48v 11.6ah downtube battery review

[Russell]

50amp max discharging current Newest 48v 11.6ah bottle battery pack, electric bike lithium battery, e-bike battery

http://www.aliexpress.com/item/Newest-48v-11-6ah-bottle-battery-pack-electric-bike-lithium-battery-e-bike-battery/1536761895.html

It sounded pretty good so in early July I ordered the battery plus a spare case (mostly to get a second mounting plate). On the 19th day after I placed the order I received notification of shipment. The tracking number provided however did not check out (btw, auto-cancellation of the order occurs at 20 days, so, hmmm...it makes me wonder...) I inquired and was told to wait a few days. I waited and checked, waited some more and checked again. The tracking number still came up invalid. After more correspondence I was told the order had been re-shipped. This time the tracking number checked out and the battery and case arrived in just a matter of a few days. The entire process however took nearly 5 weeks.

I installed the battery on my Electra Townie cruiser equipped with a Bafang BPM rear motor and a KU93 controller tweaked to 26Apeak output. After a brief top-off charge I took the bike out for a quick spin.



I was riding fast with very little pedaling during this initial shakedown run. Quick accelerations, 2 noteworthy hills and topping out at 28 mph takes its toll. The WU meter showed I used a whopping 29.5 Wh/mile for 3.06 miles, the most ever for me. Peak current was 25.84A and peak watts were 1267W. Voltage sag however is considerable at right about 1.8V per 10A. To put this in perspective the "High C Rate" 36V/15Ah battery I purchased a few months back from BMSBattery sags roughly one-third as much.

Per the Vendor the battery is equipped with 3C Samsung 29E cells. I did not open the battery to verify since doing so would break the seal and void the warranty. The specs in the ad vary, in one section they show this:

Item specifics

is_customized:Yes
Voltage:48v
Capacity:10 - 20Ah
Type:Lithium Battery
battery power:48v 11.6 ah
cycling times:1200 times
battery style:bottle battery
continous discharging current:25amp
max discharging current:40amp
net weight:5kgs
material for cell:LiNiCoMn
charger:2amp bottle battery charger
cell:lithium ion 18650 3.7v 3000mA

and in another section they list these specs:

48V 11.6AH 18650 Imported cells battery pack spec electric bike battery . (Cells are more like 2750mah so 11Ah total)
• 18650 cells 2900mAH imported , 52 cells with bms (vendor says they're Samsung 29E)
• 800 times cycling ,one year warranty
• cell weight : 48g
• discharge cut-off voltage : 2.5v for one cell
• operating temperature discharge : -20°c to 60 °c
• 48v 11.6ah discharging current continous : 35amp (the cells are 3C max so this really should be maximum discharge)
• 48v 11.6ah max discharging current : 50amp (I questioned the vendor about this and they stuck to it but c'mon, no way!)
• charging current max : 5amp

Note: The battery is protected by a replaceable 30A blade type fuse.

To date I have done 4 rides with the battery using a maximum of 8.523 Ah with a resting voltage after that ride of 45.86V. So far it has performed without a problem. One of the rides were with the battery on my Jeep Comanche equipped with an EBK geared motor and 22A KU93 (shown below).



It achieved a top speed of 28.5 mph. I removed it however since I prefer using the BMSBattery 36V/15Ah battery in the topeak rear bag with this bike as it affords better range with a still decent 24 mph top speed and better stealth.

I also tried the battery on my flatbar road E-bike with a 201 rpm Q100 and 14A KU63. Top speed was roughly 22.5 mph. The biggest inconvenience with using this type of battery is the need to find another place to mount water bottle cages. In this instance I mounted 2 cages to the handlebars. Again however I removed the battery after the test run since the second mounting plate is ultimately destined for a new build which will likely be a 48V/18A/500W Bafang BBS02.

Quoted spec's aside this is not a high power battery. It has performed fine so far however personally I would not recommend it be used with a controller over 25Ap. I would probably also advise a different vendor. I see BMSBattery now carries this type of downtube battery and then there's also EM3ev.com which gives much more reliable information.

-R

 

[Russell]

I have done a few more rides with the pack and so far have not run it out of juice yet with a maximum Amp-hours used of 8.5 when It was on my Jeep bike with a 22Apeak controller. The most used on my Townie with a 26-27Ap controller has been 8.2Ah with a resting voltage after the ride of a hair over 46V.

To find the theoretical maximum capacity I should be able to achieve with this pack before it hits the 41V LVC I extrapolated the data from published discharged curves for the Samsung 29E cells.



The thin horizontal red line is the controller 41V lower limit. The vertical red lines indicate where in the discharge curve controllers with 27A,22A and 15A limits will hit the LVC on peak loads.

Based on the plot above I should be able to get 8.2Ah, 9.0Ah and 10.0Ah with 27A, 22A and 15A controllers, respectively. I have already achieved the first result without the controller cutting power, but I was probably pretty close. It all depends how long I spent below the controller LVC and how accurate that 41V is.

Presently I have no monitoring in place so when I'm out riding I'm flying blind. A simple voltmeter should do the job.

-R

 

[Russell]

Based on the plot above I should be able to get 8.2Ah, 9.0Ah and 10.0Ah with 27A, 22A and 15A controllers, respectively. I have already achieved the first result without the controller cutting power, but I was probably pretty close. It all depends how long I spent below the controller LVC and how accurate that 41V is.

-R

I forgot when I wrote this that I kept the 36V controller on my Townie when I switched to this downtube battery just so I wouldn’t have to worry about it. The LVC on this controller is 27.5V so there’s no chance it will kick in before the battery bms senses a low cell at 2.50V.

I figured the battery could just make my 18 mile loop with no pedaling. My Bafang BPM can top out about 27.5mph on a fully charged battery but it makes an annoying racket right at 25 mph thus effectively limiting how fast I normally ride it. Much of the time I cruised at around 24 mph with a trip average speed of 22.2 mph.

The theoretical battery capacity for this pack is 11.6Ah x 46.8V = 543Wh (Real world capacity is probably more like 11Ah). For this ride I used 504Wh/10.6Ah. The resting voltage at the end of the ride was 43.29V (3.33V/cell). The minimum voltage for the trip was 39.59V or 3.045V/cell. There was no bms shutdown but it must have been imminent since I was very close to draining it completely.



-R

 

[dnmun]

most lipo, li ion BMSs use 2.5V for the LVC. if you really had 3.3V as the resting voltage it is essentially exhausted.

no way to hook up cellogs to that pack to monitor it?

i will be getting my first li ion 48V15Ah pack in a few days so maybe i will know more about them after that.

 

[Russell]

most lipo, li ion BMSs use 2.5V for the LVC. if you really had 3.3V as the resting voltage it is essentially exhausted.

no way to hook up cellogs to that pack to monitor it?

i will be getting my first li ion 48V15Ah pack in a few days so maybe i will know more about them after that.

Yeah the spec's (1st post) indicate a BMS single cell trip point of 2.5V. Had the last 1.5 miles not been mostly down grade it probably would have tripped out today. The point of the ride however was to exhaust the battery to find the useable capacity. I plan to wire in a voltmeter of some sorts in the future to keep an eye on it. The idea will be to not take the resting voltage below roughly 45V from now on.

The battery would be nicer with 25R cells but I'm pretty satisfied with it so far.

-R

 

[Russell]

This downtube (bottle) battery is being offered at a number of places. In this capacity (4x2900mah) it often has the Samsung INR18650-29E cells like mine or Panasonic NCR18650PF cells. Here is a comparison of the discharge curves for both. The Panasonic cells look slightly better than the Samsung.



-R

 

[3Dkiller]

I have the 48V 11.6 Ah downtube battery from em3ev with Samsung 29E battery (20amp discharge).I can get 50km/h with a full charge battery. But i get to much voltage drop the battery is oke but do not expect any miracles. People should go for the triangle pack for more power

 

[chvidgov.bc.ca]

I believe these are pretty good battery packs for lightweight urban commuting applications with low amperage controllers 15 amps and under, and small geared hub motors like the Cutes or yPedals kits. I like the on-off switch too, as it spares your Andersons, and the built in USB charger could be sporadically useful on a tour. There are many triangles though which won't fit these packs, like the ladies mountain bike style geometries. I think you could pretty easily get 30 miles out of these with a small motor and moderate comfortable pedalling. A couple in parallel might work pretty well for a bigger DD, but the charging isn't through the output leads, so you would sacrifice regen if that were an issue.

 

[osmanteyze]

I want to find program via connection USB. Do you know whow can we find the programme?