Goped electric speed issue

[SarDoX]

hi everyone!
I got an old goped electric scooter without batteries for $350 and put new BB SLA HR6-12 batteries.. after the first ride I noticed the problem - with fully charged batteries max motor voltage during the ride is 16.5V (it goes 11mph) and 17.2V when TURBO is on (it goes 12mph). I'm 125lbs so it should fly with me onboard))
So turbo mode is adding only 1mph and 0.7V to the motor, not even close to 20mph
What can the problem be? controller? incorrect sprocket? not a full throttle? I disassembled throttle control and find only some kind of magnetic switch (transisotor?) that looks good. :?
system voltage is 25V.

can someone check the voltage on motor (if u have SLA batteries) when u run goped on a stand in turbo mode and eco
i have a feeling that it should be something like 24 turbo / 20 eco or so...
Thank you!

p.s. overall - I really like it and thinking to get one more for my wife) :lol: :lol:

 

[dnmun]

why do you think the batteries are new? what is the manufacturing date? you have two 6Ah 12V SLA in series? what is the output voltage of your charger? what is the final voltage on the batteries when charged up to full charge? what is the voltage on each one?

do you have a wattmeter as well as the DVM? you will need some way to measure the current from the batteries in order to test capacity. so either a wattmeter or second voltmeter with a 10A scale.

 

[Ykick]

I put 1000’s of miles on an ’05 ESR750ex and something is seriously wrong here.

They do require serious current handling batteries and that seems like very significant voltage sag. You’ll need battery capable of providing a startup current nearing 100A in standard Turbo mode. 50-60A is very common with these rides.

You’ll need to qualify the batteries can provide the current ESR needs before worrying about other areas.

Brushes can and do wear out but that’s more on/off intermittent…

 

[dnmun]

he will never get 100A from 6Ah SLA even if they were new and in good shape. maybe 20A for 5 minutes.

 

[Ykick]

Stock ESR’s came with 4Qty 7.5Ah and the EX version upped to 9Ah. 2 in series and then paired as a parallel group.

Yeah, 6Ah without any parallel grouping is not gonna cut it with that motor/controller.

You could test it with a couple car starting batteries in series, LOL…

 

[SarDoX]

why do you think the batteries are new? what is the manufacturing date? you have two 6Ah 12V SLA in series? what is the output voltage of your charger? what is the final voltage on the batteries when charged up to full charge? what is the voltage on each one?

do you have a wattmeter as well as the DVM? you will need some way to measure the current from the batteries in order to test capacity. so either a wattmeter or second voltmeter with a 10A scale.

thanks! i cant locate date on batteries.. but i bought 4 of them, 12v ea, in parallel 24v . from http://www.atbatt.com so i believe they are new

right now they are charging with a build-in goped charger so I will chech in 5 hrs their voltage

unfortunately i dont have a wattmeter)

 

[SarDoX]

he will never get 100A from 6Ah SLA even if they were new and in good shape. maybe 20A for 5 minutes.

but these HR6-12 BB were stock batteries for goped some time ago and in specs goped had (up to) 20mph in turbo with them..
im not even getting 13mph now..

so... does anyone know what voltage must be on a motor on a stand? over 20v or under 20v?
is it safe to connect paired batteries(24v) directly to motor to check how its spinning on 24v?

 

[SarDoX]

ok
after 3hrs of charging ea battery has 13.4-13.3V
still i have 16.7V eco and 17.5V turbo
also i noticed that voltmeter is showing something around 25-40V for a moment(less than a sec) when i turn turbo on

 

[MrDude_1]

you need to do some testing to figure this out.
first, check how good the connections between the batteries are. that slip together connection kind of sucks. others used thin wires in a loop that also sucked. I ended up making a Capital I shaped harness that tied the middle of both packs together. It kept everything better balanced too.

next, I would make sure you are getting wide open throttle. unplug the throttle from the controller, and measure the resistance close and wide open. and I would check the switch. i dont remember the pins/colors, but if you open the throttle, it becomes obvious what goes to what.

next I would put full power to the motor and make sure it spins as expected. take the chain off for this... and use atleast 12ga wires for testing. run it through an amp meter and see what its pulling at full pack power.


I am willing to bet you either:
1. have a poor series connection between the batteries.
2. are not seeing WOT on the controller.
3. the brushes are worn out on that motor.

its most likely one of the 3. Its a simple PWM brushed DC motor. weakest link is the batteries, and if you up them, the next weak link is the motor.
the controller is pretty robust.

 

[dnmun]

your charger is not charging the batteries if they do not get over 29V. something is wrong with the charger.

you need to find the manufacturing date on the SLA packs. what was the voltage on the packs when they arrived? was it below 10V?

 

[SarDoX]

ok.. i decided to disassemble the motor..
damn spring brushes! it took me 2 hrs to put it back. i ended up making a @custom@ holder for motor and brushes

here are some pics, motor looks ok.. brushes - i dont know. any comments on pics?

thank you!

p.s. there is a some resistor/transisot N437 in the throttle and 3 wires come to it - black white blue.
i tried to measure resistance between all the possible pairs (that can be done from these 3) and change throttle position - but dont see any resistance change
may be i need to turn scooter on to see it?
hm..

 

[SarDoX]

your charger is not charging the batteries if they do not get over 29V. something is wrong with the charger.

you need to find the manufacturing date on the SLA packs. what was the voltage on the packs when they arrived? was it below 10V?

it was 12.6v ea

I will charge them overnight today so.. will check in the morning