Hi Everyone!

Happy Holidays! I am new here and first just want to say THANK YOU!!!! Thank you all for being so kind and helpful. This forum is a Godsend and has helped me tremendously.

So on to my problem. I recently purchased a 2015 Jetson 500w ebike on Craigs...I KNOW

But it wasn't as bad as you think. I got it for $200. The guy just explained it wouldn't stay on. It runs pretty good EXCEPT...the dreaded load cut off.

I've done and checked everything you guys have said could be the problem. First thing I did was to check the battery. My x is a mechanic so I used the appropriate tools for accuracy. I'm also a lab technician so I have done a battery of testing over days to get validation of my results. So I got a reading of 48v. It's a 48v battery so I thought this was appropriate. I jumped on and rode to about 9mph and it just cut off.

I read around and found that I might need to balance the battery. I was unsure what that meant at that moment and a cut off made me believe it may have needed a charge. Also it was sitting for some time. So I did the series of 3 12hr charges as stated in the manual, believing the battery had not been charged to capacity. Read it again, 53.9v.

I jump on ride it, we're doing good, and once I hit 15mph, the indicator drops to 3 bars, flickers...DEAD. I had to jump off, hit the switch and we're back on. Over the two days I charged 12hr and took it off. It increased in power/distance. But would still cut out anytime I "open" up the throttle to full speed. So then I start calling people. I was instructed to pump my tires to 50psi. I did so and again, better performance but same result. Next I took the battery out of the housing and tested each series to see if there may be a faulty cell. But from my readings everything seemed ok.

So I ask my daughter, She's a 16 year old baby genius. She literally knows everything about everything. She tells me to check the controller and tells me about a speed mod that allowed me to take her to 26mph(hehehe! LOVE MY BABY!!!) But it still cut off but not as fast. Then she tells me there are settings and they may be too low. That would mean the bike was destined to fail, which can't be true because I have seen people ride WITH the mod and no cut off. I even checked the BMS and it seemed up to speed. So maybe its got too much juice in the battery? I ran it for about an hour and a half on the stand and retested. The indicator never dipped below full and the voltage reading was 51.3v! Problem being, I have read so much that I am just unsure of the parameters at which this bike is to run. I was told the LVC is like 2.5. (Can I increase this setting?)

Here come the questions....
How can I tell if I need a more powerful battery(I have a 48v 17amh)?
If I install a 48v 20amh, will it blow my controller?
Should I just buy a new controller? and who can I trust? I have a haoling 48v 16-17amh , throttle of 4.5-5v, and low voltage of 40v?
Would a new controller solve the cut off? It only occurs when I'm on. On the kickstand, it runs like dream. I weigh 125lbs/56kgs.
Should I just fork over the $400 for a new battery? Is there any other way to mod the BMS or take it off and ride safely?

I read somewhere I might need to reset the relay setting on the LVC which can be set to 600. It is typically set at 10s. I also read that it might be a HIGH voltage cut off, although there is no such value on the controller. I also read that an overcharged battery can be rebalanced by allowing it to go almost dead and charging for 48 hours straight. I really hope someone can help me. I would like to get it going soon. Any advice I can get will be so appreciated. THANKS and so happy to be here amongst EFriends!

Does any of this make sense to anyone out there?
To recap. Battery reading as charged, runs great until I sit on it and open the throttle to full speed.(Jetson 500w ebike, 48v 17ah, haoling controller 48v 15-17ah throttle 4.5-5v low voltage 40v, 32a switch)

I did a search for Jetson Ebike 500W and came up with a scooter on Amazon. The text claims a 20mph top speed, but I suspect that's an optimistic claim involving a lot of pedaling. I think you have a scooter built to the euro top speed of 15mph, and a tired battery is probably in the equation, too.

Based on the terrible reviews when new and the fact the company seems to have disappeared, I wouldn't invest any money in it. Ride 'er slowly 'til she blows!

First, if that thing is parked within 20 feet of anything that would burn if subjected to the flame from a blowtorch, DROP what you are doing and get it a safe distance away. Right Freaking NOW! ! *M O V E* !

If you parked it in or near my home where my children are sleeping I would throw it and you thru the friggin window. Then chase you down the street with an axe.

You did not just buy a cheap piece of crap, you bought a Used cheap piece of crap which had likely been abused by a moron.

So it was stored unused for "some time"? You are a lab technician, right? Here, I just mixed "some" hydrochloric acid with "some" sodium hydroxide, Drink It. You really need some more precise information, don't you?

What you have is a battery pack with at least one, or more, cells that are either defective, or severely under-charged. Each cell in a series string should fully charge to 4.2 volts, with a "48V" pack having either 12, or 13, or 14 cells in series. Do the math, note that no observed fully charged voltage matches those numbers.

Almost nothing you have read or been told is even rational, much less makes any sense whatsoever.

Depending on the (unknown) original condition, and also on the (unknown) storage time, it MAY be simply badly unbalanced, meaning one or more cells is not fully charged. This MAY, or may not, be remedied by charging for an extended period or time, measured in days or even weeks. Catastrophic eruption of hi-temperature, hi-pressure flame is a very good possibility. Should be done OUTDOORS, ideally inside a barbeque grill under constant supervision.

A qualified individual could disassemble the battery, test each cell separately, charge as single cell, repeat test, observe for capacity, and re-assemble. A smart person would find someone with a boat that needs an anchor and get something else.

Yes, you could replace the battery and then you would have a cheap piece of crap with a good battery, assuming you went with a reputable manufacturer and vendor and spent over twice what you spent on the entire bike.

I would suggest it is simply a worn out or unbalanced battery pack. All the rest is just "noise". It runs fine when you're not on it because there is no load, therefore not much current draw, therefore little or no voltage sag causing you to get to LVC.

Re the Q on a 20Ah battery, the capacity is irrelevant as long as you have an acceptable voltage and ability to deliver the current needed.

+1; I had a similar "sag" problem which a new battery resolved. The question for you is whether it's worth the expense.

It sounds like both the battery and controller may be suspect.

You need a to get a load test on the battery to confirm that possibility. Its easy for volts to read good but everything goes to hell when you add amps into the equation.

Controllers are fairly generic and the amperage is the spec to match, or go larger. (with less battery life)

-SP

Old battery and unable to supply the amperes needed for 15 mph and more. One or more of the cell groups sags below the cutoff and bike shuts off. If you ride an ebike long enough, this will happen to you. If you buy cheapo batteries, it happens too.

Dikes explained why it runs all day with the wheel off the ground.

You probably have two cutoffs. One is in the controller and probably set around 40 volts if it uses a 48V battery. The other is in the battery, and usually works at a cell level, probably around 2.5V per cell, although some are set higher.

Not much you can do, except look for weak cells and replace them, which is logistically and economically unreasonable. Only worth if you want to learn about batteries.

Now George Jetson was an alright guy, and if you think his scooter is fun, maybe it's worth $400 on top of the $200 you already spent to replace the battery. I'm not judgemental on what people ride. I have some junky ebikes.

I will say that if even if you know what you're doing, batteries can burn your house down. I keep telling myself this, as I fool around with cheap batteries.

The BMS inside the battery will draw power from one individual cell. While a very low draw, it will, over time, run that cell very low, unbalancing the pack. This is a dangerous condition. Knowing EXACTLY HOW LONG the pack sat unattended is critically important information to help make this determination. That is why I emphasized finding out this info. Weeks not likely to be a problem, several months are usually required. Unless there is a defective cell or it was unbalanced when delivered.

Leaving the pack on the charger for an extended period of time is about the only practical fix a non-electrical engineer can do, other than purchase a new battery. This is why I stated this should be done. It IS relatively simple to test voltage on individual cells, without major dis-assembly.

There is a thread about a knowledgeable dude with years of ebike experience with a hi-quality battery with no identified problem, and it burned his house to the ground. You need to have some understanding of what it is that you are dealing with.

There is currently no indication of any kind that the controller is at fault. They are relatively inexpensive to replace, however.

The OP has talked to an amazing number of people with absolutely no clue. Modifying the controller to allow more speed from a possibly damaged battery is an Exceptionally bad idea.

Thanks for all the "Positive" responses. I actually fixed my problem. The battery was never fully charged and triggered the bms. I reset it. Charged it and now its fine.

The typical BMS has no easily accessible "reset" function. It also has no user-changeable ability to interfere with the battery receiving a full charge.

The 3 12-hour charges should have solved the issue, it is possible that just one more made a major difference, but...

The Controller IS easily resettable, and it has a charge cut-off function that, on many models, is user-changeable. IF this was set wrong from the factory, this could be an issue. HOWEVER, if the High Voltage Cutoff, or HVC, was raised based on the type of advice the OP was getting, this could be potentially extremely dangerous.

Please describe the procedure used to "reset" the BMS, future readers could benefit from this not being kept a secret. Also describe the voltage reached by the battery under a full charge.

I want to hear about this magic reset I have never encountered either.

-SP

I've been doing online troubleshooting in another arena for several decades. Odds are high the OP will never respond with any useful information. Sadly, the possibility exists that she and her genius daughter have perished in a house fire.

SFAIK - there are only three ways to "reset" a BMS. One is only if it has shut down due to low pack voltage, you can very carefully charge through the discharge leads. Another is to completely disconnect it from the battery. The third is to replace it with a new one.

Most Lithium BMS's will allow charging (but not discharging) if the voltage has gone below a cuttoff threshold although it may be at a restricted rate until the voltage recovers sufficiently. There is often a secondary voltage threshold where the battery may be permanently disabled if the voltage gets too low.

Disconnecting and reconnecting a BMW won't reset anything it will still measure the voltages on the cells and if they're out of balance reseting or restarting the BMS won't change anything.

I should have clarified that the re-connection needs to be to a properly charged battery, I guess the "reset" is more in the battery than the BMS.