Need help with modding an E-Zip 900

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Xxpect
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Need help with modding an E-Zip 900

I just bought two Currie E-Zip 900 scooters from Sam's Club.http://www.samsclub.com/shopping/navigate.do?dest=5&item=390911 They were only $170.00 each brand new in the box! The motor says it is 900W. It has 24v 12ah battery pack and a 24v 30A Motor Controller. This scooter has a chain drive, but I don't think it freewheels.(lots of motor whine when coasting downhill with the throttle off).

The scooter seems to have decent power on the flats and slight grades, but seems to lose speed rapidly on some of the steeper grades around town. The battery life seems to be really short too. I doubt I am getting more than a couple of miles before the scooter is barely crawling up the hills. I live in the Sierra mountains and there are few flat areas so I need to improve the hill climbing ability and range of this scooter. I plan to use it for my daily commute to work which is a daily total of ~6 miles.

The motor does not even get warm after dragging my 200Lbs up hill until the batteries are drained so I am thinking about overvolting. Here are my questions:

1.36v should be relatively harmless, do you think 48v would be overkill and burn out the motor? (this is assuming that I use an appropriate controller)
2.I saw the formula W=V*A and when I plugged in my 900W motor with the 24V battery pack I came up with 37.5A. My controller says 30A. Does this mean my controller is limiting my motor and that just replacing the controller could improve performance?
2a.What effect does using battery packs and/or controllers with higher or lower Amperage ratings have?
3.I don't want to spend more than a few hundred dollars to upgrade this scooter. What do you think is the most cost effective way to improve hill climbing and range?
4.Any recommendations or advice from more experienced and knowledgable people is welcome.

Thanks in Advance

sixpax2k9
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Re: Need help with modding an E-Zip 900

I am not an expert but here is what I know....

1. Its impossible to know for sure how much voltage your controller and motor will take.
In my experience with EVs, a 12v step up is usually ok, so going to 36V should be ok.

2. yes your controller limits the Current to your motor. This is what also limits its power up hills and acceleration.

2a. in regards to batteries etc. The more Voltage you use the faster the EV will go.
The more Amperage the motor gets the more torque it will produce. the 12ah of the battery is basically how long the battery will take to discharge at 1 amp per hour. IE. a 20ah battery will take you almost twice as far as a 12ah battery.

Not sure how much you know about batteries, say u have 2x 12V 12ah batteries (as you do).
in series (which they currently are) it is like 1 24V 12ah battery. If you were to wire them in parallel you would effectively have a 12V 24ah battery.

All this boils down to this.....
for better performance you need to get the motor more Amps. either by getting a new controller or modifying your stock one. Maybe you should open it up and look at it. and search for "shunt" mod on these forums to see how to increase its performance.

For a longer range, you are going to have to add or replace your current batteries with higher ah ones.
Also, increasing the performance on hills etc. will reduce your overall range as it is pulling Amps faster from the batteries.

best I could say is the add batteries and mod the controller.
going to 36V (adding a battery in series) would increase top speed and keep range about the same.
adding another battery in parallel would keep top speed the same and increase range.
modding or getting a new controller for acceleration and hill climbing will decrease overall range.

It all depends on what you want overall

Dave ; Tennessee
XB-600.

Xxpect
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Re: Need help with modding an E-Zip 900

Thanks for the quick reply.

So if I go to 36v battery setup it will increase my speed.
If the 36v battery setup is 20ah it will increase my range.
If I mod my controller or get a new one it will increase my acceleration and hill climbing, but will decrease my range.

A few more questions:

Is the shunt mod just increasing the amperage through the controller? If so, is it an arbitrary increase in amperage or is there a way to determine or control the amperage when doing the modification?

Back to this formula again: 900W=36v*25A
Does this mean that with my 900W motor and 36V batteries I only need 25 amps through the controller to run the motor at max?
If I were to use a 30 Amp controller with the above setup would that be over-amping? I assume that it will drain the batteries quicker. Would/could it be harmful to the motor or batteries to use a controller with higher amps? What could be considered a safe amount of over-amping?
If I over-volt and over-amp am I just asking for problems?

Thanks again for the quick reply. Your info has been helpful.

sixpax2k9
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Re: Need help with modding an E-Zip 900

There IS a way of calculating the shunt to allow for a certain amperage through the controller.
http://www.bergerweb.net/xb500/shuntmod.shtml
that link should give you a good idea about whats involved in doing so. It would depend on the existing controller for your scooter though.

Once again, the 900W rating of your motor...... it depends if thats nominal or max power.
For the most part motors can take more than the rated Wattage. IE. my xb-600 has a 600W hub motor, yet I am running it at 60V and on climbing hills etc. can easily hit over 20A current draw. 60*20=1200W.

Changing anything to a higher value than the STOCK configuration CAN cause problems!!!
I wouldnt suggest you do everything at once though, then you "Should" be ok. Like add another battery and run at 36V for a while and see how it goes. Then when you are confident that everything is ok, then look into modding or getting a new controller.

Like I said, I cant say for SURE with the E-Zip 900 as I have never worked on one. Hopefully someone else on here has.

Just because the controller is rated at 24Amps does not mean that it is ALWAYS providing that much to the motor. What the "shunt" mod does to a controller is this..... It effectively changes the controllers internal calculations of the amount of current to supply to the motor. IE, when you make the shunt a less resistive piece of metal it will then calculate differently. So instead of say... providing 5 amps to the motor it will provide 10 amps. those increasing its performance for acceleration and power. And the more and faster you pull Amps from the batteries, the faster they will drain.

Dave ; Tennessee
XB-600.

helcam
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Joined: Sunday, July 26, 2009 - 00:34
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Re: Need help with modding an E-Zip 900

I just got a e900. I was wondering what you found to be the best mod for your 900?
I'm mostly interested in making it climb or pull hills better.

Any input would be appreciated!

Thanks!

Helcam

myocardia
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Re: Need help with modding an E-Zip 900

adding another battery in parallel would keep top speed the same and increase range.

sixpax, I know that you know this, but for the people out there who don't, adding one battery (in parallel) to a 24V, 36V, 48V, etc battery pack won't give you any extra mileage whatsoever. You have to double the amount of batteries, which would be two more with a 24V system, three more with a 36V system, etc. Note, adding batteries in series has nothing to do with adding batteries in parallel. I.e., adding a single battery in series will in fact give you a 36V battery pack, allowing for better hill climbing ability, along with a higher top speed.

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