Multiplus 2x120 up and running

[Sportzfann]

I have the multiplus up and running, it’s my first install on a system like this. my solar panels aren’t on the roof yet, that’s coming later this month should have 3x300 watts on the roof. I bought the renogy shunt, I might change that for a Victron unit later on, so I didnt mount it yet. I have 2-200ah. Li time batteries these don’t have heating so I have an insulated box they sit in I plan to make an insulated lid for it. I also plan for a bypass to go around the multiplus in case it should fail. I still have a few things left to add but I’m mostly complet. Any suggestions from the group here is appreciated thanks for the help to get this installed! ?

 

[sunshine_eggo]

Have you configured the MP II with a MK3-USB adapter? The Victron inverter/chargers have low temp charging protection with the more recent firmware updates.

Picture is too small for me to get any detail. Did the MP II include a temp sensor? If so, do you have it installed on the battery?

 

[Rocketman]

As a full-time RVer (MotorHome). Here is my list of things to consider and why.

The Multiplus is the most expensive part - go the whole way with Victron (except batteries).

1. Use a Cerbo or Cerbo-S. Having all the information together in one place is AWESOME! It has (on the touch) a nice basic screen that even my wife understands. Plus, if you have internet and are away - setup the VRM so you can keep an eye on the system - and get alerts if something (SOC) gets too low.

The Cerbo will also control the Multiplus- as an RVer, you will need to often switch the input current limit - my usual ones are 50a -35a (generator), 30a, 20a, 15a and I use 7.5amp a lot. It is a nice easy place to control the Multiplus.

2. Use the Victron Smartshunt or BMV712. You NEED to know battery SOC, and this will integrate with the rest of the stuff. It is way worth the difference in cost.

3. I added Victron Smart Battery Protects (BP65’s) on the legs going to my 12v DC fuse boxes on the rig. This way if I leave a light,etc, on and the battery gets low - it cuts off the power to the load, then when solar starts - it charges back up because the bms never went to sleep. I was strategic in selecting the cutoff voltages for the Multiplus and the BP-65’s. That way they shut down in the order I want them to. Also, that makes a great spot to reboot the 12v (furnace looking at you!). I have to reboot it about every other year.

4. When you have everything turn on DVCC in the Cerbo. This helps the system run much better for me - I have Victron equipment in four different areas using the OEM wiring that is much longer than recommended- the DVCC help compensate for voltage drops.

5. Add a “RV tank heater” to the inside of your battery boxes - with a switch for you to power it on/off - and the temperature sensor from the Multiplus on the inside of the battery box. That you you know the temperature of the batteries, if it will be too cold of a night - turn it on at night. And with DVCC turned on the solar charge controller and the Multiplus will not charge until the batteries are above _____F (user setable- mine is 40F).

You will love the equipment- remember in addition to all the small draw items - only one heavy draw item - Microwave, hairdryer, air conditioner, or two medium draw items - toaster, etc. otherwise the inverter shuts down for 1min and it tells me - hey dummy- you did it again - let’s not do that again! Then it come back on - no issues.

Good Luck on your project

 

[Sportzfann]

Have you configured the MP II with a MK3-USB adapter? The Victron inverter/chargers have low temp charging protection with the more recent firmware updates.

Picture is too small for me to get any detail. Did the MP II include a temp sensor? If so, do you have it installed on the battery?

I configured the charger with the MK3 usb I followed the battery specs from Current connected, the multiplus came with a temp sensor but I haven’t connected it yet. I tried to submit a better photo but it was too large to submit. I updated the latest version when I changed the settings I need to find how to adjust the low temp protection, do you know where I can go to find out how to install that ? Thanks ?

 

[justinm001]

Definitely get a CerboGX or -S as it's a gamechanger. You can download them upload the config to the MP to make changes.

Id think the low temp shut off is in the battery tab of VEconfig

 

[Sportzfann]

As a full-time RVer (MotorHome). Here is my list of things to consider and why.

The Multiplus is the most expensive part - go the whole way with Victron (except batteries).

1. Use a Cerbo or Cerbo-S. Having all the information together in one place is AWESOME! It has (on the touch) a nice basic screen that even my wife understands. Plus, if you have internet and are away - setup the VRM so you can keep an eye on the system - and get alerts if something (SOC) gets too low.

The Cerbo will also control the Multiplus- as an RVer, you will need to often switch the input current limit - my usual ones are 50a -35a (generator), 30a, 20a, 15a and I use 7.5amp a lot. It is a nice easy place to control the Multiplus.

2. Use the Victron Smartshunt or BMV712. You NEED to know battery SOC, and this will integrate with the rest of the stuff. It is way worth the difference in cost.

3. I added Victron Smart Battery Protects (BP65’s) on the legs going to my 12v DC fuse boxes on the rig. This way if I leave a light,etc, on and the battery gets low - it cuts off the power to the load, then when solar starts - it charges back up because the bms never went to sleep. I was strategic in selecting the cutoff voltages for the Multiplus and the BP-65’s. That way they shut down in the order I want them to. Also, that makes a great spot to reboot the 12v (furnace looking at you!). I have to reboot it about every other year.

4. When you have everything turn on DVCC in the Cerbo. This helps the system run much better for me - I have Victron equipment in four different areas using the OEM wiring that is much longer than recommended- the DVCC help compensate for voltage drops.

5. Add a “RV tank heater” to the inside of your battery boxes - with a switch for you to power it on/off - and the temperature sensor from the Multiplus on the inside of the battery box. That you you know the temperature of the batteries, if it will be too cold of a night - turn it on at night. And with DVCC turned on the solar charge controller and the Multiplus will not charge until the batteries are above _____F (user setable- mine is 40F).

You will love the equipment- remember in addition to all the small draw items - only one heavy draw item - Microwave, hairdryer, air conditioner, or two medium draw items - toaster, etc. otherwise the inverter shuts down for 1min and it tells me - hey dummy- you did it again - let’s not do that again! Then it come back on - no issues.

Good Luck on your project

I bought the tank pad and a 12v digital thermostat to control the battery heater, not installed yet. I will look at the cerbo, I previously was using the BT dongle to control the AC input, and see the battery state of charge. I have a renogy shunt currently, but looks like I will buy the victron shunt and install it instead. I am also interested in installing a bypass in case the multiplus fails on me, I would have to disconnect the wiring and splice around it to get power to my camper if it were to fail. It seems that you can’t passthru AC power to your camper unless the multiplus is in inverter mode.
i haven’t bought my solar panels yet I’m supposed to be traveling to quartzite later this month and planned to buy panels at santan solar.
I have the 150/45 victron BT charge controller installed. Thanks for the insight!

 

[Rocketman]

I would not worry about pre-wiring in case the Multiplus fails. Just carry 3 wire nuts - if it does fail (which I doubt it will) just disconnect the 120v input and output wires and wire nut them together. Bypassed…

 

[Rocketman]

Also on the tank heater have a switch to get power to the tank heater- that way you remain in control of it. Also, you may want to run a small indicator light (LED) inside so you know when the heat pad is running.

 

[Sportzfann]

I would not worry about pre-wiring in case the Multiplus fails. Just carry 3 wire nuts - if it does fail (which I doubt it will) just disconnect the 120v input and output wires and wire nut them together. Bypassed…

That’s what I was thinking if it comes to that. Is there a way to bypass the multiplus with it in off position?
the battery will be in float mode while connected to shore power, is there a chance of battery damage if you are in this position for a month or more? Thanks ?

 

[Sportzfann]

Also on the tank heater have a switch to get power to the tank heater- that way you remain in control of it. Also, you may want to run a small indicator light (LED) inside so you know when the heat pad is running.

The indicator light is a good idea, I could install a remote switch to the controller also.

 

[justinm001]

That’s what I was thinking if it comes to that. Is there a way to bypass the multiplus with it in off position?
the battery will be in float mode while connected to shore power, is there a chance of battery damage if you are in this position for a month or more? Thanks ?

As long as you have 12v power then there's no point in physically bypassing it. You have on/charger only/inverter only/off modes using the CerboGX. It'll bypass itself.

There isn't battery damage BUT the battery will have a bit of parasitic drain from the inverter in off mode.

 

[sunshine_eggo]

I configured the charger with the MK3 usb I followed the battery specs from Current connected, the multiplus came with a temp sensor but I haven’t connected it yet. I tried to submit a better photo but it was too large to submit. I updated the latest version when I changed the settings I need to find how to adjust the low temp protection, do you know where I can go to find out how to install that ? Thanks ?

When you specify a Lithium battery type, you get a new option:

VEConfig:




Victronconnect:

 

[Sportzfann]

When you specify a Lithium battery type, you get a new option:

VEConfig:

View attachment 186308


Victronconnect:

View attachment 186309

Thanks for the update I will go back and check that out, What low temp is suggested for lifpo batteries, Just above freezing 35F. ?

 

[Sportzfann]

Trying to post this photo

 

[sunshine_eggo]

Thanks for the update I will go back and check that out, What low temp is suggested for lifpo batteries, Just above freezing 35F. ?

5°C is the default for the MPPT. I stick with that. Some cell datasheets specify 3°C.