# Thunder Sky Battery Managementsystem 100



## sourcefinder (Dec 17, 2010)

Hello!

We are working on an electric boat that is powered by 82 100 Ah Cells from Thunder Sky. We also use the BMS 100 from Thunder Sky and a charger.

So far we have connected all the cells with the BMS and they all are shown in the Display and balancing works.

But we always have the error "invalid node warning" and I don't know what to do to solve this problem.

I tried to remove all the Cells and to remove all the collecting modules, but its very strange that the the error does not go away.

I measured the cable, it ok, we have all cells in the list of the BMS on the display, the current sensor works, but we cannot charge and use the batteries because we have this strange error and the charger is switched off by the bms because of the error.

Has anybody also a BMS from TS in use and knows about that problem?
Thanks for your advice,
Best Regards from Austria,
Hermann


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## Guest (Dec 17, 2010)

> I don't know what to do to solve this problem.


Remove the BMS Oooops (BS) System. Until you figure out what is happening. If you leave it connected you risk a big loss. Is there a short in one of the modules? Wires? 

Pete


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## sourcefinder (Dec 17, 2010)

Hi,

I have tried to figure out the problem.
I checked all cables, they are ok, no short circuit, not broken.
I tried all 10 collecting modules, its always the same.

I unplugged all collecting modules, took one after the other, set the bus chanel to 0-0.

When I start the controller without any collecting module, it says low voltage warning which is because there is no collecting module.

When I plug in a collecting module and enter the amount of cells, the display shows the cells (each voltage) and the red led on the collecting module is blinking.

After some seconds the controller starts the node invalid warning alarm......

I dont know what to do now....
Should I send it back to Thunder Sky?

I removed it from the cold garage and put it for some hours in a warm room, maybe its because of the humidity that it has an internal short-circuit.....

Thanks.


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## ElectriCar (Jun 15, 2008)

Are you not getting support from TS or your distributor where you bought it? I worked in industrial electronics for decades and if you're not able to get tech support from them that's not good at all! Any reputable company has a good support system.

I'm considering TS cells but haven't decided yet. Still doing my due diligence...


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## EVfun (Mar 14, 2010)

Can you lead me to some links about the Thunder Sky Battery Management System 100? I'm finding very little info about it. I didn't find a mention of it on the TS site, I was hoping to find instructions or pdf manuals there (they have quite a bit of info about their batteries posted.)


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## sourcefinder (Dec 17, 2010)

The bms is from http://www.guantuo.com

You can find some downloads there.


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## EVfun (Mar 14, 2010)

It looks to me like that unit will be very picky about programming. The number of nodes has to be set and match what is found or it will toss a "Nods invalid alarm" [sic]. This could be programming, a single bad node, or something wrong with the head unit not "reading" correctly. 

This could be hard to figure out as the company is still in the "Engrish" phase of providing documentation. It is not all that easy to read or perfectly clear (probably makes great sense in Chinese but that doesn't help me.) I would recommend a careful reprogramming in case something was missed and see where it goes from there. 

I tend to be a BMS (no spaghetti allowed) guy myself but I am leaning toward Pete's advice. Don't allow cells to be hurt while trying to figure this out.


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## sourcefinder (Dec 17, 2010)

Hi,

Yes, I think this too.
As the BMS can be used from 1 cell up to a few hundred I tried to get it run with 10 cells (=1 collecting module). So I just have one cable and this is free of short-circuits.

As one collecting module gets 14 small cables from the batteries (12 from cells and 2 from temperature sensor) this means that communication musst be ok when I see the temperature and all 10 cells in the display.

Why do you think cells could be hurt?

At the moment the cells are not connected to the collecting modules and there is no power supply for the controller.

The strange thing is that balancing works, so when all modules are connected, they balance all cells to the same value.

But I cannot charge the cells because the controller sends the node invalid warning also to the charger and this is turned off.

We charged the cells a few days ago by cutting the comunication between charger and controller to about 80% because we had to test the complete system on that day because of mounting the electric engine.

Now I wanted to let the bms take over control of charging, but this doesnt work because of this error.

So, as I said, all cells are at the moment at 3,38 V.

I hope I get an answer from China regarding this problem and I am thinking about charging the cells for another hour with 20 A and let the bms balance the cells after that before shipping the controller to them, so that we can do another test with nearly fully charged cells.

On the other hand this could be not good for the cells when the bms cannot turn off the controller because of a high delta voltage of some cells......


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## EVfun (Mar 14, 2010)

sourcefinder said:


> Why do you think cells could be hurt?
> 
> At the moment the cells are not connected to the collecting modules and there is no power supply for the controller.
> 
> The strange thing is that balancing works, so when all modules are connected, they balance all cells to the same value.


If the cells are not connected to the collecting modules then I don't see any how the BMS can hurt the cells (or be a BMS in that condition. )

The balancing works even though the BMS isn't quite working? That is where I start to get concerned. Electronics that half works sometimes do strange things. If it is hooked up please make sure it isn't draining the cells to quickly or unevenly. A BMS represents a full time load (small one, but still a load) on the pack so you may need to charge occasionally to maintain the pack.


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## sourcefinder (Dec 17, 2010)

Yes, thats the strange thing.

When I connect all modules with batteries and the modules with the central controller everything works as it should (all cells, all temperatures on display, all red LEDs are working, the cells are getting balanced...) but I get the node invalid warning error which does not allow charging. So charger is reducing output to 4,3 Amps which would take me 3 days or something like that to charge the cells.

As we have more than 320 V in the system and a 8 kW charger, I only use it when I do some other work next to the car because I fear that something could happen and there are a lot of other expensive vehicles next to ours in the garage....

So now everything is disconnected.
So I think the cells are safe in this situation.


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## Guest (Dec 18, 2010)

I stopped the charge because a few batteries were in the 4 volt range. So our used pack which was originally charged with a BS system is way out of balance before the charge is even close to being done. Some batteries are just a bit over what the starting voltage was and about 8 have reached into the 4 volt range. Ouch. So I now must discharge and bottom balance all 34 batteries before I continue. Will start the photo album when we get our batteries in sync with each other. 

Pete


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## sourcefinder (Dec 17, 2010)

Hi again,

Finally I found the problem, it was a wrong bus adressing of one collecting module.

Now I have a question regarding the charging.

What is the best way to charge the batteries?
My charger is connected to the first and the last cell and provides a current from 0 to 23 Amps (can be choosen).

Yesterday I started charging with 17 Amps, then I tried little bit more.

It was the same like gottdi said, one cells reached 4,3 Volts when the lowest one hat 3,4.

So I unplugged the charger and over the night the BMS balanced the cells.

I did not had a look now, but I think they should all be round 3,3 or something like that now.

So whats the best Current for charging?

This would take a long time to get all of them on the same level....
The cells are new and it the first time i charge them....

Thanks.


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## 2cv (May 12, 2009)

I have the same BMS that you have and the balances are not cells.
The charge of one of the cells at the top also turn it off the charger.


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## ElectriCar (Jun 15, 2008)

sourcefinder said:


> Hi again,
> 
> Finally I found the problem, it was a wrong bus adressing of one collecting module.
> 
> ...


Are you bottom balancing? If so explain how you do it.


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## sourcefinder (Dec 17, 2010)

2cv said:


> I have the same BMS that you have and the balances are not cells.
> The charge of one of the cells at the top also turn it off the charger.


So you think there is no balancing funktion in the system?

I dont know exactly, I charged the 82 cells with the charger and when the charger says fully charged we have 317 Volts. The highest voltage is 4,6 V and the lowest is 3,6.

What is bottom balancing?


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## ElectriCar (Jun 15, 2008)

sourcefinder said:


> So you think there is no balancing funktion in the system?
> 
> I dont know exactly, I charged the 82 cells with the charger and when the charger says fully charged we have 317 Volts. The highest voltage is 4,6 V and the lowest is 3,6.
> 
> What is bottom balancing?


Are you saying you don't know if they're balanced? IF you have 4.6V on a cell you're in the danger zone friend! That ain't good AT ALL! It's recommended not to exceed 4V.


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## 2cv (May 12, 2009)

If you go into menu 2 in BMS. There can you set the charger to stop charging when the cells come up to 4V You should set it to 3.9V when you are struggling less in the cells and get more charge cycles.




*http://www.google.no/dictionary?source=translation&hl=no&q=&langpair=no|en *


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## sourcefinder (Dec 17, 2010)

Ok, we charged the battery pack again.

Now I set up that the charger should turn off when one cells reaches 4 Volts.
I have tested it, it works, when one cell reaches 4 Volts, the charger reduces the current to 0.

So know we have after 2 cycles the highest cell with 4 volts and the lowest with 3,36.

When the voltage was 3,2 all cells had the same voltage during the charging process.

As we have a small problem with our motor, we cannot use it, so I will let the BMS work and tell you about the voltages in the next days.....

Thank you very much for your answers!


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## sourcefinder (Dec 17, 2010)

Min: 3,35 V
Max: 3,78 V


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## Forse (Dec 21, 2009)

Why are you using a BMS system? What do you want it to do for you?


At 3,35 - 3,78 V your pack is full and ready to use. Don't worry about the apparent "imbalance" of your cells, they really are all at 100% charge or near. These batteries change voltage rapidly at their extremes.

I think you need to study how these cells behave to get a better understanding of your power system. Watch some of the videos on evtv.me about battery testing.


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## ElectriCar (Jun 15, 2008)

I don't think I'm going to use a BMS either. For what? Too much $$$ and too much risk of something shorting out and the vehicle/garage going up in smoke. After all I've read, I haven't really seen a need for it. If anything I'd like to monitor the voltage of each cell. 

Yes you may can get a mile or three more out of it by going a little closer to the edge, then again you might lose a cell if you drive a bit too far. If you want that extra mile or two, why not take that money and buy larger cells to begin with or use a few more & up your voltage.

I plan to use an AH counter to have a more accurate indication of the gas left in the tank. Here's one I'm looking at that will drive your existing fuel gauge for SOC, use the tach for your amps and operate an idiot light to let you know the gas tank is getting critically low.


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## sourcefinder (Dec 17, 2010)

Hi,

I dont know how many cells your are using serial and parallel and I dont know how you use them.

I have 82 cells in serial. And in the end we will get 160 cells (aprox. 52 kWh) to power a 120 kW Motor. We use the system in an electric boat.

If you compare a car to a boat, you need much more energy, even for holding the speed because the resistance of the water is much higher.

We are a small company building boats and when we sell one boat and after half a year we have to exchange some of the cells this means a lot of money for us and a long time for our customer when he cannot use the boat. The problem is always more capacity means more weight means bigger motor for same speed means more capacity....

I know that I can use the cells also when one is at 3,35 but when you charge them and you have a look how long it takes to rise voltage, you will see, that from 3,8 to 4,2 it takes just a few minutes and from 3,35 to 3,7 it takes a longer time. There is more energy saved in the cells.

This means you can go longer. We would have 10 to 20% more capacity when we could charge all cells to 3,9 and note some to 4,2 and the bad ones to 3,35.

Know we can go about an hour at full speed with our boat (26 kWh and 30 kW motor), but when we have the 120 kW engine we can go 30 minutes.

So we are just interested in using our cells as safe as possible (what if a customer does not check them every know and then and they drift more?). And we want to have them a long time in a good condition.

Our charger is also from Thundersky and it switches of at 328 V, this means every cell should be on 4,0 V. And thats what I want to get to say its fully charged now.


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## ElectriCar (Jun 15, 2008)

Sourcefinder. So you top balance cells right? And on every boat you have to replace batteries right? The way I understand it, if you balance them all to 4V and discharge them, some will bottom out early, before the rest of the pack is discharged. When it hits 0, it's gone as I understand it. 

Because of how these cells behave, when they are nearly empty, the voltage drops very very fast. I've read about bottom balancing and how it balances the cells so they are all discharged to the same amount, almost empty, around 2.8-2.9V, then charged until reaching the point just below full. At this point there will likely be some cells charged to a higher voltage than most. The cut off charging point must be decided so that no cells go over maximum recommended voltage. 

When you do this, as the entire pack begins to discharge, there's a noticeable drop in power but still some left. If you top balance and one reaches this point early, the others may still be providing plenty of power and mask this one cell losing power, causing you to continue and shortly after you have a dead cell.


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## sourcefinder (Dec 17, 2010)

Hi ElectriCar,

At the moment I havy no chance to do balancing in any way.
I try to find out whats the best way to keep the cells alive and to have them for a long time in condition.

I can not say a lot till now because I had just two times charging them, but the result is that the hughest cell reaches 4,2 V (or more if charger does not turn off) and the lowest is still 3,36 V.

So I saw now that our bms does not balance the cells.

Might be true that they are bottom balanced and have the same voltage when coming to 2,5 V or something like that.

But what you say could be true.
Where did you read about this?


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## ElectriCar (Jun 15, 2008)

Source, here's a link that should open your eyes about the subject http://jackrickard.blogspot.com/2009/11/get-rid-of-those-shunt-balancing.html. http://jackrickard.blogspot.com/sea...-max=2010-01-01T00:00:00-06:00&max-results=24


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## sourcefinder (Dec 17, 2010)

Ok, Thank you, now I understand the difference between top balancing and bottom balancing and why some people here dont want to use a bms.

I see that its ok when my cells have a different voltage when they are charged completely.

I will have a look what the voltage after discharging them and post it here, but as far as I know it from the last run, I think the difference is very small.

Thank you for your ideas!


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## sourcefinder (Dec 17, 2010)

Ok, so I understand that bottom balancing is the better way to keep the cells alive.

How often should cells be bottom balanced?

I guess when I tell you now that I did not balance them (all of them had 3,31 V) before the first time of use, you would kill me.

So how do I bottom balance cells best?

I would run the motor till the first cell reaches critical voltage (what would you recommend - 2,5 V ? 2,7 V ? 2,8 V ?). After that I take a torch or some other lamp and discharge all cells to that level.

Would this be good?
Better than buying a small board that does top balancing on the cells?

Thank you.


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## ElectriCar (Jun 15, 2008)

I really can't give you a voltage to discharge it to but you want it balanced near the bottom or minimum voltage. I think Calb is 2.5V and Rickard balanced them to 2.7 maybe.


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## Guest (Dec 28, 2010)

If the cells come from the factory balanced just hook them together and charge it up and keep watch of the cells until your charger turns off and make sure you have no cells in the 4 volt range. If you get any that are reaching 3.8 shut down and go drive your car. Then do it again. It should be just fine. But you do need to watch a few cycles to be sure. 

I will not be using a BMS. I will however monitor my packs. 

Pete 

Some of my cells need balanced. Some are just fine as is. Mine are used so I do expect to have to rebalance a bunch but not nearly all of them. Should have a pack ready to go here in a couple days.


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