Basic Nissan Leaf 7 module Lithium setup with Generic Chinese BMS

[Sergio]

The Zeva does not have built in high current handling, it uses external Solenoids in its default configuration.

You can however use its built in small relays to activate your own disconnect system that does not depend on cutting off the entire pack from the system.

If You have a CAN enabled charger that communicates with the BMS, you can get away with a simple small relay to disable the cart in case of LV or HV condition while driving.

If You are using a regular charger (not CAN enabled) then you also need a relay do disconnect the charger in case of an LV or HV condition.

I have posted a suggestion on how to wire separate relays for both Controller and charger disconnect as well as automatically placing the Zeva in sleep mode when key switch is off and not charging.

If You are not comfortable with wiring components or care about automating the sleep mode, a Zeva and CAN enabled charger are more expensive but require fewer parts.


You can find more information in this old thread:

https://www.buggiesgonewild.com/show...06#post1543106

There are many other threads about using a Zeva BMS that you should search/read for more understanding of the compromises between different implementation choices.

Member PingEye3 has some nice diagrams for Zeva setups as well.

[BLK MAJK]

I got everything wired up today on the table (only terminations not made are ksi in/out on relay 1). BMS is powered up and connected to phone and reporting results. It seems like the newer version of the software has a ton more settings and I got lost real quick. I tried to install the older version of the app, but it won't run. In any event, I need some minor help to get the settings correct (I tried following previous screen shots) and for some reason cell #3 is grey and doesn't seem to be balancing (it's the lowest reported cell in the pack). Its voltage is being reported, so the connection should be good and the reading matches my fluke. Any thoughts or suggestions? Series cart so no regen. Charger is set to 58.3vdc with no load

[Volt_Ampere]

I don't have that BMS but usually the lowest cell does not balance. The others are all balanced by lowering their voltages to match the lowest cell.

[Sergio]

First make sure you have a wire from BMS B- to pack negative or the BMS will draw its operating power from the first cell tap and give you erroneous readings.

Your undervoltage values are backwards.

Overvoltage: 4.19
Over Voltage Release: 4.17

Undervoltage: 3.20
Undervoltage release: 3.25

Did You get those cells at the same time?

[BLK MAJK]

Originally Posted by Sergio

First make sure you have a wire from BMS B- to pack negative or the BMS will draw its operating power from the first cell tap and give you erroneous readings.

Your undervoltage values are backwards.

Overvoltage: 4.19
Over Voltage Release: 4.17

Undervoltage: 3.20
Undervoltage release: 3.25

Did You get those cells at the same time?

Cells all came at same time from tech direct. One thing that's weird about the newest app, is that it sets a max allowable entry... So if I set the overvoltage at 4.19, the highest I can set the over voltage release is 4.14

I got the older app version installed on my old galaxy s6, so I'll try that for a bit. You think I should just leave it sit with the bms connected until it's ready to go into cart in a couple weeks or should I wire the cells together to allow them to balance naturally?

[BLK MAJK]

Originally Posted by Volt_Ampere

I don't have that BMS but usually the lowest cell does not balance. The others are all balanced by lowering their voltages to match the lowest cell.

Good to know, thanks for that tidbit. It answers my question/concern

[Sergio]

I am assuming that You do have the BMS B- to pack negative wired.

I think those auto suggestions only happen if you get the values to close or the first time you change one of them.

After you change the high value, change the lowest manually by tapping on the value.

If that does not work, do the opposite, change the low value first then the highest.

The undervoltage release voltage needs to be greater than the voltage that triggers the undervoltage.

Let the pack site for a while and see if the voltage drops with the shunts, there is not much charge at those high voltages so it should balance.

I am also using the latest version on my Pixel, the label under the program icon is in chinese

[BLK MAJK]

Originally Posted by Sergio

I am assuming that You do have the BMS B- to pack negative wired.

I think those auto suggestions only happen if you get the values to close or the first time you change one of them.

After you change the high value, change the lowest manually by tapping on the value.

If that does not work, do the opposite, change the low value first then the highest.

The undervoltage release voltage needs to be greater than the voltage that triggers the undervoltage.

Let the pack site for a while and see if the voltage drops with the shunts, there is not much charge at those high voltages so it should balance.

I am also using the latest version on my Pixel, the label under the program icon is in chinese

Sorry I forgot to answer your original question. Yes, the BMS B- connected to pack negative.

I'll let it sit while I head out to go hunting and will check it in a few hours. Thanks for all the help

[Bobbob]

Smbenson
I used the Zeva setup and I am very happy with it. I used Sergio relay setup to control the charging and cutoff of HV and LV. In the future I may get a CAN enabled charger but the time being using a cheap Chinese charger. I also looked at Volt-Amprere set up which he let me look at. It’s a beautiful system but a little bit more than I wanted to get into.


Sent from my iPad using Tapatalk

[BLK MAJK]

Originally Posted by BLK MAJK

The charger showed up today! 2 weeks from date of order on Ali. Was trying go figure out what voltage to set it at. I have a series cart, so no regen to worry about. I was thinking 4.1v per cell, so 57.4vdc. Seem reasonable? Too aggressive? Too conservative?

Its 53.3vdc out of the box

Edit: I can't get the voltage above 53.3. I checked it with 2 different meters (one being a Fluke). I can get it to go down, but it won't rise. Its on the bench not hooked to anything. Board is extremely similar to yours. Potato pic from tablet

Originally Posted by Sergio

That voltage table listed on the link you provided is confusing but it could just be poor Chinese translation.

That trim-pot near the LEDs should be the correct one, Did You try charging the pack yet just in case that particular charger has a higher output when loaded?

Keep the fluke voltmeter on the pack during the first charge.

I forgot to follow up with this. I figured out the issue...I'm a moron. . After wiring up the battery I tried to charge for the first time to see if maybe once the charger sees a load, it will bump the voltage. Nope, still maxing out at like 53. Then it hit me like a freight train...maybe I should check the 120/220 switch on the incoming power... Yup, set for 220vac. I set it to 120vac and boom, full voltage. The charger seems to be working perfect and I was able to dial in the unloaded voltage to 58.3vdc. So it seems like this would be another option for those looking for a charger. It arrived in less than a week too! Now I have to build a box, because it seems like Tech Direct doesn't make/sell the box anymore