BBS02 on a cargo bike.

[top drive]

While i agree in principal there must come a point where the extra weight of a monster battery becomes incumbent on the bikes primary usage as a bicycle.

Im not trying to build an electric motorbike. I want a bike that will be the legal 15 mph assisted speedlimit no matter what i load on the back so first snd foremost it must be ridable as a bike.

What would the expected weight of a 22ah battery be . Am i wildly out thinking 16-18kg ie twice that of an 11ah....

 

[anotherkiwi]

About 7 kg. My 10.4 Ah bottle battery is 3.2 kg and the aluminium tube is probably 500 grams of that.

20.8 Ah of LiPo is under 6 Kg "naked"

 

[top drive]

Thanks thats very helpful

 

[anotherkiwi]

Im not trying to build an electric motorbike. I want a bike that will be the legal 15 mph assisted speedlimit no matter what i load on the back so first snd foremost it must be ridable as a bike.

Say you have a 250 W motor connected to a vanilla 14-15 Amp controller. You ride up a hill and ask for 396 Watts = 11 Amps x 36 Volts.

With an 11 Ah battery you are drawing 1C (1 x capacity) and will experience some sag.

With a 22 Ah battery you are drawing 0.5C and there will be much less battery sag.

Same applies to a 500 W motor which will be drawing 20 Amps on climbs.

These are real world numbers I see on every ride. I have a 10 Ah LiPo pack which is 10C = 100 Amps. When I climb with it the battery sag is about 0.3 Volts. When I climb with the 10.4 Li-Ion battery (2C and 3C peak so 20 or 20 Amps) voltage sag is 3 Volts sometimes more.

As you are putting less strain on the battery you will have improved battery life over the life of the battery and more charge life which equals more range per charge.

 

[top drive]

Oh yeH i get the math.

I was just struggling to justify the weight.

It seems the numbers i plucked from various retailers websites were wildly out. Perhaps they are as shipped numbers or were numbers inclusive of the motors as well - most likely this but i swear i read it was just the battery pack weight.

Your weight seem more realistic and plausable and more importantly - workable.
I have about a week to decide. Im on a 3 week trip to luanda in angola . Id like to have it waiting for me on return and it seems to take 2 weeks to ship from those guys.

 

[anotherkiwi]

http://em3ev.com/store/index.php?route=product/product&path=35_52&product_id=132

• Weight: 4.9kg (22P and 25R), 5.2kg (29E, 32E and 30Q), not including charger or packaging.

 

[Nealh]

While i agree in principal there must come a point where the extra weight of a monster battery becomes incumbent on the bikes primary usage as a bicycle.

Im not trying to build an electric motorbike. I want a bike that will be the legal 15 mph assisted speedlimit no matter what i load on the back so first snd foremost it must be ridable as a bike.

What would the expected weight of a 22ah battery be . Am i wildly out thinking 16-18kg ie twice that of an 11ah....

With a bbs03/bshd a moped come m/bike is what you will get, if you are looking for legal then the 250s bbs01 will do the job though some tinkering with the programming settings will probably be required to get better use out of it.

 

[top drive]

The bikes rated to carry 200,lbs of cargo plus a human

Other than the legality of the power printed on it..... If I knock it back in the speed settings then surely it will cope better with the weight ? -yes it's won't be letter of the law legal but the usual rules of dont ride like a dick apply.

If I took my tt bike out on the local cycle path and rode it at full tilt (40kph sustainably)it would be as illegal and irresponsible as taking an overpowered e bike down there.

I was looking at the bbs02 as per my original post how ever it was suggested as always when it comes to weight and controller overheat that I'd be better inclined to go for a bbshd...... Buying a bbs02 saves me around 300quid.but I want to be sure it can cope with a heavy load and not melt controllers trying to sustain 15mph.

 

[anotherkiwi]

Directive 2002/24/EC
Pedelecs with a maximum continuous rated power of more than 0.25 kW and all E-bikes that can be exclusively propelled by the motor do fall within the scope of Directive 2002/24/EC. In this Directive they are classified as low-performance mopeds, i.e. vehicles with pedals, with an auxiliary engine of power not exceeding 1 kW and a maximum design speed not exceeding 25 km/h. As a result, they have to be type-approved but they are excluded from a number of type-approval requirements as listed in Annex I of Directive 2002/24/EC...

So if you were in the EU you could go to a vehicle controle station and do a one off approval and you would be a low speed moped.

I would just put the motor on and limit it to 25 km/h, ride responsibly and not lose any sleep. If you do have a responsible accident you will probably have problems with insurance companies so stay out of trouble!

There are delivery people riding such beasts in Germany etc. where you can get a number plate for them.

 

[top drive]

Well after the thorn frame failed.

I've sourced a suitable kona sutra for the job.

Just need to get the motor kit a couple chains a cassette and a some tandem brake and gear cables

Should be able to sort it out when I get home.

Now sat in an Angolan flee pit.......got home for 3days between oz and here

 

[top drive]

still in sodding angola - never mind 7 weeks at home starting in 9 days

Ive been thinking more about this -

You guys are probably right - I'm a fit guy (and the wifes fitter) only looking for a little assistance as i said above - not a moped.

My previous experiance in Ebikes was when i sold powabykes with hub motors and they sucked at hills - but ive found out how to get on youtube here and have seen a fair few reviews of real world uses and your right - a 750-1000w would be a moped it would probably do 60kph even with a load which is just dangerous.

So - staying inside the letters of the law - a bbs01 with a smaller chainring and a wide range cassete ( i have a massive chain length so chainline shouldnt be an issue) and ill just need to put in a little more effort after all 250watts is about what a TDF rider puts out average for a stage.

will i regret this ?

 

[Rohloffboy]

Have a look at the BBS02 motors that Em3v supply, they don't do the 250w model but start at the 500w model which is marked on the motor case as 250w.

You can of course de-tune yourself using the programme lead, along with other adjustments.

 

[top drive]

good spot rohloff boy .

I like that idea restricted to 250 and marked as 250 but with the stronger gubbins and controller from the 500.

annoyingly its 36v only .

any decent suppliers of high capacity 36v batteries ?

the best i can find is 17ah ....

 

[Rohloffboy]

Yep I wonder were the law stands, if using a BBS02 that is a 500w but electronically restricted to 250w.

As in effect it becomes a 250w machine, which is legal, and the markings on the motor case confirm the fact.

Of course in the real world, it would be set to 500w, but who is to know, so long as you don't ride around like a nutter.

 

[top drive]

that would be somewhat defeating the purpose of staying within the law though .

Anyway i think ive solved my own issue about the 36 volt batteries - i was being a fanny its obvious.... wire them up parallel 2 x 11Ah gives 22Ah which is plenty

cost is similar to 1 x 48v 20ah so not making much difference in that respect.

Any other draw backs ive missed to doing that ?

 

[top drive]

back and forth and back and forth ......

just pulled the trigger with em3ev since a number of bad reviews about pedalease not even responding to emails for afterservice

 

[anotherkiwi]

that would be somewhat defeating the purpose of staying within the law though .

Anyway i think ive solved my own issue about the 36 volt batteries - i was being a fanny its obvious.... wire them up parallel 2 x 11Ah gives 22Ah which is plenty

cost is similar to 1 x 48v 20ah so not making much difference in that respect.

Any other draw backs ive missed to doing that ?

As long as the batteries are identical cell count and charged to the same voltage you will be OK. Otherwise you may get a big spark...

 

[anotherkiwi]

Yep I wonder were the law stands, if using a BBS02 that is a 500w but electronically restricted to 250w.

As in effect it becomes a 250w machine, which is legal, and the markings on the motor case confirm the fact.

Of course in the real world, it would be set to 500w, but who is to know, so long as you don't ride around like a nutter.

If it is marked 250 W on the motor and the motor stops assistance at 25 km/h it is legal. My motor peaks at 576 W with the controller I am using at the moment but it stops providing power at 25 km/h. It does get to 25 km/h really quickly, about as fast as any car around here which is probably very annoying for the driver...

 

[Deleted member 4366]

It's best not to put two 11Ah batteries in parallel. It's much more complicated than you think. It should only be done if they have the type of BMS that doesn't use a separate mosfet to control charging. What's wrong with buying a battery with the capacity you want? There's loads on Aliexpress.

 

[top drive]

i havnt gone down that route anyway.

but ali express - its like a box of chocolates - you never know what your going to get. (if anything at all)