What 20AH battery pack to build?

[agniusm]

So after my misfortune with Chinese A123 seller i have started digging to see what else i could use easy acquireble on todays market without spending too much money. Someone here back home was testing CALB and thundersky batteries and the news were pleasing. Dont know the details, what i know that CALB 100ah cells were used 13kW of total capacity: http://www.emobilis.lt/. He was using the car daily for one and half years and the capacity have not changed.
Now i came across this manufacturer Elite Power Solutions (http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=145). They have distributors all over US and one in Germany. They supply all the bits and pieces plus warrant their products. Most important thing is they produce 20AH cells which is exactly what i need. Sure they will be 6kg heavier than A123 but considering that individual cells have some sort of plastic casing and terminals it comes close to A123 prismatic cells and the fact that a123 cells are very complicated to acquire plus the sky high price makes them unattractive, never mind high discharge currents, i am not planing to beat speed record.
Here is my question. I am developing a full suspension cargo bike with 6061 alloy in mind. I will be using HS3540 clyte hub motor at 72V. So 24 20AH cells @ ~16kg. So basically by the info i found HS3540 can run @ 2kW comfortably and peak out at 5kW. So doing the math the draw @ 2kW when cells are charged to 3.65V would be ~23A and peaking out @ 5kW ~57A. The cells are rated @ 2C discharge and thats 40AMPS, and 10C for 20sec which is 100AMPS, so i fit in the brackets with some reserve. Please do correct me if i am missing the point here. It is very important to me to source the right cells to design my frame without redoing it. If i would get those cells i would go for their 10AMP charger cause it looks kind a solid: url]http://elitepowersolutions.com/products/product_info.php?cPath=9&products_id=205[/url]

Some pics:

Thank you

 

[agniusm]

So here is what i would get for trouble free pack:
GBS-LFP20AHA (4-cell Pack) x 6 - 744USD
EMS-CPU (with CAN) x 1 - 240USD
EMS-4SB x 6 - 396USB
EMC72-10 x 1 - 336USD
Total: 1716USD + shipping + charges
Expensive, but if that is all good for 6 years...

 

[AussieJester]

LiPO

Methods HV/LVC boards

best of luck

KiM

 

[o00scorpion00o]

Holy Cow that's expensive, and heavy ???

How about 12 of these ?

http://www.hobbyking.com/hobbyking/store/__19717__ZIPPY_Flightmax_8000mAh_5S1P_30C_DE_Warehouse_.html

About 12 kgs and around 1000 usd, leave it sit long enough and they drop the price!

20s 3p would give you about 74 volts nominal and 24 ah and shit loads of current.

Sure you have to buy a balance charger and power supply and you have no bms but you will save a few hundred and a few kgs too!

 

[dogman dan]

From what I have heard, these are more comparable to a ping cell than a A123. In other words, for best lifespan, 1c, perhaps 1.5c discharges is the target. So you better be planning on a 20-25 amp controller for a 20 ah pack of those. They have proven to be a reliable battery, but not for high discharges.

On another subject, why the high speed winding for a cargo bike? No hills at all?

 

[Pure]

You may not be looking for a speed demon, but you will be surprised how much weight can effect amp draw. If you are building a cargo bike, just how much cargo you intend on carrying will play a major role on how many amps you need to be able to safely pull from the pack. In other words, if you need to carry more than just a few pounds of cargo it's best you stay away from the really low C rate cells, like the ones you are looking at and Pings, and start looking at Headways as a start then on up to higher discharge rate batteries like LiPo.

In your case though, once you look at cost of building a headway pack and what the bike is intended to be used for, I would seriously just go ahead and go with Lipo. Better to have the Amps on demand and not need them then need them and not have them.

 

[mihai_atanasiu]

try http://www.ev-power.eu/index.php?p=productsList&sWord=promo this;

it is near you;

 

[agniusm]

Holy Cow that's expensive, and heavy ???

How about 12 of these ?

http://www.hobbyking.com/hobbyking/store/__19717__ZIPPY_Flightmax_8000mAh_5S1P_30C_DE_Warehouse_.html

About 12 kgs and around 1000 usd, leave it sit long enough and they drop the price!

20s 3p would give you about 74 volts nominal and 24 ah and shit loads of current.

Sure you have to buy a balance charger and power supply and you have no bms but you will save a few hundred and a few kgs too!

Ok i get that you get loads of power, but there is no info on cycles who makes them warranty etc. Might be more expensive in the end. Need more support from people using them for 2 years with feedback on capacity after. Thanx thou, always good to have 100 opinions.

 

[o00scorpion00o]

Yes LiFeP04 will give you longer life but the extra weight and bulk is not worth it in my opinion.

A 48 volt 20ah ping is the absolute maximum size and weight of a battery I would put on a bicycle, unless you can find plenty of room on your bike ?

If I were you I would get 16kgs of weight and put it on your bike before you spend so much on batteries just to see what you think!

I know some guys are building proper frames here on E.S that will take a lot of batteries and maybe you could consider that ?

Most of us charge our LiPo to 4.15 volts and don't discharge much below 3.5 volts to increase cycle life, but no one yet can say how well that works, but you do loose some capacity out of the pack.

maybe you could use a lower voltage pack to save weight and bulk ?

 

[agniusm]

From what I have heard, these are more comparable to a ping cell than a A123. In other words, for best lifespan, 1c, perhaps 1.5c discharges is the target. So you better be planning on a 20-25 amp controller for a 20 ah pack of those. They have proven to be a reliable battery, but not for high discharges.

On another subject, why the high speed winding for a cargo bike? No hills at all?

Well i did not say they compare to A123 but calb and thundersky cells which were tested in Honda hrv for around 1.5 years without capacity loose. They are rated at 2C normal discharge (to get cycles stated) and 3C max thats what they claim. I dont know anything about brands and products as of yet but PING i heard is crap, now on this forum i got that headways are crap too. Looks like most lipos are crap

 

[agniusm]

Yes LiFeP04 will give you longer life but the extra weight and bulk is not worth it in my opinion.

A 48 volt 20ah ping is the absolute maximum size and weight of a battery I would put on a bicycle, unless you can find plenty of room on your bike ?

If I were you I would get 16kgs of weight and put it on your bike before you spend so much on batteries just to see what you think!

I know some guys are building proper frames here on E.S that will take a lot of batteries and maybe you could consider that ?

Most of us charge our LiPo to 4.15 volts and don't discharge much below 3.5 volts to increase cycle life, but no one yet can say how well that works, but you do loose some capacity out of the pack.

maybe you could use a lower voltage pack to save weight and bulk ?

I will be building my full suspension cargo bike bottom up, frame etc. My design, my idea there fore i am going for this capacity and voltage. The box i will be putting my pack is about 60mm high minus 3mm x 2 covers (Not decided yet on materials, could be changed if carbon) 400mm width and 500 to 600mm length.

 

[o00scorpion00o]

Yes I forgot you said you were building your own!

Well then if you think those LiFeP04 batteries are for you then go for it. If it were me I would probably go for extra capacity over higher voltage.

48 volts might be fine if you are using it as a work horse or something like that ?

Maybe you should think about a higher torque motor also like the HT motors instead of the HS, that's what I would do. I prefer more torque than speed that 72 volts would give!

Even the external controller magic pie motor would be a great motor for pulling, it's certainly got lots of torque and it's got a large diameter which helps keep it cool.

I really think your might have issues with the low C of those batteries if indeed they are only 1C. that's why I would take cell man's packs any day!

What are you going to do with the bike, how much weight are you going to carry + you and the batteries, hills etc ?

As pure said, it's better to have the amps than want them!

Check out cell-man's packs, he makes good quality packs!

http://www.emissions-free.com/catalog/i28.html

I would go with 2 52 volt 11.5ah packs and they would more than meet your needs, I don't think you need the speed of 72 volts, I think you need to make a compromise

 

[agniusm]

Thanks. I am planing on building prototype at this stage, later would like to make a production bike that is not just a bike but a handy tool for business carrying goods locally, post man transportation etc. I am looking for speed @ around 60-70kmh optimally. Weight say 70kg rider + same cargo maybe a bit more say 2 cages of beer. In front i will be making a frame from 60x30 6061 alloy, rectangular, and want to use space in between to hide batteries, BMS, controller and a charger. I cant show you specifics as at the moment they are in my head and there is no time @ the moment to do a sketch. Front is 20" BMX wheel 36H with 160mm disk brake, at the back 26" wheel with HS3450 clyte motor, 36mm width rim and same tektra 160mm disk brake. Rear suspension - Cane Creek Cloud Nine, front RST capa T10, i know that the later is not that good quality as some of marsochi but its meant for road use and not down hill etc. Tires - Maxis hookworm 1.95 i think at the front and 2 something at the back, maxis matching tubes. Thats the stuff i got at the moment. In spring i am fitting my workshop with equipment - ESAB MIG and ac/dc tig, band saw, drilling/tapping machine etc and at the moment doing my studies on batteries. If i want to sell my stuff, it has to be of the best materials for affordable price. There fore i am looking not only at C rates but more importantly at long life of the battery. After all if someone is buying from you you have to make things last, other wise there is no point in doing anything at all. Key points i have is long life, edgy look, competitive price, decent spec.
Later i will be looking into prices and availability in anodizing the frame. Thats about it

 

[agniusm]

Check out cell-man's packs, he makes good quality packs!

http://www.emissions-free.com/catalog/i28.html

I would go with 2 52 volt 11.5ah packs and they would more than meet your needs, I don't think you need the speed of 72 volts, I think you need to make a compromise

I have checked the site provided and maybe it does not look nice but it brings in some confidence. I have asked sell what he could advise. Thanks for the link.
I would go for 48V system as that i could upgrade easily to 72V system just by adding another pack. Maybe it's a good idea to start with, as i would not have to spend fortune for the full size pack and still be able to test my bike just with lesser speed.
Always good to have 100s more opinions and sometimes it changes your mind and makes you consider other possibilities. As of earlier post regarding hub motor, they are cheap compared to battery packs and there will be no problem changing it with more torky one later if needed.
Really appreciate your input, Thanks everyone

P.S. perhaps you know the dimensions of a lower pack? There is no info on the site. Cheers

 

[Pure]

Headway cells and Ping packs are far from crap. Just you bough A123s (or so you thought), so we were advising you expecting you were looking for the kind of performance those cells can provide. Headways and Pings are both tried and true cells to use, you just have to keep it in perspective what the individual cell type can handle.

 

[agniusm]

Headway cells and Ping packs are far from crap. Just you bough A123s (or so you thought), so we were advising you expecting you were looking for the kind of performance those cells can provide. Headways and Pings are both tried and true cells to use, you just have to keep it in perspective what the individual cell type can handle.

Maybe they are and maybe they're not. I have not worked as of yet with any of batteries but what i got from here is a bag of mixed opinions. Some say they ok and some say they are not worth the money, i will be holding back this time and narrow it down down the line.

 

[Pure]

Headway cells and Ping packs are far from crap. Just you bough A123s (or so you thought), so we were advising you expecting you were looking for the kind of performance those cells can provide. Headways and Pings are both tried and true cells to use, you just have to keep it in perspective what the individual cell type can handle.

Maybe they are and maybe they're not. I have not worked as of yet with any of batteries but what i got from here is a bag of mixed opinions. Some say they ok and some say they are not worth the money, i will be holding back this time and narrow it down down the line.

I'm sorry but you are sorely mistaken. You will be hard pressed to find anyone on ES that will say Ping or Headway are crap. Just because they don't have a high C rates does not make for a poor battery. It just makes for one that needs to be used for it's intended purpose and not "hot rod" cells. Both are quality products, some of the best on the market.

 

[o00scorpion00o]

I can certainly vouch for ping!

My old 48volt 20ah ping that I sold to my friend is still working perfectly well after 1 year 5 months. No balancing issues, he doesn't use all 20 ah much, so he will probably get 2000 cycles easily from it!

If you definitely want 60-70 kph you have a few options one would be to get 2x 36 volt 20ah pings and connect them in series for 72 volts.

Your max current draw from 20ah pack ping would be 40 amps max, or get 4 packs for 40 ah and 80 amps discharge. At 60-70 kph you will be pulling at least 30-40 amps from the pack at that speed, especially accelerating and hill climbing.

You have not said how far you want to travel ? if you are carrying or pulling a lot of weight travelling at that speed you would probably consume around 55 wh/mi maybe more. So with a 72 volt 20ah pack you would have 1440 wh/hrs in your pack /55 wh/hrs would give you 26 miles, that's based on my own consumption with the mac at 35-40 mph, which is around 45 wh/mi at 35-40 mph, but I'm using a little 60 volt 10ah LiPo pack, weighing 6.5 kgs and I have great slick narrow tyres pumped to 90 psi!

I could possibly see your consumption around 60wh/mile.

4 x cell man 39 volt 11.5 ah packs for 80 volts 23ah will cost 1700 USD

2 x 36 volt 20ah pings will cost 940 USD that's a lot in the difference!

 

[dogman dan]

Despite the mocking monikers, Thundersag, or Deadway, there is no reason you can't use a lower c rated cell.

Just don't go around thinking you get maximum lifespan using them at the rated c rates. Those tests that show 1000 cycles or more are made at , at most, 1c. Sometimes the tests are made at .1c. Aiming for about half the rated c rate seems to be a good rule of thumb.

Lots of us have run thousands and thousands of miles through such cells with decent lifespans by using them at the rate I mentioned before, about 1c to 1.5c. You can have a spike that's higher no problem, just don't let it spike much more than 2c for ping cells, tundersky, or the ones you are looking at now. Morph was a kook, but he got a good long run out of the cells you are looking at. He ran em with a 2c controller.

All I was saying, is use a smaller controller, or a bigger pack. Ignore the weight weenies, a good cargo bike can carry the cargo. You should be easily able to carry 30-50 pounds of battery and another 50 pounds of cargo on a good cargo bike. Just don't use a faster speed motor, or too high a gear and you can lug weight around just fine. Steeper hills would of course be a problem. Be carefull about the add more power approach, on a steep hill that power may simply make heat, and you'll melt stuff.

Keep us posted, with pictures as you build the bike. We are really interested!

 

[AussieJester]

I'm sorry but you are sorely mistaken. You will be hard pressed to find anyone on ES that will say Ping or Headway are crap. .

reing batteries... i wouldnt be too quick to say that, been SOOOO many failures of the over priced rubbish on this site since i been a member, i wouldnt touch one with a ten foot pole... Headways...meh..

KiM

 

[dogman dan]

They definitely are not the way to go, for a high amp controller. For sure, if he's going to use a small battery and a big controller, he needs 20c batteries, not 2c.

It just depends on your needs, and your expectations. My cargo bike hauls huge weight just fine, using a 48v 15 ah pingbattery and 20 amp controller. I don't need or want to go faster than 20 mph packing a load, and because I chose a slow hub motor, I can grind up hills just fine at 12 mph.

You don't have to throw watts at it. I can climb a steep hill loaded down on 1000. I do have other bikes I ride for fun that I throw watts at, and I run em on 30c lipo.

 

[o00scorpion00o]

I wouldn't exactly call 16 kgs a small battery ? That is what the first batteries would weigh!

The 20 amp pings at 40 amps will be 2C if he uses 40ah of pings that will only be 1C and 40 amps will still be plenty of current for good torque give plenty of range!

If he needed a small battery for small range then cell mans a123 is the only choice for a ready built pack.

For me though LiPo is the only sensible way to keep size and weight down.

I do think he will have to compromise on speed, 25 mph maybe. 60-70 kph on a cargo bike I don't think is realistic or safe ?

On the other hand, he will have the option to go fast if he needs to.

agniusm, you have not said what range you want ?

 

[dogman dan]

You bet. If you need to keep weight and size down, and want to pull 50 amps, only a fool would choose a 2c cell.

He could build a bigger pack. He'll have to if he's going to ride 30 mph very far! I'm jumping to conclusions, but he's talking 2000w continous. That will take 300 pounds pretty fast. But he won't be getting 30 wh/mi at that continous wattage.

 

[o00scorpion00o]

You bet. If you need to keep weight and size down, and want to pull 50 amps, only a fool would choose a 2c cell.

He could build a bigger pack. He'll have to if he's going to ride 30 mph very far! I'm jumping to conclusions, but he's talking 2000w continous. That will take 300 pounds pretty fast. But he won't be getting 30 wh/mi at that continous wattage.

That's for sure, 55-60 wh/mi if he wants 60-70 kph that's 26 miles range form a 20ah 72 v pack at 55 wh/mi, probably more with more weight, my 45-48 max consumption on the mac at 35-40 mph, so his bike will surely use more with fat tyres and more weight!

 

[Pure]

I'm sorry but you are sorely mistaken. You will be hard pressed to find anyone on ES that will say Ping or Headway are crap. .

reing batteries... i wouldnt be too quick to say that, been SOOOO many failures of the over priced rubbish on this site since i been a member, i wouldnt touch one with a ten foot pole... Headways...meh..

KiM

Most failures have been with the early Pings. The V2.5s so far seem to be doing pretty well. Even still, any battery manufacture is going to have bad cells from time to time. Especially when you put a low C rate pack on something like an ebike that usually will more times than not end up pulling a higher C rate than the battery was intended to pull. Ping at least doesn't leave you hanging when a cell goes out. I know he's even help walk people through replacing cells after his warranty period is over. You just don't see that kind of customer service out of China..

Headways are IMO, if you can ignore their size and weight, the perfect ebike battery. Their C rate is in the sweet spot of what most ebikes, looking for some kind of performance, will demand. A 20 AH pack at 3c continuous is 80 amps. That's moving even at low voltage. Add to that the fact that they are large Ah cells, keeping cell counts down, also not having to solder them, all makes for a bonus for the DIY pack.