Has anyone ever gotten their battery tested for capacity?

[blackjackel]

I'm thinking of taking my battery to an electric bike shop to get it tested for actual capacity.... Is this a thing that someone else has done? Is it possible to do?

My reasons:

I have the Dillenger 1000w 48v 10ah kit, I see the distance rating on that kit to be 55km with pedal assist and 30km without pedal assist.

They way I use my bike is that I pedal as hard as I can along with the motor from a dead stop till I get to full speed (25mph), after I hit top speed I stop pedaling and use the motor to keep me moving (I don't have a 9 speed gear or anything like that, so pedaling at top speed isn't really doable). The range I get out of that is about 24km, which is short of the 30km stated without pedal assist, and this is considering that I do assist the motor by pedaling (hard) up till full speed.

My rear rack failed on me the 2nd day I had it installed (due to the poor design or construction of the rack itself), this caused the battery to fall off the back of my bike. After I was sent a replacement rack, it failed again 17 days after I had installed it, this time my bike fell off of my bike, struck the ground, and slid a few feet till it came to a stop. I never really had enough time the first time around to test the range of the battery. My experienced range (Given above) was after the 2nd time the battery hit the ground.

I feel like maybe the battery falling has caused the battery capacity to go down? I'm not sure, but I do want to get the battery tested.

 

[made_in_the_alps_legacy]

I believe you are at a point to equip yourself with a powermeter,
it's a minimal requirement and cheap investment for you to get used to what's going on as far as voltage, current, watts, watthour, Ah, WP, Ap are concerned and even if limited to 60V max voltage, they fit just right to a 48V kit :

I think in my built thread in my signature, you should find the link how to make it a Dashboard
sidenote : my 20Ah battery developps actually 18Ah, but at a quite high discharge rate

 

[dogman dan]

Yep, really, you are in the dark until your bike has a watt meter. Then you are able to do your own capacity tests. For the best wattmeter, get a stand alone Cycleanalyst. But the cheap ones on ebay will do.

Before you test, put the battery on the charger overnight at least. Try to get it fully balanced first.

Whatever Dillenger says, 24k, 15miles, at 25 mph is just about exactly what I would expect from a fully charged, fully balanced, perfectly functioning 48v 10 ah battery. Your watthours per mile is spot on what I'd expect for 25 mph, 33 wh/mi.

So IMO, Nothing is wrong with your motor, or your battery. The only thing wrong is the range estimate from Dillenger for the max speed range. You would get that distance at 22 mph. To get 55k (35 mi) "with pedal assist" you'd also have to slow to 15-18 mph.

 

[Ykick]

I believe you are at a point to equip yourself with a powermeter,
it's a minimal requirement and cheap investment for you to get used to what's going on as far as voltage, current, watts, watthour, Ah, WP, Ap are concerned and even if limited to 60V max voltage, they fit just right to a 48V kit :

I think in my built thread in my signature, you should find the link how to make it a Dashboard
sidenote : my 20Ah battery developps actually 18Ah, but at a quite high discharge rate

While this is a great idea, be aware you'll need to figure out how to power such meter from an external battery. Should you go through all the trouble to rig a test load (old space heater, toaster oven elements, btw) when the battery "kicks off" or runs out of juice, all the Ah, Wh, Time info will be lost. There's a way to power that meter with an external battery but it's a little work to sort out and decipher the wiring/connector.

Better yet, if you own a CA (Cycle Analyst) while it also shuts down when power is removed, it will save the last parameters so when powered back up the data can be retrieved.

I just ran capacity tests yesterday on a new RC Lipo pack with BMS. For a load I mostly use an old toaster oven, bypassed the temp control circuitry and it pulls between 5-7A on my 60V battery packs. Enough load for capacity testing.

This is why it's important to get into a good quality connector scheme - APP's, Dean's, etc. The brand and type is your choice but creating good, solid power connections with good wire is paramount for this type homework.

 

[made_in_the_alps_legacy]

While this is a great idea, be aware you'll need to figure out how to power such meter from an external battery.

it powers up from the source you test. CA is extremly expensive for that application compared to those powermeter. There is a compromise for voltages higher than 60V here

 

[Ykick]

While this is a great idea, be aware you'll need to figure out how to power such meter from an external battery.

it powers up from the source you test. CA is extremly expensive for that application compared to those powermeter. There is a compromise for voltages higher than 60V here

I know, have used several of them over the years. My helpful POINT is that for "capacity testing" you must power that meter with an external battery. Or else, when the battery runs out and the meter powers down, you lose all the accumulated data.

 

[made_in_the_alps_legacy]

OK, you mean when connected "downstream" of the BMS

 

[Ykick]

OK, you mean when connected "downstream" of the BMS

Unless he's willing and able to disassemble a sealed battery pack,there's no other option for connection to perform a capacity test. I do majority of my capacity testing downstream of BMS because I don't hover over the process and I wish to avoid OD (over discharge) of the cells.

As eBikes progress, it will likely become more prevalent service item. But for now, I doubt many shops have the time, knowledge and tools to bother with capacity testing on a drop off basis. DYI...

 

[blackjackel]

I believe you are at a point to equip yourself with a powermeter,
it's a minimal requirement and cheap investment for you to get used to what's going on as far as voltage, current, watts, watthour, Ah, WP, Ap are concerned and even if limited to 60V max voltage, they fit just right to a 48V kit :
(image removed)
I think in my built thread in my signature, you should find the link how to make it a Dashboard
sidenote : my 20Ah battery developps actually 18Ah, but at a quite high discharge rate

Very cool! I think I will definitely get one of these, but probably one of the standalone versions mentioned below.... I'm weary about placing it as a dashboard as I lock my bike out in public a lot and it's quite easy to steal those things because you can just unplug them.... I think I'll start a thread to see if there are any aftermarket commercial metal boxes sold that I can attach in the triangular area in my bike so I can lock up all the components so that a thief would be forced to cut the wires to take the equipment, which would drastically reduce their value.

Yep, really, you are in the dark until your bike has a watt meter. Then you are able to do your own capacity tests. For the best wattmeter, get a stand alone Cycleanalyst. But the cheap ones on ebay will do.

Before you test, put the battery on the charger overnight at least. Try to get it fully balanced first.

Whatever Dillenger says, 24k, 15miles, at 25 mph is just about exactly what I would expect from a fully charged, fully balanced, perfectly functioning 48v 10 ah battery. Your watthours per mile is spot on what I'd expect for 25 mph, 33 wh/mi.

So IMO, Nothing is wrong with your motor, or your battery. The only thing wrong is the range estimate from Dillenger for the max speed range. You would get that distance at 22 mph. To get 55k (35 mi) "with pedal assist" you'd also have to slow to 15-18 mph.

Thanks! If my battery is performing as expected then there's really no need to test it, though I think I will get something like cycleanalyst or another stand-alone style battery tester just to keep tabs on my battery from time to time.... Also, you reminded me that my controller allows me to set the max speed on my bike, so If I want to go further I can adjust that before leaving and get the distance, albeit get there a little slower... I'll look to see if there's a calculator out there for how much distance you get per MPH/KPH reduced, I doubt it's linear.

While this is a great idea, be aware you'll need to figure out how to power such meter from an external battery. Should you go through all the trouble to rig a test load (old space heater, toaster oven elements, btw) when the battery "kicks off" or runs out of juice, all the Ah, Wh, Time info will be lost. There's a way to power that meter with an external battery but it's a little work to sort out and decipher the wiring/connector.

Better yet, if you own a CA (Cycle Analyst) while it also shuts down when power is removed, it will save the last parameters so when powered back up the data can be retrieved.

I just ran capacity tests yesterday on a new RC Lipo pack with BMS. For a load I mostly use an old toaster oven, bypassed the temp control circuitry and it pulls between 5-7A on my 60V battery packs. Enough load for capacity testing.

This is why it's important to get into a good quality connector scheme - APP's, Dean's, etc. The brand and type is your choice but creating good, solid power connections with good wire is paramount for this type homework.

A very important reply, thank you. This is where I realized that the style of analyzer posted above would be too much work for me and that I'm better off getting the standalone cycleanalyzer so that I can use the natural load of utilizing the battery instead of rigging my own dummy load.... that and the benefits of having the information saved without the use of another external battery.

I'm thinking of taking my battery to an electric bike shop to get it tested for actual capacity.... Is this a thing that someone else has done? Is it possible to do?

With out mentioning your battery cells specifications, it is like believing that all batteries act the same.
By 95% percentage, you own a the very cheapest version of SLA or Lithium cells.
Their huge weight (SLA) is impossible to be handled by a regular rack that is made to handle 2-3 Kilos at a regular city travel.

In order to make you feel nice, I will say that your problems is a common plaque that 80% of ebike owners facing when their choices in all ebike parts and the bicycle it self, is very low cost.
You overlooked many details by paying just for a 1000W motor label which is a wrong choice.

Thanks for the input, yeah, I kind of just dove head-in on this thing... which is what I've done for the beginning of all my hobbies... I start with a preassembled prebuilt kit to get started and learn from there, replacing things along the way. I think I will use up this battery until it's dead and then go for something a bit better in the future.... Hopefully the battery technology would have improved by then and I'd spend maybe a bit more cash on things and end up with something much better.

My battery is listed as a Lithium ion Polymer LiMn2O4 480 Watt Hours 48V/54.6V is the cheapest option you're talking about? I'm curious what benifits a more expensive battery chemistry or battery cell would entail? How much more amp hours would I be able to get for the same weight/size ratio? And how much more expensive are we talking?

 

[Hillhater]

Does your charger Have any volt or amp read outs ?
Most decent (cheap) RC Li chargers will give a readout of Ahr recharged into the pack, which is a fair approximation of how much you use before the charge.
Or you could just hook up that Wattmeter into the charge leads and get the capacity / usage reading that way ( during charging) rather than messing about with the wiring on the bike.
Alternative , better , batteries ....look up some of the 18650 cell pack builds using Samsung, LG, or Panasonic PF cells.

 

[dnmun]

this thing about "battery performing as expected" means what?

battery performance depends on the battery being properly maintained and balanced when these expectations of 20Ah from a 20Ah battery are made.

the battery has to be charged to full charge and discharged to full discharge on all of the cells in the pack at the same time.

a 48V battery is made of 16lifepo4 cells and each of them would have to be balanced and charged so they were holding the full 20Ah before discharge.

so if one of the cells is not fully charged then that will be the limit of the capacity.

with age it gets harder to make them all take the same amount of charge each cycle.

 

[Hillhater]

And " range with pedal assistance" is an open ended number.
..if you keep pedalling , you keep going,..no limit !
Even range unassisted is too dependant on speed, rider weight, bike type, terrain, wind, clothing, tires, etc etc etc

 

[dogman dan]

Good point Ykick, with the cheap wattmeters, you will lose data as soon as the bms pops.

I was just assuming the test would be done by riding the bike, and by watching the display, you could have a close enough look at it before it went dark. The last time I looked, 9.5 ah or whatever.

But yeah, won't work if you can't watch it right up till it goes dark. With a CA, data is not lost that way.

If you really want the best wattmeter, I highly recommend a CA. I have two stand alones, and two DP's. I love knowing how my battery is doing every ride. You learn amazing things, because each battery behaves different at times, for a variety of reasons. Like a cold battery, or one just slightly out of balance.

My allcell battery was getting worse and worse, though it seemed close to balanced, 2 ah short of expected capacity. I had to charge it to 4.21v per cell to make it balance, and bingo, 12.7 ah delivered again. Apparently the charge was stopping a hair too soon.

 

[Ykick]

Good point Ykick, with the cheap wattmeters, you will lose data as soon as the bms pops.

I was just assuming the test would be done by riding the bike, and by watching the display, you could have a close enough look at it before it went dark. The last time I looked, 9.5 ah or whatever.

But yeah, won't work if you can't watch it right up till it goes dark. With a CA, data is not lost that way.

If you really want the best wattmeter, I highly recommend a CA. I have two stand alones, and two DP's. I love knowing how my battery is doing every ride. You learn amazing things, because each battery behaves different at times, for a variety of reasons. Like a cold battery, or one just slightly out of balance.

My allcell battery was getting worse and worse, though it seemed close to balanced, 2 ah short of expected capacity. I had to charge it to 4.21v per cell to make it balance, and bingo, 12.7 ah delivered again. Apparently the charge was stopping a hair too soon.

Yep, those of us coming from the era of "naked RC Lipo" often employed "short-charging" as a method to increase cell life. Or, in reality, merely avoiding overcharge condition.

Majority balancing Li-ion (Lipoly) BMS need cells to reach 4.20-4.22V before any balance function begins. Those of us who ordered slightly under voltage chargers in hopes of preserving our homes & cells often wind up with significantly unbalanced battery packs because our cells never reach much above 4.15V. Meaningful balancing never has a chance to work. I've got an old 60V SLA charger which float charges up to around 68V (16S RC Lipo) so it's my "balance charger" used every once in a while.

Although, in many cases, 40-80mA balance current doesn't work very fast and creates some hot components it's still better than nothing. Although, when a pack gets really out of balance it's often quicker and easier to crack it open and manually charge the low cells directly.

TIP - hack old cell phone battery pack for 1S BMS which can be rigged into a single cell charger for practically any 5V wall supply or even USB port to safety charge single Li-ion (Lipoly) cells.

Good luck....

 

[dnmun]

there are two ways i avoid having the wattmeter turn off and lose data when the BMS shuts off for the LVC when i do a discharge test.

one way is to put the wattmeter in the B- lead from the BMS over to the negative terminal of the battery B-.

you cannot do that with the ping BMS because the voltage drop across the shunt affects the voltage reading on the first channel to the BMS comparator for LVC. ping uses B- from the battery for B0 sense wire.

i also use one which i power through the auxiliary power input with a 9V battery. i use a 2 pin JST plug, and the little snap connector for the battery. pop the battery connector open when done or it will drain the 9V battery.

 

[KINNINVIEKID]

My battery is listed as a Lithium ion Polymer LiMn2O4 480 Watt Hours 48V/54.6V is the cheapest option you're talking about? I'm curious what benefits a more expensive battery chemistry or battery cell would entail? How much more amp hours would I be able to get for the same weight/size ratio? And how much more expensive are we talking?

When the conversation goes to battery engineering, I will say that after significant in person research by keeping in mind long term reliability as first factor in my list,
I got in the conclusion that Headway 38120 Lifepo4 cells are the best choice.
I describe them as long sausages :lol: , Life cycle 5-7 years. Easy to replace a single cell if needed.
Individual cell diagnosis is very easy.

In my case that I need a 36V pack, I got lucky because there is available an Headway battery with rack.
http://www.ittsb.eu/forum/index.php?topic=959.0

The Dillenger battery has 22650 Headway cells....

 

[dogman dan]

That's good to know, I was assuming it was not lifepo4.

If that's the case, and he has a 16s pack, he needs to give that thing at least 58.4v.

But I still think nothing is wrong with his battery, he just believed he could go farther on less assist than he actually uses.

 

[riba2233]

Headway makes limn and lifepo4 cells.