48V 18650 configuration

[kje]

What is the best configuration for making a 48V battery with 18650 cells?

I have a Imax B6 charger and want to use it to balance charge my battery.

Is it enough with two 6s (22,2V) packs in series for a Bafang BBS02 750W? If not, is it possible to add a third pack in series with 2s? (6s + 6s + 2s = 14s)

Or is it possible to balance charge a big 13s pack with my ImaxB6?

 

[dogman dan]

Well, you might make step one, getting a better charger. The b6 is a 50w charger. So lets say you build a 500 watt hour bike battery. It will take you 10 full hours for a charge.

Two 8s 150w chargers, that would get a 14s pack charged 6 times faster, but,,,,, even that would be kind of doing it the hard way.

What you need, is a 13s or 14s bms, and a bulk charger to go with it. A 5 amps bulk charger will fill a 500wh pack in a little over two hours.

I believe you can get both at EM3ev.

You can of course, experiment with up to 6s now. Till you get your bms and charger. Like two 6s blocks, and a 2s block.

 

[kje]

Well, you might make step one, getting a better charger. The b6 is a 50w charger. So lets say you build a 500 watt hour bike battery. It will take you 10 full hours for a charge.

Two 8s 150w chargers, that would get a 14s pack charged 6 times faster, but,,,,, even that would be kind of doing it the hard way.

What you need, is a 13s or 14s bms, and a bulk charger to go with it. A 5 amps bulk charger will fill a 500wh pack in a little over two hours.

I believe you can get both at EM3ev.

You can of course, experiment with up to 6s now. Till you get your bms and charger. Like two 6s blocks, and a 2s block.

Thank you. I ordered this bulk charger: http://www.ebay.com/itm/271852793055?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

What bms should I buy, is this one ok?
http://www.ebay.com/itm/Batterie-Protection-BMS-PCB-Board-Balance-Pr-13-Packs-48V-Li-ion-Cell-Max-25A-/121713481986?hash=item1c56b05902:g:tx0AAOSw~gRVtKLm

Should I build 13s or 14s pack?

 

[joostj]

kje,

I'm new to this hobby, but have put in a great deal of research, preparing to build several packs for mine and my kids e bikes.

The bms you linked to is rated at 25amps. I would try to go to at least 50a continuous rating to avoid it shutting down under load.
Luna cycle sells a quality 48v and 52v bms rated 50a cont/80a burst.

Unless you have a reason to split your pack for other uses, why not build one 13s/14s pack with bms with single bulk charger.

How big of a pack are you looking at building?

 

[kje]

kje,

I'm new to this hobby, but have put in a great deal of research, preparing to build several packs for mine and my kids e bikes.

The bms you linked to is rated at 25amps. I would try to go to at least 50a continuous rating to avoid it shutting down under load.
Luna cycle sells a quality 48v and 52v bms rated 50a cont/80a burst.

Unless you have a reason to split your pack for other uses, why not build one 13s/14s pack with bms with single bulk charger.

How big of a pack are you looking at building?

Nice that you build for your kids as well. ☺

Do you have experience with power shutting off with a 25A bms?
What about this 30/60A bms:
http://m.aliexpress.com/item/32505181953.html

The reason for the idea of building 6s + 62 + 2s I can balance charge it with my Imax B6. But as you said it's just 50w charger and it would be time consuming.

Maybe I build a 13s9p with bms. ☺ Is that the route to go?

 

[dogman dan]

I don't get to see that bms when I click that link, not a member or something.

13s is the current standard, if such a thing exists, for 48v using cells that charge to 4.2v. And a 60 amps bms will give you some headroom so your pack does not shut itself of, unless actually shorted after the bms.

The power supply will work as a charger, but won't have the features of the EM3ev charger. Mostly, it won't have a light that turns green and tells you it's done.

If you build your pack with some additional Jst plugs on the balance wires, you still can speed balance the pack using 1s charge or discharge mode. And perhaps even better, you can use those plugs to monitor how well it's balanced, or when it's 90% charged.

What I mean is the balance wires that lead to the bms will have a Y splice, so you have wires to the bms, and wires to jst plugs. Definitely do that if you are building your own pack. Watching a cellog 8 as your pack charges can show you the bms is working, which cell fills first, which one the bms is discharging, etc. Great info to have.

 

[kje]

I don't get to see that bms when I click that link, not a member or something.

13s is the current standard, if such a thing exists, for 48v using cells that charge to 4.2v. And a 60 amps bms will give you some headroom so your pack does not shut itself of, unless actually shorted after the bms.

The power supply will work as a charger, but won't have the features of the EM3ev charger. Mostly, it won't have a light that turns green and tells you it's done.

If you build your pack with some additional Jst plugs on the balance wires, you still can speed balance the pack using 1s charge or discharge mode. And perhaps even better, you can use those plugs to monitor how well it's balanced, or when it's 90% charged.

What I mean is the balance wires that lead to the bms will have a Y splice, so you have wires to the bms, and wires to jst plugs. Definitely do that if you are building your own pack. Watching a cellog 8 as your pack charges can show you the bms is working, which cell fills first, which one the bms is discharging, etc. Great info to have.

How can Cell log 8 monitor all 13 cells?

Does this bms link work? ☺

http://m.aliexpress.com/item/1741121963.html?recommendVersion=1&productId=1741121963&productSubject=13-lithium-battery-protection-board-48v-lithium-battery-BMS-30A-continuous-60A-peak-discharge&tracelog=wwwdetail2mobilesitedetail

 

[joostj]

A 9p pack will give you the ability to pull some amps (depending on what type cells you use).

I think it's worth the extra $20 to buy something like this.

http://lunacycle.com/batteries/bare-cells/48v-13s-50amp-bms-for-18650s-digital-battery-protection-system/

Also definitely buy a charger with an auto shut off, like this one for $40.

http://lunacycle.com/chargers/48v-3amp-ebike-lithium-smart-charger/

I'm all for saving a few bucks, but sometimes it's worth spending a bit more to save a lot of hassle later on.

 

[kje]

A 9p pack will give you the ability to pull some amps (depending on what type cells you use).

I think it's worth the extra $20 to buy something like this.

http://lunacycle.com/batteries/bare-cells/48v-13s-50amp-bms-for-18650s-digital-battery-protection-system/

I didn't get this link to work?

 

[joostj]

Looks like they just sold out.

Here's another option

http://www.ebay.com/itm/48V-54-6V-13S-60A-Lithium-ion-Li-ion-Li-Po-LiPo-Polymer-Battery-BMS-PCB-System-/321751863052?hash=item4ae9e7cf0c:g:ENEAAOxywCJRa8dU

I purchased a 22s 150a BMS from them for my NYX build

 

[kje]

I don't get to see that bms when I click that link, not a member or something.

What I mean is the balance wires that lead to the bms will have a Y splice, so you have wires to the bms, and wires to jst plugs. Definitely do that if you are building your own pack. Watching a cellog 8 as your pack charges can show you the bms is working, which cell fills first, which one the bms is discharging, etc. Great info to have.

I bought this 30/60A bms. Will this do the job properly?

http://aliexpress.com/item/13-lithium-battery-protection-board-48v-lithium-battery-BMS-30A-continuous-60A-peak-discharge/1741121963.html?recommendVersion=1

Where do I buy Cellog 8? Do I need two of them on a 13s10p battery pack?

Can a 8s buzzer alarm do the same thing?

http://www.ebay.com/itm/1-8S-Battery-Tester-Low-Voltage-Buzzer-Alarm-Indicator-YUSHOP66-/221904111311?hash=item33aa8406cf:g:yYwAAOSw0HVWD9c-

 

[circuit]

I prefer 12s due to max voltage reachable to industrial 48V power supplies.

 

[AndreD.]

Hey,

Just a quick question, which type of wire did you use on the cell balance plug? I saw some guys online using 14 awg wires for power and Ethernet cable (Cat5) on the cells balance plug, is that ok?

Best regards
Andre

 

[kje]

Is it possible to use just 12s battery for a 48v motor?

 

[Voltron]

It shouldn't be the 48v motor being a problem...it's the voltage the controller is made for, and the low voltage cutoff its set to that should decide it?

 

[kje]

It shouldn't be the 48v motor being a problem...it's the voltage the controller is made for, and the low voltage cutoff its set to that should decide it?

What is the low voltage cutoff for the Bafang BBS02?

http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2014-3C-S316.027VD

 

[Overclocker]

What is the best configuration for making a 48V battery with 18650 cells?

I have a Imax B6 charger and want to use it to balance charge my battery.

Is it enough with two 6s (22,2V) packs in series for a Bafang BBS02 750W? If not, is it possible to add a third pack in series with 2s? (6s + 6s + 2s = 14s)

Or is it possible to balance charge a big 13s pack with my ImaxB6?

i use 12s w/ my GNG mid-drive. 13s gives too fast pedalling cadence

12s configuration allows me to split the pack into two 6s parts which i parallel together for simultaneous charging w/ the icharger 106b+ 250-watts

 

[kje]

What is the best configuration for making a 48V battery with 18650 cells?

I have a Imax B6 charger and want to use it to balance charge my battery.

Is it enough with two 6s (22,2V) packs in series for a Bafang BBS02 750W? If not, is it possible to add a third pack in series with 2s? (6s + 6s + 2s = 14s)

Or is it possible to balance charge a big 13s pack with my ImaxB6?

i use 12s w/ my GNG mid-drive. 13s gives too fast pedalling cadence

12s configuration allows me to split the pack into two 6s parts which i parallel together for simultaneous charging w/ the icharger 106b+ 250-watts

OK so it's possible to split the pack into two 6s parts. That's interesting cause there is too little space for a big 13s pack in the middle of my bike.

Will the BBS02 750w work OK with a 12s configuration? Or does it has to be 13s?

 

[wesnewell]

The charger you bought won't charge more than a 12s pack (50.4V). The bms you bought is for a 13s pack, so together they are worthless. You shouldn't be ordering parts if you don't know what you're doing. And someone trying to put together an 18650 pack that doesn't know what they are doing is just comical. If you're going to build a 13s pack, you need a charger that will charge to 54.6V. You can use a 12-14s pack with any 48V controller. And a 15s or higher pack with some.

 

[kje]

The charger you bought won't charge more than a 12s pack (50.4V). The bms you bought is for a 13s pack, so together they are worthless. You shouldn't be ordering parts if you don't know what you're doing. And someone trying to put together an 18650 pack that doesn't know what they are doing is just comical. If you're going to build a 13s pack, you need a charger that will charge to 54.6V. You can use a 12-14s pack with any 48V controller. And a 15s or higher pack with some.

Drk Angel recommended me this charger I bought for a 13s pack.
Adjustable MeanWell type 48V power supply (53.3V - 54.6V)

http://www.ebay.com/itm/271852793055?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Can't it go higher than 50.4v?

 

[Overclocker]

What is the best configuration for making a 48V battery with 18650 cells?

I have a Imax B6 charger and want to use it to balance charge my battery.

Is it enough with two 6s (22,2V) packs in series for a Bafang BBS02 750W? If not, is it possible to add a third pack in series with 2s? (6s + 6s + 2s = 14s)

Or is it possible to balance charge a big 13s pack with my ImaxB6?

i use 12s w/ my GNG mid-drive. 13s gives too fast pedalling cadence

12s configuration allows me to split the pack into two 6s parts which i parallel together for simultaneous charging w/ the icharger 106b+ 250-watts

OK so it's possible to split the pack into two 6s parts. That's interesting cause there is too little space for a big 13s pack in the middle of my bike.

Will the BBS02 750w work OK with a 12s configuration? Or does it has to be 13s?

depends on the configured low-voltage cutoff on the BBS02. just get a configuration cable to change it. i think the default should be around 41v which means you won't be able to squeeze the last bit of juice from the battery. but depending on the cells used there might not be much energy left at this voltage anyway. and high LVC also prolongs cell life

watch the "knee". not much energy left at 3.4v

 

[wesnewell]

Output voltage: DC 48V
Output voltage adjustment range: ±10%
110% of 48V= 48+4.8 or 52.8V
Now you may be able to crank it to 54.6V, but it's not rated for it.

 

[kje]

I wonder if 9p is enough for BBS02 750W with used laptop cells. Average capacity is 1.5A for each cell after testing. (Both voltage sag and capacity test) So the battery pack will be about 10.5A. Is that enough? ☺

The reason I ask is limited space in the middle of my bike

 

[flyingbeekeeper]

I wonder if 9p is enough for BBS02 750W with used laptop cells. Average capacity is 1.5A for each cell after testing. (Both voltage sag and capacity test) So the battery pack will be about 10.5A. Is that enough? ☺

The reason I ask is limited space in the middle of my bike

I've been using a 13s9p 18650 pack for my Bafang BBS02 750W motor on my folding bike for several months now. I live in Austin, which makes Oslo look flat. If you watch your gearing, high amps is only about 18amps, on a 20 degree hill in 1st gear. Normal biking conditions, the battery is pushing ~10 amps to get to speed, and if I don't watch it my peak will max at 25a for a fraction of a second if I forget to drop gears before a hill. So you should be fine.

 

[tomjasz]

I wonder if 9p is enough for BBS02 750W with used laptop cells. Average capacity is 1.5A for each cell after testing. (Both voltage sag and capacity test) So the battery pack will be about 10.5A. Is that enough? ☺

The reason I ask is limited space in the middle of my bike

Use laptop cells to learn building skills but be prepared for a disappointment. Been there done that. Actually I used New Old Stock 18650's from laptop and projector battery packs. It's WAY to much work for the value received IME. I know several will come in and claim it's no big deal, but improper setup can make 18650 burn rather nicely too. DarkAngels methods take hours and hours of work. You'd be better served finding a little part tie job using the hours to buy some decent 29E 2900Mah NEW. I'm building a new design using the salvage batts but not expecting much from the pack. Just good cheap learning materials.

Also the cell log does draw power and really aren't great inline of a BMS. There a tool for checking, not full time meters and alarms. At least not in my shop. As usual YMMV.