Valence XP Super Thread

[Travis]

#1: I'll try and keep this organized. We're limited to 10,000 characters so this will be a multi part post.
If you have an XP battery or a bunch of them this will be a good thread for information on how to treat them properly. We'll discuss what the Valence Brand U-BMS actually does and how to get around needing one. I have recently acquired 220 kilowatt hours of valence batteries so this is kind of like my diary for what I've learned and am continuing to learn about them. I have a huge investment here and I'm really trying my best to treat them right.

Advice here is by no means correct. I'm still reading through the attached 60-page user manual and doing real world testing and lots of manual monitoring so that I may better understand what's going on. Take what is said here with a grain of salt and compare it with the user manual. Decide for yourself what tactic you want to choose when caring for your battery bank. If it's over your head have your trusted solar installer set it up for you. But be warned most of them don't know what they're doing.
One thing I want to bring attention to is most people think the internal cell balancer will do its job when in fact it won't unless it has 4 volts coming in on the communication wire and it's also communicating with a Laptop or BMS.


#2: When good information appears in the thread I'll attach it here below in the first post, put a brief description about it in number threes changelog and reference the post number it came from.



#3: Change log.

3-21-2020

Added a paragraph called installation U27-12XP with some tips that you need to know.

Added a paragraph & link to the wire size voltage drop calculator.

Added a paragraph about proper battery bank wiring.

Added paragraph and link about a do-it-yourself BMS for programmers that approaches the topic valence style using the rs-485 communication.

Added a paragraph called OVER DISCHARGED?

Added Links at the bottom for:

Do-it-yourself Kick-Ass battery charger.

Converting my Prius to charge my house battery.



#4 INSTALLATION:

With the u27-12xp When you're tightening down the lugs on top of the battery be aware that the negative hole is not as deep as the positive hole. This will cause the post to bottom out before it clamps tight on your wires lug. You'll need to figure out what thickness of washer to put in there as a spacer. Definitely use stainless steel or brass washer.

The lugs are stainless steel which is known for maring and getting stuck and breaking off in the hole. I'm not saying these batteries are known for that I'm saying that's just an inherit trait of stainless steel so make sure you clean all of the loctite out of the threads. I had to literally scrape around the threads with a razor knife. It took a long time and then after when I screwed the post into the battery it turns out there was more loctite that fell off of the threads and got in between the battery lug and the top of the batteries mating surface. This is not a good thing because we need this area to conduct electricity without loctite residue being in between. I'm going to purchase a m8 by 1.25 tap and die set to clean these threads before I do my own installation.

And before you purchase wires you should read everything below especially the part about wire length and avoiding destroying your batteries with unequal wire lengths in parallel setups. At some point I'll have some of those high current relays for sale and the interconnecting wires that Mueller industries has for sale which are really nice for these because they're so dang thick you won't have the negative terminal problem previously mentioned.



#5 BALANCING BATTERIES:

Now I want to talk about keeping the 12 volt batteries all at the same voltage as each other. this is very important then I have personally seen these valence batteries in series very greatly in voltage when one reaches full before the other. This will cause the one that reach his full first to be damagingly high in voltage. I'll call each 12 volt battery a battery. I'll call the 4 cells inside it cells. So it takes 4 lithium iron phosphate cells in series to make one 12.8 volt battery. The internet likes to call these batteries modules. So you might see them called modules elsewhere including in the valence software. Throughout the charge and discharge cycle let's say between 20% and 90% state of charge (12.8-13.8) the batteries & their cells will probably stay exactly the same voltage all on their own even if their state of charge it's not quite the same. That's why it's so hard to balance the cells to each other in this range. But when the voltage falls low & the state of charge goes down & your approaching 0% they will start to wonder away from each other in voltage. So let's say you have 4 batteries in series for a 48 volt setup. And you are draining the batteries because the sun went down. The battery that goes dead first will suddenly and rapidly drop in voltage from 12 volts down leaving the other batteries behind as if it were suddenly racing to 0. It will likely shoot down so fast it will catch you off-guard and it will drop below the low voltage recommendation of 10.5 volts. This will damage the battery. No joke DO NOT let this happen!

It's a similar story when you're approaching full charge as well. The battery and or cell that reaches full charge first will rapidly rise and the voltage will shoot above the recommended 14.6 volt upper limit. They can handle higher voltage better than under voltage so they won't get damaged so quickly up there if the battery reaches 15 volts. But it's still not good for the battery and the batteries onboard computer will likely record the over-voltage strike in it's permanent history. That is if the computer has a 5 volt power source and is woke up meaning in communication with the laptop or BMS.

Now let's say you have a 12-volt system and all your batteries are wired in parallel. In this case you will not need a device to balance the batteries to each other because they're literally connected to each other and they will naturally force each other to be the same voltage. They will work in harmony together. Make sure before you connect them together that they are already at the same voltage. It's okay if they vary a bit in voltage if they are over 14 volts or under 11.5v when you connect them together. If you're in doubt it's best to fully charge them all one at a time before you connect them together. However you will need some sort of safety device to disconnect the batteries from the load and or charge if they approach the over voltage or under voltage condition. Your inverter might be set to shut down at 10.5 volts and it's likely you can adjust that number in the inverters menu and if you trust that inverter then I suppose that would work. You would also have to trust that your charge controller didn't have an error and decide to push the voltage higher than it's supposed to. Be careful that you read your manuals for your inverter and charger. By default they'll be set up for lead batteries. They will adjust there voltage drastically according to temperature as if you had a lead battery. You'll need to disable temperature compensation related voltage adjustments or change their settings to be correct for lithium. These are very nice and expensive batteries so it wouldn't hurt to have an extra safety mechanism in place to disconnect if things got out of hand.

 

[Travis]

#6 BATTERY BANK WIRING:

This is the most common mistake with do-it-yourself and even some professional solar installers. This applies to all parallel connections whether it be just parallel or series parallel. It's easiest to keep the wire lengths the same but it's really about the amount of resistance so you could have different lengths in strategic places that total in length the same for each set. There needs to be an exact same amount of resistance and you also have to count the number of connections. The type of connection. The quality of the connection. There's so much to think about here I like to keep the wire Gage and crimp connectors consistent in this area so it's easier. All the module 2 module balancers I've seen cannot pass very much current so this is extremely vital that you do this correctly. This is probably the number one silent killer of people's battery Banks. Here's a link to an awesome explanation you absolutely must read this it goes into great detail yet keeps it simple to understand and has diagrams. He also shows how to do the math. It's kind of like you find the resistance and call it the problem. Then you multiply the problem and it ends up being a very large problem. This article is based on the higher resistance of lead batteries so it's possible that with the lithium having a lower resistance the so-called "problem" might be multiplied less and not be so over exaggerated but I'm not sure. You tell me?

http://www.smartgauge.co.uk/batt_con.html



#7 If you want a handy online calculator to help you decide what gauge wires you need this is the easiest one that I found. You'll need to know some numbers like how many amps volts and how long the wire is going to be. After you fill it out and submit you'll have to scroll all the way back up to the top in order to see the amount of voltage you will be losing in The wire.

There's also a percentage a voltage loss shown. That represents the actual energy you lost because of that wire. If you're not okay with the results then choose a thicker wire or a higher voltage and compare the results. Was the energy savings worth the added cost for the wire? Is the wire thick enough to be considered safe? https://www.calculator.net/voltage-...ce=10&distanceunit=feet&amperes=100&x=95&y=23



#8 CHARGING:

I activated the internal cell balancer by applying 5 volts to the rs-485 connector and connecting it to my laptop and I carefully watched the batteries as they charged and noticed that the balancers become active when the battery voltage goes above 13.8. I decided to set my charge controllers upper charge voltage to 14.07 instead of 14.6 like the manual suggests. This would still enable the top balancer to do its job while staying further away from the upper single cell voltage limit. After giving it a good balance for 8 hours I was able to raise the voltage of the charger without accidentally going over 3.8 volts per cell. If the string of batteries is consuming less than 6 amps and battery voltage is above 14.1 volts it's pretty much full. If you want it to top balance you'll want to hold it around that voltage for many hours. I suggest doing a good solid top balance at least once every 3 months. And a quick top balance like for a couple hours at least once every month.



#9 OVER DISCHARGED?

Heaven forbid something goes wrong and you accidentally over discharged your battery. Disconnect all of the loads let the battery voltage stabilized and look at the LED. Read the manual to find out what the color and blink rate of the LED mean. I pulled this out of some random valence literature I forget where but if you don't find better instructions in the Valence manual then follow these instructions to revive an over discharged battery under 7 volts.

If the batteries resting voltage is below 7V:

• Charge with current regulated 0.5A until the lowest cell voltage reaches 2.7V and the LED blinks green. This will probably only take a few minutes. You can monitor the individual cell voltage using the Valence software & adapters I mention in this email. Keep in mind this is a very slow charge and it's critical that it is slow. That's the whole point so don't try and hurry through this stage buy going above 0.5 amps charge. When every cell reaches at least 2.7 volts At this point, use a normal charger to finish charging while keeping an eye on the temperatures in the Valence program. And putting your hand on the battery to make sure it's not getting warm. The battery will be damaged you'll have lost some capacity but hopefully you haven't caused a self-discharge condition where a charged cell just gets warm & goes dead over time. If this has happened and you notice the cell voltage continually going down because it's warm it's basically shorted and there's a bad cell in the battery. You would be smart to cut the battery open and rescue the individual cells for hobby projects. Or else figure out a way to locate and replace the cells that were at fault.



#10 CELL BALLENCING:

Because cells of different states of charge will pretty much be at the same voltage throughout most of its charge-discharge cycle it's normally hard to tell their true state of charge by checking the cells voltage. For this reason balancing is done at the top of the charge when they're voltage differences better reflect their true state-of-charge. The cell that reaches full first will have an exaggerated higher voltage and the on-board computer will connect a tiny heater (resistor) to that cell in order to keep that cells voltage from getting too high. This will actually cause the voltage of the other cells to go up a little and they will slowly rise in state of charge until they catch up. The battery will consume less and less power during this phase. After it's consuming less than 6 amps it's pretty much full and that's when the balancing really kicks in. It can sit in this stage indefinitely without major harm but it will degrade the battery faster than a lower state of charge would. I'd notice that for the majority of the balancing cycle the series string of batteries will consume around 0.25 amps and slowly reduce over the next 2 to 6 hours. After 6 hours or so is when I've seen all of the cells finally rise up to the fully saturated voltage. This is one of the requirements for the onboard computer to occasionally calibrate its state of charge meter.

I'm going to utilize the equalization mode on my MidNite charge controller to balance the batteries every 90 days. So every 90 days my charge controller will bring them up to 100% state of charge and hold them there for x amount of time. I'll choose 6 hours @ 14.07v. Instead I could use the skip days feature to accomplish the same thing.



#11 STORING BATTERIES:

Lithium batteries store the best & last the most years at lower percentage of charge, lower amperages and shallower cycles. But they are so much better at handling higher voltages, higher amperages and 100% state of charge cycles then lead acid could ever dream of. They do have a very small self-discharge so if you store them dead you won't have as much time before they drop below their low voltage recommendation and be immediately damaged. That's why you'll want some state of charge if you're going to store them for long periods. I think the user manual probably has a recommendation for that. Its internal computer shuts down after only 120 seconds of being disconnected from the laptop or the U-BMS so it will not drain your batteries at all.

Most of you probably only have 12 battries or less and so you'll probably be cycling them fully every night. My battery bank is large so I'll only be using 10% of its capacity at night. Understanding that sitting nearer the lower voltages will make them last more years I'm going to cycle my batteries between 30 & 40% daily instead of 90 & 100%. I'll manually turn up the voltage if I know a very cloudy week is coming in order to start into the dark week with a higher state of charge.


#12 BMS / BATTERY to BATTERY balancer:
Here's the best solution that has a very intelligent system designed to work seamlessly with these batteries it is a $500 BMS that also has relay controls capable of controlling huge relays to disconnect the battery bank if something goes wrong. But it's often out of stock. Check out there other balancers they might work primitively for our Valence battery Banks. They have a few different cheaper balancers like the ones in the Amazon links below. This BMS doesn't actually do the balancing it's simply sends commands the batteries through the rs-485 communication cables. And uses these commands to tell them to slow there charging speed if they get too far ahead of the others. This BMS is in charge of sending the correct commands to keep them balanced to each other as well as protect from over and under voltage conditions provided you also purchase a high amperage relay to go with it. It also does many other fancy things you can read about in the XP user manual.

Battery Management System MIUSA-BMSLV

MIUSA-BMSLV Battery Management Systems are designed to enable multiple system implementation options and advanced command and control ability. MIUSA-BMSLV is compatible with U27-12XP battery modules Features - Monitoring, temperature, voltage, current, SOC status - MIUSA-BMSLV can manage...

www.mullerindustriesusa.com

 

[Travis]

#13 Balancer On The Cheap.
Maybe you don't need a BMS at all? Like if your inverter shuts down before the battery gets too low and your charge controller is reliable and you have a cheap aftermarket battery to battery balancer. & Every once in awhile in order to activate the internal cell balancers you could hook up the batteries to your laptop to enable the cell balancing during an equalization charge. During normal cycling you would simply stay away from the upper percentages like try only charging it to 13.85 volts. Give or take a little bit with some experimentation you can probably come up with the right upper voltage limit that doesn't put any cell in danger. The manual says keep them under 4 volts but starts getting giving warnings when it's over 3.8 volts.

Here is a 2-channel balancer. This will work for 1 string of batteries in series for a 24 volt battery Bank. You will need one balancer for each string. Although I'm not impressed with its amperage abilities. It claims 10 amps but when I measured I was only able to get 0.2 amps moving from the highest battery to the lowest battery. I'm worried it won't pass enough amperage and if you choose this option you will have to keep an eye on it in the upper and lower voltage range to prove to yourself that it's working properly. Then you can relax or maybe you'll decide it's not good enough.

Here's a 4-channel balancer. this will work for two strings of batteries (4 batteries) in a 24v battery Bank. And it will also work for one string at 48 volts which is also 4 batteries. If I were doing a series-parallel setup I would keep all series strings independent of each other except at there main terminating ends of the string. Each series string would have its own cheap balancer. So You'll have to buy more balancers if you have more than 4 batteries. It's the same cheap style as the two channel above that didn't move many amps for me so take the precautions mentioned previously.

Amazon.com: Battery Equalizer 48V - Battery Voltage Balancer, Max 4 × 12V Battery Bank Extend Battery Life 1 Year and More support Gel Flood AGM Lead Acid Lithium Battery HA02 Balancer(Battery Equalizer 48V): Automotive

Buy Battery Equalizer 48V - Battery Voltage Balancer, Max 4 × 12V Battery Bank Extend Battery Life 1 Year and More support Gel Flood AGM Lead Acid Lithium Battery HA02 Balancer(Battery Equalizer 48V): Energy Controllers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Do-IT-YOUR SELF BMS balancer for programmers.

Here's an interesting read where a guy starts programing his own balancer for valence batteries. He has had success enough to be useful and is active in this and is looking for programmers to help with the project. https://diysolarforum.com/threads/interfacing-with-valence-built-in-monitoring.2183/


RELAY:
Here's a link to a quality used high amperage relay. Ev200a for only $30. Most eBay sellers are asking $100. This is a $200 relay. https://ebay.us/K8VX8J



STATE OF CHARGE / VOLTAGE PROTECTION:
Here is a cheap Chinese battery capacity meter that appears to have the ability to primitively protect the batteries from high and low voltage if you purchase a high current relay to go with it. I say primitively because this will only base it's disconnect protection from total series voltage not individual cell voltage so if one starts to wander it won't have a clue. I bought one of these and I'm had screen errors. The screen gets all garbally. Amazon sent me replacement February 2020 and it's working. I tested its relay control and it shorted closed (broke) when I tried to have it control a large relay so you may have to replace the transistor with a larger one or else power a small relay and then use the small relay to power the large relay. This will also show you percentage of state of charge if you programmed the correct amp hour capacity into the meter. And remember you can always plug the Valence into the laptop in order to view the on board computer that will tell you state of charge and lots of other useful info. Heads up though the valence state of charge meter probably needs to be calibrated by doing a few complete charge, discharge, charge and top balance cycles.
I've noticed the valence batteries internal on board state of charge meter is actually intelligent and adjusts its capacity on the fly according to how much wattage you're pulling out of the battery. When I pull wattage out faster I've seen as much as a 30% reduction in the projected capacity. But when I pull power out very slowly I can get dang near 100% of its original rated capacity out during a externally metered capacity discharge test.

Amazon.com

#14 rs-485 ON BOARD COMPUTER communicating with laptop.

Plugging a laptop into the communication plug of the valance will show you % of charge remaining on an individual battery, temperature, voltage total and voltage of each cell, among many other things. But it only shows one battery at a time which is kind of annoying. I'm not sure which temperature sensor is where inside the battery. I get some very wild temperature readings uncensor 5 & 6 that very a lot between batteries of the same temperature.


VALENCE software:
Here is a link to download a zip file containing the valence software to connect the laptop to its onboard computer. This one has three tabs in the bottom section and I heard there is a version that has four tabs if you know where I can get it let me know. It's for Windows only and will not work with Apple unless you run Windows in a virtual machine on your Apple with all kinds of hassle. If you're not plugging the batteries into a laptop I would suggest plugging the two communication cables into each other on the same battery to form a sort of handle that you should not lift the battery with. This will keep the metal pins inside the connectors clean and corrosion free. When you open the software after you install it you'll need to find the ModuleDiagG2.exe file in the program's folder (x86) folder. Right click on it and run as administrator. On my computer I was not able to right click on the desktop shortcut to accomplish this. Now you should have the valence program running and you'll see the main valence page with mostly blank boxes.
Next you need to set the logging path in the battery info tab. Near the bottom right side click on browse and choose a place somewhere on your computer probably in my documents folder you can create a folder called valence log files or something and choose that folder. Every once in a while like if my laptop goes to sleep and then wakes back up again I noticed the data reported in the software no longer reflects the correct battery when I switch between batteries. If this happens I simply restart the program and it's good to go again. If anyone knows how to write some basic code so that we can see the info on all the batteries on a live active spreadsheet that would be great if you help me out with that I'll share it with everyone. https://drive.google.com/file/d/1qCrYA6lAHl2Cx31xhAd_p3dqowhRImJ8/view?usp=drivesdk

RS485 USB ADAPTER:
There are several to choose from. Some of them don't Supply Power to the valence onboard computer like it needs. The one I'm using doesn't so I literally had to get a 4 volt battery and run 4.2v into the communication plug on the valence battery. After you get the adapter in the mail you'll have to plug it into the USB port on your computer. I used Windows 10 and it automatically installed the drivers. If you're using an older windows version or something you might have to install the drivers yourself. Maybe the adapter comes with a disc or something I'm not sure. Here's a link to one that does Supply power like we need https://amzn.to/2zn3S6s

PIN OUT COMMMUNICATIONS connector diagram:
In this picture that you can also find in the user manual you will see a connector that you can purchase from a link a few paragraphs below. You would want to crimp wires to this connector and run them over to the rs-232 to rs-485 USB adapter. It will label each pin in the connector.
This is just a screenshot of Page 47 of the user manual. https://drive.google.com/file/d/14LlaJXSz5dLehfCwMOcftLAKhKveqAl8/view?usp=drivesdk

COM PORT:
Now about choosing the comport. In the valence software click the comport drop down and you'll see that it's blank. There are no comm ports to choose even if have you previously set up the comport properly. You'll have to go to your hardware page to discover the com number. Then go to the software and literally type com7 or com5 or whatever the number was. And remember no spaces. Next look at the ID number I wrote on the battery and choose that in the drop-down. Connect to the communication wire from the balance computer into the rs485 USB adapter Then click start communication. You should now be seeing all the boxes filled with data from the batteries onboard computer. You can switch between batteries without ending and restarting communication but it only shows one battery at a time which is kind of annoying.

 

[Travis]

#15 CONNECTOR KIT
I bought this connector kit so I could make connecting to the valance plug easier but I can't find it so I ended up Jerry rigging the thing. https://amzn.to/2Hr3zM8


#16 User guide. XP battery manufacturers user guide.

256622731-XP-Power-System-User-Manual-Rev-4-8.pdf

drive.google.com

#17 XP battery datasheet https://drive.google.com/file/d/1-uMSW193DDkemyiyo1DrAHvlRcl29U5y/view?usp=drivesdk and


#18 Discharge performance chart https://drive.google.com/file/d/1-ojlESRekc6YGMK3L0s4tJvwB3a3QRg4/view?usp=drivesdk



#19 Educational Understanding battery specifications

understanding_battery_specifications.pdf

drive.google.com

#20 Basic lithium battery educational material https://drive.google.com/file/d/113QJs-9EtNgnfsCYqjTM3fswdRYgbgoA/view?usp=drivesdk


#21 Educational: Importance of good wiring & The math behind series parallel and battery resistance formulas.

Wiring-Unlimited-EN.pdf

drive.google.com

#22 Do it yourself grid charger. this is for people that have huge battery Banks and need to charge with massive amount of power from a large generator or the grid but don't want to spend thousands and thousands of dollars for the hardware. Basically open inverter. Org has decoded the communications and controls on hybrid vehicles inverters. Some people are using this control to make chargers. They purchase a cheap hybrid vehicle inverter or electric vehicle charger and then convert it to be able to charge their houses battery Bank. https://openinverter.org/wiki/Main_Page



#23 Prius hybrid car charging my house battery. It took a long time but I finally decided to try it and it works. It uses half of the fuel compared to my Honda eu2000. The Prius only uses one gallon for 16 hours. I now started acquiring Priuses and converting them for people. But now that I'm switching to the lithium battery bank it might not work as well I'll update the thread in this link as I progressed with this.

Prius as backup generator with midnight classic as voltage converter possible? - Solar Panels - Solar Panels Forum

!!UPDATE!! 6-10-2020 below you will find the thread and my thought process I went through to make this work. Yes you heard it right it's working and so far been working 8 months 16 hours every night. If you want to know more I suggest you read the whole thread but skipping to February 3rd will...

www.solarpaneltalk.com

#24 ERRORS with Outback flexmax charge controllers. There's a rumor that the flex Max charge controllers have errors with some lithium batteries. I suspect these problems come up with batteries that have mosfets between the cells and their output. The XP line does not have mosfets. The cells are connected purely to their outputs. The only thing the internal computer does is log performance history and activate resistors on the cells and or the entire battery module. I don't suspect anyone will have any of these errors.


I'm glad you spent hours reading this and even more hours reading all the links LOL. We are all invested in this so let's share our knowledge in the comments below to help protect our investment.

 

[Travis]

The black circles on the side of the u27-12xp reveal screws. You can remove the side cover and you'll have access to the individual wires going to the cell blocks so you could actually hook up a traditional cell balancer like a Batrium or many other far cheaper than Batrium choices. But if you have more than a few batteries that would be a hell of a lot of wires and I'd recommend getting the actual BMS designed for these.

Photo courtesy of http://cogito44.free.fr/technologie.html#wa-anchor-jrc1z2om1dqjuxl91c

 

[Travis]

Reserved for future use

 

[Travis]

Reserved for future use 2

 

[Travis]

Does anybody know how much current balancers like this can pass through between cells and do they make this type for modules? I'm not asking you to read the spec sheet for me I'm asking you if you've actually measured it yourself?https://www.ebay.com/sch/i.html?_fr...r+Lithium.TRS0&_nkw=balancer+Lithium&_sacat=0

 

[somewhereinusa]

Would it be enough for balancing to simply supply 5v from a voltage reducer to the canbus for cell balancing?

 

[mitchk1303]

Thank you for this post. Like I said in another post I am completely new to all of this stuff so I am still trying to figure it all out. I will be using 3 modules in parallel for my system. Here are the steps I will be taking to maintain my battery life, please correct anything that is wrong:

1. Since I'm running in parallel the voltages between modules should stay pretty similar. To be safe I could set the charge voltage max to around 14-14.2V.

2. Every month or so I need to program my charge controller to do a float charge to a specific voltage (you used 14.07 for 6 hours). While the batteries are charging I plug in my computer with 5V to make sure all of the individual cells are balanced? Do you just open the program and the cell balancing happens automatically? It looks like the RS485 to USB that I bought has a 5V port so I should just be use that to do the balancing correct? I would need to do this for each of the 3 batteries so it would actually take 18 hours total right? I could split it up into 3 different nights and do one battery per night? In order to do this I would need to make sure nothing is drawing power from the battery bank?

3. I can set my victron charge controller to around 14.2V (or maybe lower?). If I balance the battery cells every month I might be able to get away with 14.4V? Most of my power will be 12V DC output so I would need to find out how to ensure that I don't over discharge my battery bank. I could possibly use the chinese battery capacity monitor that you talked about to prevent overdischarge.

Is there anything that I am missing? Sorry for the long winded post, like I said I really want to get a good understanding of this stuff and unfortunately I am starting out with no knowledge on the subject.

 

[mannytheseacow]

Hey Mitch. Regarding your Q - #3, probably the easiest way to protect your batteries from over-discharge would be using something like the Victron Battery Protect (BP-100, 100AMP - 6-35v). It's a pretty inexpensive insurance policy for pricey batteries.

 

[Justin Laureltec]

^^There are a lot of limitations as to how the BatteryProtect may be used, however, so don't buy one without research/talking to an authorized Victron distributor. The BatteryProtect is the single most commonly misused component made by Victron, so do your research: https://www.victronenergy.com/battery_protect

 

[mannytheseacow]

Can you elaborate? I thought the battery protect is intended to protect the battery?

 

[Justin Laureltec]

Can you elaborate? I thought the battery protect is intended to protect the battery?

The BatteryProtect is designed to disconnect non-critical loads from a battery bank before catastrophic discharge (in the case of Pb batteries) or before the BMS shuts down (in the case of LFP batteries), but it must not be used to directly disconnect an inverter from the batteries, nor an inverter/charger, nor any point to which reverse current could be applied - such as, for instance, a DC bus which also has a charger attached to it.
Permitted connections and methods of use are detailed in the user manuals available from the product page I linked above; this is important because forbidden connections 100% will result in failure of the device, sometimes catastrophically, and are not covered by warranty.
Thus why I say it's the single most commonly-misused Victron component in their lineup... I have processed literally hundreds of RMA requests for these, and denied an unfortunately high number of them where they've clearly been connected in ways expressly forbidden by the user manual. As with literally every Victron component, these are professional-grade, designed to be installed by professionals, and require very careful RTFM -preferably before purchasing.

In this case I thought to mention this because whether or not a BatteryProtect can be used on @mitchk1303's system depends entirely on how the system is set up and what's connected to it... these are very emphatically not universal devices.

 

[mannytheseacow]

Gotcha. Good to know.
Yes, reading the instruction manual is always a sound practice.

 

[Travis]

Would it be enough for balancing to simply supply 5v from a voltage reducer to the canbus for cell balancing?

No I tried that. Simply supplying 5 volts was not enough to activate the on-board cell balancer. It absolutely must have some sort of communication with a laptop or BMS before the internal cell balancing resistors become warm. I even did a test and drove one cell block up over 4 volts and even then with 5 volts applied or not didn't matter with that high of voltage the resistor did not become warm. But the very second that I click the start unication button in the software the resistors became warm and it started taking more current from the charger

 

[Travis]

My reply to mitchk1303,:
2. Every month or so I need to program my charge controller to do a float charge to a specific voltage (you used 14.07 for 6 hours). While the batteries are charging I plug in my computer with 5V to make sure all of the individual cells are balanced? Do you just open the program and the cell balancing happens automatically?
No you must initiate communication. so open the software and then click on the start communication button make sure you see information from the batteries appearing.

It looks like the RS485 to USB that I bought has a 5V port so I should just be use that to do the balancing correct? I would need to do this for each of the 3 batteries so it would actually take 18 hours total right?
No actually you can do all three at the same time.

In order to do this I would need to make sure nothing is drawing power from the battery bank?
Likely likely yes. The point to remember is to maintain the desired voltage if you can maintain that voltage while the loads are present then you can leave the loads connected. Some voltage fluctuation would probably be okay. Just monitor the software and decide for yourself if it's balancing or not. It's software shows you which cells are actively balancing and which ones are not.

3. I can set my victron charge controller to around 14.2V (or maybe lower?). regular daily charging without balancing initiated you should probably stop around 13.8 or 13.95 you'll have to monitor them to learn the correct voltage. The idea is to not let any cell go over 3.8. monitoring the cell voltage with the laptop connected will be deceiving because it will activate the bleed off resistor when the cell gets too far above the others and it will also activate the bleed off resistor when the cell gets above 3.65. To get an accurate voltage measurement of a cell block you'll probably need to remove the side cover and use a trusted digital multimeter.

If I balance the battery cells every month I might be able to get away with 14.4V?
Yes probably but only testing will confirm. With the few batteries that I've monitored very closely I've had to keep the voltage down at 13.95 for the first balance but the cell voltage is still or not exactly the same voltage so then I did increase the voltage and then increase some more and when I got every battery to read 100% state of charge the voltage of the battery was around 14.2. Then I could actually increase all the way up to 14.5v without any one cell going over 3.65 volts. The goal isn't really to get the battery up to the 14.6. The goal is simply to balance the cell blocks.

 

[Travis]

Thank you for this post...

3. I can set my victron charge controller...

Is there anything that I am missing?

Yes but with only two batteries my suggestion below is probably not economically viable. So the guy below has figure it out how to control the victron charge controllers with the U-BMS. This would be a dream come true especially when it comes to balancing purposes. The BMS would command the exact voltage and amperage required during the balancing stage. This foliage and amperage would be actively changing according to the needs and it would greatly speed up the balancing time. If you were to purchase a U BMS from him it could cover all of your concerns.

https://www.facebook.com/alexis.bazin3

http://cogito44.free.fr/technologie.html#wa-anchor-jrc1z2om1dqjuxl91c[/QUOTE]

 

[Travis]

Apparently my "reserved for future use" is useless because I cannot edit them. I guess there's a time limit on editing abilities. That really sucks because I'm not going to be able to update and correct the original posts as our learning progresses. people will be forced to read through hundreds or thousands of post to extract pertinent data instead of having it all compiled in the first few posts. does anyone know a solution to this? Maybe a different website?

 

[somewhereinusa]

Yes but with only two batteries my suggestion below is probably not economically viable. So the guy below has figure it out how to control the victron charge controllers with the U-BMS. This would be a dream come true especially when it comes to balancing purposes. The BMS would command the exact voltage and amperage required during the balancing stage. This foliage and amperage would be actively changing according to the needs and it would greatly speed up the balancing time. If you were to purchase a U BMS from him it could cover all of your concerns.

https://www.facebook.com/alexis.bazin3

http://cogito44.free.fr/technologie.html#wa-anchor-jrc1z2om1dqjuxl91c

[/QUOTE]
I had some conversations with that guy, kinda, he always replies in French. His website has changed a lot since I last visited. Google will translate the written part but much of his explanations are captions on a photo.