green "Jet Stream" electric scooter help request

[PeterBC]

I have an folding electric scooter with the name "jet stream" on the side.
It has a regular sized barrel plug socket for charging (also called DC power plug)

it contains 2 12v 7ah SLA batteries.

I have searched online but cannot find any information under the name "jet stream"

Would this be the same as a more common electric scooter I could learn about?

What voltage, and polarity should I use to charge it? I have tried small amounts of DC with center positive or negative and also AC 24v and it seems to act the same. the green light comes on but it only pulls approx 0.2Amps.
I am planning to install barrel plug sockets on each battery directly so I can have more control of the charging (also my tenergy lipo charger which does PB(lead) batteries does not do more than 20volts.)
I have car chargers(both regular and float), 2 car batteries, and some old broken stereo equipment that I might be able to use the transformers from for charging.


If I were to convert it it lipo batteries, what is the minimum size I could get away with? I would only need a 5 minute run time to try it out. I weigh 230lbs, but it does not seem to have problems moving me other than the fact that the SLA batteries are very old and weak.


In the photos, the red multimeter on the handlebars is so I could watch the voltage as I rode, the exposed wires were for charging.

Thank you for any assistance.

[Mozart]

Hi, and welcome to E.S.

I would recommend you to check this first... http://endless-sphere.com/forums/viewtopic.php?f=14&t=26621
Lots of good information here.

[Gfaust372@gmail.com]

Hi,

were you able to get this scooter running?
I have two similar ones and am trying to get new batteries for them.

[sk8norcal]

i tried 6 cell lipo before,
3.7 * 6 = 22.2
4.2 * 6 = 25.2 (fully charged)

my brushed controller cuts off @22v

[PeterBC]

I finally got around to working on my scooter
adding 2 barrel plug sockets (1 per 12v SLA battery) has made charging easier
now it seems a bit better, able to go further on a charge

I still want to upgrade it to LIPO batteries for more power & speed, it is slow on slight hills and I have to baby the throttle so it does not cut out.
I did some testing with the original batteries and also 2 car booster packs in series
it pulls up to 15 amps (more commonly up to 12)
the voltage shutoff on the scooter seems to be around 22v

I am thinking a 7s (7 cells) setup should be ok
from what I have read you should never discharge a lipo below 3v per cell (7 * 3= 21)
nominal would be 25.9 volts (3.7 * 7)
and fully charged maximum would be 29.4 volts (4.2 *7)
in a strange coincidence the minimum and maximum for 7c lipo is the same as 2 12v lead batteries!
I will run buzzers to let me know if any of the cells get too low.

Does anyone think this is a bad idea and I should do 6s instead?
If I get 3000mah(3Ah) cells, that should be able to do 12 amps for 15 minutes, right?

Thanks for any help

[SamTexas]

7s is fine. Most of these scooters use brushed controller and motor. The controller itself usually supports much higher voltage, 50V or 63V. So even 10s is safe. To be certain, you need to open the controller and look at the voltage printed on the big capacitor(s).

As for range, you can expect almost double going from SLA to Lithium. That is: 7Ah Lithium should give twice the range of 7Ah SLA.

[PeterBC]

thanks for all the help
I think I will start with a 6s for simplicity and price
I found a 3000mah 6s 20c for $24 which looks like the best price per watt hour.
too many choices
it sounds like even with this cheap small battery it should do better than with the current weak SLAs, I think they only have around 1500mah capacity left.

The next time I open it I will see what is written on the Capacitors to see the maximum voltage, thanks for that info.

[SamTexas]

I think I will start with a 6s for simplicity and price

6s might not work if your 24V controller has a conservative LVC (low voltage cutoff).