Jay64
100 kW
Oops, I meant 5 lbs! The stock battery was 15 lbs. Sorry, my bad.
1800vtx said:first of 12 packs
pwbset said:1800vtx said:first of 12 packs
You're nuts man! And that's a... good thing!
Joey said:I just assembled a 3s2p Milwaukee 28V Li-Mn pack on a bike with an EV-Tech BMC rear hub motor, and Crystalyte 72V 35A analog controller from ebikes.ca. The batteries and chargers are brand new and were all purchased at the same time. I made a few test runs two evenings ago and everything worked beautifully. I then rode the bike into work (7.7 miles) the next day, taking it easy since it was downhill and I wanted to conserve capacity for the uphill return trip. My bike was parked outside all day at work and the outdoor temperature hit 94 degrees. The batteries were in a black rack trunk bag on top of my rear carrier. I left the batteries connected to the controller but the controller power button was off. As I left work that afternoon and travelled about 100 ft or so on level ground, power dropped suddenly and I had to rediscover the pedals. The CA display showed a combined pack voltage of 43V. It had showed over 52V after arriving at work that same morning. As I pedaled home, I switched on the controller occasionally and observe the CA display. After a few times, the display started showing random characters, and eventually went dead.
I was wondering what might have caused this problem. When I got back home, I put the batteries on their Milwaukee chargers and they immediately showed 3 LEDs on indicating that they had not lost more than 1/4 of their charge. After reaching full charge in minutes, I connected them back up on the bike and went for another test drive. Once again, everything worked beautifully. Do you think the problem was thermal? Does the red button on the Crystalyte controller power off everything, or does it still draw some power even when this switch is off? What else could have been the problem?
-- Joey
1800vtx said:If you don't mind bypassing the BMS and voiding the warranty (5 year/2,000 charges) to get your 84V, go for it.
Joey said:It had showed over 52V after arriving at work that same morning.
pwbset said:You can indeed leave a 3s2p pack build in tact with warranty in place if you solder some diodes inline on your assembly blocks so if (more like when) your battery pack BMS trips the diodes conduct and protect the pack (see fechter's thread in EV Basics on BMS protection ).
paultrafalgar said:If you're only interested in extra range, rather than speed
Joey said:Darn, I meant to say 2s3p (56 volts) when I mentioned my problem. I still need help.
Joey said:P.S. What would be a good LVC value to set my Cycle Analyst at for this 56V pack configuration?
Joey said:Is it better to let the Milwaukee pack BMS LVC trip or is it better to set the CA LVC at a higher voltage, e.g. 42V as you suggested, so it will trip first?
pwbset said:paultrafalgar said:If you're only interested in extra range, rather than speed
I chose 3s2p because I have a rear 4011 and need to climb 1,600ft over 3.5mi every morning to get to work and at 56v the 4011 is okay, but at 84v it really shines and pulls hard at lower amp levels. Having the ability to burst up to 30mph through traffic helps to.
I do like your idea of just having some spare packs in a backpack and swapping as needed for long trips. Gotta save some money first! Batts are getting expensive!
Jay64 said:I think the problem with the battery that I just killed was because I had ran it all the way down, and then didn't charge it up for a very long time.