DIY stage 5: prepping and fitting electricals [photos]

[daniel.weck]

Table of Contents:

http://www.pedelecs.co.uk/forum/electric-bicycles/4682-diy-stage-1-received-bafang-tongxin-kits-photos.html#post59183

http://www.pedelecs.co.uk/forum/electric-bicycles/4734-diy-stage-2-received-li-ping-lifepo4-battery-photos.html#post59988

http://www.pedelecs.co.uk/forum/electric-bicycles/4737-diy-stage-3-motor-testing-fork-photos.html#post60039

http://www.pedelecs.co.uk/forum/electric-bicycles/4747-diy-stage-4-16-wheel-lacing-building-photos.html#post60153

http://www.pedelecs.co.uk/forum/electric-bicycles/4769-diy-stage-5-prepping-fitting-electricals-photos.html#post60345

http://www.pedelecs.co.uk/forum/electric-bicycles/4778-diy-stage-6-fork-hub-torque-protection-photos.html#post60504

http://www.pedelecs.co.uk/forum/electric-bicycles/4786-diy-stage-7-first-ride.html#post60641

http://www.pedelecs.co.uk/forum/electric-bicycles/4825-diy-stage-8-continuous-improvements.html#post60991

http://www.pedelecs.co.uk/forum/electric-bicycles/6956-diy-stage-9-a123-nano-battery-pack-photos.html#post88165

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I've decided to open a new thread to focus just on prepping and fitting electricals, because that's an area where I need to ensure water-proofing and shock-protection, as well as to design fittings that are discrete yet practical on a day-to-day basis.

The battery and controller units are the most vulnerable and expensive parts, so the casing quality is all-important. My main e-bike project being an folding e-Brompton, I will obviously benefit from specific design features that are not found on full-size bikes. For example, I will use the front luggage block (attached to the frame, not the handle bar) to "suspend" the battery and controller units. I will be able to use the generous front "touring" bag to conveniently hide and protect the main electrical parts. All the cables will be short, as I only need to pull wires between the front wheel and the area immediately above it.

The controller just needs extra protection against rain splashes, as it already comes with a robust aluminium case. I'll look into silicon-based products to seal the remaining openings.

The Ping battery comes with no protection at all, but I found a fantastic aluminium box that just fits perfectly, whilst allowing some padding (dense Polyurethane "foam" sheets). This is actually a CD box !! It took me a while to find one of the right dimensions, as most CD/DVD boxes are far too big ! This is a "Hyundai 100 pc aluminium CD case (HY7006)" (just under 9 GBP including postage), for those interested in building their own case for the standard 10Ah 36V Ping battery (150x150x105mm). I think it's fantastic, as I get a nice little handle to carry it around, and a little lock to prevent opening the box by mistake (see photos below).

Note: the Nano battery is a standard long battery, like the ones that slot behind the saddle post. It therefore spreads across the bottom of the Brompton touring bag, which in my opinion is a sub-optimal use of the storage space. I most often need the depth of the bag, not its width. The Ping battery will occupy a big chunk of space on either side of the bag (or in the middle), but it'll give me much more flexibility for carrying shopping items, etc. I'll take photos when it stops raining...

Alloy box: 624g

Total battery + case: 4.525Kg

 

[daniel.weck]

The final result looks like this:

Read on below to see how it was done !

 

[daniel.weck]

Ok, so I've got the aluminium box to protect the battery cells against direct shocks, now I need to design the padding so that the battery "floats" inside its case. I decided to use left-overs of floor underlay, which is a material that feels like neoprene: a dense foam-like sheet that springs back to its original shape when squeezed.

It's easy to cut and shape to requirements, so I can fill the "holes" on the side where the BMS is attached:

Without further ado, here is the finished product:

I allowed a flap so that I can check on the red balancing LEDs when needed:

 

[daniel.weck]

The other side looks much neater:

It all fits nicely and snug:

Of course, we need an exit hole for the cable:

And here's how it's done:

 

[daniel.weck]

Here's how much space the battery takes inside the Brompton touring bag (less than half the bottom surface, but more than a third). There is space above the battery box to carry extra items. I prefer this layout compared to the one offered by the Nano battery (which is a conventional long battery case, as found vertically behind the saddle post of a regular e-bike). That's because I make more use of the depth of the bag, rather than its width (shopping, bottles, etc. standing vertically). There's no denying that this is a slightly larger and heavier battery than the equivalent 10Ah Lithium Ion / Polymer. However this is the kind of power I will need for my cycle trips. By comparison, the Freedom E-bikes smaller A123 cells (much less capacity) would fit snug in the back pockets, leaving the bag completely empty.

 

[eddieo]

But the case is unlikely to be weather proof don't you think? I know it looks like a mini flightcase and very cute, but its not a flightcase and I doubt lt it will do well against driving rain..........

But as a rank amateur I an finding your threads fascinating...Good luck!

 

[daniel.weck]

But the case is unlikely to be weather proof don't you think? I know it looks like a mini flightcase and very cute, but its not a flightcase and I doubt lt it will do well against driving rain..........

But as a rank amateur I an finding your threads fascinating...Good luck!

You are correct, the case is obviously not water-proof. This is for protecting the (otherwise exposed) battery cells against direct contact/shocks. I will inject silicon joints wherever needed, which will make the box largely rain-splash-proof, but clearly not water-proof

This box will never face the weather elements directly. I rarely ride my Brompton without the front touring bag on, so I will probably add additional rain protection using a modified dry-bag (to let cables out), or simply by using the high-visibility Brompton cover.

Cheers, Dan

 

[geostorm]

connections

Hi good pics. keep it up, i find it difficult to start new thread inc, pics. not much info. on site instructions for us old thickies, any advise please ?

i find it very difficult to obtain decent waterproof connecters from anywhere somebody suggested model shop ,what do you think ?
Geoff

 

[RobinC]

Thanks for all the photos. How much does the case weigh empty?

 

[daniel.weck]

Thanks for all the photos. How much does the case weigh empty?

624g, scroll-up for photos.

 

[eddieo]

All this and a gourmet cook as well....

 

[daniel.weck]

Alright, I've finished building the battery padding, see here:

http://www.pedelecs.co.uk/forum/electric-bicycles/4769-diy-stage-5-prepping-fitting-electricals-photos.html#post60347

 

[jerrysimon]

Daniel,

I have been away on business the last few days and am enjoying catching up with all your build threads

Looks like there is plenty of room in the bag

Jerry

 

[RobinC]

Will you put a fuse inside the case somewhere? You might also want to put something so the cable isn't directly rubbing on the metal where it exits the case. Maybe a bit of old inner tube or something. Other than that it all looks good.
Would the battery also fit in the case with the leds facing upwards? I have already found a plastic box for my extremely slow progress project but I'm tempted to get one of these cases to see it would be a better solution. I have a pile of CDs that could do with a box so it won't be money wasted if I stick with my current scheme.

 

[daniel.weck]

Will you put a fuse inside the case somewhere?

No. Should I ?

You might also want to put something so the cable isn't directly rubbing on the metal where it exits the case. Maybe a bit of old inner tube or something.

Yes, I intend to improve this indeed !

Would the battery also fit in the case with the leds facing upwards?

I tried before I added the extra padding, and it worked. However it made more sense the way it is now, to avoid movement along the horizontal plane. Vertical motion is not really a problem (the bag being suspended, bumps in the road are absorbed already)

I have already found a plastic box for my extremely slow progress project but I'm tempted to get one of these cases to see it would be a better solution. I have a pile of CDs that could do with a box so it won't be money wasted if I stick with my current scheme.

Go ahead, it's a cheap but nice CD case.

 

[RobinC]

OK I will probably go ahead and order one of these cases.

Since a Ping battery is a fair sized outlay a fuse to protect it in case of short would seem a wise precaution. You could use an in-line fuseholder of suitable current rating.

 

[daniel.weck]

Since a Ping battery is a fair sized outlay a fuse to protect it in case of short would seem a wise precaution. You could use an in-line fuseholder of suitable current rating.

I see, this would protect the battery. Should the fuse be on the PLUS side (red wire), as "near" as possible to the battery ? I don't have a Cycle Analyst or the cheaper Watts Up yet...what fuse Amp should I get ? (20A max current draw ?)

 

[RobinC]

I see, this would protect the battery. Should the fuse be on the PLUS side (red wire), as "near" as possible to the battery ? I don't have a Cycle Analyst or the cheaper Watts Up yet...what fuse Amp should I get ? (20A max current draw ?)

You could put the fuse on either wire. Not sure about the Bafang but a 20A fuse is what I plan to use initially with a Tongxin. Does the controller you are using have a built in current limit?
I've just ordered one of the aluminium cases thanks.

 

[daniel.weck]

Does the controller you are using have a built in current limit?

I believe so. The Cycle Analyst also includes that kind of protection, if I am not mistaken.

However the battery fuse idea is good just in case I short wires by mistake whilst manipulating the bunch of cables...

A small fuse box that I could splice onto the existing battery cable would be ideal. Any idea of what I should get ? (technical name, brand, etc. so I can search for an online shop that sells it)

 

[geostorm]

lost message

Hi Daniel can you tell me if recieved last message please, as i have had problems sending, and recieving nothing back to several posts, cant start new thread or send pics.
regards
Geostorm