Three swollen batteries due to over charging for 72v hub motor led to intermittent slow power/batteries or controller
Hi all,
I have a Chinese electric scooter that I got running (YAY) with self made, brain racking wire diagram diagnostics, and the help of an English guy and his new controller (Thank you for your help btw).
Immediately afterward I set up the "smart" charger to do it's job overnight and woke up to go to work. I worked till 230, got home @ 3pm, opened the garage and found three of the six 12v batteries swollen and smoking from the long charge. The supposedly "smart" charger was dumb indeed and did not stop charging for basically 24 hrs. (red light still on)...AAUGH!! I put out my cigarette immediately, disconnected the thing, let it cool a day and go to run the thing and it won't go well. With slow throttle it spins the wheel with little power and can hear the halls doing their job, but full throttle the wheel spins in short spurts of VERY little power. I checked the throttle for juice going in (5v right) and about 4.8/4v coming out at full throttle and find 4.8 going in but only 2.2 coming out.
I am assuming that the batteries are gone...DUH...and need to be replaced
Questions:
1. Must I replace all 6 batteries or can I get by with replacing just the 3 swollen ones (their freakishly expensive and I have little $$$)?
2. Where can I get inexpensive sealed lead acid batteries (or just batteries) from quick in San Diego?
3. Is the throttle bad or are my test results just the symptom of the bad batteries?
4. Why didn't the so called "smart" charger turn off like it was supposed to, is this common in a 6 battery bank (they all have the same charge btw)
I'd appreciate any advice from any of you eride guru's
Oil resiliant,
Steve
I can only try and answer one question for sure and I do have experience in that area.
I am assuming that the batteries are gone...DUH...and need to be replaced
Questions:
1. Must I replace all 6 batteries or can I get by with replacing just the 3 swollen ones (their freakishly expensive and I have little $$$)?
2. Where can I get inexpensive sealed lead acid batteries (or just batteries) from quick in San Diego?
3. Is the throttle bad or are my test results just the symptom of the bad batteries?
4. Why didn't the so called "smart" charger turn off like it was supposed to, is this common in a 6 battery bank (they all have the same charge btw)
When I got my first Chinese scooter the charger did what you descibed and over charged them and I replace the fat batteries and left the other three. I ordered a new regulated charger and in a very short time the new ones failed and I went back to Interstate and they said you have to replace the whole pack and wouldn't warranty the bad "new" batteries. I ordered a new pack and in two or three charge cycles got in perfect balance. Reason is ampere hour has to be the same in series string. An old pack battery group will be out of whack and less AH capacity. You can put in a few good batteries to see if scooter can run a OK but that is about it.
I have a about 60 / 40 ratio of getting a good charger made in China. When I get a charger from TNC in Tenn, USA they smoke test all of them that they sell. If they let the smoke out of them they deal with it. If it is able to keep the smoke in and it charges the pack then it is good for re-sale. I don't know of battery sellers in California but most scooter use an alarm type of battery like a 20 AH EVX12200 and Yuasa 17 AH types.Throttle? Don't know - too many variables.
So I would go with replace the pack and test each one for a week and make sure they are good with a new charger. Believe me they will self balance if same run and date code. Charger must be C/5 to C/2 or 3 for good charge time or no less than C/10. I hope you get on the road soon on electric. Let us know AH of pack voltage total, and charger manufacture.
Ok, so I found that I did in fact overcharge the batteries and believe a bad battery ruined it for all of the others with the "smart" charger...all are shot now.
So I get six new 12v18ah SLA batteries from awesome amazon.com ($39 each and free shipping too BTW). Then I install and charge to capacity (NOT trusting the "smart" charger, but by checking the voltage of each (around 13.3 each). O.K., then I hook up the scooter to them and try the motor....YAY it spins under power, great!!
Only problem is it doesn't spin quite as fast as it once did on the center-stand, and when I try to ride it it goes REAL slow. Plus my GF smelled something burning after the ride so I turned it off and found the phase wires were so hot the zip ties used to hold them down were stuck (melted) to the wires upon removal aaugh!!
Then I tried spinning the hub motor (by hand, off power on it's axle) and find it has a lot of friction somewhere. More in one spot around the 360 degree circumference than the rest. So I remove all the allen bolts on the wire side of the hub motor, place it flat on two paint cans so that the wheel rests flat, between, and on top of the cans but just so that only the tire is touching the top of them. Then I take a block of wood and rest it atop the axel )with the nut attached) and hit the wood with one of my old swollen batteries. The stator drops out nicely leaving the nut to keep it from falling all the way to the floor.
Now I inspect the stator and magnets and find that the bearings SEEM to be great, nice spin, not loose or wonky at all. I do notice a wear mark (rubbing line) though, on the magnets and the top of the stator in certain areas. Also there seems to be some kind of white, dry, chalky kinda build up on the magnets.....
What is going on here?
Lots of questions:
Could the bearings be good and still the motor rubs or must the bearings be bad?
If the bearings are good, how could I put the motor back together without it happening again?
If the bearings are bad I could try Acer or Boca bearings, but then would it just rub again anyway?
Do the bearing seals cause enough drag to create resistance to fry the wires that were once working fine
Do I need to grease the bearing seals at the axle?
How can I install newer, thicker phase wires so the ambient heat wont melt them in the future? The wires seem to be fine inside the motor (it's outside the motor that they melted) but the thicker wires wont fit through the axle hole, and if I connect them before the motor won't the old phase wires (though short) be a bottleneck for current and create that bad heat (that I now cannot see) anyway?
How do I re-seal the motor so my I do not do damage to the stator?
Is the white stuff on the magnets normal, can I clean it off, does it mean there's a short somewhere?
I just need to get the motor to spin freely without drag when ridden and I believe that would cure this problem One of many).
I tried hooking up the charger to the scoot and the same results applied