14hrs to go on that elephant ebay auction... highest bid now $255...

What is the difference between 10 AH and a highter AH?
Ken said that I would need 48volts min of 10 AH.

Think about your motor using "watts"... the electric unit for energy... and Watt-hours as the electric units for power... how much energy over time.

Watts are calculated as volts times amps... at 48V, a 500W load will be using 500W/48V = about 10.4A

If you average 10.4A for one hour you would need a 48V 10.4Ah sized pack...

...or if a 24V pack, 20.8Ah to accomplish the same effort...

So just convert all packs to Whs by multiplying pack voltages by Ah size to give Wh sizes for comparisons. Of course if the packs are all 48V then Ah ratings will be enough for comparison.

You just need to pop the battery compartment in yer ebike and look at the size of the original lead batteries... They're probably 12V each, but what are their Ah size? Might be 10Ah? 12Ah? or larger?

Knowing what sort of performance (range) you get out of the original lead pack will tell you what Ah-sized pack you need to buy as a replacement assuming same voltage (48V I expect.)

If your battery compartment can accept a larger Ah-size of pack this will translate as more range from the new pack. (Remember LiFePO4 cells have higher energy density than sealed lead acid batteries, so a "larger" pack in terms of Ahs does not mean necessarily a larger physical size of pack. For the same Ah rating and voltage, the LiFePO4 pack will be smaller and lighter. You only need to consider form factor - whether the brick shape of the LiFePO4 pack will fit into the shape of the battery compartment.)

But even if you replace the lead pack with a LiFePO4 pack of the same rated Ah size, the lithium will give you more range... For one thing lithium chemistry is "stiffer"... as the charge is reduced or higher power taken from the pack the voltage doesn't "sag" the way that lead acid does. The lower voltages experienced as lead batteries are drained usually translates directly as lower motor RPMs, so under motor the ebike starts going slower and slower...

...while with Lithium the voltage stays pretty constant almost to the last minute that the pack has any remaining charge... In practice you don't ever want to go there with lithium, where at end-of-charge the voltage level drops as off a cliff, and the BMS is designed to prevent this from happening by cutting off power to the controller usually at some conservative voltage level well above the end-of-charge state.

Controllers do this even for lead packs, where ya don't want to run lead down below 20% of its remaining charge. Measuring voltage levels for lead and lithium chemistries as a way to figure remaining charge is the common way to go, but an inexact way to go. A better way is to know the pack size in Ahs, and to use a "gauge" like a Watts-Up meter to measure actual Ahs consumed along the trip.

Also, what does "no memory" mean?
Is lithium the kind of battery that does better or worse being charged after each ride?
angela

The term "memory" first came from earlier versions of nicad batteries, where if they were left partly discharged when they were plugged in they would "forget" what their full capacity was to begin with. With lead chemistry there is a "memory" sort-of effect where if discharged batts are left for some period of time usually thought of as several hours or a day or more the lead will start "sulfating"... This is actually how lead acid chemistry works! Converting lead to lead sulphate and acid into water and then reversing the process, but "sulphating" in its negative sense means that the lead converts but cannot be reversed back into lead again by charging, so capacity is lost.

So the rule for lead is to plug in early and plug in often!

...Lithium OTOH... doesn't care! Yay! In fact LiFePO4 packs are shipped and stored normally in only a partially charged state. If ya leave them discharged overnight... or over a weekend... doesn't matter! Yay!

...so from this perspective, less likely to damage your investment in a battery pack if you forget to plug in some time or the charger burns up whatever...

Most folks tap about "commissioning" lead packs, as breaking them in for the first dozen discharges or so and over this time capacity actually improves. Even a used lead pack left unused over the winter will seem to "wake up" once it is in regular use again the next spring...

Most SLA specs rate the batts as good for 300 cycles if discharged to only 20% charge every time... Although technically this usually means that at 300 cycles the batt will have lost 20% of its original capacity, so your 10Ah pack only can put out 8Ah maybe...

LiFePO4 is the same way, although the numbers are waaaaay different. Common specs talk about 85% of original capacity after over 1000 cycles... If you are gentle with the LiFePO4 (not using high C rates) the manufacturers *claim* 2000 or more cycles possible... And again, the first dozen or so cycles should be gentle... 50%-ish...

Note, LiFePO4 specs are mostly *claims* still at this point. Think about how many cycles 1000 is, if you cycle once each day six days a week... over three years! LiFePO4 hasn't even been available for us regular mortals for this long! Very few folks jumped on this flavour of lithium when it was very new as it was retailing for more than twice the price it is today... Lots of stories about low-quality and defective China-made BMSs... ya had to really like bleeding edge and to be a gambler with money to lose in the early daze of LiFePO4...

Today there are now ebike folks that can report several hundred cycles on LiFePO4 packs with little noticeable degradation in performance, so the 1000+ cycle claims seem possible. There are others driving LiFePO4 from the top-tier manufacturers known for their high specs, high quality and high prices that can report even more cycles so far, but most folks are concerned only with the cheaper ebay product...

Basically most of the risk comes at time of purchase. If the cells are good and the BMS electronics are good and you install and cycle the pack a dozen or few times with no problems evident, likely you will be "good to go" for three years of constant use...

Lock

Well, well... Auction over and "Winning bid: US $255.00"... Have to say I have never shopped ebay myself, but read about the process enough that I expected some last minute automated bidding that would see the sale price jump a bunch... but nope. Didn't happen!

So that looks like a terrific deal *if* the cell quality and build quality and BMS electronics are OK... I expect the seller will have other identical packs for sale going fwd... and final sale prices will be similar. So WOW, yes, pretty cheap for a pack if it means 3x the cycle life and better performance versus an equivalent Wh size of SLA pack...

Good stuff! Still don't know if a 270 x 180 x 140 mm brick shape would fit in the battery compartment designed for four SLAs... If yes, there'd likely be room to stuff padding/insulation around the pack that would probably mean better cold weather performance as well...

Lock

...*if* the cell quality and build quality and BMS electronics are OK...

Incidently... I am reading reports now about LiFePO4 packs like this failing because of poor assembly. Basically beyond the basic specs the China manufacturers will cut corners wherever they can...

The sense wires that connect the BMS to each cell need to be only *tiny* electrically. They don't need to handle pack voltages and watts. The sensing and balancing is only done at milliamp levels... so the folks assembling these packs use stuff like #24 wire for the sensing wires. (#24 is 0.02 inches in diameter!)

These are rather frail, and *mechanically* from road vibration they can break, leaving one cell unmonitored.

If I were buying one of these "no name" ebay packs the first thing I would do is strip off the duct tape (carefully!) and check each of the connections for the sensing wires. Probably add solder to each end and maybe just replace each wire using a little larger wire size. Some mfgrs augment the solder connections w/a dab of silicone glue for extra mechanical strength.

Just a heads up!
Lock

Lock...I appreciate ANY heads up...and all this generous info.
Ok...I'll start with measuring my battery pack and seeing whether the dimensions are a fit.
Are ALL the packs listed on ebay "no name"? Including the ones sold by PING?
Also, my scooter needs 10AH min...48 volts. Would 20AH give even MORE range?

btw, send me your bill:)

thanks alot and take care
Angela

HAHA! Angela... Now you tell me... Your existing pack sounds like it is only four 12V 10Ah slas, or 4x12x10=480Whs in size, so yes, one LiFePO4 48V 20Ah pack (or 48x20=960Wh) will double the range you are familiar with, and because of the differences in the way the chemistries behave it will seem like MORE than twice the the range. When you pointed out that ebay auction for 48V 20Ah I just assumed that was your existing pack size.

Note that this same ebay seller does also list 48V 10Ah packs at a "Buy Now" fixed price of $256 plus shipping... so that is watt makes that recent action result so amazing... 48V 20Ah pack for half price (cost per Wh)

Yeah those ebay sellers are all "no name"... Actually most have MORE than one "no name"... Sorta like Whack-A-Mole, popping up here/there.

The diff. is, Ping actually is Mr. Li Ping and he has been selling packs for a couple of years now and has established a track record in the ebike community for standing behind his product and making good on any warranty claims...

Generally these folks are all just sitting in a room somewhere in Hong Kong etc and brokering deals with assemblers on the Mainland. They have to source packs where the assemblers in turn will take care to find quality components and assemble them carefully. These packs are all still hand assembled!

I expect you have read the many stories from China about chemicals being substituted in powdered milk, toys recalled `cause of lead in the paint... China is a big country and there are def. business folks there that will sell you the lowest quality imaginable... if that is watt you ask for? Mostly it's watt you DON'T ask for is where they "Gotcha"...

So it's up to folks like Mr.Ping to understand the Western business ethic where a certain level of quality and reliability are expected... Hard to compete w/the fly-by-nighters that don't have to honour their warranty claims `cause they are gone in a few months and resurface using a different name? Westerners bring this upon themselves these daze, demanding the lowest prices then being surprised when watt they bought turns out to be junk.

Have ya ever walked down Spadina Ave through the Chinatown part and seen the warez laid out on the sidewalk, including plastic bits, their colours already fading from sunlight? I used to chuckle going by the main offices of Daymak. For years they had one of the littlest Yong Kang electric scoots mounted outdoors on top of their sign by the road. The plastic body of the scooter all faded and chalked by the sun...

The diff. of course is that quality plastics include UV inhibitors and plasticizers in the molded plastics to stop fading.

Read watt Percy wrote here recently:

My bottom-of-the-line Gio 500 (shipped to Toronto from Vancouver) cost $600 all in, delivered to my house. I had to install the front tire and figure out how to dispose of the giant cardboard box it came in.

It is cheap, in almost every sense. Plastic fairings are not PVC, they are brittle and easily snapped ABS. Things that on more expensive bikes are PVC or aluminum are ABS on the Gio. Only the floorboards are PVC. Screw anchor holes are easily snapped. Tires are 2.75 inch wide, when in Toronto with all the streetcar tracks 3 or 4 is better. Motor is 350w average, 500w peak. Pedals are well known to fall off unless you weld/shim/drill them into place. Glove compartment hinges break easily. Theft alarm is oversensitive. Horn and turn signal beeper are one integrated unit so the turn signal sounds are extremely loud and annoying. No torque, no pickup when starting from zero. Lighting system is 48v, not 12. Stylishly pudgy -- it looks like it could use some exercise-- one kid called it "tubby".

I love it.

...that's fine for those that like to tinker, but I'll suggest that most folks just want to get around town in a reliable and safe manner and do NOT want to learn automechanics as a hobby?

No Bill. Happy to Help. Glad to see the rise (finally) of the 21th-century electric bicycle. Just wish the market would make more informed decisions. Lots of sellers jumping on the bandwagon prepared to buy containers full of cheap ebikes from China and they need to sell this stuff for profit. I hope the public will not use these folks as their only source of information about the options out there. I hope folks will ask themselves why ebikes in the USA and the EU don't look anything like most of the ebikes being sold in Toronto...

Cheers
Lock

Hi Lock,
I always WONDERED what that faded Chinatown plastic was about...thanks for enlightening me. oy.
So...I feel abit preoccupied with the battery business lately...but I'm down to 9 km/charge.
I double checked my manual and see that they are 48 volt 20 AH! Not, 10AH. So, I assume I need to match the AH at a min? PING is selling 48volt 20 AH on his website right now for $600. They are not the ones being auctioned on ebay, so I may could PROB get one sooner. The outside length and width of my current battery case is 11" x 11"
The PING battery is 7.7x8.3x5.9 inches. The URL is below. Does it look like the HEIGHT is 7.7 "?
I should probably open the battery case today to see what the exact inside dimensions are, just to be certain. Anything I should know about opening a battery case? IF the battery is a fit, what would I use to keep it from rattling around inside the larger case? The insulation your talked about buying months ago? Something else? Would foam be safe or not?
DO YOU KNOW ANYONE ELSE WHO HAS USED A LiFepo4 battery with a SCOOTER style ebike before?

Enjoy the scooting weather!
angela

http://www.pingbatter...

A 20Ah Lead Acid Battery can only be safely discharged to 50% whereas Lifepo4 can be fully discharged although 80% is the norm if you wish to extend your cycle life. Remember that with any chemistry the shallower the discharge the longer the attainable life you can achieve.

So a 20Ah Li Ping Lifepo4 pack will be the equivalent to a 32Ah Lead Acid battery pack which translates into quite a long range compared to what you now use.

You could get a Li Ping 15Ah Lifepo4 pack and still have a better range than your Lead Acid pack when it was new.

IF your current SLA batteries are giving you only 9 KM you really need to switch batteries OR you are having a Cell Balancing issue. Try charging and discharging each 12V X 20Ah and do it a few cycles (a cycle being charge/discharge). I use an Inverter and hook up a 13W CFL and drain the SLA to 10.2V and then use a 12V Charger and take the cell back up as high as it can go and drain it to 10.2V again.

Lead Acid Batteries are toast if they sink below 10.2V and while desulfication might bring them back above 10.2V it will be a very short term remedy.

Dealers who sell e-bikes and e-scooters NEED to teach people about how to properly manage their batteries and if you encounter a Dealer who does not bother explaining the proper care of don't bother giving the Dealer any of your money.

One fairly overlooked point about Lifepo4 batteries is that you need to understand the AMP Rating and how it compares to your Lead Acid batteries that you've become accustomed to using.

Li Ping Lifepo4 is typically Rated around 15A Continuous and 25-30A Peak for 30 seconds (am guessing here because Li Ping changes his suppliers so often it is hard to keep track) but 15A to 20A is pretty standard for the cheap PRC Lifepo4. Nuthin at all wrong with 15A to 20A providing that is all you need. Lead Acid can provide mucho higher Amps and have a Peak that can be sustained up to 3 minutes without failing.

Where you need PEAK Amps is when starting from a Dead Stop and for climbing hills/going into strong gusting headwinds. So Li Ping will not be able to deliver the very High Amps you are used to getting via SLA. You should see a decrease in starting torque and the e-scooter will feel sluggish on hills. Where you might have a problem is on steep hills your Lifepo4 BMS might kick in and shutdown your battery pack.

Li Ping has been pretty good as a supplier for almost 3 years and the only complaint I am aware of was his BMS boards are prone to failure within the first 21 days of daily use but Li Ping will send you a replacement Board fairly soon after you tell him yours is toast.

You need to see what the Amp Rating is on your Controller before buying Lifepo4. Daymak might use a 36V Brushed Controller Rated at only 13A and then the Li Ping Lifepo4 woulod be an ideal match. IF your E-Scooter or E-Bike Controller is Rated at say 35A or like mine at 40A then the Li Ping Lifepo4 would be almost useless.

I sell Lifepo4 packs but you cannot afford them (even I cannot afford them) and they'd be total overkill on an E-Scooter and most commercial E-Bikes.

When you are replacing your Batteries call the City of Toronto and they will come and pick up your old SLA free of charge. The Lead does have Value when recycled but what the City does not want is your Lead plates entering the ground water.

Hi Lock,
I always WONDERED what that faded Chinatown plastic was about...thanks for enlightening me. oy.
So...I feel abit preoccupied with the battery business lately...but I'm down to 9 km/charge.
I double checked my manual and see that they are 48 volt 20 AH! Not, 10AH. So, I assume I need to match the AH at a min? PING is selling 48volt 20 AH on his website right now for $600. They are not the ones being auctioned on ebay, so I may could PROB get one sooner. The outside length and width of my current battery case is 11" x 11"
The PING battery is 7.7x8.3x5.9 inches. The URL is below. Does it look like the HEIGHT is 7.7 "?
I should probably open the battery case today to see what the exact inside dimensions are, just to be certain. Anything I should know about opening a battery case? IF the battery is a fit, what would I use to keep it from rattling around inside the larger case? The insulation your talked about buying months ago? Something else? Would foam be safe or not?
DO YOU KNOW ANYONE ELSE WHO HAS USED A LiFepo4 battery with a SCOOTER style ebike before?

Enjoy the scooting weather!
angela

http://www.pingbatter...

Hey Angela,

I use LifeP04 on my scooter. I highly recommend measuring the inside on the case before you order a battery. I wasn't careful enough when I ordered mine. it didn't fit in my case BUT it did fit the battery bay perfectly. Although it works for me I'm always scared someone will steal my battery because I have no proper way of securing it.

So here's what you should do. Open up the case. Measure the height, length and width of all four SLA batteries combined inside the case. You have to shorten it maybe 1 to 2 inches on one side, I recommend the side closest to your handle bars. Reason being LifeP04 batteries come with a balancing circuit board for the batteries (Called a BMS). As Joshua pointed out you don't necessarily need a 20AH battery. I have one and I get 55 to 60KM range. So if you don't travel too far 15AH will do. To keep things from shifting around I use a piece of wood (2 X 4). But hard Styrofoam would work too.

One other precaution you should consider is polarity. Some scooters have reverse polarity electrical connections which is my situation. Connecting the battery backwards could potentially damage your controller. A multimeter is a good investment in this case. Hope that helps a bit.

-Vic

Li Ping Lifepo4 is typically Rated around 15A Continuous and 25-30A Peak for 30 seconds (am guessing here because Li Ping changes his suppliers so often it is hard to keep track) but 15A to 20A is pretty standard for the cheap PRC Lifepo4. Nuthin at all wrong with 15A to 20A providing that is all you need. Lead Acid can provide mucho higher Amps and have a Peak that can be sustained up to 3 minutes without failing.

Where you need PEAK Amps is when starting from a Dead Stop and for climbing hills/going into strong gusting headwinds. So Li Ping will not be able to deliver the very High Amps you are used to getting via SLA. You should see a decrease in starting torque and the e-scooter will feel sluggish on hills. Where you might have a problem is on steep hills your Lifepo4 BMS might kick in and shutdown your battery pack.

While the specs for the 20Ah Ping pack that Angela referenced say:

Rated Discharging Amperage: 20 Amps
Max Continuous Discharging Amperage: 40 Amps
Maximum Discharging Current: 60 Amps
Discharging Cut-off Protection: 50 Amps


So capable of twice rated capacity continuous and up to 2.5 times before cut-off protection kicks in...

40A continuous at 48V would be 1920W (!) I'da thought the controller would cut out first before reaching this power level.

To be fair, Mr.Ping rates the life (cycles) of his packs based on only 1C charge and discharge rates... How much would a lot of 2C discharging shorten pack life, any idea?

Lock

It sounds like the scooter-style ebikes have the batts enclosed in a case and the case in turn fits into the battery compartment? Not sure why this case would be necessary... sounds a bit like overkill, but anyway... If I were replacing a SLA pack w/a lithium "brick" I'd probably ditch the internal case used for the SLAs and pad the space around the lithium with closed cell foam insulation as vibration dampener... EVerywhere except around the BMS which probably needs a bit of breathing space as ventilation...
I'd cut up a cardboard box and tape it up to the dimensions listed for the pack (actually a little bigger to accomodate the BMS plus insulation,) remove the SLAs and case wattever from the battery compartment and see how the cardboard box fits.

Lock