Yep and I'm not reading the posts anyway.I guess we are going off topic
How to verify BMS (Daly) is working?
- Thread starter jzpchen
- Start date
Strange that you still reply them
I started this thread. I learned a lot here. Thanks. For my situation, I am sending my 120a BMS back to Daly in China. After their inspection, if it is not working, they will ship me back a new one. I know Will highly recommend Daly. I hope it will work.
I understand Daly BMS's limitation now. However, I think it is still valuable. If one cell is overcharging or over-discharging, it will at least cutoff the whole battery system. My BLS battery cell costs $100 each. So this protection is worth it. The balancing is probably not going to do much a benefit for my 150ah cell. Victory charger/inverter will only protect overcharging or over-discharging if the whole battery pack is crossing the limits. The problem I ran into was one cell overcharging.
I am ordering an active BMS. https://www.aliexpress.com/item/33002903687.html?spm=a2g0s.9042311.0.0.73d74c4dAhEQYQ. I hope it will go hand in hand with Daly BMS. Will had a good review on it. David had a bad review:
. I would also like to try this active BMS with bluetooth: https://www.aliexpress.com/item/32945565819.html?spm=a2g0o.cart.0.0.25ef3c00kg5zcc&mp=1. It is extremely valuable to actually monitor the actual values of each cell. David had a review on this:
.
I understand Daly BMS's limitation now. However, I think it is still valuable. If one cell is overcharging or over-discharging, it will at least cutoff the whole battery system. My BLS battery cell costs $100 each. So this protection is worth it. The balancing is probably not going to do much a benefit for my 150ah cell. Victory charger/inverter will only protect overcharging or over-discharging if the whole battery pack is crossing the limits. The problem I ran into was one cell overcharging.
I am ordering an active BMS. https://www.aliexpress.com/item/33002903687.html?spm=a2g0s.9042311.0.0.73d74c4dAhEQYQ. I hope it will go hand in hand with Daly BMS. Will had a good review on it. David had a bad review:
Pretty empty he No sophisticated IC or mosfet drivers or whatever. Just what I expected.
There are 14 Mosfets for the charge port and 14 for the B- P-. They come from a Chinese manufacturer with very few component diversity and they are 37A 10V.
Have no idea about RDSon but I guess it is not low. I hope they are much lower than the ones on the manufacturer site...
All the plastic around the mosfets was molten and cracked but finally it died just by plugging in the 16 wires loom.
No sophisticated IC or mosfet drivers or whatever. Just what I expected.There are 14 Mosfets for the charge port and 14 for the B- P-. They come from a Chinese manufacturer with very few component diversity and they are 37A 10V.
Have no idea about RDSon but I guess it is not low. I hope they are much lower than the ones on the manufacturer site...
All the plastic around the mosfets was molten and cracked but finally it died just by plugging in the 16 wires loom.
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MisterSandals
Participation Medalist
Is that "liquid magic smoke"?
Here you can see most of the mosfets have heated up and molten the plastic, except 4 of them. The reason is that Daly put an aluminium sticker on the heatsink above 4 mosfets (see red line). These made better contact with the outside aluminium plate and the others less. So they heated up seriously.
There is current detection on the mosfet board. But that's all there is on the power side.
They drive the mosfets parallel in groups of 7 and they measure current.
They just add more or less R003 resistors depending on the model they sell.
They use 220 ohm resistors and a small mosfet to do the balancing . Cell V +-3.4 /220 = 15mA; may be two resistors used is 30mA. That's what they advertise.
Can't find the specs of the small 6 pin IC's on the control board. Chinese brand I think. May be ordinary comparators.
They drive the mosfets parallel in groups of 7 and they measure current.
They just add more or less R003 resistors depending on the model they sell.
They use 220 ohm resistors and a small mosfet to do the balancing . Cell V +-3.4 /220 = 15mA; may be two resistors used is 30mA. That's what they advertise.
Can't find the specs of the small 6 pin IC's on the control board. Chinese brand I think. May be ordinary comparators.
thedodgersonline
New Member
- Joined
- Nov 19, 2019
- Messages
- 204
Hi
I have had Ali step in and refund when the vendor has refused to. Follow the process and if possible post videos of the problem. Ali give the guarantee, not the vendor. Just follow the process.
Regards
On the current paths, the mosfets are used. They are essentially on-off switches. Heat results when running high current. The balancing has little current. I would assume the circuits just need to measure the voltage to control the balance or the mosfets. An earlier message indicated some connecting sequence on the black and red wires could damage the circuit. I am not quite understanding. I hope when I get the new device, I would avoid triggering the mishap.
Every mosfet, even the same production, has a small deviation. For this reason parallel mosfets should always have small resisters (4-8ohm) in series with the gate. If not, some mosfets will ignite first and get the most inrush current and can fail. Then the next follows, etc
Daly does not use gate resistors.
Of course these mosfets here are not using high frequency switching, just on and off.
Daly does not use gate resistors.
Of course these mosfets here are not using high frequency switching, just on and off.
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Yes right , but with RDSon of +- 5mohm that should be 12W at 50A (I²R) , divided by 7 mosfets is less than 2W per mosfet. Since I did not use more than 50A load and charge, I guess they used very cheap mosfets with high RDSON because plastic will not melt from 2W, certainly not with 2.5mm alu heatsink on both sides.
No, No Daly in my system ever again.
I bought such 16S balancer and I thought first it did not work as well. Actually it does not start balancing at 0.1V difference as advertised. There must be more than 0.2V diff. It does not balance until 30 mV difference, it's more 70-50mV.
Now it does a good job, even it starts a little late. It heats up a little, seems to be efficient at 1A.
Not sure if you can use it in parallel with a DALY BMS with balancing function.
