It depends on the size of the water bottle. A small one might fit on the seat tube behind the battery. A 16oz or larger would have to go on the top tube near the stem. This could make mounting the bike more difficult though. In either case, I recommend the Velcro strap 2 Fish Quick cage adapter with the cage of your choice. A side load model like the Zefal might be necessary for tight places. The 2 Fish adapter will fit on any shape bike member, round, oval or square.
2 Fish Adapter : https://www.amazon.com/gp/product/B003RLJ8L6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Zefal side mount cage : https://www.amazon.com/gp/product/B002BWPKYQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I use both on all my bikes and never had a problem. Others have reported a slipping issue though. If so, put a wrap of friction tape under it.
There are also a few good stem and handlebar mount cages that work if you don't mind handlebar clutter.
Thanks for the suggestion. I will look into this but handle bar and seat post real estate is slim for me. I can barely mount my GoPro camera. Once I even tried to get fancy and mount a Niterider micro headlight under the stem of the handle bar. It looked really cool under there. Didn't take top bar space and hidden, yet functional. The hidden part got me. The light fell off without me realizing it until I got home. I looked for it the next day but never found it. Again, thank you for your suggestion. I will research it.Consider a feedbag. They velcro onto your handlebars next to the stem and put the water bottle right where you can get it. Usually they also have small additional pockets for a granola bar and the like.
I don't own a Haibike so I can't answer your question directly. these are pics of the 2 Fish adapter with Zefal cage & 16 oz bottle mounted on the down tube of my Pedego. The measurement from the surface of the tube to the outside of the cage is 3".I have a 2018 SDURO Trekking 6.0 and am looking for a water bottle solution also. I had my water bottle cage mounted on the rack but I ended up never using the rack except to mount the water bottles. I finally removed the rack but now find that I can't mount the bottle in the desired location. I purchased this adapter and not the one you suggested because I wanted to save a few dollars.
My desired location is on the seat tube back of the battery. I tried several of the cages I have and none of them would fit in this location with the adapter. The adapter sits too high making the cage hit the battery. Even if I could mount the cage, the bottle would end up hitting the battery.
Question, do you own a Haibike and did your recommend solutions work with your bike where you could mount the cage on the seat tube, back of the battery? If yes, a picture would be great. Your adapter suggestion looks like it sits lower and the cage looks smaller in diameter so it just might work.
I got the moosetracks handlebar bag, have been using it for a few months, and am very happy with it. Carries a water bottle, can of Halt for fractious dogs, and an energy bar, doesn’t interfere with steeringConsider a feedbag. They velcro onto your handlebars next to the stem and put the water bottle right where you can get it. Usually they also have small additional pockets for a granola bar and the like.