (Caravan) system that is Lithium based but I DO NOT have Victron Lithium batteries. My batteries also do not have an accessible BMS. They are a Renogy 170 AH lithium batteries.


My system is charged via a Victron 100/50 Smart Solar MPPT and a Victron 30 amp AC charger. I also have fitted a BMV712, smart battery sense and a 65 amp Smart Battery Protect.

I am about to install a NON Victron Inverter 2800/5600 watts to see how much I can do via 240v instead of gas. Induction cooking etc.

my question is about how I best protect my batteries from over discharge whilst using the inverter.

I have read that you should not use a Smart Battery Protect on an inverter. Is this correct?


if you can then the 220 amp model it may be a bit small (2640 watts).

Can I use the BMV712 to activate a relay to disconnect the inverter?


Are there any other alternatives?


Thanks

Battery Protectinverter current draw
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

The easiest thing would be that you can programing a low voltage cut-off directly at the inverter. Set this to 11V or 11.5V and you should be safe.

OR

If the inverter have a connector for a remote on/off switch (like all Victron inverters) than you can wire this connector to the relay of your BMV-712.

3 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Thanks, that takes care of the inverter, but not the ELV lights, or 12 volt water pump etc.

0 Likes 0 ·

For other DC loads you can use the Battery Protect.
https://www.victronenergy.com/battery_protect

0 Likes 0 ·

@Matthias Lange - DE this may be dangerous for your Li bank, my 12V 3kW Phoenix inverter consumes ~ 400mA when in LVP! So that will quite quickly drain the last bits out of your Li bank. The remote on/off switch seems to be a better solution, although that also seems to consume a little bit of energy.

0 Likes 0 ·
tex260z avatar image
tex260z answered ·

Firstly be aware of the maximum amps discharge limitation of any LiFePO4 battery with built in BMS, I got caught out on that. That is a pretty big inverter. I am running an induction cooktop flat out on a 200 Amp LiFePO4 for more than enough time to cook meals.

Secondly if everything is running through your BMS, that will provide low voltage cutout protection. I bought a Victron BP, but ended up not needing it.

I am still waiting for confirmation that my hookup for everything through my 3 port BMS is correct from others, (see my pictures attached to my last question).

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

aceclement avatar image
aceclement answered ·

I just recently embarked on the idea of a diy solar battery generator and was having a hard time grasping the battery protect instructions. I finally figured out how to properly set up my battery protect with an inverter that had no remote switch.

I made a video about it to help anyone else having a hard time. https://youtu.be/U10wdEWVctk

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

"This video isn't available anymore"

0 Likes 0 ·