48 v 35.2ah li-ion battery pack

[TwoWayStreet]

He currently has 16 4p packs. He needs 12 more 4p packs. With 28 4p packs he can build a 14s8p, 51.8V, 17.6Ah battery pack for his ebike. 35.2A burst discharge and 8.8A continuous discharge. 1,823W burst and 456W continuous is plenty to power a legal ebike, even for a lazy, pedal pretending, old, know-it-all guy.

 

[parabellum]

He currently has 16 4p packs. He needs 12 more 4p packs. With 28 4p packs he can build a 14s8p, 51.8V, 17.6Ah battery pack for his ebike. 35.2A burst discharge and 8.8A continuous discharge. 1,823W burst and 456W continuous is plenty to power a legal ebike, even for a lazy, pedal pretending, old, know-it-all guy.

And most likely, the pack, will have very short life expectancy in tandem wich 850w motor/controller kit and no way to limit the current closer to its normal discharge rate.

 

[TwoWayStreet]

Just because he has a 850W motor/controller doesn't mean it has to be run at 850W. 456W is more than enough to run a legal ebike at 20mph without any pedal assist. But yeah, anyone can ruin a battery, no matter how large or powerful, by simply drawing more than the battery can sustain. As for current limiting, it can be done by anyone with a Cycle Analyst.

 

[dogman dan]

Yes, if he already has 16 packs, then buying 12 more would allow him to build a 48v pack of about 17.5 ah size.

If it's not been made clear yet, when you do get a "48v" 14s lico bms, each of your four packs would be one cell to the bms. One wire to the bms per each 4 cell group on the positive terminal. last bms wire on the end negative terminal. If you buy more 4p packs, then you can parallel the packs into 8 cell groups for a total of 17.5 ah on the entire 14s pack.

The spec sheet says discharge at .5c max. That means you would have a pack able to discharge 8.75 amps. (if you make an 8p pack) That's getting better, but if your bike has a 20 amps controller, you'd have to ride awfully careful to avoid discharging it a 15 amps, thus ruining your cells. I would believe I'm going to win the lottery before I believe in 2c burst rate not damaging those cells. But a 1c rate sounds plausible, so a 15 amps controller would work if ridden incredibly carefully.

Buying an even more, you could build a 24 ah pack, that would have a chance of lasting, if you have a typical 22 amps controller on that motor.

So, you gonna have to limit amps. Pop open that controller, and cut one of the two shunt wires, so you have an 11 amps controller. That will give you power to cruise, and prevent you from ruining a 17 ah pack. It will be a pokey bike, but not ruin your 16 ah pack.

If you just make an 8 ah pack, you need to get a tiny scooter. Welcome to ebikes, where batteries cost all you have, no matter how much you have.

 

[Takemehome]

I have never been so misunderstood so it must be the internet here in NYC. I'm going to start over by desoldering 16 -four packs of 18650 cells. Each 4 pack has four 2200 mah cells welded together with battery tabs and factory specs of 8800mah for each 4pack. The total of these 16 -4packs is 64-18650 cells. Which part of 16 cells do you not understand, New Mexico?. These cell packs were advertised and sold on EBay as four 4 packs of 35.2ah per 16 cells. If this is false advertising show me how and where. What configuration of four 4packs of 16 cells produces 35.2ah?. According to the above experts my current configuration is only about 8ah. Assuming you experts know what your talking about I took apart my battery pack and I'm back to square one with $254.00 in the form of 16 four packs of 4 -18650 cells. How much of this is still not clear to you, in New Mexico?. What should my new configuration be for a 48 v. Battery pack. Keep in mind that I'm not going to buy another 16 packs of cells based on the above advise. I'm willing to live with a 15 or 20 ah battery pack.

Dogman,
You still help this guy even if he insults you ?
I salute you, my friend

 

[dogman dan]

Why get ticked because he doesn't get it yet that he can't make a 20 ah pack out of what he has, unless he makes it much lower voltage.

I just misunderstood what exactly he had until he made it all clear by posting the specifications page. Now, if he got really pissed off, and started really abusing members, he'd just get moderator attention. My guess is he'll never come back and read any of this anyway.

Bet he hooks his lico up to his lifepo4 bms anyway, then he'll go off charged to 3.7v and have a capacity of about .5 ah in his entire pack. The pack will charge to 48v at 16s because it's barely charged at all.

He'll learn the hard way, just like I always have to do. It's basic stuff, 4p the capacity adds up so the groups are 8.8 ah. 16s of that, the capacities don't add up so it's still 8.8 ah.

The 35ah in the ad refers to paralleling 4 of the 4 packs. So if he wants that at 48v, he needs four 14s sets of the 4p packs.

56 four packs, 224 cells. Right now he has 64 cells. He can make a pretty good 35 ah 15v pack with what he has. or a 17.5 ah 30v.

 

[Humberto]

Thank you Dogman, Wesnewell, and Major. I'm sure that all of you are secure with your manhood, as you have no problem imparting your skill set to the lay person. I'll put away my 64cells for a life time supply of bike lights. My nose told me buy the $12.00 lifepo4 cells in 3400, 4000 and 5000mah but a YouTube anarchist mislead me away to the $3.00 Sanyo cells. I was told that many of the lifepo4 cells were re-packaged and re-sold as new. I want to buy lifepo4 cells for my lifepo4 BMS. What quantity and brand name should I be shopping for on EBay. Your ratio of series to parallel cells is loud and clear. However, it's the 16 balance wires that sounds like I must start with 16 cells, and who knows how many rows of cells for a total of whatever. I also suspect that under shrink wrap of Chinese battery packs, is a dumping ground for poor quality cells . I refuse to send my money to Hong Kong, so that they can take 8 weeks to play with my funds before they ship. Why have you experts allowed the rest of us to become battery dependent on China. Where is the battery pack for dummies book?. Where is the YouTube video from Endless-Sphere to counter all the miss information . Battery packs are not rocket science, so you guys don't need to use an overdose of tech talk to impress each other or beginners. Just keep it simple, I'm building a battery pack, not an electro-magnetic pulse devise for my rear carrier. Thanks again.

 

[dnmun]

you do not have to use all 16 channels on the BMSs from Bestechpower. if you only have enuff for 14 channels you can still use a 16S BMS with the channels populated, but not connected through a sense wire to the cells that are missing.

building a battery pack is not trivial. a lot of people have been mislead by others into thinking they could just solder a buncha laptop cells together and have enuff power to run a powerful motor but they just do not have the C rate needed.

you may be able to salvage some of what you have collected, but soldering is likely to reduce the performance of the cells on a random basis. jmho

sorry you are brainwashed about the battery suppliers from china and need to make up stories about how they steal your money for 6 weeks. of course you are beginning only now to understand how much more advanced they are than you when it comes to making batteries. none of them use these little laptop cells.

 

[wesnewell]

Welcome to ES****Do this before your first post or now (it's retroactive)*****
Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum) and save it. This will help people help you. Example: Wylie, TX, USA. Without knowing what country you are in it's hard to make any recommendations and you will waste your time and others. Thank you.

There's all kind of lifepo4 cells you could use to make a 48V battery pack. And yes, you want 16s using lifepo4. That's 51.2V nominal figured at 3.2V per cell (group). And you can use your 16s bms with it. Personally, I use nothing but rc lipo, but if I were to build a lifepo4 pack I wouldn't use anything lower than 3C cells unless I was building a 30ah pack or larger. Many people use these cells.
http://headway-headquarters.com/headway-cells/
They look very easy to put together with screw terminals. Anyone should be able to do it.
Others may prefer pouch cells. A123 20AH cells have a higher C rate I think, but I really don't pay much attention to it since I'll never use lifepo4. Building a pouch pack will take more time an require good soldering skills. So take your pick, or use something else.

 

[dogman dan]

Me too brother. Where are those good sources of affordable cells that are not in china?

The cells you bought will work, you just need lots of them. It takes way too many to run the more powerful bikes. We can't control the other info on the net. That's like trying to mop up the ocean with a single sheet of paper towel. We just dope slap misinformation and misunderstandings that appear here as you now know.

My list of people in China I recommend trusting is very short. Bottom line is, a good battery large enough to run a moderate power ebike will set you back close to $500 minimum, and better ones more. But if you get a good one, it should last you for several years.


The short list from China

EM3ev

Pingbattery Get at least 36v 20 ah or 48v 15 ah size to have enough discharge rate to run a 20 amps controller bike.

Sunthing on Ebay, has a more affordable lifepo4 battery using cells similar to pings.

Hobby King, has the RC lipo (lithium cobalt) batteries, but if you order those from them, you use the local warehouse. Don't order lico from china.

 

[Humberto]

Thank you Wesnelwell, you made my day . Unlike California, here in New York City we have and sell everything except lifepo4 cells.

 

[Humberto]

I'm ready to order this Lifepo4 8000mah cell. How many in a series and how many in parallel do I need for a 48 v. 20 or 30AH battery pack?.

Does using the 2 hole busbar eliminate the need to solder, or must it be soldered in place?.

 

[Humberto]

I'm ready to order this Lifepo4 8000mah cell. How many in a series and how many in parallel do I need for a 48 v. 20 or 30AH battery pack?.

Does using the 2 hole busbar eliminate the need to solder, or must it be soldered in place?.

 

[migueralliart]

For a 48V 24Ah pack you will need 16S3P 16 x 3 equals 48 cells total. That is if you consider 16S lifepo4 a 48V nominal pack. I'd rather go with 16 than 15.

 

[pdf]

To get to 48v (nominal), this is usually a 15 or 16 cells-in-series (shorthand is 15s or 16s) pack with LiFePO4. Let's assume 16. That will be like 58V right off the charger. Then, to get to your desired capacity, you will just multiply the single cell capacity (since they are in series, the capacity is only the single cell capacity) times the number of these 16 cell units. You have settled on an 8 Ahr cell. So 2 of these series units will give you 2 x 8 = 16 Ahr. 3 will give you 3 x 8 = 24 Ahr. If you want between 20 and 30 Ahr, you would use 3 of the 16 cell units, or 48 cells. That is a lot of cells. A 24 Ahr, 48v pack is pretty large, but I don't know your application. You will need to think out how you are going to mount it, depending on what sort of vehicle it is going on. If a bike, that is a BIG pack and will be large and heavy and awkward to mount on the bike.

Make sure you get the right charger and BMS for whatever battery type you buy. The bus bars on these cells are designed to fit screw terminals, if I am not mistaken, so no soldering. We had a battery like that on a student project I worked on once. The downside of these kits is that the geometries are somewhat limited and there is more free space because the cells are held apart slightly but they are easier to put together into a battery than for example pouch cells.

EDIT: While I was typing, someone else answered. Sorry for the duplicate.

 

[TwoWayStreet]

Take a look at the bigger picture before making another mistake:

1) Do you know anything about BMSes? None of them works. So by adding it, you are creating more problems for yourself down the road. The best thing you can do with your already bought LiFePO4 BMS is to put it in the trash can. With the exception of a few delusional members here, BMS stands for Battery Murdering Systems.

2) LiFePO4 has a much much much lower energy density than your Sanyo 18650 LiCo. LiFePO4 has the lowest energy density of all lithium batteries. Do you really want to carry at least 50% more weight for the same amount of energy? Worse, most LiFePO4 cells come from no-name manufacturers and their quality is always questionable. So is their claimed capacity, usually measured at 0.2C or lower. Which means that you will get a lot less running at 0.5C, let alone at 1C or 2C (if they are at all capable of those rate) continuously.

3) You already own 16 4p Sanyo packs. If you want a 48V, 26.4Ah pack, buy 23 more. 26.4Ah is a very large pack. I am confident you will do fine with a 48V, 17.6Ah pack, in which case you only need 10 more 4p Sanyo packs. Your Sanyo Ebay vendor is very conservative (not a bad thing) with the discharge rate. Those cells will have no problem running 1C safely. There are other vendors who sell the exact same cell and claim a 2C continuous discharge rate. Obviously that's just bullshit. Bottom line, 0.5C is very conservative, 1.0C continuous is fine, but nothing more than that. 2C burst (30 seconds or less) is also perfectly fine.

 

[agniusm]

First, ignore above post, talks crap.
A123 ANR26650M1 density 108wh/Kg, sanyo cell - 215wh/kg. It will work out better on a123 favour cause you will need 4+ times more battery from sanyo to at least have fraction of a123 discharge potential. So power wise a123 is more than 4 times lighter. A123 20ah pack from usa. 2.3ah cell, 30c. You need 8 in p and 16 in s. Dont know why people saing 15s when 48v system is 16s, even all bms' es for lifepo4 comes in 12s, 16s, 24s, and not odd 11s or 15s wank. 128 cells total for 640usd should outlast couple of bikes with 2k cycles rather then 800. 9.4Kg battery. This is prooven good stuff.
They will ship to new york 128 cells for 16 bucks.
http://www.buya123batteries.com/ProductDetails.asp?ProductCode=300001-001BB

 

[agniusm]

Read on here why its b grade, member from a123 explained:
Because product is discontinued thats all. Nothing wrong with it and it Is from official dealer.

 

[TwoWayStreet]

Grade-B? That means junk. Remember A123 does not have a grade specification. So grade-B is just a term created by junk vendors selling QA rejected cells.

What the heck is an official dealer? There is no official dealer. The company is dead.

 

[Humberto]

Thanks for all of the new commers who have dumped another load of facts to confuse my new choice of battery selection. I thought I made it clear that I was not going to double my 64 cells just to get about 16 AH. I certainly will not ever buy 170 cells to lug around on my folding bike. America has fast become a dumpping ground for Chinese products. New Yorkers don't buy schrink wraped items without knowing exactly what's inside or the technical contents including all parts. I won't but from predatory Chinese merchants anymore.

 

[TwoWayStreet]

You're welcome. Go ahead with your smart choice and lug around twice the weight to get your 25Ah capacity. Or buy the junk A123 suggested by the above idiot.

 

[agniusm]

Grade-B? That means junk. Remember A123 does not have a grade specification. So grade-B is just a term created by junk vendors selling QA rejected cells.

What the heck is an official dealer? There is no official dealer. The company is dead.

http://www.info.a123systems.com/blog/?BBPage=1
Direct link on a123 blog to a buya123battery site. Its far from dead, Wanxiang group bought it and operational.
You are confusing people.
"8amp discharge is nothing. I am pulling up to 24a on my folding scooter. You will ruin your battery and loose your money. Lots of folks exept above, gives a good advice and you ignore it and go by your twisted imagination, you waisting everybody's time here." - Miss read, ignore, my apologies.
Oh, and there is 50.4v hoc 32ah battery pack from enerdel sold in usa. Major sells them for 480usd, 150amp discharge, but we know, you will go with laptop size battery pack on a bike, good luck

 

[gogo]

You're welcome. Go ahead with your smart choice and lug around twice the weight to get your 25Ah capacity. Or buy the junk A123 suggested by the above idiot.

Lol, there are no idiots here, but there is some idiocy. The A123 cells are 'B-grade' by virtue of being discontinued, not by any quality measure.

Consider the source of information offered.

 

[Humberto]

For the last time, I'm no longer trying to salvage my 64 li-ion cells. They are not compatable with my Lifepo4 BMS. WHICH PART OF NOT COMPATABLE DO YOU NOT UNDERSTAND?. If you want to add your two cents, at least read the above posts from number one. My new direction is Lifepo4, not Li-ion. If your so hot for Li-ion, I'll give them to you for half price. Thank you again.

 

[TwoWayStreet]

Lol, there are no idiots here, but there is some idiocy. The A123 cells are 'B-grade' by virtue of being discontinued, not by any quality measure.

Very logical! A perfectly good product is "down graded" to b-grade simply because it's discontinued. Where can I buy a b-grade new laptop, or car, or TV... Talk about idiocy. There are no idiot here? There is at least one now.