How to test if problem is battery or controller?

[ikeonabike]

Hello-

I've read tons of posts on ES while preparing to build my first ebike, but this is my first time posting.

I'm building my first electric bike from a 48V 1000W rear hub motor I picked up on ebay and a 48V 18ah (5-parallel, 13-series) battery I picked up on Aliexpress. I believe I have hooked everything up correctly, but I'm getting no juice. Nothing happens when I turn the throttle, and nothing shows up on the LCD screen.

I thought the problem might be the crappy crimped bullet connectors that came with the controller, so I replaced them with soldered XT60 plugs. Didn't help.

I have tested the battery with a multimeter and fully charged it shows 53.9, which is slightly lower than the company's claimed charge cutoff voltage of 54.6. I don't know if that means something is actually wrong with the battery.

How do I figure out if the battery or the controller is the problem? The battery company says it's probably the controller and the motor company says it's probably the battery.

Thanks!

 

[wesnewell]

What's the voltage of the battery when it's connected to the controller?

 

[spiros]

Can you connect the battery to another ebike?

 

[fechter]

Sounds like maybe the battery just needs to be charged. Try to measure the voltage with the controller connected and turned on.

 

[ikeonabike]

When I connected the battery to the controller and tested the connection with the multimeter I got the same reading as when I checked the battery straight off the charger after being left charging all weekend: 53.9

Does the fact that the battery does not charge all the way to 54.6 mean that it's a dud?

Thanks!

~isaac

 

[docw009]

I figure you have the polarity of the battery connector correct or bad stuff would have happened. The 53.9 volts would have me thinking, but I'd first make sure my meter is correct. However controller would power up at 44 volts, so you should look at that.

I would look at the wiring from the LCD to the controller. Does it use the round plugs. They can be hard to insert and worse, some users manage to force them w/o aligning the arrows. If it uses the JST plastic plugs, make sure the wire colors match on both sides. Make sure the pins are not loose.

If it still doesn't come up, depending on your controller design, you can jumper a few pins to work around the chance of a dead LCD unit. You can also test the plug to see if the controller passes the battery voltage to it. If nothing works out, the controller is probably dead.

 

[ikeonabike]

I figure you have the polarity of the battery connector correct or bad stuff would have happened. The 53.9 volts would have me thinking, but I'd first make sure my meter is correct. However controller would power up at 44 volts, so you should look at that.

I would look at the wiring from the LCD to the controller. Does it use the round plugs. They can be hard to insert and worse, some users manage to force them w/o aligning the arrows. If it uses the JST plastic plugs, make sure the wire colors match on both sides. Make sure the pins are not loose.

If it still doesn't come up, depending on your controller design, you can jumper a few pins to work around the chance of a dead LCD unit. You can also test the plug to see if the controller passes the battery voltage to it. If nothing works out, the controller is probably dead.

Good to know that the battery is probably not the cause, if the controller would power up at 44 volts.

How would I "test the plug to see if the controller passes voltage"? I hooked the battery to the controller and used the multimeter to measure the wattage at the points of connection. Is that what you mean, or is there another way to test it?

Thanks!

 

[fechter]

When I connected the battery to the controller and tested the connection with the multimeter I got the same reading as when I checked the battery straight off the charger after being left charging all weekend: 53.9

Does the fact that the battery does not charge all the way to 54.6 mean that it's a dud?

Thanks!

~isaac

That's close enough. The charger determines this more than the battery. 54.6v will make the cells last longer. Sounds like the battery is OK. If it dropped to zero when the controller was connected, then it would be the battery.

Is there an on/off switch on the display? With some of these you have to press and hold for several seconds before it will turn on. Other models may have a switch on the controller itself.

 

[999zip999]

Carefully check all connections and wire in the connector. Plug and unplug

 

[999zip999]

Plus where do you live maybe someone local could help you

 

[docw009]

Best to describe your kit. If they still sell it on ebay, show the link with the picture of the controller, the LCD display, and any handlebar controls.

 

[ikeonabike]

This is the kit I got: http://www.ebay.com/itm/222117405994?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Like I said, I've hooked it all up, but I'm getting no power. I've disconnected and reconnected all the wires multiple times. Haven't tried opening up the controller to check the other ends of the wires. I'll give it a look when I get home from work.

I'm in Santa Rosa and would welcome help from anyone in the area

 

[docw009]

That helps a bit. When you plug in your XT60's with a live battery. do they make a pop or spark? Unless using a sparkless connector, this usually happens.

Look at the 5 pin plug for the LCD display. Make sure the colors match up on the corresponding connector from the controller. On mine , the colors go red-blue-black-green-yellow.

Black is ground. Red will be the battery voltage. You can check that on the plug from the controller. If your colors are not in the above order, well that would be a puzzle. If that were the case, I'd still figure the middle is ground. Then the top or the bottom is battery. You cannot fry anything just checking power on a connector, unless you're clumsy and short out the pins.

 

[wesnewell]

I'm in Santa Rosa and would welcome help from anyone in the area

There are many places in the world named Santa Rosa. This is a world wide forum. Please follow the instructions at the top of this for your location.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=66302

 

[ikeonabike]

I got it running, although I'm not sure exactly how. Last night I opened up the controller to check the connection of the wires inside. All I did was gently push down each wire to where it connected to the circuit board. I didn't think that I had found anything wrong, but when I reconnected it to the bike it worked! Hopefully it keeps working.

Thanks for all the advice.

 

[fechter]

Good work. I'd guess the connection that goes to the display or wherever the power switch is. Sometimes these things get dropped during shipping and connectors can come loose.

 

[999zip999]

Let us know how it works out.