Btrpower 48v 10ah LiFePO4, what's up with this battery?

[EMGX]

I've ridden over 90 miles and it is still over 50v. Fully charged it 3-4 weeks ago then rode 50 miles on the Olympic discovery trail, let it sit a couple weeks then rode again yesterday and today another 40+ miles. Probably in the neighborhood of 4,500 ft of climbing total. Still over 50v briefly saw it drop to 49.x volts on a steep long grade today. I don't think my Yamaha 500wh battery can match this. I hadn't used it much over the past year because it weighs a good 10#.

From the last 2 days of riding + the 50 miles riding the Olympic peninsula.
Crazy
BTW both the mileage and voltage are accurate

 

[harryS]

That's living with the flat LiFePO4 discharge curve. Eventually it starts falling and then I believe it falls off quickly, so you want to be close to home.

 

[EMGX]

I'll try to do another 20ish mile ride and tell my wife to have her phone with her and be ready to come pick me up if it goes flat. Mileage is very individual but I'm pretty sure that my Yamaha battery on a similar but lighter bike wouldn't have made 90+ of the same miles and still had much, if any, capacity left.
Another member of EBR mentioned that LiFePO4 batteries have memory which is why I wanted to discharge it more before charging again, prior charges have been fairly shallow. I did look it up and apparently the memory effect is minor and not supposed to be significant. The original scientific article is behind a paywall but others have read it and commented.
Edit: I found the article without a paywall. The authors characterized the effect as occurring even with the first partial charge/discharge cycle and slight and reversible but with significant consequences in some systems. Whatever.

 

[Nvreloader]

I would check it with a meter, just to be sure,
start a log book with the info to keep track of what is going on, use/charging spec's
discharge spec's etc.

 

[EMGX]

I did confirm with a multimeter, only 1/10v difference. The display voltage is odd in that the max voltage that will display is 51.7 v even if the battery has higher voltage but once it hits anything below 51.7v, even by a fraction then the displayed voltage is correct (at least the times I have double checked with a multimeter).

 

[EMGX]

Battery dropped off at the worst time, just before a 1000ft climb over 2.5miles to get home. Went from 47.x volts then fairly quickly to 42v then cut out over maybe 1/2-1 mile of moderate climbing.
Still, it gave me good assist over the 110 miles that the current charge lasted.
now I know

Wife coming to the rescue.

 

[EMGX]

Found this chart, not sure if it is accurate but if it is it explains a lot

State of Charge	Voltage
100% (charging voltage)	57.6V
100% (resting voltage)	54.0V
99%	53.6V
90%	53.2V
70%	52.8V
40%	52.4V
30%	52.0V
20%	51.6V
10%	49.2V
1%	43.2V
0%	38V

State of Charge (SoC) x Measured Voltage
table for a 48V LiFePO4 battery


as does this

LiFePO4 State Of Charge Charts - Climatebiz

In this article, we'll discuss LiFePO4 state of charge in detail. In addition, we'll provide you with LiFePO4 State of Charge charts.

climatebiz.com

 

[J.R.]

I have an old, 2014 ebike with a Lifepo4 pack. It was spec'd as 36V, 16Ah. It was actually 37.5 volts as labeled. They use prismatic pouch batteries for a lot of them, not 18650 cells. I have seen 18650 cells labeled Lifepo4 for sale, but I've never seen one in person.

I have never opened the pack case, but I know someone that did. My 2014 pack has more than 14k miles on it and it still works well. I don't ride that bike much anymore, I will occasionally take it for a 20 mile spin.

Lifepo4 are hearty batteries, they don't dump power well for high speed; they do stand up to heavy use. Hope it gives you many miles and smiles!