Help building a battery

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RonnieBrowen2106
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Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 9:42 am

I want to build a lipo battery for.my electric bike. My bike is a 48v bike. I want to have a 15ah battery. How many cells do I need in series and parallel? How many "s" equals a 48v battery? What bms should I use. And so on. I have lots of questions. I want to do it right the first time. Thank you.

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rojitor
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Re: Help building a battery

Post by rojitor » May 18, 2017 10:22 am

The usual for 48v is 12s . I recommend you to buy 4 6s bricks of 8000 mah
so you will have 48v 16ah. Since the full voltage you can get is 4.2vx6= 25.2vx2=50.4v most of the time you will be under 48v Therefore some people prefers going for 7s instead. 7s is not so common not so cheap and most probably not 8000 mah available. Also you will need special chargers able to run above 6s. Not worth it.
4 of these
https://hobbyking.com/es_es/turnigy-nan ... -pack.html or zippy will do.
do you know how to make a harness?

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RonnieBrowen2106
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Re: Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 10:43 am

rojitor wrote:The usual for 48v is 12s . I recommend you to buy 4 6s bricks of 8000 mah
so you will have 48v 16ah. Since the full voltage you can get is 4.2vx6= 25.2vx2=50.4v most of the time you will be under 48v Therefore some people prefers going for 7s instead. 7s is not so common not so cheap and most probably not 8000 mah available. Also you will need special chargers able to run above 6s. Not worth it.
4 of these
https://hobbyking.com/es_es/turnigy-nan ... -pack.html or zippy will do.
do you know how to make a harness?
No I do not know how to make a harness. I know nothing about building a battery. Just thought I would give it a shot.

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rojitor
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Re: Help building a battery

Post by rojitor » May 18, 2017 10:53 am

You can do the harness with bullets. I prefer andersons. The risk is lower.
You can tape all the bricks together and gather the connectors.
Image
now you have 6s4p
Image
This is the view from another angle.
Now you make the series section cable
Image
if you plug it now you have 12s2p use it for discharge.
for charge again you need to make not her parallel section as the one you have in the lipo pack.
And get an end-user harness for the balance.

Image
and you are done. You only have to plug/unplug the series cable to use it. If you get a bulk charger you use the series cable to charge as well.
bulk charge has some risks so you better don't Rush it to 4.2v 4.15 or 4.10 is enough. Balance the pack at least once every 10 charges. It is better if you do it often though. I do it once every two charges.

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Re: Help building a battery

Post by rojitor » May 18, 2017 11:46 am

maybe i didn't explain myself correctly. now that i see my post i think you will not understand.
Image
this is a 18s2p i did time ago.
Image
these are the parallel charge and series discharge cables
if you have 4 lipos you need to parallel them so you should make a cable to convert 4 sets of connectors into 2 so you can do as i said
Image
two cables like this one. in one side bullets and the other side andersons. so now you have 2 red and 2 black and can do as i said.
maybe it is a little confusing but is very easy when you see it.

Wait for a second opinion. Maybe someone can tell you about multistar and graphene. I have no exp with those lipos. two of those will do and you skip making the harness
https://hobbyking.com/en_us/multistar-h ... -pack.html
+https://hobbyking.com/en_us/xt90-batter ... eries.html
https://hobbyking.com/en_us/turnigy-gra ... ector.html
+https://hobbyking.com/en_us/hxt4mm-batt ... eries.html(actually you need 5.5 bullets)

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RonnieBrowen2106
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Re: Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 3:41 pm


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Re: Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 3:48 pm


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Re: Help building a battery

Post by rojitor » May 18, 2017 3:55 pm

2s? I don't think you want to make a battery pack with Those. Try to make it 2-4 bricks.
Take in consideration 18650 li-ion packs too. The risk is lower and the prices have improved a lot lately. Most people is quitting lipo for that reason.

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Re: Help building a battery

Post by rojitor » May 18, 2017 4:00 pm

Those turnigy hard case used to be very popular here. High density, cheap price and hard case... but as I said you better do very few bricks. Balancing big packs is annoying. The fewer the better unless they have low c.

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Re: Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 6:22 pm

I like the turnigy multistar 22.2v 16ah packs you linked. I will buy two of those for 44.4v at 16Ah. They will do. I really like the 2c charge rate. Half an hour is Awsome. My current li-ion takes 5hours to charge. At $240 I can't complain. I bought my 48v 15ah li-ion for $317

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Re: Help building a battery

Post by rojitor » May 18, 2017 6:37 pm

You don't need to make the harness if you get Those. That series cable they sell will work. I never used multistar nor the graphene. Dunno which is better. I'd ask for a second opinion before buying.

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Re: Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 8:39 pm

rojitor wrote:You don't need to make the harness if you get Those. That series cable they sell will work. I never used multistar nor the graphene. Dunno which is better. I'd ask for a second opinion before buying.
rojitor wrote:You don't need to make the harness if you get Those. That series cable they sell will work. I never used multistar nor the graphene. Dunno which is better. I'd ask for a second opinion before buying.
Ok sure will

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Re: Help building a battery

Post by RonnieBrowen2106 » May 18, 2017 9:06 pm

https://endless-sphere.com/forums/viewt ... 14&t=88382 created thread asking about batteries

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rojitor
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Re: Help building a battery

Post by rojitor » May 19, 2017 4:07 am

The sheet specs look cool and all but it's always better when someone talks about real life experience. Use the search engine as well. Probably many members discussed about their performance. Good luck with your build ronnie.

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Re: Help building a battery

Post by RonnieBrowen2106 » May 19, 2017 12:44 pm

Thanks. They say that the batteries last at least 16,000 miles with proper care. I will have to get a voltage alarm or some kind of programmable LVC. Thanks for your help rojitor. :D

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Re: Help building a battery

Post by RonnieBrowen2106 » May 19, 2017 12:50 pm

Also, I have a li-ion battery. I want Lipo because of faster charging and Lipo batteries cost a little less. But mainly for faster charging. Lighter weight is also a plus as well.

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Re: Help building a battery

Post by rojitor » May 19, 2017 4:27 pm

If your controller is not programmable those buzzers are a good solution. Inexpensive and efficient.
http://www.ebay.com/itm/RC-Lipo-Battery ... 1746517929

I have a cycle analyst. I see the voltage and the amps spent so I always know the juice I have left.
Be extra careful charging and Balancing. They are not meant to leave unattended.
A smoke detector and lipo charge bag is a convenient investment too.
https://es.aliexpress.com/category/2040 ... ector.html

https://www.aliexpress.com/cheap/cheap- ... y-bag.html
take care pal 8)

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Re: Help building a battery

Post by motomech » May 19, 2017 7:12 pm

Mr. Browen posts so many questions, it hard to know which to respond to;

https://endless-sphere.com/forums/viewt ... 14&t=88382
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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RonnieBrowen2106
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Re: Help building a battery

Post by RonnieBrowen2106 » May 20, 2017 10:54 am

motomech wrote:Mr. Browen posts so many questions, it hard to know which to respond to;

https://endless-sphere.com/forums/viewt ... 14&t=88382
I love to ask lots of quetions. Better to ask poeple who are experienced in these matters. I want to do everything right the first time

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