Battery starting to fail?

[Deacon Blues]

No, I haven't contacted Ravi yet.
I ran both batteries to 0% and then charged both.
I put one of the batteries back on the bike and it showed 92%. So far I've done a couple of short rides and the percentage is looks to be dropping at a 1km = 1% rate.

 

[DaveMatthews]

No, I haven't contacted Ravi yet.
I ran both batteries to 0% and then charged both.
I put one of the batteries back on the bike and it showed 92%. So far I've done a couple of short rides and the percentage is looks to be dropping at a 1km = 1% rate.

1km = 1% rate is what I get on my Giant when in assist level 3 (out of 5).
Get about 1.5km = 1% in level 2.

 

[PCeBiker]

I have an AliExpress controller and display that automatically detects a 36V or 48V battery and adjusts the display accordingly.
I had my 48V battery drained down to ~42V and the voltage sag under load brought the Voltage down to the LVC and my e-bike shut off.

I turned my display back on, and it thought I had a 36V battery installed so it showed something like ¾ battery left, but the voltage reading was the same at ~42V.

Your voltage readings are confusing.
I've never had more than a 0.2V difference between my display reading and my Voltmeter reading.

Does your battery have a third communication wire/pin on the power output or the charge input?
That could be why your getting erroneous voltage readings?

All my batteries only have positive and negative terminals/pins on both the charge and discharge ports.

 

[Deacon Blues]

95% of my rides are in level 1. I seldom need to use a higher level, since in level 1 the motor peaks out at around 400W.

 

[DaveMatthews]

95% of my rides are in level 1. I seldom need to use a higher level, since in level 1 the motor peaks out at around 400W.

Not sure what to say. I would expect level 1 for me might yield 1.75+kms? I rarely use it.

 

[DaveMatthews]

Shouldn't be a diff between a 48v and 36v system, right?

 

[PCeBiker]

Interesting update: As I mentioned, on my last ride I drained the battery.
I charged the battery up yesterday and mounted it back on the bike. to my surprise the voltage (on the display) read 57.7V and the percentage showed 92%

I did some testing today on one of my batteries
meter reading: 49.6V
bike's display: 54.9V Switch to percent 69%
Using Hydra's display: 55.1V Switch to percent 69%

Keep in mind that 57.7V is dangerous for a 48V battery, but it sounds like it's the display that's giving an erroneous reading.

Voltage is voltage though, and a display should always give an accurate voltage reading regardless of programming or what battery is installed.

 

[PCeBiker]

Shouldn't be a diff between a 48v and 36v system, right?

Not for the the actual voltage reading.

A 48v battery's voltage ranges between 54.6v and ~40v (LVC) and a 36v battery's voltage ranges between 42.1v and ~31.5v (LVC).

The actual voltage of the battery, and what's shown on the display should never differ by 5v.

 

[PCeBiker]

Are you sure that you have a 48 Volt battery?

This is a review that I found of the 2020 Watt Wagons Ultimate Commuter Pro,..
It says that it comes with a 52V battery.

2020 Watt Wagons Ultimate Commuter Pro Review

The Watt Wagons Ultimate Commuter Pro is an extremely high-end, reliable, do-everything electric bike that’s built for the long haul....

electrifiedreviews.com

 

[PCeBiker]

I have had friends charge there 52v battery’s with 48v and 60v chargers and they then complained on the actual battery charge.
I 100% realize you are using the correct voltage chargers just wanted to show some knucklehead examples of incorrect battery charger usage.

I have two chargers. One is similar to Grin's Satiator charger, with adjustable percentages and charging rates. The other, which came with my Hydra, is a standard charger, with no adjustments.
I've used both, with the same results.

I'm thinking that you have two 52 Volt batteries and the original UC charger is a 52 Volt charger and the one that is similar to Grin's Satiator charger, is for a 48 Volt battery?

 

[PCeBiker]

The Hydra appears to have a 52 Volt battery as well,..

Hydra (Gen 2)

Hydra Gen 2 is the most complete e-MTB with super light Aluminum frame, and Bafang Ultra with supercharge upgrade option. We have added a lot more new features that pack a punch ! Key Gen 2 Updates: Updated geometry and comfort Stronger, more balanced frame developed by Watt Wagons Larger...

wattwagons.com

 

[PCeBiker]

My 48v 13s battery needed to be at LVC to confuse my display/controller into thinking that I had a 36v 10s battery installed.

It's much easier for a partially discharged 52v 14s battery to confuse a display/controller into thinking a 48v 13s battery is installed.

 

[PCeBiker]

14s = 52v nominal and full charge at 58.8v. All day long
13s = 48v nominal and full charge at 54.6v. Pretty common
12s = 45v nominal none that I know of. Maybe Euro bike?
11s = 42v nominal none that I know of either.
10s =36v nominal and full charge at 42v. Most common.

The part that sucks about all that is that the nominal voltage per cell group for a 10s battery is 3.6 volts.

At that rate a 13s battery should have a nominal voltage of 46.8 and be called a 47 Volt battery.

A 14s battery should have a nominal voltage of 50.4 and be called a 50 Volt battery.


I don't like all the number fudging.
Apple to Apple comparisons are difficult when the Apples are different sizes.

 

[il Munduato]

The part that sucks about all that is that the nominal voltage per cell group for a 10s battery is 3.6 volts.

At that rate a 13s battery should have a nominal voltage of 46.8 and be called a 47 Volt battery.

A 14s battery should have a nominal voltage of 50.4 and be called a 50 Volt battery.


I don't like all the number fudging.
Apple to Apple comparisons are difficult when the Apples are different sizes.

You're reading too much into it as well as different manufacturers can have slightly different nominal voltage ratings for similar cells. I've seen 18650 cells with a nominal of 3.7 so then 48v would be correct in your example of a 13S.
Nominal is not an exact specification but just a reference number assigned.

Dictionary adjective

1. 1.
   (of a role or status) existing in name only.

When comparing batteries typically ah and discharge rate are the key figures as the nominal voltage is predetermined by the rest of the system anywho.

 

[PCeBiker]

When comparing batteries typically ah and discharge rate are the key figures as the nominal voltage is predetermined by the rest of the system anywho.

My 25ah 48v battery has Samsung 50e 21700 cells with a nominal voltage of 3.6, so I think that they should add another cell group and make it a 14s battery with a nominal voltage of 50.4v

That only makes sense.
Sometimes the status quo is stupid.

Then they should make a proper 15s 52v battery too.

 

[il Munduato]

My 25ah 48v battery has Samsung 50e 21700 cells with a nominal voltage of 3.6, so I think that they should add another cell group and make it a 14s battery with a nominal voltage of 50.4v

That only makes sense.
Sometimes the status quo is stupid.


View attachment 178480



Then they should make a proper 15s 52v battery too.

I think there is plans for this with the Department of Standards Weights and Measures.
It's just stuck in the queue behind the lumber industry producing an actual 2x4.

 

[PCeBiker]

It's just stuck in the queue behind the lumber industry producing an actual 2x4.

Yeah, what a load of crap that is.

I miss the good ole days when a rough cut 2x4 actually measured 2x4, and the fully dressed version only got shaved down enough to be smooth.

If they start selling two-fours with with 22 beers or smaller beers, I'm gunna be pissed.

(Well, it just be harder to get pissed. )

We here in Canada had a hard time converting to metric beers in the mid 70's.

 

[il Munduato]

95% of my rides are in level 1. I seldom need to use a higher level, since in level 1 the motor peaks out at around 400W.

I guess if you can get it to do what you want with pedal pressure that's OK but I have the Ultra tuned with PAS 1 to about 100w. Then subsequent PAS to add in about the same. Yeah this does have you changing PAS as you ride but I figure that's why I have nine anyway.
I like being able to dial in the exact amount of assistance desired.
That said 95% of my rides are in PAS 1 - 4 so about the same as you.
I've never monitored my %/mi but lately I've been using around 9wh/mi. Was getting that to around 8wh/mi and even lower in the cooler springtime... but today for instance it's 88°f/74°dew point.
Anywho there are so many variables it's hard to compare different bikes/riders/terrain/weather... etc...

Shouldn't be a diff between a 48v and 36v system, right?

In theory 48v should be somewhat more efficient... but like above, the variables between situations are too many to make any meaningful comparison unless you duplicate scenarios.

 

[greeno]

Just for a bit of clarity a HIGHER voltage battery will always be more efficient in theory.
Here is a quick example.

52v motor and let’s just say a 52v rated 14s 10ahr battery ok.
So that’s a 520w battery.
If your using 200w of power you could do that for 2hrs 36min.
This is in theory remember.

Now you have a 48 v motor with a different battery rated at 48v 13s 10ahr.
So that battery is rated at 480w of power.
Again if you use 200w of power you could run that for 2hrs 24min.

Higher the volts, lower the amperage as far as wattage is concerned.
Higher amperage more heat, larger wire or higher capacity components = more $.
You see where Im going with this.
And yes almost ALL battery manufacture’s round up for there ratings.
Hell even some of the Chinese AliExpress junk spec out higher rated cells and then actually install lower capacity ones that were cheaper.

The highest rated 18650 cells availible are rated at 3.5ahr.
The highest rated 21700 cells come in at 5ahr. A little larger and heavier but better as far as cost goes.

 

[greeno]

PCeBiker if you added a 14th 21700 cell to each of your five existing groups you do know you would need to use a 52v charger to get 100% charge.
52v chargers max out at 58.8v
48v chargers max out at 54.6v.

I know a lot of Bafang motors are rated for 48v or 52v but they will actually operate up to 60.0v without harm.
Hense that is why a lot of guys go with the 52v version.
More power, better economy.

Another thing to remember is you need to change out an older Bafang controller and the version you have is for 48v and your using a 52v battery do not I repeat do not replace it with another 48v unit you need to use a 52v unit or it won’t work plus you will get an error code until the voltage on the battery drops to below 54.6v
Ther is a fix for this online but it requires a PC and downloading software and replacing the hard drive on the 48v version to the 52v version.
Dont ask me how I know.