3 scooter batteries in series: too good: 54 V!!!? Answered
For 2 months now I have an Aldi (low end) e-bike. The Li-battery allows 25-35 km travel (depending on terrain and wind conditions) on max power assist. According to specs, the battery has a voltage of ca. 40 V when fully charged, going down to a cutoff point of ca. 35 V when empty.
For a relatively cheap 2nd battery solution (to increase travel distance for another 20- 30 km) I put 3 brand new motorcycle batteries in series. Charged individually with a good (LIDL) charger, the batteries give a whopping 17.3 V, with a halogen light load15 V!!
I don't dare to hook this up to my bike! Of course I can bleed the 3 batteries to ca. 13.5 V to make it safe, but so much capacity is lost!
There has to be a common solution/ circuit: 55-41 V, ca.10 A, to a stable 40-36 V.