Has anybody upgraded their Xb-610 to a lithium battery?

"By "match the controller box" I assume that they just mean the lithium cells you pick have the capacity to handle the current your scooter draws - otherwise, you will lose some of the top speed that you would otherwise have. But nothing will be damaged - although too high current draw is hard on the cells - if they don't. Or maybe they mean voltage, but this is simple enough - 4 lithium cells = one, 12 volt lead acid battery.

I assume that you would be using 40AH cells, which can put out 120 amps at 3 volts (in warm weather anyway) and I suspect an XB601 probably draws no more than 70 amps or so.

It is not going to be entirely plug-and-play because you are replacing each 12 volt (actually 13.2 volt) batteries with four, 3 volt (actually 3.3 bolt) lithium cells. But the connections are fairly simple - you may need differnt lengths positive and negative leads to the pack. Assuming the scooter is 48 volt (is it?) the first job is to measure your battery box and find an arrangement of 16 appropriately sized cells that will physically fit in the box in an orientation where they can be connected and won't short against anything. As far as the cell themselves, then need to be oriented either terminals up or sideways with a narrow side-down.

You also really need to get electronic module or modules that will assure the cell all charge in a balanced manner and are also protected from over-discharge - i.e. a BMS, or you will be unnecessarily replacing expensive cells.

You will need to have some basic understanding or electric principles, and have a multi-meter handy, to do the job. It is handy to also have a charger that can charge single cells so you can do manual pre-balancing of the cells before putting the pack together.

These are all just very general pointers - there are scooter-specific things you will have to figure out.

But, at least you can usually use the lead-acid charger for the lithium cells, so that saves a good bit of money.

I guess if it is only 20AH you might find such a already-assembled-with-BMS pack. I used to hear about these "Ping" packs (the name of the Chinese guy who sold them) that were basically assembled and ready to go.

Yes, Li Ping, whose site is http://www.pingbattery.com I think, builds excellent packs, with BMS and charger included. A little expensive by DIY standards, but worth the price. I've been running a Ping 24V 20AH pack on my EZIP Trailz for most of a year now (Winter included) and have had zero issues with the pack. He also responds promptly and helpfully to emails.

Yes, I'm not familiar with what type of bike the XB-610 is. I had assumed that it was a 50cc level (1500-2000 watt) scooter, and used a 40AH pack. But if all he needs is 20AH, then Ping is the way to go.

My xb-600 draws independtly from two (48 & 60v) lifepo4 20ah packs .It still has 25 amp fuses inline which are never blown (except if turning front wheel all the way one side breaking inertia ona slant)so regular draw must be less than 20 amps.My humble recomendation is to use two packs since BMS disconect of all juice when getting too low .60 volts to have fun,48 to return ,if necessary.Also ,upgraded controller to enjoy 60v.Yes started with PIN batteries about 5 years ago but now it uses less expensive ones.