Batrium Watchmon Install

[Rocketman]

Hello everyone,

I have a 2000 Monaco MotorHome, I will be installing eight 272ah Lishen LiFePo4 cells making a 2p4s 12v 500Ah (useable) battery. My two largest loads are a Victron MultiPlus 12/3000 inverter/charger and the engine "Boost" if my chassis battery gets low. For the BMS I chose a Batrium Watchmon with four Blockmons (cell monitors) and the expansion board.
The main reasons for this BMS are its ability to connect to my Victron CCGX on the CAN-Bus. This will pass bms info to the CCGX. Also I will have a 400 amps of power available. (The size of my Class T Fuse). It will control Fans (to help cool things) and a Heater (for under the battery). I also liked how the software was easy to understand and change. This BMS checked all my "Must Have" boxes and many of my "Like to Have" boxes. The biggest downside is it is an expensive BMS's - especially when adding all the other parts.

		Supplier
1	Batrium BMS	Batrium	Power 12v 3A Fuse on Pos & Neg - Relays 12v@5A
2	Shunt	Batrium	Power 1A Fuse Positive - Shunt wire to BMS
3	Batteries	Lishen	Eight 272Ah Cells 2P4S 544Ah @ 13v (w/4 Blockmon8's on cells)
4	Blockmon8	Batrium	Blockmon8 Qty 4 - one on each SuperCell
5	400A Class T Fuse	Blue Sea 5502	Class T Fuse Holder + Fuse +(1 backup fuse)
6	Contactor 500A	Kilovac EV200AAANA500	Kilovac EV200AAANA500 Amp Contractor Relay - Max Inrush 3.7A - Holding 1.7W)
7	Pre-Charge	REC-BMS	Pre Charge Controller 5A Fuse
8	Terminal Blocks w/ Fuse		Fuse Box w/ Neg. 6 Fuses
9	2 Relays 10A	CZH-Labs	Fuses (BMS Side) 5A combined
10	Fans (2)	Amazon	Fuses 5A
11	Heating Pad 12"x 18"	Amazon-Facon CW-T12218	65 watts (Fuse 10A)
12	Victron CCGX	Victron CCGX	Need Can-Bus Wire ran between BMS & CCGX
13	Switch	Amazon	Fuse 5A
14	LED Lights	Amazon	12" Lights Qty 3 or 4

Here are my plans for the stuff attached to the BMS.

I have finally received everything except the batteries - they are on a slow boat from China... a very slow boat...

I also decided to make a small portable 12v 50ah lithium battery. I decided on a Harbor Freight "Pelican" case -Apache 2800. For the batteries, I am using eight 25ah Fortune cells in a 2p4s 12v 50ah battery. I picked up those batteries (local to me) at Electric Car Parts Company. I will be putting an Overkill BMS on this battery. I really like these Fortune batteries, I got to see the 60ah & 100ah when I was picking them up. They are very nice!

I figured since I had cells, I would startup the Batrium BMS and start "Playing" around with it. So I put the 25ah cells into supercells, and created the 12v battery. I attached them together with VHB tape. These cells were all at the exact same voltage 3.329v for shipping. I decided rather that doing a traditional top-balance, I would let the Batrium Top balance the cells.

So I have added the Blockmons to the cells and started wiring it up. Have the Shunt and the 30a breaker installed - Yes it is a bit of a mess!





And I am slowly charging it. I feel comfortable letting the Blockmons do the Top balance because they can balance 28.8ah per day. (That's half the size the this battery...).

Well - that's about all for tonight. I will update as I work on the project.

 

[snoobler]

Pretty sure I've settled on the same but for 2X 14S LMO/NMC batteries, so 28 Blockmons.

 

[Rocketman]

Snoobler - wouldn’t the watchmon5 (or whichever does 14 or so cells) be a little easier/better -except it has much lower cell balancing ?

 

[schmism]

You going to use Leaf NMC? They also have the leafmon for them.

 

[snoobler]

Snoobler - wouldn’t the watchmon5 (or whichever does 14 or so cells) be a little easier/better -except it has much lower cell balancing ?

No. I need monitoring for 28 cells (two parallel 14S batteries), so WM4 + 28 blockmons + shunt.

You going to use Leaf NMC? They also have the leafmon for them.

No.

 

[Rocketman]

Snoobler - I would think a Watchmon5 and a watchmon8 would be good - The 5 is the main one and every 8 you add monitors another 14 (or so) cells.

As I was dreaming about an off-grid battery that's what looked really interesting to me. Two 15 cell LiFePo4 batteries.

But first I gotta get an off-grid property to put the off-grid battery on. lol. (It's all about the battery around here... )

 

[snoobler]

Interesting. My initial config (16S) and conversations with Batrium steered me to the block mon. An MM5 +1 MM8 is about $230 cheaper than MM4+28 blockmon.

I'm not too concerned about .3A balancing vs. 1.2A isn't a big concern. All cells have been tested for capacity and interleaved within a module to ensure each 21P cell capacity is extremely close. I'll have 4A active balancers on there and plan to disable Batrium balancing in most cases.

I may actually like not having the balance heat at the cells.

Thanks for that.

I have all the components including the land... just not the time!

 

[lance]

Hello everyone,

I have a 2000 Monaco MotorHome, I will be installing eight 272ah Lishen LiFePo4 cells making a 2p4s 12v 500Ah (useable) battery. My two largest loads are a Victron MultiPlus 12/3000 inverter/charger and the engine "Boost" if my chassis battery gets low. For the BMS I chose a Batrium Watchmon with four Blockmons (cell monitors) and the expansion board.
The main reasons for this BMS are its ability to connect to my Victron CCGX on the CAN-Bus. This will pass bms info to the CCGX. Also I will have a 400 amps of power available. (The size of my Class T Fuse). It will control Fans (to help cool things) and a Heater (for under the battery). I also liked how the software was easy to understand and change. This BMS checked all my "Must Have" boxes and many of my "Like to Have" boxes. The biggest downside is it is an expensive BMS's - especially when adding all the other parts.

This is great Rocketman; thank you for starting this thread and showing this much detail on the project. It is helping immensely as I review what you're doing/saying here and see how it fits into my project. Will be keen to follow along....

 

[Rocketman]

Tonight - I made progress and got the basic wiring done.



Yes my work area is still a mess.
I got the cells charged to 3.5v each. One little issue is one of my Blockmons #3 is reading .03 or .04 volts high. I noticed it on the charging, because these Fortune cells were exactly the same voltage to begin and evidently exactly the same charge level - because they all hit 3.5 v at the same time - except the Cell #3 which reported hitting 3.5 a little earlier. The batrium did exactly what was expected and bled off the energy from that cell. I have contacted Batrium and there is a calibration tool to adjust the Blockmon. I figured I will wait until I setup the RV battery pack to run it, besides .03 or .04 really won't matter that much in the knees of the charging or discharging curves. This weekend I will run a discharge cycle and see how close to 50Ah I get. (I think is goes over just a little).

I also got the contactor (relay) wired up directly (Have not wired the pre-charge unit in). The Batrium is running it just fine. It makes a nice clunk sound when turned off or on.
I also used the terminal blocks from Dinkle for my fuses and negative wires. (The items on the rail on the right side). Because there will be like 6 or 7 fuses in this setup, I decided to try terminal blocks. I gotta say I really like them. I think they will help me organize my wiring and keep it looking good. (A real challenge for me - as you can tell from the photo's).

I also got the BMS powering itself from the battery, and the wireless hooked up - so now I don't need the USB cable to have the computer software run the BMS.

Also the OverKill BMS arrived in the mail today - the BMS that these batteries will be attached to.

 

[lance]

Was/is there any reason to consider Victron's Smart Shunt in lieu of Batrium's Shuntmon? I assume the Shuntmon has advantages in working in the Batrium environment but, I wonder if there'd be advantages to Smart Shunt and it's possibly better integration into the Victron environment and if it would work just as well with the Batrium environment.

 

[Rocketman]

The Batrium bms will only connect to the Shuntmon (Batrium's Shunt). So the BMS requires the Batrium Shunt. If connecting the Batrium BMS via Can-Bus to a GX device, I believe it will pass along all the same info that the Victron BMV712 or Smartshunt would pass along. Have not verified that yet (and will be able able until springtime). Having the Batrium Shunt I think is important to the overall bms.

I really like the BMV712's software for my iphone. Currently, I am planning on just leaving the BMV712 installed, but disconnecting the wire to the CCGX, and just using the app to see what it thinks is happening. I may even take it out of the system after a while.

One item of info I just discovered is the differences in the shunts. Victron's shunt is rated at 500amps - but it can handle more - but will not record more - so it will be inaccurate above 500 amps. Batrium's 500 amp shunt is really rated at 400 amps, but it can handle 500amps. This has just given me some thoughts, because I wanted to use my lithium battery to boost my engine batteries - maybe I will need to upgrade to the Batrium 1000 amp shunt - which is rated at 800 amps, but can handle a 1000 for a short time. Gotta think about that...

 

[snoobler]

Something important to remember about shunts: they should generally not be operated routinely above 66-80% of their rated capacity, depending on manufacturer. A shunt is basically just a resistor, and operation at or near its peak rating, or operation for shorter periods above its rating can permanently alter their response and make them inaccurate.

Unless Victron says explicitly, their shunts can be run at 500A continuous, I wouldn't ever assume that. At a .05V drop and 500A, that's 25W. Ever felt a 25W light bulb? They get damn hot. Most shunt manufacturers indicate that they can be operated for brief periods of time above their rating, but the time is ultimately limited by the temperature change. Get them too hot, and you'll change their voltage drop characteristics.

Since I want CAN communication with the Victron hardware, I will be getting the Batrium shunt.

 

[lance]

The Batrium bms will only connect to the Shuntmon (Batrium's Shunt). So the BMS requires the Batrium Shunt. If connecting the Batrium BMS via Can-Bus to a GX device, I believe it will pass along all the same info that the Victron BMV712 or Smartshunt would pass along. Have not verified that yet (and will be able able until springtime). Having the Batrium Shunt I think is important to the overall bms.

Well, just that first fact answers my somewhat baseless wondering; I didn't realize the Watchmon's required the Shuntmon's to work. And yes, my plan, if I can afford it when it comes time to execute, is to go with the Cerbo + GX Touch 50; I was so impressed with that when I read about it! I currently have it diagrammed to use one of it's temperature sensors to read the ambient temp at the top of the cabinet and then, through the one automatic relay of the two available, turn on an outflow fan mounted at the top of the cabinet. I, not already owning the BMV712, was glad to be able to remove it from my purchase list. Without digging back into things, I left my reading with the memory that the Cerbo too can be accessed by smartphone. (I'm assuming everyone is building for iOS and Android.)

One item of info I just discovered is the differences in the shunts. Victron's shunt is rated at 500amps - but it can handle more - but will not record more - so it will be inaccurate above 500 amps. Batrium's 500 amp shunt is really rated at 400 amps, but it can handle 500amps. This has just given me some thoughts, because I wanted to use my lithium battery to boost my engine batteries - maybe I will need to upgrade to the Batrium 1000 amp shunt - which is rated at 800 amps, but can handle a 1000 for a short time. Gotta think about that...

Thanks for digging up that fact. That in combination with snoobler's information is very helpful in determining whether to go with the 500A or the 1000A Shuntmon. I wonder is there any reason, if there's any doubt whatsoever that one might be pushing up past or too far into these tolerance levels, not to just go with the larger shunt? The price difference between the two, in the scheme of things, is pretty negligible. Doing my math for my system I'm saying that the most I could ever possibly have on at one time, and that would be almost impossible and if it did happen it would be for a very short time, would be 248A. Using snoobler's rules regarding shunt usage, and being conservative at the 66% end, I'm still safely below that figure with the 500A shunt. So, perhaps I just answered my own question.... regardless if the 1000A is roughly the same in terms of cost and power consumption, it would be total overkill for me.

P.S. You wouldn't be able to pass on the dimensions of your Shuntmon easily would you? I don't, for the life of me, understand why Batrium's so lame about posting a spec sheet with this info on it. It looks like a large shunt and I currently have diagrammed some dimension I picked up long ago and am pretty sure it is too small.

 

[lance]

Something important to remember about shunts: they should generally not be operated routinely above 66-80% of their rated capacity, depending on manufacturer. A shunt is basically just a resistor, and operation at or near its peak rating, or operation for shorter periods above its rating can permanently alter their response and make them inaccurate.

Thanks for the info snoobler. This is the kind of thing that someone like myself, designing this system would quite possibly have never come across. Granted, I'd not yet spent much time reading about shunts as I'd perceived them to be pretty simple and passive piece of the puzzle. So, perhaps somewhere in there I would have encountered that but, just now reading through Batrium's Shuntmon pages, this admonition not to run continuously above the 66 - 80% range does not show up.

 

[snoobler]

DC Digital Current Shunt - 500A - Blue Sea Systems

For use with DC Ammeters.

www.bluesea.com

"For continuous operation, it is recommended that shunts not to be run at more than two-thirds (66%) the rated current under normal conditions"

 

[lance]

"For continuous operation, it is recommended that shunts not to be run at more than two-thirds (66%) the rated current under normal conditions"

It appears that Blue Sea makes the info readily available.

I assume you know my comment wasn't a doubting of your knowledge and much less a dig at the industry as failing in any way; someone doing what I'm planning to do has to be fully responsible for finding out this info. But, I am glad there's folks such as yourselves on boards such as these willing to share what they've learned and this is one of those facts that easily could've been missed by someone such as myself.

 

[snoobler]

Just providing evidence supporting my statement. I don't always do it.

 

[Rocketman]

Lance - Here are the details on the Shontmon 500amp:




For reference the black wires attached to the lugs are 10ga THHN wire from Home Depot and yellow crimp connectors 3/8" stud. The red sense wire is 20ga.

Length is 5-1/2" (but really 6" because of the positive sense wire (right side of photo))
Width is 2"
Height is 1.75" - (but probably 2" with larger lugs on it).



OK... Here are my "issues" with the shunt. You may need to design around these like I will.

1. Mounting hole or holes... Only one mounting hole is accessible. As you can see from the top view. The base is some kind of epoxy molded base - and would be fine - except the electronics section is covering the second mounting hole. I see two solutions - either remove the electronics mount the second base down then reattach the electronics board, or to use my drill press and make 2 more mounting holes (Right side of photo top & bottom). My thoughts right now are to remove the electronics - then attach it to another base (3" x 6" x 1/2" oak board) then screw that board down. Dumb design flaw.

2.The second issue is the electronics section sits above the brass lugs (another dumb design flaw). This might make for shaving the side or top of a 4/0 lug down and having to be careful if attaching with bus bars.

Other than those two issues it is fine. The wires to the bms plug in nicely, and the positive sense wire just needs a 1A fuse. My understanding on shunts is the smaller they are the more accurate they are. So if you only need a 500a shunt - get that one.

Here is the shunt hardware setting from the software.



Right now the battery is idle - using 3.35 watts to run the bms, shunt, and the contactor. If I turn the contactor off the shunt & bms are using 1.4 watts.

Any other questions???

 

[lance]

Length is 5-1/2" (but really 6" because of the positive sense wire (right side of photo))
Width is 2"
Height is 1.75" - (but probably 2" with larger lugs on it).

Awesome! Thank you...

1. Mounting hole or holes... Only one mounting hole is accessible.

That is just a bizarre fail. Maybe they just expect folks to disassemble, mount and reassemble but, that remains a fail.

This might make for shaving the side or top of a 4/0 lug down and having to be careful if attaching with bus bars.

And another. I don't have a solid sense of lug and wire sizing yet so, this is a little greek to me but, I'm reading a 4/0 lug as being on the large side. If it is the size called for in most or all wiring schematics, it seems, again, bizarre that the unit wouldn't be designed to accommodate the lug without modifications.

My understanding on shunts is the smaller they are the more accurate they are. So if you only need a 500a shunt - get that one.

Awesome! Thank you.

Right now the battery is idle - using 3.35 watts to run the bms, shunt, and the contactor. If I turn the contactor off the shunt & bms are using 1.4 watts.

Seems like an overall low draw in the scheme of things.

Any other questions???

Now that you mention it! ;-) Do they have a Mac OS version of the software or, am I going to have to borrow someone's PC? I suspect I can get that answer pretty quickly on their site but, it just came back to mind seeing your screen shot here.

Thank you sir!

 

[Rocketman]

As far as a 4/0 lug... because I am working in 12v, and I want LOTS of amps I need 4/0 to fully power my Multiplus 12/3000. However, if I was working on 48v something much smaller would work - like 1 ga.

Mac OS - who uses Mac OS??? (besides my wife... Oh no I better stop typing right now! ). I do not recall seeing anything about Mac OS... If not... You may want/need to have a small cheaper device that can connect and modify the system on the road.