Another activate Daly smart bms question...

[JohanB]

Been trying to get my BMS activated for hours now without success. I really hope someone here can help me out!

I have a 4s 250A common port Daly smart bms that has been working great for two years in my camper van. Whenever it shut down I could reactivate with charging. Now I decided to disassemble the package and top balance the cells since one cell started drifting off a bit. After top balancing and putting it all together I can't get the BMS to wake up. I guess it kind of makes sense since that it doesn't respond to charging since the battery is already 14.5V with all the cells fully charged. Also tried connecting p- and b- ans turning on the charger. I've been going through the forum and YouTube videos to figure out how to activate with the 2 pin switch method. I don't have the light board switch. The solutions I have found is to connect the two pins for ground and switch. In most cases it seems to be pin 1 and 3 on the 8 pin connector to the light board switch. My BMS does not have this connector slot. Any ideas on what to do?

Attached pictures of the BMS and the available slots and pins. Apart from the balance cables, NTC and UART there is an unmarked 5 pin slot on the front and on the back a 3 pin marked monitor, an unmarked 2 pin and an unmarked 6 pin slot.

Any help greatly appreciated! I need to be on the road tomorrow.

 

[sunshine_eggo]

DALY used to require shorting B- and P- to wake them up.

 

[JohanB]

Problem solved! Found the correct pins Ans shorting them worked.

 

[JohanB]

The two pin connector on the back. b- to p- did not work.

 

[JohanB]

Well that was a short lived joy. Now the BMS got activated but it shows the wrong voltage on two of the cells. And got into shutting off from faulty high voltage protection. Cell 2 shows 3.65 and cell 3 3.40 and they are both 3.53 when measured. Any ideas on what to do? Balance leads are connected correctly, double checked. Might try a factory reset and see what happens.

 

[sunshine_eggo]

Triple check the connections and the pins in the harness connector.

 

[Zwy]

Did you read the this thread? https://diysolarforum.com/threads/daly-24v-8s-initiation-and-software.18644/

3.654V is over 3.650V so that is probably why it shuts down. If you top balanced cells in parallel using C.V. with a power supply, then why the cell discrepency? What does the multimeter say?

 

[JohanB]

Did you read the this thread? https://diysolarforum.com/threads/daly-24v-8s-initiation-and-software.18644/

3.654V is over 3.650V so that is probably why it shuts down. If you top balanced cells in parallel using C.V. with a power supply, then why the cell discrepency? What does the multimeter say?

Yes that's what happened, high voltage on cell 3. The multimeter at that point said all the cells were 3.53. Daly app showed the values posted above. So the BMS shows about 0.13V too high for cell 3 and about the same amount lower than actual value for cell 2. I temporarily raised the high cell voltage protect to 3.75 and connected a load until the voltage got down to below 3.5 for all cells.

 

[JohanB]

Triple check the connections and the pins in the harness connector.

Do you mean the harness connector to the individual cells? I did triple check that all the wires are connected to the correct pin and position on the cells. Is there anything else i can triple check and how?

 

[JohanB]

Any ideas on what can cause the incorrect cell voltage values? Any tricks I can try or just get a new BMS? If I can't fix it, does anyone see any risks with temporarily using this setup until I get a new BMS? It will hit the high voltage protect before the charge controller reaches fully charged, but the only impact would be not fully charged battery right? I can turn off the charge switch manually when the one cell with faulty value is maxed out.

 

[JohanB]

Did you read the this thread? https://diysolarforum.com/threads/daly-24v-8s-initiation-and-software.18644/

3.654V is over 3.650V so that is probably why it shuts down. If you top balanced cells in parallel using C.V. with a power supply, then why the cell discrepency? What does the multimeter say?

Thanks, great thread! I somehow missed it before. And it had the answer to my initial question.

 

[sunshine_eggo]

Do you mean the harness connector to the individual cells? I did triple check that all the wires are connected to the correct pin and position on the cells. Is there anything else i can triple check and how?

crimps? Nut/bolt torque?

 

[JohanB]

crimps? Nut/bolt torque?

Thank you this hint, kept me until i found one of the crimps had a shitty connection. It was a hot and miss when moving the cable, so when i measured the first time it all seemed fine. Anyways, its all fixed and I learned a lot about the system on the way.

 

[JohanB]

?

 

[sunshine_eggo]

Thank you this hint, kept me until i found one of the crimps had a shitty connection. It was a hot and miss when moving the cable, so when i measured the first time it all seemed fine. Anyways, its all fixed and I learned a lot about the system on the way.

Seems like "weird" stuff is traceable to a bad connection somewhere 90% of the time. I still struggle to remember to make that recommendation FIRST!

 

[JohanB]

Seems like "weird" stuff is traceable to a bad connection somewhere 90% of the time. I still struggle to remember to make that recommendation FIRST!

Yeah great advice :D Seems almost too simple, but very very useful. Would be pretty awesome with a little "how to check connections" tutorial. Just measuring voltage and resistance without moving and flexing the wires didn't do it for me this time. Anyway, thanks for helping me out!

 

[Zwy]

Yeah great advice :D Seems almost too simple, but very very useful. Would be pretty awesome with a little "how to check connections" tutorial. Just measuring voltage and resistance without moving and flexing the wires didn't do it for me this time. Anyway, thanks for helping me out!

Use voltage drop. https://diysolarforum.com/threads/do-i-have-a-ground-fault-situation.62090/post-776775

Create a "load" such as a light bulb. Measure the drop across the connection. And you can move the wire while measuring to see if the voltage drop increases.

Just remember you need a load. Resistance basically tells you if the circuit is open or closed. I use voltage drop tests almost daily.

 

[Supervstech]

I had a lot of trouble connecting the microscopic bms leads on my Daly units, my solution was stripping the leads back an inch and folding them over into the connectors for crimping.
Made infinitely better connections after that.
The next issue I had was with the molex connector to the bms body, the pins and their connections had minor issues I had to order new pins and recrimp them into the molex...