Need Help Selecting Victron Equipment when Upgrading from AGM to LiFePO4 Batteries

DIY
1

I have a travel trailer with Victron Phoenix Smart IP43 Charger 12/50 (1+1), a single, roof-mounted solar panel and two AGM batteries. I’m replacing the AGMs with two LiTime 100 Ah Bluetooth Self-heating batteries (already purchased). The batteries will be in an external battery box on the A-frame.
My plan was to install the following:

  • Victron SmartSolar MPPT 75/15 or possibly the 100/20 (some room for expansion)
  • BMV-712

My questions:

  1. Do I need the BMV-712 if the LiTime batteries have their own, internal BMS? The LiTime manual doesn’t have any info on their BMS.
  2. Do I need to add battery temperature sensing? If so, it seems installing the Victron Smart Battery Sense would be easier as the entire device with wiring could be in the battery box, whereas if I went with the optional Temperature Sensor for use with the BMV-712 there would be wires running from near the negative bus bar running out to the battery.
  3. If I install the Smart Battery Sense, does it “communicate” with the BMV to decide which is controlling the charging?

Thanks in advance, Mark

2

You should use the bmv712 or the smartshunt

For lithium temperature compensation is not necessary.

3

You dont need a shunt if the battery has one. You can check on your phone to see the SOC or current. If they are parallel you will have to check each battery to see the current but they should share equally. If you want a display of current and capacity the BMV is good.

A better option would be the smart shunt and GX device and you can ve direct the charger. You could also get the gx device display if you don’t want to use your phone. You will need the temperature from the smart shunt to disable charge if it is too cold. The battery BMS with heater should be able to heat the battery or shut down charging. They are things you will need to test.

It really depends what you want and need.

4

One other questions: So, the BMV-712 obtains actual battery voltage (so Smart Battery Sense not needed)?
Thanks, Mark

5

Exactly

6

How would I know if the battery has a shunt? Or is it a given if LiTime states it has a BMS?

I think the GX stuff is beyond me, plus it looks like there would be a monthly fee. I do want a display, so I guess I’ll go with the BMV-712.

7

GX is only usefull.for large and/or grid connected systems.

For a simple installation like yours the 712 or smartshunt will do, i have a larger installation without gx, the 712 display is programmed to solely display power and SoC.

You might want to add a bleutooth interface to the bmv712, then with a smartphone you’ll have more data incl. Graphic displays

The smartshunt has bt built-in, you’ll always use the smartphone. I glued an old one to the wall and have a display for next to nothing

8

The BMV-712 also has bluetooth built in.

9

Too many different products…

10

thanks again. Mark

11

Thanks, Justin. Mark

12

All bms’s have a shunt to manage over current protection and short circuit protection. Some cheap ones without Bluetooth might only do cell balancing and under voltage over voltage. If you want a simple system then the BMV is fine. You will need a negative bus bar or connect every negative cable to the shunt and then to the battery bank.

13

Thanks, Mark