Batrium Watchmon Install

[Rocketman]

Boy! I am not very good at doing updates...
I have been using the batteries for about 6 months now. No problems (other than my own stupid mistakes that I will list below).

A few other updates first - Heating.

Because my motorhome batteries (starting & lithium) are basically outside, I built in a RV tank heating pad under the batteries. I have a 1/2" plywood for the base of the battery box, then is the RV tank heater pad. Side-to-side it fits but it was about 3 to 4" too long - so it sticks out the front. Because the heater pad in designed to stick on RV holding tanks, one side was very sticky. I didn't want the sticky mess getting on the batteries (wanted to remove the batteries if needed), and I also wanted an extra electrical insulator, I got a couple of sheets of MICA from amazon (Mica is an electrical insulator, but also allows good thermal conductivity - it is usually used in the microwaves). I stuck the Mica to the heating pads. The sides of the box is 3/4" plywood with a plexiglass top (plus a couple of fan holes and holes for buss bars). I used foam and sealed up the battery bay as much as I could - but it is a metal box exposed to the outside.

When it started to get cold in the fall, the temperature of the Victron SmartShunt was warmer than the outside by only about 5 degrees in the morning. I wanted the batteries even warmer, so I got some foil insulation (the kind that looks like plastic bubble wrap covered in aluminum foil), and taped together a cover to go over the battery. I also used masking tape to cover the inside of the cover because I noticed the foil insulation would conduct some electricity.

Since adding the cover, the batteries stay much warmer. Probably because the heat that is generated gets trapped inside the insulation cover - instead of just escaping. I call the heating part of this project a SUCESS!

Update - Communications between Batrium & Victron.

I have not yet connected the communication wires between the Batrium & the Victron CCGX. Busy, Lazy, other projects, and it is working just fine without it. At first I could say I didn't have the wire in place... but I can't use that excuse anymore. Because the charging is working very well without the communications, I have not felt the need to get it done. Funny how I was so sure I was going to use this and now it just a maybe.

Path of Woe. First let me state it's all my fault! As we were getting ready to head out after installing the lithium battery, I went through and checked all the fluids (good right!). Well I checked the starting battery and noticed the cells were a bit low on water. So I got some distilled water and topped them up. After a short run, I was checking on the lithium battery and I noticed drips on the BMS! The starting battery and bubbled some acid out and it was dripping on my new lithium battery!!! (The starting battery sits just above the house batteries). I cleaned it up the best I could. Now I was really MAD at myself, because when I started this project I decided to replace the 2 year old starting battery with an AGM battery. I had forgotten to do that. So I ordered the 8D AGM starting battery, and cleaned everything up the best I could. The BMS was still running just fine.

About a week or so later we were camping and all of a sudden weird things were happening with the power. The 12v was flickering at strange times and I could hear a click. I soon realized the BMS was shutting off for a moment then back on. Because we had good sun, the solar was running the rig. it kept doing that for longer periods. I plugged the computer into the batrium and found out it was losing connection with its shunt. At this point I was comfortable running the system , so all I could do was set the contactor to run continually and run without a bms. I ordered a new set of everything. (The Batrium Core was now available). Got it - installed it and its been running great. This bummed me out for a while.

Future Updates:
Someday I may have the batrium control the charging through the cam buss, or maybe I will just enable the 2-wire bms assistant in the victron and use some of the extra relays to run that.
Another idea is to get a small intel nuk computer with a 7" screen and have it display the batrium software all the time. I have a great place next to my CCGX.

 

[lance]

Hey Rocketman! Can you tell me where the lead from the REC Pre-Charge's "BMS INPUT" connects to the Watchon? And/or maybe a link to the info that explains where it goes? I reached out REC on another topic early on, and they wouldn't really help with a system that was not also using their BMS.... I've not tried Batrium yet.

 

[Rocketman]

Hi Lance,

https://www.rec-bms.com/datasheet/UserManualPrecharge.pdf

This data sheet shows how to wire up the Pre charge controller.

Here is what I did:

System + connected to the load side of the contactor.

Battery+ connects to the battery side of the contactor - in my case, I have a wire that connects to the battery side of the contactor then it goes to four terminal blocks that have fuses - these then feed the
1. main power for the Batrium
2. Batrium shunt power
3. Rec- bms pre charge (Battery+)
4. Relay#1 (input) on Batrium (which will signal the pre- charge - which will then signal the contactor 4 seconds later after it add power to hopefully fill the capacitors in the inverter.

Bms input+ this connects to the Batrium Relay1 (output),

System- This connects to my negative terminal blocks which connects to negative just after all the shunts. (That way the power for the bms and contactor are figured into the loads and tracked for battery capacity).

Contactor + connects to the small wire on the contactor (positive)

Contactor- connects to the small wire on the contactor (negative).

The pre-charge unit always controls the contactor (that is why both signal wires on the contactor are connected to the pre-charge).

I wired it up this way so the Batrium could start and restart itself. The BMS, Batrium shunt, PreCharge controller, and relay power for precharge/contactor are all “on” and fused all the time. If I need to turn off the Batrium BMS I pop the fuse for it. If I want to just turn off the contactor- I get into the Batrium software and change relay#1 to manual off (from critical battery ok).

I have the expansion board on the Batrium and so I picked one relay on it to control the pre-charge & contactor. The Batrium just closes a relay which sends power down the signal wire. Look at the Batrium documentation for where to connect.

Did that help you - or did I confuse the subject…?

 

[lance]

Hi Lance,

https://www.rec-bms.com/datasheet/UserManualPrecharge.pdf

This data sheet shows how to wire up the Pre charge controller.

Here is what I did:

System + connected to the load side of the contactor.

Battery+ connects to the battery side of the contactor - in my case, I have a wire that connects to the battery side of the contactor then it goes to four terminal blocks that have fuses - these then feed the
1. main power for the Batrium
2. Batrium shunt power
3. Rec- bms pre charge (Battery+)
4. Relay#1 (input) on Batrium (which will signal the pre- charge - which will then signal the contactor 4 seconds later after it add power to hopefully fill the capacitors in the inverter.

Bms input+ this connects to the Batrium Relay1 (output),

System- This connects to my negative terminal blocks which connects to negative just after all the shunts. (That way the power for the bms and contactor are figured into the loads and tracked for battery capacity).

Contactor + connects to the small wire on the contactor (positive)

Contactor- connects to the small wire on the contactor (negative).

The pre-charge unit always controls the contactor (that is why both signal wires on the contactor are connected to the pre-charge).

I wired it up this way so the Batrium could start and restart itself. The BMS, Batrium shunt, PreCharge controller, and relay power for precharge/contactor are all “on” and fused all the time. If I need to turn off the Batrium BMS I pop the fuse for it. If I want to just turn off the contactor- I get into the Batrium software and change relay#1 to manual off (from critical battery ok).

I have the expansion board on the Batrium and so I picked one relay on it to control the pre-charge & contactor. The Batrium just closes a relay which sends power down the signal wire. Look at the Batrium documentation for where to connect.

Did that help you - or did I confuse the subject…?

Thank you! Certainly didn't make things worse, no. Much of it though is pretty clear to me but, still there's some details in there that I'm going to comb through when I get back out to the rig and see how your thinking/methodology applies to my set up. I've yet to get the software for the Watchmon... actually, I'm yet to even get the PC on which I'm going to run the software but, I'm getting close to that one. Once I do I suspect this will be a little more clear but, do I understand that in this case you're using the relay on the BMS purely as a manual on/off switch for the precharge? There's no criteria you're setting for that relay that determines when it is on and when it is off? As long as the BMS is on, it is sending power to the precharge UNLESS you go in, and turn it off manually?

 

[lance]

Battery+ connects to the battery side of the contactor - in my case, I have a wire that connects to the battery side of the contactor then it goes to four terminal blocks that have fuses - these then feed the
1. main power for the Batrium
2. Batrium shunt power
3. Rec- bms pre charge (Battery+)
4. Relay#1 (input) on Batrium (which will signal the pre- charge - which will then signal the contactor 4 seconds later after it add power to hopefully fill the capacitors in the inverter.

Actually, revisiting this after sending previous response I realize THIS is where I need to spend some time processing.

 

[Rocketman]

Lance, it could be operated that way - but I would not recommend it - that defeats the whole purpose of a BMS.

There are seven relays on my Batrium Core plus the expansion board. Each relay can be programmed for different things (or the same things).

Right now I am using three relays.

#3 is set as “Critical BattOK”. As long as the battery is OK this relay is on. The power flowing through this relay goes to the Pre-Charge which then turns on the contactor. If my battery goes critical (too high/low cell voltage, temp, overall battery voltage, etc, etc…) then this relay turns off. As soon as the relay turns off, the pre-charge cuts power to the contactor and the contactor goes “thud” as it breaks the power going out of the battery. If I want to do some maintenance on the electrical system, I change Relay#3 to “Manual Off”. The contactor shuts down and I can go to work. When I am done - change it back to “Critical BattOK” the relay closes, the Pre-Charge starts charging for the four seconds and then “thud” the contactor turns back on.

The other two relays I am using are:

#6 “Heating Required” when the cells get below 7 degrees C - Relay #6 closes and that power goes to another larger relay which turns on the heating pad the batteries sit on. (There is a sheet of Mica between the heating pad and the bottom of the cells).

#7 is “Cooling Required” if the cells get too hot or when the system is doing it’s balancing this relay closes and a fan turns on to hopefully blow some of the hot air away.

A couple other relays I may (or may not) use in the future are:
“Charging On” if I decide I need a battery-battery charger to charge the House battery from the alternator. This way the bms is controlling the battery-to-battery charger. When the battery is full - no more charging.
“SofC% Limit1” - so I can turn on the electric hot water heater when the battery is basically full. Use the solar panels instead of propane to heat water.
There are also some control logic that can be set as alarms.

There are a bunch of other control logic settings that can be used (37 total).

 

[Rocketman]

One area you need to give thought to is the logic of how you want to power the Batrium BMS.

I see two different options:
First the way I did it. The Batrium, shunt, pre-charge, and signal relay to pre-charge/contactor are all wired “before” the contactor. This allows the bms to start and restart.

The second way is those four items are powered after the contactor. That way if the battery goes Critical everything shuts down and YOU have to manually restart it. (You will need to figure out the manual restart procedures.)

The advantage of the second method is if there is a problem you know it because you have to restart the system manually. If the problem is with the solar and no charging then the bms does not continue to slowly drain the battery until those nice lithium cells are completely flat and junk.

The reason I choose the first way (auto restarts) is I am living full-time with the battery. If there is a problem I already know about it. Even if I was not full-time I would still set it up the first way, but when I was leaving the rig I would shut down the bms. (Make sure I ran it once a quarter or so just to keep it running and recharge any blockmon useage.

 

[lance]

#3 is set as “Critical BattOK”. As long as the battery is OK this relay is on. The power flowing through this relay goes to the Pre-Charge which then turns on the contactor. If my battery goes critical (too high/low cell voltage, temp, overall battery voltage, etc, etc…) then this relay turns off. As soon as the relay turns off, the pre-charge cuts power to the contactor and the contactor goes “thud” as it breaks the power going out of the battery. If I want to do some maintenance on the electrical system, I change Relay#3 to “Manual Off”. The contactor shuts down and I can go to work. When I am done - change it back to “Critical BattOK” the relay closes, the Pre-Charge starts charging for the four seconds and then “thud” the contactor turns back on.

Okay yes, this is much more in line with my understanding. I was just misunderstanding your initial description. This makes perfect sense to me. BTW: shortly after receiving my contactor I connected the 24v power supply to it, just so I could hear that "thud." ;-) Strangely satisfying! Another strangely satisfying thing I'm finding as I work on this project is heat shrink..... love that stuff!

 

[lance]

I see two different options:
First the way I did it. The Batrium, shunt, pre-charge, and signal relay to pre-charge/contactor are all wired “before” the contactor. This allows the bms to start and restart.

Okay, finally sitting down to this in more detail, and I believe that my schematic is showing essentially what you're saying here, and that it shows that because we covered this once awhile back and it made sense to me to keep these items powered from the battery side of the contactor. Now, revisiting this, I'm wondering if the Cerbo too should not be powered before the contactor so as to keep it alive in the case of a shut down. While not living with the system like you are, at least not for the foreseeable future, I will be right with it most of the time. I'm going to attach a screenshot of just the relevant portion of my schematic and see if you agree that this is following your proscription. I realize I'm likely going to have a bunch of inline fuses where you've simplified that with the terminal/fuse block but, at this point I don't think I have room for that addition to my cabinet. I'm currently waiting for ordered smaller gauge wire, and ring terminals and such to start these smaller connections on the system. All of my big connections have been made, and I'm approaching bringing the batteries in for top balancing.

 

[lance]

So, in my slow way, I've been processing this pre-charge concept, and kept meeting something that didn't make sense, and now have it clarified to the point of being able to ask another question about it. This goes to Rocketman or anyone else following this thread that might know the answer. I'm getting that the device is sending a pre-charge to the capacitors in the system so that they don't get a big in-rush of current. Let's say, for conversation sake, that we're talking only about the inverter's capacitors. When the contactor closes and allows the power from the battery bank to it, it is power that, in my case, is traveling through 1/0 cable from a 24v/280ah battery bank. With the contactor in the open position, that power is not flowing to the inverter. So, instead it is traveling from the battery bank to the battery side of the contactor where it is then being picked up by the precharge unit through 20awg wire, and for 4 seconds is sending power to the capacitors. That just doesn't seem right. I'm not saying anyone is wrong! I just don't get how that is working to have any serious impact on the state of the capacitors' charge.

 

[Rocketman]

Actually you have it right, the pre-charge sends power down the small wire for 4 seconds- evidently that’s enough to charge up the capacitors ( or at least mostly full). Then then contactor goes thunk and the circuit is made.

 

[rhino]

Thank you for this discussion since I will also have similar setup with Watchman Core and K9 as well as the REC pre-charge that recently arrived..

 

[lance]

Actually you have it right, the pre-charge sends power down the small wire for 4 seconds- evidently that’s enough to charge up the capacitors ( or at least mostly full). Then then contactor goes thunk and the circuit is made.

I guess the 1/0 then is more about flowing power when the inverter's drawing hard to supply 110v to an appliance.....

 

[Jbbonnette]

Hello everyone,

I figured I should finish posting about building the battery (about time... I have been using it for months now).

Here is the photo of the eight cells. I used kevlar cord (from my rocket hobby). Its strong and doesn't stretch. This is so I can lift the cells when I need to.


View attachment 67993

Next I need the posts. I ordered M6 x 30mm flat tipped steel set screw (bag of 25) from McMaster-Carr Plus some M6 locknuts. My batteries included 20mm set screws - but I needed them longer. I found some silver epoxy from Atom Adhesives. For $20 I figured it was a good idea to have the epoxy conduct electricity.

View attachment 67994
Adding a little bit to the end of the set screw, I screwed the set screws in to "very snug" and let epoxy do its work. In my opinion this was very successful choice. I have not had any issues or problems with any of the screws. [ After 3 months on the road - no issues ].

View attachment 67996

Next up is the buss bars... I order 1/4" x 1" copper bar (Nickle plated) from on-line metals. Cut and driller my own buss bars.

View attachment 67997


View attachment 67998

Coming together... Used some strapping tape to lock each 4pk of cells. I also got an RV 12v tank heating pad, for the bottom to hopefully keep the cells warm. I got a Mica sheet (from Amazon) and stuck it to the sticky side of the heat pad. I wanted something that would not conduct electricity and also would conduct heat. The power for the heating pad will run through a relay controlled by the Batrium - the heat pad has a thermostat, but it has a much larger range - so the Batrium gets to control the power. The slot on the top is for some plexiglass to slide in - so no dirt can fall on the batteries. The circles are for fans to add some ventilation - when they might need to cool off.

View attachment 68000
I wanted as neat of a control panel as I could make, so I ordered some Dinkle Terminal Blocks to help out. There are a lot of fuses needed for the Batrium BMS, I have two power sections - one always on (Batrium, Shunt, and Pre-Charge & Contactor), and one that is switched by the contactor. (fans, heater, Victron Shunt). The Black CZH box is two 10amp relays, The Batrium relays could not handle the heater, so they run this relay - which runs the heater.


View attachment 68001

The positive line goes into a 400A Class T fuse, then down to the contactor (the 10 ga wires will be replaced with 4/0 wires). The contactor is a Kilovac EV200AAANA (from Onlinecomponets.com). I have a Pre-Charge from Rec-Bms. to precharge the system for a few seconds (four if I remember correctly) so the capacitors in the inverter get pre-charged, so there is not a giant spark when the system switched on.

The negative line goes to the Batrium Shunt, then will go through the Victron Shunt then out to the system. I really like the Victron data from the shunt, so I added it in.

One of my design criteria, is to be able to keep the Boost ability of the motorhome (this battery can help start the big diesel motor if needed). So I made sure the battery can handle 1000 amp of discharge. Hopefully I never find out... (That's a 2C discharge on the cells for a couple of seconds). If I need to do that, I need to replace the 400 amp Class T fuse. I did make a small buss bar, to replace that fuse for the battery start.

View attachment 68002
View attachment 68003

Well, that's good for tonight. Later I will explain my "path of woe" (all my own fault).

Rocketman

is your use of the Kilovac EV200AAANA just for critical faults?

 

[Rocketman]

Yes - the Kilovac is just for critical faults - it breaks the positive cable leaving the battery going to the MotorHome.

The logic my system is using is - if battery is OK - then the relay closes - which powers the Kilovac. If the battery goes critical, the battery is no longer OK and the relay shuts off - and then the Kilovac goes “thunk” and it breaks the connection.
I have my battery set to self start - so when the battery is no longer at critical - the Kilovac will engage again (after a 4sec delay as the pre-charge runs).

 

[hummmingbear]

Ayyyy, came here from my post we were commenting on. Question about your pre-charge. Since the contactor/relay is wired through the pre-charge, and the pre-charge to the BMS, is there any special setting on the BMS you needed to do, or do you just configure it as if it's a relay?

 

[Rocketman]

The BMS just handles the pre-charge + relay as a relay. It really doesn’t know the pre-charge is even there.
The setting on the Batrium is “CriticalBatteryOK”(the actual command lost a few vowels - but you get the idea). When the battery is ok it closes the relay on the expansion board (I think #1 - but it really doesn’t matter - there are six of them). If the battery goes critical it shuts the power off.

Four seconds after the bms turns the relay on - the pre-charge is sending a trickle of power to charge the inverter then the Kilovac relay engages with a nice THUNK.

 

[hummmingbear]

The BMS just handles the pre-charge + relay as a relay. It really doesn’t know the pre-charge is even there.

Ok this is exactly what I was thinking, good to know.

...then the Kilovac relay engages with a nice THUNK.

This made me laugh. Looking forward to it, and thanks for all the help. Very appreciated!

 

[Rocketman]

I just took a picture of the cover to keep heat in:

It’s not the prettiest thing - but it works. Since it is now springtime and the threat of a hard freeze is gone - I have taken it off and stored it until the fall.

 

[callmeburton]

Going to be adding this configuration to a prewired midnite solar SMA panel ... only thing I am missing is how to charge the batteries when I need to do it through a generator. I think my RSP2000's need to pull from LOAD and connect to north of the shunt, and between the contactor and the breaker.

Would appreciate an extra set of eyes on this. https://drive.google.com/file/d/1c-yxLZrEqDSq_9AdXp7pCc9mIo35pdD9/view?usp=sharing