Battery series wiring

General Discussion about electric bicycles.
Post Reply
sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Battery series wiring

Post by sutty86 » Apr 15, 2018 6:45 pm

Guys really struggling to get my head around wiring this up it's a 14s9p 20ah battery using used cells,
First time soldering so please don't flame .

I've managed to solder Nickle in the parrarel groups .
But unsure how to wire into a series m
Easier the better I'm afraid as I'm absolutely useless
thanks
Attachments
rsz_img_20180415_215545.jpg
rsz_img_20180415_215545.jpg (152.96 KiB) Viewed 216 times

markz
100 GW
100 GW
Posts: 5224
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Battery series wiring

Post by markz » Apr 15, 2018 6:52 pm

You need a Digital Multi-Meter to see which is (+) Positive and which is (-) Negative, then you need to flip flop them. So in the picture, if the 9 parallel strings are all with their (+) up, then you need to flip every second one so that each parallel strings goes like this, + then - then + then - until the last one. I hope that makes sense.

The bottom 9P string with its + up showing to the camera and the top would be - showing to the camera. Then double and triple check it all before you solder the series.

Hopefully you connected all the + and all the neg when you did the paralleling.
Series it alternates.

And the critical part is increasing the conductor material to 10AWG and evenly spacing them out .
series.jpg
(95.7 KiB) Not downloaded yet
Now this is the top side as pictured
series 1.jpg
series 1.jpg (55.13 KiB) Viewed 209 times
then when you flip the pack over to work on the other side
series 2.jpg
series 2.jpg (59.89 KiB) Viewed 209 times
I hope you notice the subtle difference between the sides.

Then you need to work on the battery harness. Get some 10AWG wire and place it where you made the series connection. And would be on the bottom side of the pack, luckily your both your + and - side harness comes out on the same side, which would be the BOTTOM.
series 3.jpg
series 3.jpg (61.02 KiB) Viewed 206 times
Then you buy some duct tape and some 1/8" wood and duct tape the frock outta it.

sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Re: Battery series wiring

Post by sutty86 » Apr 15, 2018 7:35 pm

:D Very kind of you thank you,
Here I was ,thinking I was going to get flamed.
What would I use the wood for ,to support the battery.
Thanks
Again wow will print off photo immediately

Jon NCal
1 kW
1 kW
Posts: 356
Joined: Jun 15, 2015 3:59 pm
Location: Mendocino, California

Re: Battery series wiring

Post by Jon NCal » Apr 15, 2018 7:50 pm

Before you take this guy's advice, realize he doesn't seem to know what a positive and negative ends of the cells look like and also has labeled the + and - incorrectly. So how much experience does he have?

sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Re: Battery series wiring

Post by sutty86 » Apr 15, 2018 9:37 pm

Do you want to help john,

I'm a noob but I know the difference.
OP was just trying to help

markz
100 GW
100 GW
Posts: 5224
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Battery series wiring

Post by markz » Apr 15, 2018 9:55 pm

Jon NCal wrote:
Apr 15, 2018 7:50 pm
Before you take this guy's advice, realize he doesn't seem to know what a positive and negative ends of the cells look like and also has labeled the + and - incorrectly. So how much experience does he have?
Only he would know which side is positive and negative, how would I know.

Built 3 packs now all been working fine. Latest pack is Makita power packs.

markz
100 GW
100 GW
Posts: 5224
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Battery series wiring

Post by markz » Apr 15, 2018 10:14 pm

sutty86 wrote:
Apr 15, 2018 7:35 pm
:D Very kind of you thank you,
Here I was ,thinking I was going to get flamed.
What would I use the wood for ,to support the battery.
Thanks
Again wow will print off photo immediately
Wood is to protect the battery pack from shorting out due to a crash, or something puncturing through just a duct tape wrap. I've used a plastic ammo can and made sure the battery would not move around inside. I have also used 3/8" plywood and secured it to make it look like a pannier bag on the rear rack.

You arrange each parallel segment that you soldered up, into the configuration I posted, that is what the Digital Multimeter is for, or if you can see the wrap with pos & neg markings, or if theres a button on one side and you know what polarity that is.

edit - I did make one mistake. The light blue at the ends, should be in the middle, in between each can. Perhaps it'd be one more series wire. I will bring up the old pic and post it. Saves heating up the battery can and potentially damaging it.

markz
100 GW
100 GW
Posts: 5224
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Battery series wiring

Post by markz » Apr 15, 2018 10:21 pm

Something like this picture, but make sure every light blue wire is the same length.
Solder on one side, then go to the other so that area can cool down a bit. But I guess it really dont matter now that I think of it, because you already soldered directly onto the battery can anyway. Be easier to do it the way I posted in the previous thread. Less wires to solder together the better, especially for you.
series 22.jpg
series 22.jpg (60.53 KiB) Viewed 176 times

DAND214
1 GW
1 GW
Posts: 3278
Joined: Aug 10, 2008 8:28 pm
Location: Chicagoland nw suburb Mt. Prospect IL. USA

Re: Battery series wiring

Post by DAND214 » Apr 15, 2018 11:12 pm

You might want to put something between the rows of cells, so they don't rub and short.

Dan

User avatar
MadRhino
100 GW
100 GW
Posts: 5056
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Battery series wiring

Post by MadRhino » Apr 16, 2018 12:51 am

I don’t know why, and I may be wrong but...

I have a doubt that your cells are all the same. I mean, a good battery is made with cells that are all equal and equivalent for type, capacity, impedance, age... And each one tested 2 cycles at least, before assembly.

Anyway, wish you success.

The assembly is simple. Parallel groups are all + together and all - together. Series are - to + to - to +... make sure each weld is sound

If you fit a BMS, follow the instructions, they are pretty straightforward.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Re: Battery series wiring

Post by sutty86 » Apr 16, 2018 7:03 am

Thanks gents

sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Re: Battery series wiring

Post by sutty86 » Apr 16, 2018 8:47 am

My cells are all branded , Panasonic, Samsung,and lg all tested with a litokala and are all between 2600mah to 2200mah
Pulled from Dell laptop batteries I have around 200 more from 1500mah to 2100mah

User avatar
MadRhino
100 GW
100 GW
Posts: 5056
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Battery series wiring

Post by MadRhino » Apr 16, 2018 11:59 am

Building a battery with cells that are not all the same capacity, C rate and impedance, it will get out of balance every discharge cycle. Its limit will be that of the weakest link, and proper balance charging will take a long time, every time.

If you don’t fit a BMS to them, some of the cells are likely to die pretty soon, maybe set fire. Battery assembly is a precision task, that is why the price and reliability of batteries does vary a lot.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Re: Battery series wiring

Post by sutty86 » Apr 16, 2018 12:37 pm

Thanks Madrhino totally understand but cannot justify spending so much on an end product,
I have lots of 18650 and wanted to put them to use,
I'm going to sort out the pack today,make sure battery's won't rub etc.
Going to buy a bms and keep it on a pannier rack on the bike , I will carry some sort of fire aid on the bike also.

Bike will only be used to commute at a max 11 miles then I have 12 hours to charge.

I honestly get you guys are worried about the safety of the pack , but I just don't have £300 to spend on a battery , I've only just managed to afford to take my family abroad for the first time this year.

markz
100 GW
100 GW
Posts: 5224
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Battery series wiring

Post by markz » Apr 16, 2018 10:28 pm

Did you measure IR or did you let them sit for a long while to see how each one lost voltage then put the closest ones together.
sutty86 wrote:
Apr 16, 2018 12:37 pm
-

sutty86
1 mW
1 mW
Posts: 12
Joined: Jan 20, 2018 2:23 pm

Re: Battery series wiring

Post by sutty86 » Apr 17, 2018 1:32 am

Yes the batteries have been sitting for a few months since I started doing this before Xmas and all stayed around 4.1v.

I've finished soldering the pack as in the photos,is there any benefit to soldering more series connections at the minute there's 3 going across,
All voltages are good and pack is 58v

markz
100 GW
100 GW
Posts: 5224
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Battery series wiring

Post by markz » Apr 18, 2018 1:20 am

Best not to have voltages at that level, 4.10V for very long, overnight is fine but not days, weeks, months. I usually charge to 3.8V and let sit for a month or two.

As for more series connection, you want everything to be as even as possible, the three I painted (neon green) on your picture should be good, its not like its high discharge 18650's.

How did you do the positive end and negative end connector wires?
for the charger connection and controller connection.

Post Reply