Smaller, subtle 48v battery options?

lovelock

Finding my (electric) wheels
Mar 27, 2018
18
0
33
Southampton
Hey guys, I've finished my eBike conversion but finding the battery is a bit overkill what the journeys I do.

I purchased the 48v 18aH battery from Insat Batteries / Jimmy and its amazing no doubt. The issue is that I have a road bike with no suspension and the battery is a bit too 'wobbly' on the frame and adding a bit too much extra weight to that area.

I did a 16mile ride last week and the battery display didn't drop a single bar out of the 4. My commute is only 6 miles!

I understand that you need a big battery so that when its depleted slightly it still has plenty of power, but I think for these smaller journeys I could do with something smaller.

I ideally wan't to get a bottle battery and actually fit it inside of a real water battle for the stealthy look, has anyone has luck with a smaller 48v battery for around 10 miles max and knows roughly what aH I should look for?

Picture of said bike, just because :)

 

Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk
I can sell you a 48V 12AH HL battery.
 

Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
HI style are more stealthy and fit lower and sleeker on the tube. On my medium size frame it looks like this



For a truly stealth build in an actual water bottle you'll need to diy. Or have someone like Jimmy at bga reworking do it for you. It's trickier with 48v as you'll need more cells for the same ah pack. D8veh did a good build thread on this subject . I'll find it for you . I think he got enough cells and a bms inside which gave a 6ah pack (using 3000ah cells )


Thing is you need 13 in series not 10 to get 48v so it's a bit of a struggle . I think you need to find an oversize bottle to get it to work as 26 cells is really your minimum. Which may defeat the objective .



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KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
Here it is

http://www.pedelecs.co.uk/forum/threads/how-to-make-a-lightweight-battery.28437/


As i thought he used 20 cells in total (2 layers of 10 cells , 10s 2p formation to get 36v ah from 3000ah cells) but you'd need 26 to get 48v . So you need a bottle that can either fit 13 per layer or is longer to take 3 layers

Hope that makes sense.

It's the downside to 48v I'm afraid , need more cells ! A single cell series of 13 cells will not give you the range you need (looking at 3.5ah max)

Hl are my favourite design of mainstream packs to date though. Stick some extra rivenuts into your frame so you have three (or more ) anchor points

My bike has been thrown down some serious trails and done 1000miles without issue in this setup.

Your only other option is to buy a frame /triangle bag and stick a battery in that. Looks less ebike but more like a trekking machine. And it isn't anchored in the same.way

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anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
Or 12S 44.4v nominative (50v hot off the charger) with 24 x Sanyo 20700 cells for an 8 Ah battery with 30 Amp discharge weighing 1.51 kg without the BMS.
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
Or 12S 44.4v nominative (50v hot off the charger) with 24 x Sanyo 20700 cells for an 8 Ah battery with 30 Amp discharge weighing 1.51 kg without the BMS.
Yeah but the lvc will kick in a bit too early so the 8ah won't all be usable , I think ?


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anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
If you use a KT LCD-3 you can set it and get down to about 3.5v per cell so yes you miss out on the last 0.2v.

On the other hand the Sanyo is rated for over 4100 mAh so... I was being pessimistic when I said 8 Ah :)
 

Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk
a side observation: batteries need to be in a UN 38.3 casing if it is on public roads.
Cell packs in a bike bag would be illegal.
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton

Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk
Im not convinced about this woosh. 38.3 is about shipping saftey. It's s not a requirement for use on a bike as far as I can see.

http://www.metlabs.com/battery/un-38-3-transportation-testing-required-for-lithium-battery-safety-during-shipping/


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reasons:
1. the cell pack has to be shipped to you. It needs to be done in an UN 38.3 case.
2. If an accident happens on a public road involving your cell pack, how are you going to defend the case?
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
Its air freight regulation. Nothing to do with use at all

I buy a battery from jimmy in north London and collect by car. I put in a frame bag

In case of accident what case is there to answer , I have done nothing wrong that I can see. What law is broken ?

if the 38.3 relates to anything other than Air freight and , in particular , relates to use by individuals on their bikes then I'd like to see the evidince for that please




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Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk
Its air freight regulation. Nothing to do with use at all

I buy a battery from jimmy in north London and collect by car. I put in a frame bag

In case of accident what case is there to answer , I have done nothing wrong that I can see. What law is broken ?

if the 38.3 relates to anything other than Air freight and , in particular , relates to use by individuals on their bikes then I'd like to see the evidince for that please




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https://www.bike-eu.com/laws-regulations/artikel/2010/08/eu-regulations-for-e-bikes-pedelecs-part-4-battery-transportation-1018848

QUOTE:

Any Lithium-Ion battery over 100 Wh is classified as CLASS 9 – MISCELLANEOUS DANGEROUS GOODS under the dangerous good regulations for transport by road (ADR), by air (IATA & IACO) and by sea (IMDG). Lithium-Ion batteries for pedelecs are more than 100 Watt-hours. As a result, their transport has to comply with these regulations. The UN number for Lithium-Ion batteries is 3480, if contained in or packed with equipment 3481.

These rules do not only concern transport of batteries for instance from manufacturer to dealer, but all transport except transport for private purposes. First of all, to ship goods in the CLASS 9 category means that the battery needs to be tested in accordance with the UN Manual of tests and criteria, Part III, subsection 38.3.1.

PS: even the carton and infill should be made with 4G certified board.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,918
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West Sx RH
UN 38.3 above implies transportation from manufacturer to supplier/seller to end user, the transportation does not apply to the end user in a private capacity.
 

Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk
before I buy a battery from a factory, I always ask for their UN certificates.
without UN38.3 casing, the battery is not safe if it hits the road, not safe if it is left outside in hot weather.
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
UN 38.3 above implies transportation from manufacturer to supplier/seller to end user, the transportation does not apply to the end user in a private capacity.
Exactly Nealh. Thus the initial statement by Woosh simply isn't true


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Woosh

Trade Member
May 19, 2012
20,376
16,875
Southend on Sea
wooshbikes.co.uk
you guys should read the article I linked to, in its entirety if possible.
The author explains better than I could possibly do.
I have no interest in alarming unnecessarily anyone.
All batteries for e-bikes must be tested for puncture and overcharging without bursting into flames.
Single, custom cell packs can't be tested and therefore illegal to use.
The problem is the law does not stop people selling something illegal to use.

https://www.bike-eu.com/laws-regula...edelecs-part-4-battery-transportation-1018848

PS:

Here is a quote from Halfords

https://www.halfords.com/advice/cycling/expert-advice/e-bikes-faqs

  • The battery pack has to be fully approved to UN / DOT 38.3. This includes extreme charging and discharge testing, along with high temperature and physical abuse tests.
 
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