Another 3 x BMS broke!! WTF? Capacitor based this time, help

[Spacey]

Ok this is driving me round the bend. I bought one of the newer Capacitor based 16 Cell BMS from (won't mention company until I am certain I am not in the wrong) in the vain hope that this one would work as the last two just did not at all. This one worked for 6 mins then after disconnecting the controller (infineon) and re plugging in decided not to even power on the Cycle Analyst. The total voltage from the BMS was 51.3V but the main battery pack was 53.8V?

But when you apply any load to the "OUT-" of the BMS it just dies.

"B-" from the BMS is connected to battery pack Negative. "

"P-" from BMS is wired to charge in as per evessemble instructions. But I have found from this site http://www.ecitypower.com/download/...BMS Discharge and charge together Circuit.jpg that they like the load to be from "P-" with the "OUT-" not even wired up? Looking at the BMS wiring picture though it looks like their are 2 cells between each connection?

Now I have checked the BMS sensor wires and all is in order:

Sensor wire "0" goes to Cell 1 Negative and all the rest from Sensor wire 1 to 16 go to the positives on the cells from 1 to 16. Voltages go up in increments of 3.3V

So what the hell am I doing wrong, have been up 2 nights with this and is starting to make me think there is something wrong with me. The same thing has happened with the resistor based BMS from same place Model: AE-LBB16 REV A1



Here is the letter below that I have just written to them:

Dear *******

I am a very very unhappy man!

The AE-LMD17 REV A1 16 cell BMS balanced the pack fine whilst charging, although the highest cell hit 4.1v for a long time!

But.....It does not bloody work!! It worked for about 6 mins then not even enough power to light the Cycle Analyst. Voltage on "OUT-" is 51.7volts but voltage from battery is 53.8Volts, but if you attach any load to the "OUT-" on the BMS it just turns off!

I have wired the cells as below: Have checked volts on BMS Sensor wire from 0 to 16.

BMS Sensor 0: is wired to Cell 1 Negative
BMS Sensor 1: is wired to Cell 1 Positive 3.3V
BMS Sensor 2: is wired to Cell 2 Positive 6.6V
BMS Sensor 3: is wired to Cell 3 Positive 9.9V
BMS Sensor 4: is wired to Cell 4 Positive 13.2V.......

all the way up to ......

BMS Sensor 16: is wired to Cell 16 Positive 53.8Volts

Is the above the Correct wiring because something is not correct!

B- on the BMS is wired to Battery Pack Negative (Cell 1)
OUT- on the BMS is wired to Negative Load/controller out i.e Infineon controller
P- on the BMS is wired to Negative Charge in from Charger

What am I doing wrong? This is the 3rd BMS to go bad, the first two are AE-LBB16 REV A1 they do exactly the same!

The BMS from my Headway pack works just fine so does my Ping Signal Lab BMS, what is wrong with these 3 BMS's. Unless I have done something wrong I will be sending them back.

The capacitor BMS worked for a few mins, disconnected the controller (BMS still all wired up) then reconnected controller and nothing. There is a 2Volt difference between "OUT-" and "B-"

Could you please check that my connections are correct.

 

[Spacey]

Have just re attached everything up and with the Cycle Analyst connected I get 4.0V yes ...4.0V coming out from "Battery Positive" and BMS "OUT-"

If I turn off the Cycle Analyst the voltage gradually creeps up to 51.8V and as soon as you turn the Cycle Analyst back on it shoots down to 4.0V?

It can't be me.... not 3 times in a row, I really think that these BMS are broken. The only other person from this forum to try the capacitor based bms said theirs broke the first time they used it as well.

Re: Capacitance balancing BMS connection
by Gow864 » Sun Dec 12, 2010 11:09 pm

I had one of these BMS's from EVARSEMBLE. First charge something in the BMS died and it drained one cell to 0. I replaced it with a BMS from headway (plus a replacement cell), it's a big ugly BMS but it works....

Good luck,
Gow.

Someone on a Croatian web site commented on the cells getting high over 3.8V if the battery pack was over a certain size. I certainly measured 4.1V for a while when it was on charge using this BMS but settled down to 3.4V over night.

 

[Gow864]

Spacey, Abandon those BMS's they are shit, also abandon that vendor he is shit! my headway BMS is working great, outputs all the amps i need and keeps my cells well balanced, only thing is the size, but I can live with that.

PS: I've still got the CRAPacitor BMS that evarsemble mugged me with if anyone wants it to pull apart or whatever.

I sent the charger that i got from evarsemble, you know the one that died just a little quicker than the BMS (5 mins) back registered post, probably 4 weeks ago the tosser keeps telling me "no word from the post office" BS! So, if you're thinking of sending stuff back to him be prepared to pay for notified registered mail, that way you'll get told when it's been delivered. according to my mail carrier my parcel has been delivered.

DO NOT DO BUSINESS WITH EVARSEMBLE.

Gow.

 

[heathyoung]

I had one of those burn a hole through the board and discharge a cell to 1.2V before I caught it. Avoid avoid avoid.

 

[CamLight]

PS: I've still got the CRAPacitor BMS that evarsemble mugged me with if anyone wants it to pull apart or whatever.
Gow.

I'd love to reverse engineer some of that BMS. I don't know if I'll be able to determine why it's not working but it would be interesting to see what components they use for balancing and the overall architecture of the design.

What country are you in?

 

[grindz145]

I'd love to see what this thing is made out of. A lesson in cheap from the Chinese... I seriously hope someone is working on an alternative simple BMS. It's a huge barrier to entry for so many willing to put the time in but aren't electrical engineers.

 

[Spacey]

Thank you for the replies, made me feel better knowing that it is not my incompetence with wiring these BMS.

CRAPacitor made me laugh he he...... But i must say that I have never been so close to tears as trying to wire re wire...strip apart...test...re wire etc as these BMS.

Luckily I have 2 Headway BMS left which I will use for these two builds. Looks like one of my orders will be late due to this mess up But I refuse to put sub standard parts on my builds for other people.

I will wait to see about what the vendor says, actually no......I don't care...... Just not ever going to buy from them again. Getting fed up like Beavinator of having to spend a day stripping back down the battery packs and re building using safe materials rather than the fire hazard bell wire with sellotaped sensor wires to cells.

Just sucks that I am down a few hundred quid at Christmas lol.

 

[Spacey]

Well who would have thought it.....the Headway BMS works first time and is still working......coincidence?

No word back from the seller of those other BMS. I think a BMS thread is needed to stop others from making costly mistakes.