Senada DRIFTER Compact Fat Tire 500W E-Bike (Black) Expired

Quoting you, but there are others with similar questions.

For the ghost pedaling, you can upgrade to a Litepro 58T crankset [amazon.com]. That crank is nice for 55 bucks, but you can buy it for less than $30 from AliExpress.
All of these bikes use the same square taper bottom bracket and this makes a crankset swap extremely easy, even to non-bike mechanics. A square taper puller [amazon.com] is only $8 on Amazon and I swear it takes 2 minutes to swap each arm. They are simple devices:
1) Unscrew the crank center cap with a Hex wrench.
2) Make sure the wrench supplied sits freely between the silver part and the black part.
3) Use the wrench to screw in the black crank puller part so it becomes tight with the crank arm you are about to remove.
4) Slide the wrench back onto the silver part to start screwing into the black part. As it goes in, it eventually rests upon the bottom bracket. Keep turning to keep screwing it and it will start pulling the crank arm away from the bottom bracket. Lots of YouTube videos if unsure.
5) Pop the crank arm off and unscrew the black part of the puller.
6) Put the new crank arm on and you simply use the center cap you initially removed to install it. You just screw it back in with the same Hex wrench and it will push the new crank arm against the bottom bracket. Use 40nm of force or realistically for those without a torque wrench... just wrench it down pretty hard.
7) Done.

Enjoy not ghost pedaling until about 24mph+. Additionally you'll actually use the low end gears once in awhile as well. Even from Amazon at $65 all-in, it's a no-brainer upgrade.

As for the battery level indicator. I don't own this Seneda bike and unsure on the controller/display, but if it has a Voltage display option that is the true battery level indicator. This chart [google.com] will show you the more realistic numbers to look for. If your bike doesn't have a voltage readout available then you have options still. I would wager most here aren't trying to become junior electricians so I'll skip the tutorial on adding in inline 12v battery monitor, but you'll still need to own a multimeter.

This one is $10 [amazon.com]. Plug the black prod into the center port and the red into the right port then turn the dial counter-clockwise a few steps to the "200v" settings. Here's the cumbersome part...
1) Charge battery to 100%. Feel free to pop it off the bike and look for the pin outs, they should have two labeled for positive (+) and minus (-) on the terminals. Put black to the Neg- and red to the Pos+ and se the reading. Should be 54+ volts.
2) Ride the bike until the first battery bar disappears. and instantly pull over, pull the battery and check the voltage again. Follow the chart I linked. Write that down until you memorize it, but that is what the actual percentage of battery you have left will always be.
3) Do the same for each bar that drops.
4) Put those numbers somewhere you can find or see them easily until you have memorized them. That way you'll have better knowledge on what voltage those battery bars actually mean when they are first discharged.

Note it is essential to take the number when there is no stress on the battery (not being actively used). The bike should cut out around 42v, about 20% usable battery left. If it doesn't, know that 39v, 99.9% of the time is a battery so dead it cannot be recharged and revived. Once you hit 42v, you are on borrowed time. Even thought 42v means you have 20% battery left, every percentage point is more chance your battery is going to suffer permanent damage of some form.

Additionally since I don't know what display is used here the general way most run is you are have 20% battery not on the last bar showing, but when the last bar starts flashing. Of course you'd have to test the batter with that multimeter when that happens to know for sure.

Both these steps can take an hour or so the first time, but I highly recommend you just do them. Imagine not knowing how much battery you actually have for the life of the bike compared to just taking the time to figure it out and actually knowing the entire time... not getting stuck on a dead battery once will pay for itself.

Excellent price and highly recommend it to anyone on the fence. I bought the "Austin" model back when it was on sale for $520. Looks like some differences to the two, but the Austin has been a nice little ebike and I like being able to fold it (fits in my small apartment well). Only have three mild negatives to it. The first is the brakes are a tad squeeky/not my favorite but that might just be how disc brakes are. Second is that once you hit 15mph, you're basically ghost pedaling. I wish you could drop to a different gear to still pedal at a quicker speed. Last, battery shows full on the screen even after a 17 mile ride which annoys me (I wish it had a "remaining mileage" estimation instead) - it seems to guess based on pedal amount and may not actually know the capacity but I could be wrong.

I changed the rear freewheel gears to a 11-34t and now there's no ghost pedaling. The freewheel is about $28 on Amazon.