Newb Help

[MX763]

Hello! Killer forum here!

I purchased 4 280AH prismatic cells from AliExpress for my Old Town Autopilot electric Kayak. I was using a 100AH Relion that was ok but would not last the whole day running upstream pretty wide open. I also purchased the Daly 120 Amp, 4s, BT smart BMS. It’s wired up correctly and I’ve checked this thing 25 times to verify. Total battery voltage is 13.33 volts when I put the multimeter on main +/-. I checked the cells and the individual voltage is as follows.

1.) 3.32
2.) 3.32
3.) 3.32
4.) 3.29

When I touch the multimeter to battery + and P-, I get 10.43 volts. When I touch the multimeter to battery + and B- on the BMS, I get 13.33 volts. I’ve hooked it up to my 5 amp, 3 bank Minn Kota charger and I don’t know if the BMS is working. When the charger is hooked up to battery + and P-, I get 7.33 volts.

The BMS came with Bluetooth and a usb cable but it does nothing when I connect the BMS to my laptop and there is no BT device in my Bluetooth list. I am using an iPhone with iOS and a PC for the USB connection.
I have no clue if I’m about to blow anything up.
1.) Should I let’er eat for a few hours on the charger or am I doing something wrong?
2.) Shouldn’t I get the full battery voltage when the multimeter is connected to Battery + and P-?
3.) How can I tell when this BMS kicks on?

I’ve tried the shorting out of the BMS with the P- to B- and I still get 10.43 volts at P-.

I’m only a halfway idiot with electronics so be patient with me.
Thanks in advance!

 

[Supervstech]

It doesn’t take much to damage the BMS.
Did you wire the sense leads BEFORE you connected to the BMS?
I would pull the sense connector, and check from the connector end, voltage climbs 3.3v each pin from main negative.

 

[MX763]

I disconnected the balance wire harness from the BMS and checked each plug on the harness. The voltage on the plug end was the same as each cell.

 

[Supervstech]

When you were building the battery.
Did you wire the leads in while it was connected to the bms?

 

[Just John]

Make sure the temperature sensor is plugged in. Connect the sense wires to the battery in the correct order, and make sure there are no bad connections. Hook up the B-, then plug in the sense wiring cable to the BMS last. Daly makes many different BMS, but the "activation" to wake up the BMS can be done many ways. Try charging. There are frequently (depending on the model) two pins to short together, plugging the USB cable into your PC, etc. Many, many different topics here on the subject (pictures and everything), try the search feature.

 

[MX763]

When you were building the battery.
Did you wire the leads in while it was connected to the bms?

I did not. Everything was disconnected from the BMS when it was wired up.

 

[MX763]

Make sure the temperature sensor is plugged in. Connect the sense wires to the battery in the correct order, and make sure there are no bad connections. Hook up the B-, then plug in the sense wiring cable to the BMS last. Daly makes many different BMS, but the "activation" to wake up the BMS can be done many ways. Try charging. There are frequently (depending on the model) two pins to short together, plugging the USB cable into your PC, etc. Many, many different topics here on the subject (pictures and everything), try the search feature.

Temp. sensor is plugged in. As I mentioned above, I connected everything in the correct order and tried shorting the P- to B- with no luck. Same with plugging the USB in the to PC. I have searched the many different topics with no avail. Is it possible this BMS is bad or is there something I’m missing trying to wake this BMS up via PC?

 

[Just John]

Temp. sensor is plugged in. As I mentioned above, I connected everything in the correct order and tried shorting the P- to B- with no luck. Same with plugging the USB in the to PC. I have searched the many different topics with no avail. Is it possible this BMS is bad or is there something I’m missing trying to wake this BMS up via PC?

Not sure which BMS you have, but shorting the reset pins is the most reliable method.

Post in thread 'More DALY smart BMS issues' https://diysolarforum.com/threads/more-daly-smart-bms-issues.19751/post-243924

Note that Daly seems to have recently changed where they are located on new 12v models.

 

[MX763]

I am pretty sure this thing is a pile of garbage. I requested a return. It blows my mind this is ok. I should have kept the overpriced 100AH Tracker/ Relion battery from Bass Pro. Do I even need a BMS to run these cells on my Kayak? Can't I just charge them individually on the charger after each use with out screwing anything up?

 

[MX763]

Is a BMS necessary for these cells and my application?

 

[BretS]

Is a BMS necessary for these cells and my application?

If you don't have a BMS, what would stop you from over-discharging them?

 

[MisterSandals]

If you do not have an BMS then YOU become the BMS. You will need to ensure that each of the cells never goes below 2.5v and 3.65v. That will be the most important tasks of a BMS that you need to do, diligently.

You can make this easier by top balancing and implementing a very conservative charge and discharge strategy. But you need to always know the voltage of EACH cell since they run away and self destruct quickly.

Since kayaks are small, you will be close to your battery. If you use a battery monitor like a Battgo that has a configurable alarm, that can help quite a bit. It will also help you out by displaying all cell voltages.
Also has some balance capabilities.

It is doable but not without effort, diligence and risks.

ISDT BattGo BG-8S Battery Meter, LCD Display Digital Battery Capacity Checker Battery Balancer Battery Tester for LiPo/Life/Li-ion/NiMH/Nicd https://www.amazon.com/dp/B07797N9BG/

 

[Just John]

Is a BMS necessary for these cells and my application?

As MisterSandals indicates, it's not "required". A lot like brakes and speedometer are not "required" in a car, but are really useful features to have. It helps stop from over-discharge and over-charge, both of which will ruin your cells in short order. You can do without, just plan on replacing cells regularly.

 

[MX763]

Great information! Thank you! This is not as cut and dry as I thought it would be. It isn't difficult per se but this BMS and its inconsistencies are BS. I bought the BMS thinking I could hook it up and the problem is solved. This is far from the case. I get different voltages on every point of contact of the BMS. With it hooked up, my charger goes into a protect mode and won't charge. The people at Daly have been.......responsive but their "help" leaves very little to be desired.