BMS short circuit with Extreme Team and Navitas 600

[WalterM6]

One other thing that might be causing your problem is the outside temperature. Battery performance fall off quickly once it starts getting cold. What part of the country do you live in? Also if it was regen shutting you down it would just shut off the BMS charge switch. The discharge switch would still be on so you would still be able to drive.
Why don't you post screenshots of your Navita settings. Somebody here might see what's wrong with it.

[shoomba]

Originally Posted by WalterM6

One other thing that might be causing your problem is the outside temperature. Battery performance fall off quickly once it starts getting cold. What part of the country do you live in? Also if it was regen shutting you down it would just shut off the BMS charge switch. The discharge switch would still be on so you would still be able to drive.
Why don't you post screenshots of your Navita settings. Somebody here might see what's wrong with it.

I am in North Texas so we havent gotten to that kind of cold yet.

I emailed Navitas and they called me back same day and spent about 30 minutes on the phone with me. Luckily back in August I had recorded some logs that I guess get sent to them so he had some data to look at. The gist of it is the regen numbers were maybe on the high end but should have been within range for what the battery could handle. Current theory is possibly a faulty OTF controller. I keep the regen on the OTF at the recommended mark but his theory is maybe the OTF is getting triggered somehow bumping the regen up without me knowing and then sending too much back to the battery. So he asked me to send him some logs with the OTF dialed into about 50 for regen and some logs with the OTF disconnected and set in the app to 50. I wont get a chance to do that until next week though.

I took some screenshots of my settings. I didnt tweak too much. I have the amps backed down to 500. I have a stock motor so I set the max rpm down to 5500. I had a speed magnet on it before doing the controller and rather than take it off I just set it to 4 poles instead of 8.

[WalterM6]

I see an "Overdrive" setting. That is probably the setting I was talking about when I mentioned the Alltrax Turbo setting. It's probably creating a large current surge when you stomp it. Turn it off and see if your problem goes away.

[DaveTM]

I'm no expert on these drop 'n drive setups.....but I see some where they provide a "steady" current of say....260amps, and a "peak" current of 600amps. (Using your data)

But it's my understanding that if the amp draw exceeds the "steady" current of 260amps....the 10 second window (or 6 second...or whatever) "starts the clock."

So, even if your controller is limited to the 500amp draw....the battery pack's BMS is set to shutdown IF the amp draw exceeds the "steady" current allowance of 260amps.

So...if your cart demands say...300amps for longer than the (say) 6 seconds....it's going to shut down the pack at that. So...I'm thinking as long as your pack is outputting amps over that "standard" the clock on the shutdown starts and will shutdown the pack.

It would seem to me that setting your controller to a "max" draw of say.....240amps you would never experience the shutdown....but how that would effect performance when you "need" more than the 260amps.....I dunno.

[Volt_Ampere]

My carts both have Alltrax 500 amp controllers but I have the max current set at 300 - and that does not limit my performance at all. I don't drive on big hills though.

[shoomba]

Seems like I have some options to prevent it from happening. I can try turning the over drive off and lowering the controller amps. My battery supposedly can do 600 for 10 seconds and 200 continuous. I drive probably less than a mile mostly crossing through a parking lot to my golf course and play golf. I dont think ive ever had an issue while out on the course because cant really go all that fast out there or that far. So I dont really need all that perfomance but it is fun and its a shame to have paid extra for those higher numbers and not really be able to use them as advertised but it is what it is.

[jasonojordan]

Originally Posted by shoomba

Seems like I have some options to prevent it from happening. I can try turning the over drive off and lowering the controller amps. My battery supposedly can do 600 for 10 seconds and 200 continuous. I drive probably less than a mile mostly crossing through a parking lot to my golf course and play golf. I dont think ive ever had an issue while out on the course because cant really go all that fast out there or that far. So I dont really need all that perfomance but it is fun and its a shame to have paid extra for those higher numbers and not really be able to use them as advertised but it is what it is.

Well what people here are saying is its possibly that you are exceeding one of the high numbers you paid for too long. So to fix it might just have to dial it back a little and you may not even notice it.

[WalterM6]

If there is one thing that lithium batteries has taught us is that you don't need these big 5 and 6 hundred amp controllers except to remove the limits imposed by the Curtis controllers.

[CP241]

Originally Posted by WalterM6

If there is one thing that lithium batteries has taught us is that you don't need these big 5 and 6 hundred amp controllers except to remove the limits imposed by the Curtis controllers.

What he said. To put it rather simplified, Because of the way lithium discharges and voltage doesn’t sag under load like FLA batteries do, you get more performance. That voltage drop with FLA’s is “compensated” for by additional amperage draw.

I doubt you or anyone would notice a difference between a 600 amp alltrax/navitas controller on FLA batteries vs a 300 amp alltrax/navitas on lithium. If anything the smaller controller paired with lithium would likely still outperform the bigger controller on FLA because of how lithium discharges and the weight differences.

Besides, outside of climbing massive hills or accelerating quickly from a stop, most motor/controllers don’t pull more than I’d estimate 70 amps or so to maintain cruising at full speed.

[Volt_Ampere]

The other difference can be the battery voltage. My Leaf pack charges to almost 58 Volts and remains above the FLA voltages all the way through discharge. Higher voltage gives more performance.