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Decathon bike. Adding a second battery?

Posted: 4 Jun 2020, 4:04pm
by adri123
Hi

Thinking of getting a decathlon e-st520.

Would it be possible to add a second battery? I was thinking of getting one of the rear rack mounted ones.

Any thoughts appreciated.

Adri

Re: Decathon bike. Adding a second battery?

Posted: 4 Jun 2020, 8:31pm
by hemo
It might be possible if the electronics are quite basic and have no CANbus style handshaking between battery and motor/controller, a rack will change the ride style/feel of the bike esp if you use it for off road.

Re: Decathon bike. Adding a second battery?

Posted: 4 Jun 2020, 8:32pm
by al_yrpal
I'm 99% sure you cant do that.

Al :wink:

Re: Decathon bike. Adding a second battery?

Posted: 5 Jun 2020, 10:37am
by borisface
Probably your best option would be to buy a spare battery from decathlon when you buy the bike, if they will sell you one, carry it in a saddle bag and swap over when needed.

Re: Decathon bike. Adding a second battery?

Posted: 5 Jun 2020, 10:52am
by hemo
The battery charger will tell you if it is possible to wire in a another battery but you would need to know if the pin connector is two wire or four wires.

Re: Decathon bike. Adding a second battery?

Posted: 5 Jun 2020, 11:40am
by fivebikes
Have looked at that bike too.....
Spare batteries are available and could be carried on rides and swapped if needed.
https://www.decathlon.co.uk/battery-36v ... 37311.html

Re: Decathon bike. Adding a second battery?

Posted: 5 Jun 2020, 8:10pm
by borisface
2 batteries = 800+w/h for under £2k is going to get you some very serious range. Maybe 100 miles.

Re: Decathon bike. Adding a second battery?

Posted: 14 Aug 2020, 9:05am
by bikes4two
There was a recent discussion on the UK pedelec forum about 'paralleling up' two batteries including a DIY effort using Schotky diodes and somewhere either in that thread or an associated one, Woosh (as in Woosh cycles Southend) indicated that he was going to be selling a commercial product for 'joining' two batteries.

https://www.pedelecs.co.uk/forum/thread ... ost-574931

Re: Decathon bike. Adding a second battery?

Posted: 14 Aug 2020, 9:16am
by philg
2 batteries = 800+w/h for under £2k

£2k!! - I'm expecting delivery of another Hailong type battery next week, 540Wh for £220

Re: Decathon bike. Adding a second battery?

Posted: 14 Aug 2020, 1:41pm
by hemo
The Woosh device simply allows two batteries to be connected and one at a time will be used and alternated though not properly in parallel as becoming one larger battery with capacity and discharge.
The advantage of paralleling is that two batteries can be used with supply coming from both simultaneously thus reducing stress on the battery cells through discharge. The Schottky route is for lazy bods who can't be bothered to charge batteries to near same voltage to prevent connection damage via large current flows as battery voltages equalise transferring vast amounts of heat along the process. Tbh the Schottky diode is bit of a waste of time because who goes on a long ride or a good ride with a depleted battery.

Re: Decathon bike. Adding a second battery?

Posted: 14 Aug 2020, 4:15pm
by borisface
philg wrote:
2 batteries = 800+w/h for under £2k

£2k!! - I'm expecting delivery of another Hailong type battery next week, 540Wh for £220



That was including the bike!

Re: Decathon bike. Adding a second battery?

Posted: 18 Aug 2020, 5:15am
by MarcusT
I would ask an authorized Bosch dealer or Bosch themselves. The last thing you want to do is void the warranty for a new bike.
The Stilus can also fit a 625 W battery which from experience gives a lot of mileage.
If Bosch has a solution, then you're good with both batteries, if not, carry it as a spare