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Re: clunk from battery area after climbing 2000ft (600m)

Posted: Thu Sep 10, 2015 9:33 pm
by JeremyW
If the BMS opens the contactor because of a problem with the battery, you will certainly have dummy lights on the dash. I don't think that's it considering you say you have minimal loss.

While leaf contactors almost never fail, it was a common problem in early tesla packs. Drivers heard a "thunk" too. But you'd also lose drive power instantly...

You don't have a screwdriver or anything that could roll around under the seat could you?? :)

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Fri Sep 11, 2015 10:05 am
by Nubo
achewt wrote:A cursory google search turned up this page (http://www.lithiumbalance.com/powerswit ... or-control). So if I have some individual cells that are overheating due to the sustained power draw and the contactor opens, does it reclose later? I've had this happen a good dozen times now, and no noticeable battery capacity loss or dummy lights on the dash. I don't have Leaf Spy, but maybe I should get it to check the health of each of the cells?

What do you mean "I've had this happen..."? If the main contactor opens, the car stops. I don't recall ever reading of a scenario where the car disconnected a module from the pack, or at least one where the car continued driving. AFAIK, the car "turtles" and shuts down based on the lowest cell-pair voltage. If you have a bad cell pair I think you're going to be shutting down, not continuing to drive on the remainder.

FWIW, the continuous 20-30kW draw mentioned by the OP really shouldn't be working up a sweat for this pack. Not much above a 1C discharge.

Edit: oops, you are the OP. Sorry! :oops:

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Fri Sep 11, 2015 10:18 am
by Valdemar
The sound may travel in mysterious ways inside the body structural elements and the source of the clunk that is seemingly coming from under the drivers seat can be located anywhere. The hot electronics smell with no apparent ill side effects has been reported previously, I also feel it once in a while but no clunk, so these 2 may be completely unrelated.

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Fri Sep 11, 2015 11:08 am
by achewt
I've had the sound a dozen or more times now. I've only noticed the smell once, on my most recent 'clunk'. I've never smelt anything aside from that. I'll be doing the drive that it has occurred on most often again this Sunday and will do my best to record it.

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Fri Sep 11, 2015 12:40 pm
by Nubo
I remember a bit of a smell on our 2012, during my first high-speed testing. Just a mild whiff and I attributed it to volatiles baking off. This involved repeated full 80kW accelerations to top speed though.

The only clunk I periodically feel is the ABS doing its self-test thing, at low speed when first starting off. Sounds like dropping a coffee can half-full of nickles from about 1/2 inch onto a carpeted floor. Any chance you're stopping and turning off the car before resuming your driving into this town?

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Wed Sep 16, 2015 7:46 pm
by achewt
Ok I recorded the whole drive up the hill - I did shorten it somewhat but it still amounts to 6 minutes. I did a running commentary with most of the info I have given in this thread (though I was wrong about power consumption, it is at least 30kW, often 40kW, and sustains at 60kW for some sections. If you want to skip to the "clunk" part, it is at 5:12, then I replayed it louder at 5:19. Started the climb at 5 battery bars, ended in Rossland at 6. When we stopped, I put my hand in numerous places in the car and under the car and did not feel any heat at all. Ambient temperature was around 10C.

Link --> https://youtu.be/7uUmIwMojhM

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Wed Sep 16, 2015 8:52 pm
by Valdemar
Sounds like something metallic pops due to the change in atmospheric pressure. Drill a small hole in the battery housing and see if it helps :)

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Wed Dec 30, 2015 10:47 pm
by achewt
I continue to have 'clunk' sounds associated with sustained elevation climbs of > 500 m. In September and October I twice went over the pass from the west Kootenays to the Boundary region (the Paulson Pass, from ~480m up to 1500 m, then back down again to about the same on the other side), over about 70 km, typical speed of 90 km/h. The 'thunk' didn't happen until we were close to the summit. Interestingly, as we started down the other side of the summit, it 'thunked' again as we started to regen, and only about 100 m below the summit. Colour me confused! :?

I've also had it leaving my town and heading up to the local ski area (earlier in the thread I said I hadn't noticed it last winter), this year I purposely kept the music off to listen for it, and after about 500 m elevation gain I got the 'thunk'. Last night I didn't quite get to the 'thunk' zone as I pulled off at the XC ski area slightly lower, but I instead had the hot electrical smell. This car gives me mild anxiety ;)

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Thu Dec 31, 2015 2:21 pm
by Nubo
Sounds to me like a metal panel "beer-canning" due to pressure change. As I think I previously noted, I'm not sure if there is any provision in the battery case for pressure equalization, or if the case is simply meant to expand and contract. If the former, then perhaps a valve/vent/filter is blocked. If the latter then could just be an accident of geometry or stamping. Or I could speculate that pack attachment bolts (or something bolted TO the pack) need to be re-torqued. I might consider it a minor annoyance but given the electrical smell I'd say have Nissan look into it.

Re: clunk from battery area after climbing 2000ft (600m)

Posted: Thu Dec 31, 2015 4:27 pm
by knightmb
What was the beep before the clunk sound? It sounds like the beep confirmation is turned on in the NAV but I didn't see anyone using the NAV in the video? It sounded like the low battery warning beep?