Battery Box Interfering with Pedals

[Wolvyr]

I have made plans to put together a bike using a Beach Cruiser style bicycle and a 1000w 48v ebike kit, all from eBay. In this build, I plan to build a fibreglass box for the centre of the frame to hold the batteries and speed controller, but have run into some design problems. I will be using 4x 12v 12Ah SLA Lucas to produce one 48v battery. I have based my designs around the size specifications of these cells ( 151x100x100mm), so the width of this box will be 150mm to accomodate for the 100mm width of the batteries and any wiring to the sides. The big problem is that I worry that the bicycle pedals will not be able to fully rotate as they will be obstructed by the box. Is there any such technique or product I can use to space out the pedals about 2 cm on either side? Would i have to bend the pedals themselves? I will attach images of the design so you guys can see what i mean.
All suggestions appreciated, thanks for reading

Edit: Added images

 

[Wolvyr]

As a side note, what are your feelings on using these SLA batteries? I'm using them because they're the only thing in my price range - £200 for a lithium just seems ridiculous to me and right now it's out of my budget. I have serious considerations for eventually building my own battery from 18650's, but that won't be for a while.
Will I get particularly good mileage out of these batteries?
What are the measurable signs that an SLA battery is degrading? (like voltage, resistance etc)

 

[anotherkiwi]

Feelings: not good - too heavy for starters and performance wise nowhere near lithium.

You should make your battery box 110 mm wide you have plenty of room for wires in the drawing. These are fully sealed gel batteries with no acid inside? Because otherwise you have two that will leak. How do they vent?

Not a good idea, save up a little more lithium batteries are worth it.

 

[D8ve]

Sla has very limited discharge cycle. If you used the full 12ah then I don't expect it to have 12ah next time, rule of thumb is use 50% so rate it as 6 ah .
Then the weight as well.

Look at Lipo Hobbyking have offers and I got my 16ah 36 volt setup for £100.
A 3*5s lipo build standard price for 5.8ah around £140.

 

[Wolvyr]

You should make your battery box 110 mm wide you have plenty of room for wires in the drawing. These are fully sealed gel batteries with no acid inside? Because otherwise you have two that will leak. How do they vent?

If I make the box 110 and I still come into problems with obstruction, is there still a method of spacing out the pedal levers a little? Or do I just need to bed them? Thanks for the response

Look at Lipo Hobbyking have offers and I got my 16ah 36 volt setup for £100.
A 3*5s lipo build standard price for 5.8ah around £140.

5.8ah just seems so small :'( and then there's the problem of balance charging. I have very little experience here and I felt like dealing with SLAs required less knowledge for a beginner - just solder up the terminals and you're ready. I understand that with lithium chemistry batteries you need to balance charge and soldering the terminals can head the chemicals and reduce its life. Any suggestions for an absolute beginner like me when it comes to lithium cells?

 

[Wolvyr]

If I make the box 110 and I still come into problems with obstruction, is there still a method of spacing out the pedal levers a little? Or do I just need to bed them? Thanks for the response


5.8ah just seems so small :'( and then there's the problem of balance charging. I have very little experience here and I felt like dealing with SLAs required less knowledge for a beginner - just solder up the terminals and you're ready. I understand that with lithium chemistry batteries you need to balance charge and soldering the terminals can head the chemicals and reduce its life. Any suggestions for an absolute beginner like me when it comes to lithium cells?

Edit:
Looking on hobby King, found these http://www.hobbyking.com/mobile/viewproduct.asp?idproduct=18495
Using two of these to bring the voltage close to 48v, what do you guys think?

 

[Zack @ Byocycles]

Hi Wolvyr,

If you need a little bit more distance between the two crank arms, you could always install a longer axled bottom bracket.

You will of course come into problems with chainline, Q factor etc...but it is an option.

Hope that helps a litle...

Thanks,

 

[anotherkiwi]

Edit:
Looking on hobby King, found these http://www.hobbyking.com/mobile/viewproduct.asp?idproduct=18495
Using two of these to bring the voltage close to 48v, what do you guys think?

"B-grade packs are sold as is and no warranty is implied or given"

That about sums it up. Don't try saving on batteries, it isn't the same as using used chip oil to fuel a diesel car! Lipos can be dangerous, choosing sub-standard ones is increasing your chances of having a problem while charging.

Two times this pack is 49.8 V hot off the charger and will provide power down to about 43.8 V. But are you ready to be around the whole time they are charging? You also have to invest in chargers, alarms and various other bits and pieces to control them.

My initial outlay on lipo was 180€ (sale price quality lipo) and in due course I will increase capacity spending another 150€ which will give me in the end a 20 Ah 36 V pack with a couple of chargers and all the wires and plugs and safety equipment.

My first bike was built on a shoestring I understand where you are coming from but I overspent on the battery because that is the key part to your build. Motors are a dime a dozen I think you could have chosen a 250 W geared hub for the same if not better performance. Chuck 48 V at your basic 250 W hub motor and you will be surprised by the results. You will also have less problems with wheel strength and the extra weight of your huge boat anchor direct drive.

 

[D8ve]

Edit:
Looking on hobby King, found these http://www.hobbyking.com/mobile/viewproduct.asp?idproduct=18495
Using two of these to bring the voltage close to 48v, what do you guys think?

That gives you the voltage. My spare sets ate 3ah. So you would need 2s3p setup to give a 46volt 9ah battery pack. A couple as spares and chargers it could be done cheaply.
The question of safely and easily is second. Rigging a safe charge point. And easy connection that's extra effort.
Doing a normal battery pack is much simpler and easier. You just have to spend some time earning a few extra Bob first.

 

[Nealh]

Going Lipo and buying the battery packs can be done cheaply, the extra's required will may be add a bit more. The important bit is to read up and understand how to look after them in keeping them form wandering to much so no over discharging and over charging, when charging stop at 41.5v and not below 3.5 -3.6v in use.
Read all of this how to lipo tutorial first before doing any thing.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=52240

 

[Alan Quay]

If I make the box 110 and I still come into problems with obstruction, is there still a method of spacing out the pedal levers a little? Or do I just need to bed them? Thanks for the response


5.8ah just seems so small :'( and then there's the problem of balance charging. I have very little experience here and I felt like dealing with SLAs required less knowledge for a beginner - just solder up the terminals and you're ready. I understand that with lithium chemistry batteries you need to balance charge and soldering the terminals can head the chemicals and reduce its life. Any suggestions for an absolute beginner like me when it comes to lithium cells?

5.8Ah of lithium is probably about the same as 16Ah of SLA.

A 16Ah SLA will be closer to 10-12Ah at the sort of discharge rate you need for a (very) heavy bike. Then, you can halve that value, as that's all you can use without killing it. Then, if you have bought high quality cells you may get 300 cycles.

Add the problems of weight and size, and it just not worth doing.

Moving the pedals further apart to accommodate the batteries? Please don't do this.

If you can't afford it now, you'd be better off waiting, or borrowing the money. For £240 you could have 12Ah of Lithium Ion. It'll last 800 cycles (prob more) and need nothing more than connecting to a charger.

SLA is the wrong answer these days.

Sent from my HTC One_M8 using Tapatalk

 

[Wolvyr]

My first bike was built on a shoestring I understand where you are coming from but I overspent on the battery because that is the key part to your build. Motors are a dime a dozen I think you could have chosen a 250 W geared hub for the same if not better performance. Chuck 48 V at your basic 250 W hub motor and you will be surprised by the results. You will also have less problems with wheel strength and the extra weight of your huge boat anchor direct drive.

You mentioned putting 48v through a 250W motor and having similar performance to a 1000W? Would this not be extremely dangerous and risk burning the motor out? It sounds like youre saying that there are a lot of negatives with going with 1000W, to my understanding 1000W was the best option for a high power build, was i wrong?

Also, thanks everyone for the responses, they all really helped. I've decided on just going with lithium and biting the bullet, accepting my woes with the price. I have found something that seems somewhat promising, but of course, I ask that you experts take a look: http://www.dhgate.com/product/e-bike-li-ion-battery-case-24v-36v-48v-battery/381050241.html#s1-2-1b;searl|1028640759
at around £80 this seems too good to be true, is it?
Thanks again everyone

 

[Alan Quay]

You mentioned putting 48v through a 250W motor and having similar performance to a 1000W? Would this not be extremely dangerous and risk burning the motor out? It sounds like youre saying that there are a lot of negatives with going with 1000W, to my understanding 1000W was the best option for a high power build, was i wrong?

Also, thanks everyone for the responses, they all really helped. I've decided on just going with lithium and biting the bullet, accepting my woes with the price. I have found something that seems somewhat promising, but of course, I ask that you experts take a look: http://www.dhgate.com/product/e-bike-li-ion-battery-case-24v-36v-48v-battery/381050241.html#s1-2-1b;searl|1028640759
at around £80 this seems too good to be true, is it?
Thanks again everyone

I expect that '1000w' motor is a direct drive unit. Unless you want to go along the flat at 35mph, then its not what you need.

For normal cycling you need a geared motor, which will give you a good balance of torque and speed. About 18mph top whack at 250w (which will peak around 700w). Trust me, fast enough on a cruiser.

These DD units on eBay are a bit of an exercise in miss-selling. They are not what most people want or need, but they look 4 times better than 250w versions.

Sent from my HTC One_M8 using Tapatalk

 

[Nealh]

You will need some 18650 cells to fill that empty case if you read the description correctly.
Stick to something with a bit of back up and some sort of guarantee Eclipse sell 36v 13ah Samsung celled batts for £240 & 246 in uk, the difference beside the case is one has 15-20a BMS and the other 20 -25 BMS.
http://www.eclipsebikes.com/hailong-13ah-lithium-frame-battery-samsung-cells-p-1118.html
http://www.eclipsebikes.com/13ah-lithium-frame-battery-samsung-cells-p-1103.html

 

[Wolvyr]

I expect that '1000w' motor is a direct drive unit. Unless you want to go along the flat at 35mph, then its not what you need.

For normal cycling you need a geared motor, which will give you a good balance of torque and speed. About 18mph top whack at 250w (which will peak around 700w). Trust me, fast enough on a cruiser.

Sent from my HTC One_M8 using Tapatalk

Im looking for a build that has the capacity to reach ~30mph on flat, but will use it almost always in the 5-15mph area. I just want the ability to go high speed if I ever needed to, in a safe environment of course. Im guessing the 250W set up you described is not suitable for this? What are the cons of a 1000W motor, and how would I know if it is direct drive? It's a rear wheel hub motor that im interested in, if that helps at all.

 

[Wolvyr]

You will need some 18650 cells to fill that empty case if you read the description correctly.
Stick to something with a bit of back up and some sort of guarantee Eclipse sell 36v 13ah Samsung celled batts for £246 in uk.

Ahahaha, thank you for pointing that out! I would have been very annoyed if I had gone through and purchased that :')

 

[anotherkiwi]

Quite frankly I don't know how fast my hub motor goes on the flat, I do know what flat is I have a little bit around here but nothing that will let me get up to speed, it is all in town...

A 250 W motor goes about 20 mph on 36 V and about 27 mph at 48 V without user input. These numbers have been cited here on this forum by some very tech savy memebers so I trust them. With the right gearing and a bit of pedal input you should reach 30. If aerodynamics doesn't get in the way...

If it says 1000W and it is very big it is direct drive.

 

[Wolvyr]

Quite frankly I don't know how fast my hub motor goes on the flat, I do know what flat is I have a little bit around here but nothing that will let me get up to speed, it is all in town...
A 250 W motor goes about 20 mph on 36 V and about 27 mph at 48 V without user input. These numbers have been cited here on this forum by some very tech savy memebers so I trust them. With the right gearing and a bit of pedal input you should reach 30. If aerodynamics doesn't get in the way...

I have a nice, straight, flat, mostly unused cycle path of tarmac that goes for miles, its perfect for high speed cycling.
Won't putting 48V through a 250W motor absolutely destroy it? I imagined it would overheat, melt off the waxy coating of the copper wires in the electromagnet and short circuit the whole thing in minutes?

 

[Alan Quay]

Im looking for a build that has the capacity to reach ~30mph on flat, but will use it almost always in the 5-15mph area. I just want the ability to go high speed if I ever needed to, in a safe environment of course. Im guessing the 250W set up you described is not suitable for this? What are the cons of a 1000W motor, and how would I know if it is direct drive? It's a rear wheel hub motor that im interested in, if that helps at all.

Trust me, you don't want to be doing 30mph on a cruiser with plastic brakes and pedals.

To be even remotely safe at that sort of performance you need a much better bike.

Not trying to spoil your fun here, just don't want you to waste you money or get hurt.

Sent from my HTC One_M8 using Tapatalk

 

[D8ve]

The 250 watt BBS01 mid motor is capable of peak power of around 750 watts.
On the flat 250 watts will get you 15 mph easy. No speed restrictions and the BBS will do 30 if you work with it, but it is legally a motorbike at that speed. If anything happens you could end up in deep brown stuff.buying a moped is simple and legal.
Having 15 mph cut out I have still had 40 mph on my legal bike.
It is just me and gravity. And uphill 750 watts makes me as fast as any Tour de France rider :-0