New Battery Case for my eBrompton

[Bernard Manansala]

Cannibalized parts from an O-Bag Mini and mated them with a Pelican 1200 Case.

Tell me what you guys think...

 

[D8ve]

Fits great with the style and colour of the brommie. Much posher than my B&Q toolbox

 

[Deleted member 4366]

It's very neat, but why LiFePO4, which is (IMHO) much too big and heavy for any electric bike, let alone a nice Brompton like yours? This battery has the same capacity as yours, but is 1/3 of the weight. It's powering a 1500w motor too:

 

[KirstinS]

It's very neat, but why LiFePO4, which is (IMHO) much to big and heavy for any electric bike, let alone a nice Brompton like yours? This battery has the same capacity as yours, but is 1/3 of the weight. It's powering a 1500w motor too:

There is a 10ah 36v battery in that tiny saddle pack ?! What's it made from ? Lipo ? 3600 mah Panasonic's ?

 

[Deleted member 4366]

It's a 52v 6Ah 14S2P 18650 pack with Samsung 30Q 3000mA cells. Panasonic GA cells would work as well, and give you 7Ah. A Bromptom could do 25 miles on a 10S2P Panasonic pack, which would weigh 1.0kg and fit in your pocket if you wanted.

 

[jerrysimon]

Wow its been an age since I posted here. After riding my E-Brompton most days to work since I first posted here in 2009. I have over 10K miles on it now and its still running on the same clackerty old Tongxin! My config has all the electrics in the Brompton bag with an umbilical plug that joins bag to bike to keep things light, bag in one hand Brompton in the other

As shown started with A123 cells but been using Sony, Konions 18650 cells in 10S2P and 10S4P configs for a number of years now. As Dave states although mine are only 1500mA cells my small pack is 1Kg and larger 2Kg and both fit in one of the Brompton bag back pockets. I get about 15 miles on one and about 25-30 on the other. Would change them but they still seem to be holding out well.

So Dave, would those cells work in an DIY pack like the Konions without a BMS ?

Jerry

 

[jerrysimon]

Bernard I notice you run with a three speed hub. I have found that the two speed is fine with electric assistance i.e. one speed to start and one to cruise plus keeps things even lighter.

If you really want to go light how about this 11.5kg E-Brompton Ti. Though I have gone back and now use the black stock Brompton daily.

 

[Deleted member 4366]

So Dave, would those cells work in an DIY pack like the Konions without a BMS ?

I'm not sure. Probably, but you can get a BMS for about £8, so why not have one, then all you have to do is plug in the charger.

https://www.aliexpress.com/item/Battery-Protection-BMS-PCB-Board-For-10-Packs-36V-Li-ion-Cell-Max-40A-W-Balance/32682462334.html?spm=2114.13010608.0.0.JrcaNu

Without a BMS, you could solder on a couple of 5S balance connectors and use a BC168 balance charger, but by the time you've done that, you could have soldered on the BMS!

I think it's time to get the soldering iron out again, Jerry.

 

[KirstinS]

It's a 52v 6Ah 14S2P 18650 pack with Samsung 30Q 3000mA cells. Panasonic GA cells would work as well, and give you 7Ah. A Bromptom could do 25 miles on a 10S2P Panasonic pack, which would weigh 1.0kg and fit in your pocket if you wanted.

Hmm, interesting stuff. More food for thought on my super lightweight titanium build (as of now it's just a frame

 

[Bernard Manansala]

It's very neat, but why LiFePO4, which is (IMHO) much too big and heavy for any electric bike, let alone a nice Brompton like yours? This battery has the same capacity as yours, but is 1/3 of the weight. It's powering a 1500w motor too:

This was my 1st eBike build so my knowledge of battery chemistries was very limited at the time.

 

[Deleted member 4366]

I see, that makes sense. There's still a lot of people around on Endless Sphere still recommending that people get LiFePO4 batteries for Ebikes, presumably because they've no idea what alternatives are available. About 5 years ago, there was a strong case for them, but things have moved on now. It's the same with lipos. They haven't kept up with the 18650-type cells, so it's getting harder to make a case for them too. Hopefully, in another 5 years, battery weight will be half what it is today if progress carries on at the same rate.

 

[shemozzle999]

Hi Bernard,

a Peli case is and excellent choice, I have specified them on numerous security surveillance products I used to design and build, totally waterproof, highly robust and the inbuilt pressure relief valve allows safe aircraft cargo hold transportation.


Williams have been playing with Sodium ion batteries which allow high charging and discharging currents, I would not be surprised to see them linked sometime with the new Kers motor they have developed for the eBrompton.

 

[anotherkiwi]

It's the same with lipos. They haven't kept up with the 18650-type cells, so it's getting harder to make a case for them too.

Is there a 18650 based battery that doesn't sag more than 0.7 V and which costs 12.50€ an Ah?

A 48 V battery that breaks down into 8 Ah bricks but which can be assembled into a 16 or 24 Ah one when more range is needed?

Those continue to be the advantages of LiPo along with short charging times.

I agree they are heavier and need to be stored in a safe place.

 

[Deleted member 4366]

Voltage sag isn't normally a significant characteristic on an electric bike. You might just as well say that lipo batteries are better because the blue heatshrink looks prettier. These modern cells have low internal resistance, so sag is nothing like what you used to get when you tried to draw too much current from the Chinese knock-offs. All batteries sag a bit when you draw current from them, but it's nothing that would be of any concern to the rider.

Cost per Ah needs to be considered, but you have to look at the total cost. Lipo has less than half the life of NCR18650GA cells, plus, you need relatively expensive equipment to charge and manage lipos, and some extra cost to connect and install them.

I went through the lipo phase about 5 years ago. My house is full of broken cheap chargers, expensive not broken ones, harnesses, balance boards, alarms and other monitoring devices, and worst of all, bricked lipo packs. I therefore have a good idea of what the total costs are.

5 years ago, the only way you could get a 10Ah battery that wasn't too heavy, which was capable of delivering 30 amps for your high power motor was to use lipos, which is why I did it. Modern batteries are almost half the weight of lipos, last more than twice as long, and the overall cost is about the same.

 

[anotherkiwi]

Voltage sag isn't normally a significant characteristic on an electric bike.

Coming home it is an issue... My Li-ion battery sags 3 to 4 Volts up that hill which means if I have ridden a few extra km in the day it packs it in on the way back home. Oh I get back up to 36-37 Volts on the way back down, very useful!

I think LiPo must have been much heavier 5 years ago?

My first shot at a 10 Ah pack cost me 180€ wires and charger included, a 10.4 Ah Samsung celled Li-ion is 266€ charger included.

I wouldn't recommend LiPo to anyone else it is just that it works very well for me in my situation. I couldn't have rode up Jaizkibel without it, or maybe if I had spent +600€ for a lunacycle Li-ion battery, my 20 Ah battery cost half that. Also the house we go to out in the woods doesn't have electricity, it does have a solar panel and a 12 V battery I can recharge from...

 

[Deleted member 4366]

View attachment 15992
Coming home it is an issue... My Li-ion battery sags 3 to 4 Volts up that hill which means if I have ridden a few extra km in the day it packs it in on the way back home.

Your Li-ion battery doesn't have INR18650GA or Samsung 18650 30Q cells. I also have old 18650s that sag, and I also have old lipos that sag even worse. Samsumg 18650 22P cells in your battery have been around since at least 2010. They're old technology, like lipos. Most of them are probably fakes anyway.