Vertical battery and bottle on down tube: why is it uncommon?

[Hutch]

Could you tell me why there aren't a lot of ebikes with vertical battery along the seat tube AND a bottle cage on the down tube. Is there a practical reason for that?

I'm always riding with a water bottle, I always need to drink a lot in summer, but also a bit in winter. So to me, the prefect ebike should keep space on the frame to place a water bottle.

And to keep the weight centered a vertical battery and a frame bottle is the best solution.

Otherwise I have to put a bag on my back or on the rear rack. Wich is cumbersome if the only thing I place in it is a bottle. I have the impression it is such a waste of space to put a battery on the down tube.

But most ebikes on the market don't have such a structure. Is there a factory reason? I've heard some people say a vertical battery looks "old" but I don't think so. I like it a lot. It makes the bike a bit longer, but unless you must move and turn into very tiny places, it's never a problem.

Vertical batteries seem to be limited when it comes to autonomy. There are more models and options for rear rack and down tube batteries. Is that the reason?

 

[trex]

both battery locations are good on weight distribution.
Most people prefer the rear wheel to be as close to the seat post as possible (the bike feels nippier), so in general, downtube battery gives to the bike better handling.

 

[flecc]

There have been plenty of bikes with the battery behind the seat tube, but their number has been decreasing due to many disliking the longer wheelbase. It's also considered by some to be an old fashioned.look.

Just in front of the seat tube isn't popular for a several reasons. One is that the length is limited on the shorter frames, another is that the frame triangle size has often become smaller due to rear suspension swing arms on many designs. Still another reason is that in front of the seat tube doesn't suit step-through frames. Many crossbar bikes cannot fit both a good sized battery and a water bottle within the triangle.
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[gray198]

My Freego Eagle has the battery behind the seat tube. It's OK but does make the bike feel very heavy at the back. It also seems to make the seat a bit too close to the handlebars and whatever seat / handlebars combination I try, my backside hangs over the back of the seat. Maybe that could be corrected by a different seat post.

 

[Cyclezee]

Hi Hutch,

I guess what you are really looking for is greater capacity, would I be right in thinking that?

eZee have been offering the option of dual batteries for a number of years, normally a vertical one behind the seat post and a rear rack mounted one.

Both batteries feed into the same controller and each can be used independently or in parallel.

There is also option of a vertical and downtube battery.

The obvious advantage of greater capacity is greater range, but the penalty is greater weight.

 

[anotherkiwi]

I liked the way SLAs were sometimes carried vertical on the rack:
- CG is kept low
- the weight is directly over the rear axle

This to me is a much better solution than in a cage on top of the rack.

 

[FreeGo Electric Bikes]

The advantage to having the battery vertical behind the seat post is keeping the centre of gravity low and central. The FreeGo battery is in its own moulded black case and not in the cheaper looking aluminium generic case. It encloses top grade Samsung battery cells and even has a USB charging point in it .
Having the battery on the rack raises the centre of gravity and puts all the weight over the rear if the motor is in the rear wheel as well.

 

[KirstinS]

I prefer downtube batteries both in looks and in keeping a normal bike geometry

However, for me, a disadvantage is a heavy high capacity downtube battery can really stress the frame lugs. One minor crash and the battery rips out the lugs and damaged the frame.

I now carry my mtb battery in a backpack for proper trails etc

 

[anotherkiwi]

Now that I have a comfortable bike I am back to thinking long range travels again. The trailer seems to be the perfect place for range extender batteries. Yes there is some loss due to wire length but it keeps the weight off the bike which remains more mangeable. Hydraulic brakes required all round though.

For the moment the panier battery box will do, I can have 6 Kg of lipo in one bag and all my personal gear in the other. That could mean about 42 Ah of lipo which is about 1245 Wh and a potential range of 185 - 200 km. Plenty enough for a days riding.

 

[Gringo]

the prefect ebike should keep space on the frame to place a water bottle.

So that would be my Cube then

 

[Alan Quay]

I think some people have become confused. The OP is not looking for two batteries or a bigger battery, just a place for a water bottle.

I've seen bottle cages on the seat post before, although I can't remember where....

Me, I only carry a water bottle on my non powered bike. On my electrics I either put it in a rucksack or rely on passing an establishment licensed to sell 'refreshments'.





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[Gringo]

I think some people have become confused. The OP is not looking for two batte

It's not difficult to cable tie a cage onto your top tube or get a handlebar bottle cage bracket. Both options put your drink in a convenient location, IMO better than you down tube.

 

[flecc]

I've seen bottle cages on the seat post before, although I can't remember where....

I've seen twin bottles on the occasional Tour de France bike, one on down tube and one on seat tube. Not a popular choice though, probably due to weight. However, team members do occasionally relay bottles to other team members, so it may be more comfortable than the extra bottle stuffed up one's T shirt.
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[Alan Quay]

http://www.ebay.co.uk/itm/361625377924

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[LeighPing]

So that would be my Cube then

I agree. It's the best solution that I could find.