New user battery questions

[OldHarley]

Old Harley you most likely got a Vpower battery that has been sitting in a warehouse in China since 2009. They sell them cheap because they are old.

Yeah, I had that suspicion once I saw it was marked "Use no later than year of the Rat" :lol: Har,har, har

 

[Jason27]

Unfortunately people post here all the time thinking they got a "good deal" when really they got scammed and bought junk. The battery companies in China overproduced battery packs in 2008-2009 and they sit for long periods of time uncharged and neglected. They then sell the packs to ebike newbies at a crazy discounted rate to simply dump them. Then when someone complains they say ship it back to us. Lol.. shipping a battery back to China simply does not happen for the fact that it would cost you hundreds of dollars and months of waiting. Its not worth it.

I just wish more people new the truth about cheap battery packs from certain chinese vendors. I learned the hard way back in 2011 and lost a chunk of change. If you dont believe me just read past postings in the battery forum. See how many people are having problems.

 

[dogman dan]

It could stand some storage though, if they don't plug in the bms for storage. But it IS true, not too many v power packs 4 years old and still running have been heard from.

So if it was made in 2009, it could be about ready to time out anyway. But, if you use it wisely, charge it when you can, and try to not ride it till the bms trips every ride, you might get your money's worth out of it in the end. A voltmeter on the bike would be very good, so you can know when you are below 36v when the bike is not running, and think about finding a charge soon.

22 amp controllers are very common, and are found on motor kits that are called anything from 500w to 1000w. Only a wattmeter or amp meter will tell you exactly what you have. There is a thread lately about where to get a pretty affordable one on ebay. Less than 20 bucks shipped, so getting one would be a good idea. Then you can try to ride so that you baby that battery as much as possible, keeping amps down to 10 or less at cruise speed.

 

[Jason27]

Just to be clear when I say cheap batteries from China I am talking about the ones sold on eBay. Like vpower or cammy cc or daoj or taobao .. etc

 

[999zip999]

Junk maybe made all at the same place. Chineese as a rule don't buy lifepo4 just mainly sla. So who sends there junk battery back.
Still we can see how this battery last.

 

[circuit]

Sam, my comment was a little tongue-in-cheek, but since I just got the battery a day or so ago, I will be able to do as others have suggested to let the cells balance themselves before I push it too far.

Cells don't balance themselves. Do as Sam says: charge overnight (in fire-tolerant environment) and ride as you like. All those talks about 1Ah/mile etc is an absolute nonsense.

 

[OldHarley]

Do as Sam says: charge overnight (in fire-tolerant environment) and ride as you like. All those talks about 1Ah/mile etc is an absolute nonsense.

On flat ground, I am hoping to get 15 miles range from 10 Ah without too much pedaling. So far I have found that when going over 12 mph, it does absolutely no good trying to pedal my 7 speed Comfort bike - I can't keep up with the motor. I use motor as pedal assist only from 8-12 mph.

I mention this since I originally asked the question regarding using BMS to determine range.

In using the search feature, I have noticed most answers given to "how far can I ride?" usually end up with a discussion regarding amount of hilly terrain, advice on keeping battery usage well under the battery capacity, and comments regarding how much pedaling are you willing to do - all of which are somewhat vague answers.

My new battery measured 42.7 volts yesterday - under the BMS upper limit. While I plan to keep track of my numbers, advice regarding never allowing the battery voltage below 36v at rest will obviously limit my range if I only use that number and not allow BMS to assist.

OH

 

[circuit]

When comparing batteries and mileage, you should talk about Wh, not Ah.
My practice is this (450Wh battery, mountain ebike with hub motor, no regen, terrain with some hills):
15mph: 20 miles
35mph: 7 miles.

 

[dnmun]

"My new battery measured 42.7 volts yesterday - under the BMS upper limit. While I plan to keep track of my numbers, advice regarding never allowing the battery voltage below 36v at rest will obviously limit my range if I only use that number and not allow BMS to assist."

your battery should charge up to around 44V. nobody would tell you to stop using the battery at 36V. a 12S lifepo4 should discharge down below 30V before it gets close to the LVC on any of the cells. and if the pack is healthy and well balanced it can go as low as 27V with no problems.

but your BMS will shut it down if you draw one cell down to 2V.

 

[OldHarley]

your battery should charge up to around 44V. nobody would tell you to stop using the battery at 36V.

Guess I misunderstood this, then...

... if you use it wisely, charge it when you can, and try to not ride it till the bms trips every ride, you might get your money's worth out of it in the end. A voltmeter on the bike would be very good, so you can know when you are below 36v when the bike is not running, and think about finding a charge soon.

Thanks for the info, battery measured 44.3v last evening after charging. This morning I got 42.7v again before I used it, but being new to all this and unsure of this batterys' capabilities, I plan to watch it as I have said.

If I have good luck, I will let you know.

OH

 

[dnmun]

the voltage drops off when you take it off the charger. that is normal. you just need to be sure your charger charges it up to the full voltage so the BMS can balance the cells.