Parasitic battery drain from ZEVA BMS

DaveTM

I don't charge my cart anymore after short runs. However, I walk past my cart several times a day and "peek" at the monitor. So, a few days ago I see a "WARNING" banner across the monitor. This warning was telling me that the LV on a cell or two was at the setting I told it to warn me at.

Now, I just can't recall what the pack voltage was when I last parked it......but it was about 52.0-V. When it gets to 42.0-V the warning "Will Rodgers" will go off. (Not really Will Rodgers....but as a kid I watched a lot of lost in space)

So, I plugged it in and after a full charge, I wrote down the voltage. Yesterday the pack voltage was 57.5. So today I looked at it and it was 57.4.

I'm going to keep a daily log of what the voltage is as since hunting season is over I won't use it a lot until the weather warms....or I decide to go coyote hunting.

Just posting to ask your thoughts on the parasitic drain. Does this seem reasonable?

BTW.....when I will be going away for a week or so, I plan on disconnecting the pack to avoid any BMS drain.

BGW

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Sergio

Next time it happens you will need to write down each individual cell voltage in order to determine if it is a parasitic drain (all cells down) or a bad cell(s).

Keep in mind the balancing shunts will run for up to 1 hour after the charge finishes, so most likely the pack voltage will go down a little bit.

Volt_Ampere

I'm really surprised that there would be enough drain to notice in a few days. When I leave my cart for the summer I disconnect everything from the pack and put it at storage charge. It doesn't change much at all over the 5 months I am gone. I guess I would recommend checking to make sure your cart isn't drawing any current when it's off and do disconnect everything including the BMS if you won't be using it for an extended period of time.

DaveTM

I did select the individual cell charges when I got the warning banner, and all cells were (if my memory is correct) 2.9XX and my LV cell warning is 3.0V.

I checked the individual cells as I wanted to make sure I didn't have once cell that was causing a problem.

I'll check the pack voltage daily and the individual cell screen as well.

Now, my monitor brightness is set to max....or near max. I dunno how much that would drain.....but I'm sure it's some.

NCPW

Dave; I've noticed the same kind of voltage loss too.

My pack settles at 57.6v after a charge up to 58.4v and BMS balancing and by the end of the week, without driving the cart, my voltage will be around 54.x volts.

I last charged it Saturday and I haven't touched it since. I'll report back on Friday what my exact voltage is.

I have my monitor night brightness set to 20% and unplug the SB50 connector to my charger when not using it.

Sergio

If You guys did not implement the "sleep" function of the Zeva BMS, it is always using power.

DaveTM

I did not use the sleep function. That could change though.

bronsonj

Wow, I haven't installed my BMS yet but my V stays put. I have only watched it sit for 3-ish days at a time, but the full pack voltage doesn't change 0.1v in 3 days. Might be a different story if I left it for a month or 5, but from what I've seen thus far it stays where it's put.

So when I get the Chargery BMS installed it will have to be with a quick disconnect method...

Volt_Ampere

I leave mine for 5 months in the summer and the voltage barely drops at all.

NCPW

So, is using the sleep function just as simple as running a lead from pack negative to the sleep terminal?