Could this be an option?

[onmebike]

I recently saw this add for a 10 cell Lipo for R/C models. At 37volt 4.5amp I wondered if it could be used to power a bicycle.
It doesn't have the management system of a bicycle battery and a purpose made charger would be needed to balance charge it.
Advantages may be price and light weight.


Turnigy nano-tech A-SPEC 4500mah 10S 65~130C Lipo Pack

 

[KirstinS]

LIPO has a niche following for sure - usually have to harness together 4 or 6 small packs

Two of these would make a decent enough pack at 37v 9ah

However, most folk seem touse Lipo to get a higher voltage (44.4v) and run it on 36v kits to get more speed

two of this pack would not give that advantage

Aslo it would be very expensive solution as each one is $222 (so $444 or £300) and the charger needed would be quite dear

 

[KirstinS]

thats 222USD from european warehouse

Turnigy nano-tech A-SPEC 4500mah 10S 65~130C Lipo Pack (DE Warehouse)

 

[Deleted member 4366]

It's very expensive because it has an extra high discharge rate. You'd be better using a combination of these packs. 3x2 gives about 48v and 10aH to get about 20% extra speed and torque from your 36v bike for about £120. You'll need an intelligent lipo charger, a power supply, connectors and wire to join them up:
Turnigy 5000mAh 4S1P 14.8v 20C hardcase pack (UK Warehouse)

 

[hech]

Good advice d8veh. Any idea why the 6 blocks of 4s lipo at $162 are cheaper than 4 blocks of 6s at $192, both from the uk warehouse?

 

[JimB]

Check the 'C' description. A 20C battery can be safely discharged at up to 20 X it's nominal capacity and a 130C at 130 X.

So a 5000mAh 20C pack can deliver 20 x 5 amps = 100 amps and the same capacity 130C could deliver 130 x 5 amps = 650 amps.

The higher the 'C' rating the higher the performance of the cells (in theory at least) therefore at higher cost.

Jim

 

[Deleted member 4366]

Good advice d8veh. Any idea why the 6 blocks of 4s lipo at $162 are cheaper than 4 blocks of 6s at $192, both from the uk warehouse?

Don't look a gift horse in the mouth. You can always sell it to Aldi to make beefburgers.

I think they're on special offer. They're in a hard case too, which is better for an ebike. I just ordered eight for a 16s pack. Should pep up my bike a bit, but a bit tight with 63v capacitors in the controller.

 

[amigafan2003]

My lipo pack:-

9 x 5s (18.5v) 4ah Zippy compact packed arranged as 15s3p giving one 55.5v (63v max) 12ah pack.

 

[countryman663]

Could this be an option? Once again I am in awe of the technical expertise that is casually dispensed on this site and opens up a range of possibilities for the technically capable. For those who are on the fringes of these detailed insights is there any chance of developing a virtual "shed" along the lines of, say, instructables

How to Make battery powered bikes - search Instructables
where you can set out in detail some of the great projects and tech solutions and induct other people with a bit of know-how and and desire to learn more into the theory and practice of :-

• Power supplies
• motor choices and use
• gearing and drive mechanisms
• matching controllers to motors/power supplies etc.

I know I would be keen and if organised into a new Forum it could be like an "Open University" of electric biking and we could become ..............bike-oligists I suppose.

go on you know we's love it!!!

 

[amigafan2003]

It's all here and on endless sphere (ok, more of it's on endless sphere actually) - all you need to do is search and read.

No one showed me how to build an ebike. I knew nothing about lipos before two years ago. I had no idea what a geared motor was or what a controller did or what the difference between sensored or sensorless was.

And now, two years later, people are saying I'm an expert

Put the time in and the rewards are yours - don't wait for it to be laid out on a plate.

 

[countryman663]

don't wait for it to be laid out on a plate.

It was more about sharing in a structured way in a kind of manufacturing forum rather than getting someone to do it for me! I thought it was a nice idea but there you go

 

[KirstinS]

I do see what you are getting at countryman (i think!) Thing is an "ebike" can cover the breadth and range of, say, a "house"

you can't really have an instructable for a house because there are so many questions in what the right house for an individual. Your idea of a perfect pad may be my nightmarish hell (or vice versa !)

You need to need to know the factors important to you first and work from there. And once you've got that there tr many members prepared to effectively provide that instructable on a personal ad hoc basis !

A year ago I knew next to naff all. Now I have taken apart a bottle battery, tested all parts , rewired it to bypass the BMS, built a booster battery pack to increase my speed, soldered balance leads, understand what 2s6p means, get the difference between battery chemistries ..,.to name just a few

And it's all down to help from from this board (and endless sphere)

And mostly d8veh on both actually (credit where it's due !

 

[amigafan2003]

It was more about sharing in a structured way in a kind of manufacturing forum rather than getting someone to do it for me! I thought it was a nice idea but there you go

Sorry - didn't mean to sound rude in my response - let's try it another way.

I'm not very good at organising my thoughts - I'm a learner, not a lecturer - so I can't do what you're suggesting.

However I did keep a diary - see this thread - http://www.pedelecs.co.uk/forum/electric-bicycles/9442-new-build.html

You should find a lot on info in there, but you'll need to correlate the information with other sources - it took a lot of time just to keep that diary and make the posts and take the photos - I didn't (and still don't) have the time to present the information in a more coherent manner.

 

[mountainsport]

amigafan2003,

Nice one I like your lipo pack setup, is there any need for BMS? Teach me.

Moutainsport

 

[Scimitar]

amigafan2003,

Nice one I like your lipo pack setup, is there any need for BMS? Teach me.

Moutainsport

You can get away without a BMS, for a while, then your shed burns down during the night.
Seriously, it's really dependent on what battery chemistry you use. Myself, I deliberately chose Bosch Fatpacks (36V power tool batteries) because they're lithium manganese and inherently very safe and don't need a BMS. If I were using other types of lithium chemistry I'd definitely have a BMS, although some have found you can get away without balancing on every charge, but that requires vigilance and is no longer a fit and forget exercise.

 

[103Alex1]

amigafan2003,

Nice one I like your lipo pack setup, is there any need for BMS? Teach me.

Moutainsport

I like it too. The case is a nice touch as well. But he's a "learner not a lecturer" so you may struggle with getting taught lol.

 

[mountainsport]

You can get away without a BMS, for a while, then your shed burns down during the night.
Seriously, it's really dependent on what battery chemistry you use. Myself, I deliberately chose Bosch Fatpacks (36V power tool batteries) because they're lithium manganese and inherently very safe and don't need a BMS. If I were using other types of lithium chemistry I'd definitely have a BMS, although some have found you can get away without balancing on every charge, but that requires vigilance and is no longer a fit and forget exercise.

Do you have any photos showing your batteries , or am I asking too little?

Mountainsport

 

[amigafan2003]

amigafan2003,

Nice one I like your lipo pack setup, is there any need for BMS? Teach me.

Moutainsport

I don't use a BMS but I've set the controller to cut of at a pack voltage of 54.75v - which is approx 3.65v per cell, preventing a low depth of discharge which is the primary reason for cell inbalance. I've had the pack built since October and after around 100 cycles I've NEVER had to balance the pack - I just use the Meanwell to bulk charge up to 62.25v or 4.15v per cell and the cell balance is always withing a few mv - in fact I charged up a couple of days ago and all packs were at 0mv balance!

I do however take NOTHING for granted. I check the cell balance before I leave for work, when I get to work, when I leave work, when I get home prior to the charge and immediately after the charge. Checking like this *should" hopefully sport a problem with the pack before it develops into something serious - this routine helped me catch a bust cell on my old 44v cell and let me remove the pack before I attempted to charge it. 99% of lipo magic smoke incidents happen when charging and are the result of trying to overcharge a cell - either because the wrong voltage has been selected or because you have a faulty cell.

As schimitar says - using lipo is not a fit and forget exercise but for me, exotic batteries are part of the ebike experience and I actully like being "hands on" with the batteries and for me the benefits of lipo (high energy density, light weight, modularity and high discharge and charge rates) make the vigilance worth while.

I accept that I'm dealing with lipo though and all it's associated risks and thus have a smoke alarm installed in the garage that is wired direct to the house. When charging and being stored, the bike is always next to the door - it's quite simple just to wheel the bike outside and there are aa couple of powder fire extinguishers to hand should the unfortunate happen.

 

[KirstinS]

As my main pack has died and I'm more confident these days so I am seriously considering going lipo over replacing my bottle battery at 220. I like modular aspect as well.

Can you help me with a shopping list please to help me decide?

I think I need

1. 6 x packs above to get 44.4v 10ah
2. Xtr and 14g wire to make a harness
3. Charger - what one ? Can I charge 6 packs at once ?
4. Lipo alarm to prevent over discharge. Where to buy?

Thanks
Kirstin

 

[Deleted member 4366]

After trying loads of cheaper chargers, I've settled on this one. It charges the cells individually through the balance leads. It comes with a board to charge 4 batteries at once, so you might want to consider 6s packs if they're not too expensive. You need a power supply for this one, which you can make in about one minute from a PC power supply. I'm sure you or one of your mates has an old PC lying around somewhere.
BC168 RC Model Super Speed Li-ion Li-Polymer Li-Fe Hobby Balance Charger BC016 | eBay

You can get all the connectors, alarms etc from Ebay cheaply enough. You need a voltmeter to show pack voltage in real-time in case of problems. I think this thing might be useful for that. I'm still waiting for mine to arrive, so I can''t yet say how good it is, although I have ahigh level of confidence:
New Digital 60V/100A Battery Balance LCD Voltage Power Analyzer Watt Meter | eBay