BMS tripping... repaired/picture incl.

[recumbent]

My 15 cell 48 volt lifepo4 pack started tripping when fully charged for a couple days. Tore it open to see what was wrong and found out i had a few loose connections, particular the one in the top right corner with the two wires.
Tightened bolts and all is well, must have loosened from vibration, check your nuts folks

 

[Ypedal]

fyi, be careful when tightening the nuts, as the Vents ( between the + and - terminals ) are live , if you touch the + terminal and an exposed vent at the same time you will get sparks !! :wink:

I used a dab of hot glue to keep the nuts tight on my packs..

 

[swbluto]

Hot glue works. So does lock nuts.

And I finally learn what recumbent is using. Yesa 1.0(Or is it?).

 

[dogman dan]

My grandpa used a regular checklist before leaving the house, got my spectacles, got my testicles. Got those two you can do without just about everything else.

 

[recumbent]

I used a dab of hot glue to keep the nuts tight on my packs..

I'm sure the glue will keep the nuts from unscrewing, but afraid the soft copper, washer and threads combined, jiggle loose (or settle-in) after assembly, and not nessesarily unscrew :?

Thanks for the sparks warning, been there, done that, and jump everytime

swbluto, The batteries are from ebike.ca, not sure the original source though.
Not getting enough ah's from them and will have to buy another LIFEPO4 pack next season, this time I'm going straight to 20 amp hour rating so if they give me less than labeled it will still be enough amperage.

Sheesh, i'll be competing with Ypedal for most lifepo4's bought& $pent in one year

 

[swbluto]

I used a dab of hot glue to keep the nuts tight on my packs..

I'm sure the glue will keep the nuts from unscrewing, but afraid the soft copper, washer and threads combined, jiggle loose (or settle-in) after assembly, and not nessesarily unscrew :?

Thanks for the sparks warning, been there, done that, and jump everytime

swbluto, The batteries are from ebike.ca, not sure the original source though.
Not getting enough ah's from them and will have to buy another LIFEPO4 pack next season, this time I'm going straight to 20 amp hour rating so if they give me less than labeled it will still be enough amperage.

Sheesh, i'll be competing with Ypedal for most lifepo4's bought& $pent in one year

Hmmm. Ok. That's really interesting because I'm asking ebikes.ca for a few replacement Aten Energy cells(the prismatic kind, though. And they're rated by Justin at "12AH". It appears you have non-prismatic ones.), but they haven't responded. Have you conducted any capacity tests on the lowest-voltage cells in the pack(Lowest voltage after LVC)? I'm curious if your cells have actually declined in capacity. If they have, how many cycles have they had and what's the average DOD?

 

[recumbent]

Have you conducted any capacity tests on the lowest-voltage cells in the pack(Lowest voltage after LVC)? I'm curious if your cells have actually declined in capacity. If they have, how many cycles have they had and what's the average DOD?

My battery pack has almost 200 cycles already, but i do "opportunity charging" in the park or shopping center often.
So, complete charging cycles would be around 150 i'd guess.

Most people with lifepo4 batteries, (regardless of manufacture), complain about not getting full amp hours. Perhaps they are rated without LVC connected. If you use your bike daily like i do, get 20 amp hr cells if you can, plus we get more torque also with higher amperage.

I have not conducted tests on my lowest cell after LVC yet. This pack has definately wore down after only one season of use. But could very well be BMS related, perhaps combined with a low cell tripping. Either way I'm going to find out by the end of summer, the daily temperatures are still over 20 deg C.

 

[miro13car]

recumbent, sorry for addressing you recumbent,
I am so bad with names , maybe I am getting old, but I forgot your name since I visited you in BC.
I suppose only once I came very close to complete deplating my LifeBatt HPS battery when I got 11Ah out of it but it was with frequent 10-15 minutes long stops whan battery could recover.
My has about 100 cycles on it.
Real test is coming soon in the cold.
Any experience in cold weather with your batt???
MC

 

[recumbent]

... I forgot your name since I visited you in BC.

Any experience in cold weather with your batt???

Miroslaw, My name is Marty, but for some strange reason there are 5 others on this forum with the same spelling so i hesitated using it to halt any confusion.

Cold weather has not effected performance or longevity that I could notice, I'm happy to say.

I was speaking to a lady yesterday who asked the very same question, she said her LEAD ACID batteries were substancially sluggish on her electric car. She had a new e-car that looked like a VW bug, and very colourful.

 

[miro13car]

Marty,
that's good news for me your experience.
I must admit that I am worried how LifeBatt will perform in cold weather.
But from Sandia Labs tests of LifeBatt cells it is clear that performance will deteriorate below zero and really deteriorate in like minus 10C. They measured capacity in cold and for example at -30C it is down to only 4%.
So capacity is really affected by cold but how are amps affected??
I don't know.
What coldest temp you rode your bike? /with LiFePh of course/.
Miroslaw