So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

My ZEVA BMS has developed a touch screen issue where I can't change parameters. My current settings are all fine 'n good....but the LCD touch screen has now become "wonky"....and the BMS is now 4 years old. Old by any tech standards.

I think I need to replace what I have as I "fear" the domino effect...once it starts it doesn't stop.

It could be just the LCD screen that's bad...but ZEVA AU is no longer in business. I also can't find a US ZEVA dealer.

So....what's the "latest and greatest" BMS for those who are building Lithium Ion packs? :help:

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

Dave, are you passing all current through the BMS or are you using Sergio’s design where only the charge current is passed and the discharge current is taken directly from the cells?

If it’s the Sergio design, then I would recommend a JBD BMS that’s rated at at least double your charge current. If not, I would still look at a JBD but it’s rating would have to be considerably higher.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

My existing setup has neither charge current or discharge current running through the BMS. Charge current is controlled via Canbus of the charger, and the pack and cell voltage is monitored via the BMS, and any cell that charges over a set limit, the BMS opens the relay of the positive charger wire & charging stops.

The discharge side is similar in that if a cell drops below a set value, the LV relay opens and cuts power to the solenoid. (I’m going from memory here…but I’m sure it cuts power to the solenoid.).

I have no “cable” current running through the BMS.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

Hi Dave,

Zeva are still offering support for existing customers. See here
https://www.zeva.com.au/Contact/
I believe the touch screen used is a HY-TFT320 and there should be some calibration buried in software/hardware, probably not user accessible. Or there may be a hardware failure of the screen itself. It's about a 50USD item.


Otherwise, I guess as a direct replacement you'll need to get another BMS with CANbus.

If you want a more generic BMS then have a look at Sergio's thread.

https://www.buggiesgonewild.com/showthread.php?t=160302

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

Thanks Pat.

I did send Ian an email. I just responded to one of his old support emails he sent me hoping it would not get tossed into his junk mail. Plus, it had his order # on it.

But I just now hit the link you provided and sent an inquiry to him.

The Monitor is not "required" for the BMS to work. However, it's very convent accessory to have so I don't have to check cell voltages with a MM. The settings in the BMS are "locked in" so nothing is going to change.

Odd thing is just before the screen got wonky, I changed the pack voltage from 57V to 56V and the "full voltage" from 56V to 55V. I did this because of the pack charge going up to 57.5V....over what my setting was.

I also searched for a replacement screen as Ian had "published" the data for his build. I've found what looks like a replacement....but the voltages are different that what Ian stated in his data. I'm not a programmer ....nor do I want to be.

I'll give Ian some time to respond. If he does, that will help me make a decision. If he doesn't, that will also "force" me to make a decision.

I appreciate your help in providing advice. I know that there isn't much that can be done unless Ian or some other tech engineer provides "dummy down" direction. I really don't want to swap out the BMS. OTOH, I doubt it will be to difficult as I have everything wired. It would be the CANbus settings for my existing charger that may be the biggest hurdle...thus requiring a new charger if a replacement BMS does not have CANbus.

For now....the pack is good. When I did this build back in 2018, I know that "Chargery" was a big consideration vs the ZEVA. But I did a quick search and Chargery seems to have dropped off the planet as well. I'm guessing the new drop in packs have had their economic effect.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

I looked at his data as well to find the actual screen used. I see that you’ve purchased a new screen so let’s see how that goes. That should fix it unless the firmware has somehow become corrupted. Ian does have the source files to reflash the firmware but that’s getting quite in depth and we’ll cross that bridge if we need to. Keep us informed.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

Yeah....I read the documentation he published and it's getting waaayyy above my head.

Today (and I didn't break anything...thank goodness) I attempted to separate the LCD display from the control board. That didn't happen. After some attempts with fingers, and screwdrivers (very light attempts) I determined there was more here than meets the eye.

So, upon reading further (and really....who reads it all up front? :mrgreen:) I discovered that Ian soldered each of the 34 connector pins. :shock::shock:

So...this pic is one that Ian provided:

https://i.imgur.com/h52U35Ch.jpg

And these pics are the front and back views of my LCD and Control Board attached together:

https://i.imgur.com/Qfv1SZ8h.jpghttps://i.imgur.com/x0CxCzEh.jpg

So...it's difficult to tell from the web site where I purchased the new LED screen https://www.aliexpress.us/item/22557...andl_shipto=US if the "pins" are pre-soldered on the LCD screen, or pre-soldered onto the Control Board.

I'm thinking...hoping...they are pre-solderd on the Control Board. I have a few old laptops in my garage junk pile that I can pull out the board and practice "un-soldering".

If I can't "un-solder" and maintain visual board integrity....then I may not attempt to do this. I'm rolling the dice that the LCD screen is the culprit and not the Control Board.

However, If I unsolder this and destroy the Control Board....I'm still not outta luck as the BMS settings are set...and they are good settings.

But...if I destroy the Control Board then I'm out of having the convince of seeing individual cell balances at a glance. I'd have to do the MM check each cell every now 'n then. I have another digital volt meter connected, so I will know when I approach the magic 50V don't go farther number.

My preference would be to just buy a new monitor.....but sometimes we don't get what we want.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

The pins will most likely be soldered to the LCD board.

Now, you could unsolder from the LCD but you’ll have to remove the pins from the new one as well. Double the work but you won’t risk damaging the control PCB.

Do you have a fine tip low wattage soldering iron, or better still, a friend that has some experience in this? A temperature controlled iron is best as too much heat will lift the pads. A “Solder Sucker” and/or desoldering braid will also be required.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

Doing the double de-soldering wouldn’t be all that difficult. (…🥶 ) I’ll have to check my soldering iron…I doubt it fits the specs of what’s needed.

I can buy desoldering braid….but keeping my 66yo hands steady may be a challenge.

I’m confident I can get this done….it would just be disappointing if I do all this work only to find out it’s not the touch screen.

If it’s determined to be the control board I doubt I will go down that road.

I’m up in the air right now as to what direction to go. I’ll wait until the new screen comes & figure it out from there.

Re: So..Who's selling a good BMS system for a 48V Lithium Ion Leaf pack?
 

I'm thinking that taking it to an electronics repairs shop might be the best solution ... spend $50 and get it done right. :shock:

I'm cheering for you Dave from the side lines :-P