Batrium Watchmon Install

[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 ].

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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.

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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
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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

 

[Rocketman]

A couple of little things…
From the batteries - you have a class T fuse (great!), then the battery disconnect (great), then it looks like (if I am reading it correctly) it goes to your contactor (which is powered through a Pre-Charge - Great), but then there is a 250a breaker (Why? - if the breaker is off - you just wasted the pre-charge voltage ramp-up). If you just want a switch use the contactor (through the Batrium software).

Also, does your solar charge controllers have a wire/relay, etc so that the Batrium can control the charging- charge OK vs Not OK.

Also, you have three 300VDC (lighting arrestors?). I can see the purpose of each at the combinator panel, but then you have only one more after that - I would have thought you need zero or two or both panels going through it. ( I really don’t know enough here to comment- other than it seems off to me.

Have you already purchased the Batrium? You may want to look at the K9?

God luck

 

[Nobodybusiness]

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!

Why didn’t you go with the Watchmon Core and & K9s?

 

[callmeburton]

Thank you both for your input.

Why didn’t you go with the Watchmon Core and & K9s?

Have you already purchased the Batrium? You may want to look at the K9?

Pictured, although redrawn by hand as a rough representation, is the WatchMoCore + CellMate-K9 bundle ? https://www.batrium.com/collections/kits/products/watchmon-core-k9

but then there is a 250a breaker (Why?

Because it is built into the prewired SMA Midnite Panel? It wont be hard to ensure it is turned on before sending current down the normal connection terminal. I eventually plan on making multiple battery modules like the one seen in the diagram, each 16s with its own k9 as pictured.
Should I move the contactor north of the breaker? to make better use of the precharge function?

Also, you have three 300VDC (lighting arrestors?).

One is VAC at Line 1 IN / OUT
One is VDC used for the Classic charge controllers input
Both of these are found on the main panel under the SMA. This is the standard configuration for this box. When I add another Classic charge controller I will have to add another VDC arrester as well (something I am thinking about as I have enough panels on my pallet to operate three charge controllers)

There is one extra on each combiner box which are VDC as well. I actually ended up getting a midnite 12 panel box and installing two arrestors on it, one for each "leg" going back to the charge controllers.

Updated drawing to be more clear and moved relay down range of the breaker. EDIT: Upating url to v5 which is cleaner https://drive.google.com/file/d/1zBiWcO6m7j04EqA0LuignK4pw0Ez3b8m/view?usp=sharing

 

[LithiumSolar]

Why didn’t you go with the Watchmon Core and & K9s?

Original post was from Jan 2021. The K9 wasn't released until a few months later.

 

[callmeburton]

Sorry for the attention there LithiumSolar, wanted to post here given you are the only place I could find in the forums with a documented build out and I wanted to contribute and seek out guidance inside the same thread vs starting another thread

 

[OffGridInTheCity]

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.)

In my trailer I power the Watchmon in 2 different ways....

1) Powered from the battery - the circuit has a breaker (on/off switch). This is normal mode when the MPP Solar 3048LV and battery is active.

2) Powered via the USB from the trailer computer. When in storage, I use a bypass to skip the MPP Solar and feed 120v directly to the distribution panel. This let's me shut off the inverter and disconnect the battery but yet use the trailer computer's USB to power the Watchmon (without draining the batteries) so I can monitor the cells and the temp either on the trailer computer or via wifi of the Watchmon.


My point is the USB option can be useful as an alternate power source to monitor without the battery being 'enabled'.

 

[callmeburton]

solarSetupv5.pdf

drive.google.com

Updated the drawing to be a little cleaner in my previous post. Is there any downside to having the watchmon take power from B+ while the PreCharge is down stream of the main breaker if the breaker is off? Just thinking "what ifs" ... from what I can tell the watchmon > precharge is just a input sensor vs providing power which is likely from the B+ source down stream on the breaker in the way I have it configured now.

 

[callmeburton]

Also, does your solar charge controllers have a wire/relay, etc so that the Batrium can control the charging- charge OK vs Not OK

Just now remembering to respond to this.

The batrium will only control the contactor which would cut off charging to the battery ... BUT that was with version 3 of the diagram before you mentioned the 250v breaker being useless in how I had it configured.

The solar charge controllers themselves have their own shunt to monitor the batteries ... my RSP2000's I don't think have an input either ... they are just CC CV ...

Looks like I might have to reconsider my diagram again to bring back the usefulness of the contactor. Or revert to the previous version and change startup procedures for the inverter.

 

[Rocketman]

I just figured I would give an update on my lithium battery- it has been working great! Boring - huh ?.

In other news…
When I was a the Quartsite RV show last January- I picked up a Victron Dc-Dc charger (non-isolated). It sat around for a while - but I finally got it (mostly) installed. I want to add a relay so it will not run except when the ignition is on. My rig has a dc charger to charge the chassis batteries when the generator/shore/solar is charging the chassis batteries. I need to add the relay because I end up in a charging loop (that Just wastes power).

I added the Dc-Dc charger because I wanted to make sure that on a driving day we arrived with a full battery- even if the weather is very poor. Also, I want to re-wire a bit so I can run one Air conditioner off the inverter and this will provide a third of the power for it.

 

[Shawn Hayes]

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


View attachment 35286

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).

View attachment 35287

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.

View attachment 35296

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???

May be too late now, but for those looking, here’s how I configured my Batrium 500a shunt with two 4/0 cable/lugs.
Using 1/4” x 1” copper bar with holes appropriately drilled to line up with the shunt pre-drilled holes, to accommodate my needs.
There are two pieces of copper bar on each side of my 4/0 lugs. They are sandwiched in between, nut/bolted together for secure contact.

 

[Rocketman]

Update on the batteries in my MotorHome.

Today I did a useable capacity check and I am excited!

I installed eight 272ah Lishen cells - 12v - 544Ah battery about 1-3/4 years ago. I did not do individual cell capacity tests, but after I got the battery made and installed I did a useable capacity test.

The way I did my test was when the battery is in absorbing mode and charging very little, and my Victron Smartshunt has reset to 100%. I cut all incoming energy and then used power until my Victron Multiplus cuts out. I call that the end of the test (yes my cells still have some Ah left in them - but I figure this gives me a good-safe- repeatable mark to test).

Right after I installed the battery, I got 527ah out of the battery. I was happy with my purchase! I figure a bit of the difference between 527ah and 544 ah is in the bottom few percentage.

We have been full-time RVers, so now 1-3/4 years later I redid the test and I got 521ah out. Wow! That really gives me confidence in these cells. They have probably operated the whole time above 50%, most days they get charged to 100% then down to 70 to 80% overnight, then back to 100%.

Anyway I just wanted to share how my cells are aging!