Replace controller on my electric scooter?

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Rambongo
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Joined: 06/20/2007
Points: 7

I am a newbie, so would appreciate some advice. I have an X-900 scooter from: http://www.eastcoastwholesales.com/electric_scooters_x900.htm

Bought over a year back. Never worked. I just got around to putting on the workbench to take a looksee. I worked with the ebayer that sold me the thing for a bit, but life got extremely busy and I just didn't have time to follow through.

When I first tried to use it, fuses kept blowing as soon as I put them in. Made no difference whether the cutoff was on or off.

Now, when I open it I immediately noticed that one of the wires from the controller to the motor was pressed onto a battery terminal so hard it broke through the insulation and the bare wire must have been toching the terminal. Looked like the wire was not damaged and I wrapped it in electrical tape. I put another fuse in, and it still made a pop when I put it in, but becasue the batteries were so low (from sitting for more than a year) it wasn't enough to blow out the new fuse.

It also doesn't charge the battery, even after I wrapped up the wire. Charger lights green and never turns red. So, I think I need a new controller. Now I don't mind spending a few bucks on a controller, even though I'm not exaclty sure how to know I'm buying the right one - has all the right connections and is right for the application (36 V, 900 watt motor).

It looks like Andrew (http://www.austinev.org/evalbum/813) has the exact same scooter as me and in the above link had upgraded his controller to: Navitas TSP100-36.

These don't appear to be sold much that I can see. Does anyone know if I can still get one somewhere? Or what other controller should I buy? Was hoping to stay in the $100 or under range, but if the consensus is that I should spend more to get a quality controller, then I will. I just don't know what/where to get it.

Thanks!
Rambongo

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chas_stevenson
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Re: Replace controller on my electric scooter?

Lets take this one step at a time.

1. I don't think you should jump to the conclusion that the controller is bad because it has nothing to do with charging the batteries.

2. The cut off switch on these type of controllers is NOT an off/on switch for power from the batteries. The only thing the switch does is disable the controller. As long as the batteries are connected to the controller a small amount of current flows.

3. With the batteries sitting as long as you say they are dead!!! The charges for these scooters are designed so it will not charge the battery if the battery voltage is not at a minimum voltage.

With this information lets trouble shoot the problem.

Step 1. Disconnect the controller from the batteries.
Step 2. Check the voltage of each battery with a volt meter. Must be at least 10-volts each for the charger to operate.

    If the batteries are lower than 10-volts then use a standard auto charger on each 12-volt battery to try to bring them back up. Do NOT set the charger to charge at greater than 4 amps. CLOSELY monitor the battery voltage of each battery during the charge process, I would check on them every 15 minutes. Also place your hand on the side of the battery, if it gets warm you may need to lower the charge current. Do NOT let the battery get hot!!!

Step 3. Assuming your batteries take a charge, they may not hold it long in which case you will have to replace them. But if they do connect the scooter charger to the batteries and be sure you bypass the controller. It does NOT need to be in the circuit.

Let me know what you find and we will continue the process.

Chas S.
My Bicycle Pages

Gman
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Re: Replace controller on my electric scooter?

`Rambongo,
BTW, welcome to the V is for Voltage Community.
Chas is among our most knowledgeable Community Members.

Peace Out,
Gman

Now that we have clarified our beliefs, your invited to join us as we begin building on them to define our Community Mission Statement

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Gman

Rambongo
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Joined: 06/20/2007
Points: 7
Re: Replace controller on my electric scooter?

Thanks, GMan. Thanks, Chas! Appreciate u taking the time to help me! I will follow ur steps and come back. One question:

"connect the scooter charger to the batteries and be sure you bypass the controller. It does NOT need to be in the circuit."

Right now the port the charger plugs into has a connector to the controller, and similarly from the controller to the batteries there is a connector. To bypass, I'm assuming that I disconnect the connectors to and from the controller (from the charger port and to the batteries from the controller) and connect 2 new wires between those 2 connectors?

Thanks again,
R

Fechter
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Points: 199
Re: Replace controller on my electric scooter?

If you have a meter, try disconnecting the batteries and measure the resistance (ohms) across the battery wires going to the controller. Reverse the polarity of the meter probes and measure again. If the controller is shorted, the measurements will be near zero in both directions.

If the controller is healthy with the probes in the normal polarity (red to red), the reading should start out low and increase over several seconds to a fairly high value (over 100k ohms).

It's possible that the cut in the insulation allowed a short that blew the controller.

As Chas points out, this may be unrelated to the batteries being dead.
On my scooters, I cut off the charger wires and ran them straight to the batteries so they don't go through the controller anymore. You could probably do the same thing, but in rare cases the controller contains the charge regulation circuitry. The way to tell might be by looking at the charger and see what the label says (what the output votage is stated as).

If the controller is dead, you can get a cheap replacement from TNC scooters, but you might need to adapt the wiring a bit to make it work.

Rambongo
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Joined: 06/20/2007
Points: 7
Re: Replace controller on my electric scooter?

Ok, I disconnected the controller from the battery and took a reading on each battery. All three came up approx 12V. I double checked when I bought the scooter - it was Marh 2006

Then I measured the resistance across the battery wires going to the controller as Fechter suggested reversing polarity (that's just switching the probes between terminals, right?) as soon as I make the connection, the meter pins to 0 very quickly switching from side to side as I switch polarity.

Does this mean that the controller is bad?

I also did a stupid thing. I thought that maybe the fuse housing may be bad and I shorted the battery to itself bypassing the fuse. Nice pop on the battery terminal and about half the 1/4" terminal is burned off. Hope that doesn't mean I'll have to buy new batteries. Still came up 12V when I put the meter on the battery. Should I fill in the gap with solder?

Fechter
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Re: Replace controller on my electric scooter?

It would be normal for the meter to go to zero right at first, but if you keep the probes on there for a few seconds, it should climb up slowly in 10 seconds or so, in one of the directions. If it just stays at zero, both ways, the controller is shorted (toast). Correct about reversing the probes.

Yes, batteries have a lot of juice. Good news is it sounds like the batteries might still be good. To fix the burned off terminal, I would just solder the wire direclty to the terminal on that one. If you swap the battery positions, you can solder directly on one of the jumpers that goes between batteries. This way you don't have to snip the connector on the main wire. Clean the terminal with a wire brush or sandpaper before attempting to solder. If you replace the batteries later, you can install a new connector.

If the controller tests bad, you have nothing to lose by opening it up and taking a look inside. Sometimes the problem is mechanical, like a blob of solder bridging the traces, pinched wire, etc.

Rambongo
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Points: 7
Re: Replace controller on my electric scooter?

ah, you're right. When I left it on (red to red), it drifted up to 22K or so after a good 10-15 seconds.

Now what?

MB-1-E
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Re: Replace controller on my electric scooter?

Sounds like the controller may still be ok.
Something is still shorting out though.
I'm guessing that somewhere the insulation is worn through on one of the positive wires.
A visual inspection from one end (the motor) to the other (battery positive) would be where I'd look.

I don't know scooters, so take my comment(s) with a grain of salt.

Chas and Fechter are the ones to listen to, they'll get ya rollin'.

Dave

MB-1-E
Electric - Bridgestone MB-1 Mountain Bike
Icon Photo of lighning striking Eiffel Tower Jun 3, 1902, taken by MG Loppe'

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Rambongo
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Re: Replace controller on my electric scooter?

Checked all the wires. No cuts or breaks. The only thing I saw was one of the wires connecting the batteries in series had a nice crimp in it and is pretty flat. The insulation is still intact, so I thought it was ok... Nothing else. Everything is clean.

Chas, I think, mentioned to bypass the controller when charging. Not sure how to do that... Currently, the batteries are hooked up in throug the fuse (is there a way to test the fuse housing? do they ever go bad?) into a connector that goes into the controller. The charger also plugs directly into the controller with a connector.

There aren't that many parts here, so it's got to be something!
Does anyone want pictures of anything?

:(

Gman
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Re: Replace controller on my electric scooter?

`
You need a way to check continuity, a ohm meter or a cheap continuity checker. Be sure to turn off the power. If you have a way to check voltage, check before and after the fuse for power. Probably the cheapest way is to buy a good fuse. Sometime you can look at them and see if the filament is broken also.
You already have two of the best working with you, so I'll leave it to them for some better advice. Don't need too many Chefs in the Kitchen.

Peace Out,
Gman

Now that we have clarified our beliefs, your invited to join us as we begin building on them to define our Community Mission Statement

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Peace Out,
Gman

Rambongo
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Points: 7
Re: Replace controller on my electric scooter?

Ok. I do have Micronta meter. It looks like the fuse holder is shot. I hook one probe to my neg battery. Touch the positive battery terminal - 36 volts. Follow the pos terminal on the battery to where it connects to the fuse and touch that terminal - 36 volts. touch the other fuse terminal - 0V. No juice flowing through the fuse. I tried 3 brand new fuses. The fuse cap doesn't even screw down all the way because when I was burning up fuses in the beginning, the threads of the fuse housing got very burned.

I think I still have another problem because I touched the wires that connect to the fuse together, basically bypassing the fuse, with everything else hooked up and I got a nice spark/pop that I think indicates there's still a short. Maybe the controller. Going to pen that up to see if I can see something there and order a new fuse holder.

Any further troubleshooting tips would be appreciated. Thanks everyone!

Gman
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Re: Replace controller on my electric scooter?

` ;)
Congrats, your now a EV Tech.
Since I haven't been really following the problem, I don't know if it's safe to just temp bypass the fuse, or you could use alligator clips to hold the wires on each end of the the fuse just to complete your trouble shooting.

Peace Out,
Gman

Now that we have clarified our beliefs, your invited to join us as we begin building on them to define our Community Mission Statement

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Peace Out,
Gman

chas_stevenson
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Re: Replace controller on my electric scooter?

It is normal to see a spark when the batteries are connected but it should not be a large one.

Here is a simple wiring diagram that should help you understand bypassing the controller for the charger. I also show where a switch should be added so when you power off the system no current will flow through the controller. I did not show a fuse but it is a good idea to put one in on the plus (positive) side of the battery connection.

Chas S.
My Bicycle Pages

Fechter
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Re: Replace controller on my electric scooter?

It is normal to get a pretty substantial spark when you connect the batteries to the controller.
The resistance measurement of the controller indicates it is not shorted, so that is a good sign.

Here's a really dumb question: Are you sure the controller polarity is correct? In other words, are you sure the battery positive is going to the red wire on the controller?

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