Small frame. No room for battery.

[Davie dab]

Hi folks. Since getting my ebike and hitting the roads commuting to and from work, then the occasional blast around some tracks.... my wife has seen me getting fitter and generally enjoying the ride out. Now she wants part of the action and bought a 14 inch frame carrera. Yes i know, be kind.. i come from a background of working with my hands and not scared to build a basic kit to her bike. But now hitting many walls on trying to find a suitable battery for this small frame. Unless its on a rear rack or a small water bottle version, i cant see a way around this. Mine is 1000w rear hub kit and would like something as close to this as possible. Maybe 500 or 750 watt. Is 36v going to be enough? to keep size down.
Frame is 12 inch x 14 x 7 triangle...

 

[fauconnier]

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[Art Deco]

Hi folks. Since getting my ebike and hitting the roads commuting to and from work, then the occasional blast around some tracks.... my wife has seen me getting fitter and generally enjoying the ride out. Now she wants part of the action and bought a 14 inch frame carrera. Yes i know, be kind.. i come from a background of working with my hands and not scared to build a basic kit to her bike. But now hitting many walls on trying to find a suitable battery for this small frame. Unless its on a rear rack or a small water bottle version, i cant see a way around this. Mine is 1000w rear hub kit and would like something as close to this as possible. Maybe 500 or 750 watt. Is 36v going to be enough? to keep size down.
Frame is 12 inch x 14 x 7 triangle...

Consider a 500w mid-drive and water bottle battery like one of the many @PedalUma keeps posting.


This is a pink girl's bike that doesn't stand out and say "steal me" in a bike rack. 500 watt mid-drive. Needs a pink Unicorn on the battery...

 

[harryS]

Is your wife going to follow you around on your tracks? For that, a rack battery is not optimum, mainly because of the stress. I'm sure it would break. For pavement though, all my bikes can carry batteries on the racks, and I don't know why so many people complain about balance. There are dirt riders carrying 10 lb batteries on their backs.

 

[Davie dab]

Consider a 500w mid-drive and water bottle battery like one of the many @PedalUma keeps posting.
View attachment 117576

This is a pink girl's bike that doesn't stand out and say "steal me" in a bike rack. 500 watt mid-drive. Needs a pink Unicorn on the battery...

This could be the best option. She will be also commuting but not doing any off road.. i will contact pedaluma. Thankyou for your help. D

 

[indianajo]

Plenty of room to put a dolphin battery on top of the top tube. You'll have to run angle down to the bottom tube to keep it from falling over, but oh well. 4 oz extra. Don't even need to drill the bottom tube, just let the fork ride against it both sides.
I cage my battery in aluminum angle and hang it off the front for better balance. However without bosses in the frame for a front basket, you have to steer the battery. 7 lb might be okay on road but I had 13 lb on a rutted grassy driveway and really couldn't keep up with steering it at 1 mph. Advantage of a battery cage, 18 screws with elastic stop nuts and screw heads you cant reach without a 8" shank screwdriver really discourages wannabe thieves. 2 attempts at a couple of screws at the grocery, no nuts actually spun off.
36 v is the new standard in geared hub motors. It is very hard to find a 48 v version anymore. 48 v would push a motor to 1000 or 1300 w, but the laws are covering the planet limiting ebikes to 750 w. My state went 3 class last year.

 

[Davie dab]

Is your wife going to follow you around on your tracks? For that, a rack battery is not optimum, mainly because of the stress. I'm sure it would break. For pavement though, all my bikes can carry batteries on the racks, and I don't know why so many people complain about balance. There are dirt riders carrying 10 lb batteries on their backs.

Hi there, wife will be commuting with me but not going off road so only road riding. Prefer a little amount of power so 500w should do the trick. I was also a bit sceptical about racks with battery on but not after you say they work well. Do you build them or supply a kit ? Cheers D

 

[Davie dab]

Plenty of room to put a dolphin battery on top of the top tube. You'll have to run angle down to the bottom tube to keep it from falling over, but oh well. 4 oz extra. Don't even need to drill the bottom tube, just let the fork ride against it both sides.
36 v is the new standard in geared hub motors. It is very hard to find a 48 v version anymore. 48 v would push a motor to 1000 or 1300 w, but the laws are covering the planet limiting ebikes to 750 w. My state went 3 class last year.

Think with the advice i will go 500w. But mid motor or rear hub?????.
Wife is only 5'2" so anything on top tube would get in way when she jumps off as tippy toes only just touch floor when she is on seat.. suggestion on where to buy are welcome. I know uk is 250w max motor so we will skip that subject.

 

[indianajo]

Here is my 13 lb LiFePo4 battery hung off the front. Vertical angle went between motor axle on fork & two clamps to the handlebars. Vertical struts were drilled & filed to act as torque arms on geared hub motor. . Was hard to find extra 14 mm x 1.75 nuts for the hub motor. Had to make them with a tap. Handlebar clamps were sawn out of box fan frame, string of holes for 10-32 screws to tighten up. Too heavy to steer at 1 mph through ruts. Current bike left has bosses welded in frame for front basket, which I replaced with my battery frame.
Only mid drive and direct drive hub can climb 1000' in an hour without overheating. No 1000' mountains in UK, IMHO. Bosch & Shimano get you into sole source $1300 (B) or $1000 (S) replacement batteries if one is stolen. Bosch lower 3 lines, bafang, other mid drives drag power off. Brose, shimano, yamaha don't. With geared hub motor I get 5000 miles per 8 speed chain, any mid drive owner want to top that? Replaced at 100% wear, no damage to sprocket tips.
DD motors accelerate slowly and use too many watthours climbing hills slowly. Geared hubs accelerate quickly & mine can start 330 lb on a 15% grade. Geared hubs do wear out the gears, my first @ ~4500 miles but they are cheap. It cost $221 with all installation kit. I'm getting used bafangs front geared hubs for $23 + freight. I like front hub motor, but don't use power on ice, wet or muddy metal plates, rock, or wood bridge decks. Don't climb mountains off road with a front hub motor.

 

[PedalUma]

Here is my latest. Another of these is coming in today. The ladies are underserved. They do not want heavy bikes. And they do not want to ride for over 2.5 hours at a time. They want them to be comfortable, practical, and girly.

 

[stanmiller]

This is my wife's Trek I converted with a Bafang SWX02 250W hub motor. It's plenty of power for our moderate hills in Charlotte and gets about 15 miles a charge.

 

[harryS]

Think with the advice i will go 500w. But mid motor or rear hub?????.
Wife is only 5'2" so anything on top tube would get in way when she jumps off as tippy toes only just touch floor when she is on seat.. suggestion on where to buy are welcome. I know uk is 250w max motor so we will skip that subject.

That was my thought too, when I saw how low you had that seat. I mounted a battery on the top tube of my wife's bike and it took away important space needed to get on/off.,

Mid motor is always an upgrade. This might be a TSDZ2 dominated thread, but I like the BBS02. They just work.

 

[Art Deco]

Think with the advice i will go 500w. But mid motor or rear hub?????.
Wife is only 5'2" so anything on top tube would get in way when she jumps off as tippy toes only just touch floor when she is on seat.. suggestion on where to buy are welcome. I know uk is 250w max motor so we will skip that subject.

Not just UK and EU are 250 watts... Trek, Specialized, Giant and almost all ebikes built as ebikes and sold in shops are 250 watt rated, and honestly that's fine for a middrive for even steep climbs. But you said you wanted to do a kit build instead.
My wife and her 250w pink ladies bike.

 

[PedalUma]

There is nothing wrong with a BBS02. They are fine for something like a cargo bike for people who don't want feel and want to ghost pedal. I am getting more like 50 miles with a small battery, not 15. A guy wants to sell me a new 250W today. I am not so sure anyone will want it when that is what store bikes have.

 

[Davie dab]

That was my thought too, when I saw how low you had that seat. I mounted a battery on the top tube of my wife's bike and it took away important space needed to get on/off.,

Mid motor is always an upgrade. This might be a TSDZ2 dominated thread, but I like the BBS02. They just work.

Think ive settled on a mid drive motor and found a place that builds small triangle battery that would just fit in the frame £800. Other option is same motor with bike rack and battery for £720. The 800 option is Bafang and cheaper one is chineseium of some sort with no name...

 

[Davie dab]

Think ive settled on a mid drive motor and found a place that builds small triangle battery that would just fit in the frame £800. Other option is similar motor with bike rack and battery for £720. The 800 option is Bafang and cheaper one is chineseium of some sort with no name...

 

[Davie dab]

Bafang BBS02B 750W 48V mid drive electric bike motor conversion kit with P850C Colour screen

UK Stock - Bafang BBS02b 750W 48V electric bike conversion kit. Latest version of the powerful, high torque mid drive ebike motor upgrade from Bafang.

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48V 14Ah Small Triangular Bag eBike Battery

These batteries come in a tough bag designed to fit within small frames, such as those found on full suspension bikes. We use good quality branded Samsung cells. We use a BMS to protect your battery. These offer Over-Current Protection, Over-Discharge Protection, Over-Charge Protection...

custombuilt-ebikes.co.uk

 

[PedalUma]

Bafang BBS02B 750W 48V mid drive electric bike motor conversion kit with P850C Colour screen

UK Stock - Bafang BBS02b 750W 48V electric bike conversion kit. Latest version of the powerful, high torque mid drive ebike motor upgrade from Bafang.

custombuilt-ebikes.co.uk

48V 14Ah Small Triangular Bag eBike Battery

These batteries come in a tough bag designed to fit within small frames, such as those found on full suspension bikes. We use good quality branded Samsung cells. We use a BMS to protect your battery. These offer Over-Current Protection, Over-Discharge Protection, Over-Charge Protection...

custombuilt-ebikes.co.uk

So you are going for the 750 in the land of 250 max? Power level 1 with that setup is almost too much for many to handle. If she pedals at 10 RPM she will be doing 32 Kph in power level one with eight more power levels to go. You will want to cut radial notches every 40 degrees into the left side end of the bike's bottom bracket shell. You will see why, when the kit arrives.

 

[Davie dab]

So you are going for the 750 in the land of 250 max? Power level 1 with that setup is almost too much for many to handle. If she pedals at 10 RPM she will be doing 32 Kph in power level one with eight more power levels to go. You will want to cut radial notches every 40 degrees into the left side end of the bike's bottom bracket shell. You will see why, when the kit arrives.

Obviously very new to this. And you made it worse rather than explaining the reasons which seem like i made a terrible decision, instead of helping the like of us with hardly a clue. A figured my 1000 w hub was too much but also the 750 above is only available after being unlocked and is shipped as a 250w. Maybe im totally in the wrong, but thats why im in the group asking

 

[Davie dab]

This is my wife's Trek I converted with a Bafang SWX02 250W hub motor. It's plenty of power for our moderate hills in Charlotte and gets about 15 miles a charge.

View attachment 117660