EVT Z-20 / R-20 Battery Information
This is directly from Fernando.
Spec Sheet: -Click Here-
Large pic of batteries: -Click Here-
They are indeed 12v 35 ah. I'm very pleased with the fact that they went through the trouble to produce a spec sheet on the batteries. Obviously EVT most likely doesn't manufacturer the batteries, but at least they are providing adequate information.
Waiting to hear back if the bike has battery balancers.
`:?
Thanks Andrew, I'm back to my computer now, and will post everything Fernando has sent me ASAP.
Peace Out,
Gman
What is your vision for the future our growing community?
Peace Out,
Gman
Hi guys,
I wonder why Z20 using smaller batteries?
This is an oem model that using in my EVT-4000e. I found the origional maker, KLB, a TW listed company, big on UPS, and motor battery fields. You may check the spec: http://www.klb.com.tw/dbf/WP50-12NE.pdf
I'm aware of that EVT is different company from EVTAmerica. EVTAmerica is selling EVT's(a TW based company) products, but also import and resale other e-scooters to the States from China.
Jay, Taipei
Jay,
Yes,EVT didn't import from Taiwan any more.I think their 35AH(20hr) battery is too small capacity to bear big current from controller.
Taiwan EVT use 50AH big batteries,still difficulty to bear big current.
So, let me get this right, because I am surely no expert when it comes to batteries, but doesn't it seem as if these batteries are kinda weenie-ish for this scooter? If it's a 2500 Watt motor and the batteries are 35AH, won't they get discharged relatively fast? Leading to shorter range? Or do you just baby the throttle to keep the magic smoke going longer?
kringle777
Red XM-2000
Moss Green "Charger" ebike
Sacramento, CA
Yes,I know Z-20 Max current because their motor/controller come from http://www.yzkg.com
With 35AH battery ,I guess its range would be less than 20mile with full speed testing.
Mountain chen
andrew,
I notice you are a EV Tech Advisor here, just by looking at the spec sheet, what are your thoughts on the EVT Battery?
I know nothing about the technical side of EVs. It seems like people are saying that the batteries for the Z-20 aren't so great and you're likely going to have a very short range at high speeds. My question is, is it possible to replace the batteries and put a different kind in there, something more high end?
Thanks,
Christopher
Hi Christopher,
Yes you will be able to replace the batteries - but the question is with what?
Your best (not accounting for cost) battery choice will be LiFePO4s (these are the best/safest/latest form of Lithium batteries and don't have the thermal runaway (exploding) problems with the Li-Ion cells that made the news a while back).
usatracy is figuring out how to get a good deal on a 60V 10Ah pack and/or a 60V 20Ah pack as a replacement for the XM2000. This will most likely fit in the Z20 - however because most folks haven't seen a Z-20 we don't know for sure if they will fit yet. The Lithium based packs won't suffer from worse performance at high speed because they are more capable of handling sustained large current draws. Also, a 10Ah Lithium pack is apparently about as capable as a 20Ah to 30Ah lead acid pack. It might be that a 10Ah pack is as good as the supplied Z-20 pack - or you might need a 20Ah pack. Time will tell - when folks start riding their Z-20s.
I'm hoping that usatracy's batteries will come in less than $1000 for a 60V 10Ah pack and less than $1500 for a 60V 20Ah pack. But that's just speculation. Keep an eye on this post: http://visforvoltage.org/forum/batteries-and-chargers/1770 And when you hear usatracy cry "Eureka! I've solved it" send him a PM and ask about the possibilities of a Z-20 compatible pack.
Hope this helps.
John H.
Blue XM-2000
Ann Arbor, MI
http://www.revevllc.com - Authorized X-Treme dealer
Thanks for the info. Is there a notion as to how much this could potentially improve range and performance?
If you already answered this in your previous reply I apologize, but when I say I have no technical knowledge I really mean it. I do understand that 20Ah pack is twice as big as a 10Ah pack, but truly I don't even know what an "Ah" is other than a mild exclamation.
Thanks,
Christopher
`DonCristobal ,
Welcome to the V is for Voltage Community, the best person probably to answer that question is Fernando Pruna, President of EVT America.
Since this is a new thread, I don't know if he's monitoring it or not. I can drop him a email or you can info@evtamerica.com and I'm sure he will personally answer your question ASAP.
Peace Out,
Gman
What is your vision for the future our growing community?
Peace Out,
Gman
Hi Christopher,
Even when I try and write clearly I end up throwing about acronyms and terms too much :-)
Ah = Amp Hours = the amount of charge a battery holds. So in theory a 20Ah battery holds twice as much energy as a 10Ah one. And, in theory, the 20Ah battery should take you twice as far. With me so far?
Well, unfortunately it's not as straightforward as that! One has to take into account both the chemistry of the battery (is it lead acid or is it lithium?) and the discharge rate (how much power are we asking the battery to deliver).
Until we have some real world data on the Z-20 that's readily available it's going to be really hard to come up with meaningful figures. I believe we can say with high confidence that LiFePO4 batteries will be significantly better than the stock lead acid batteries - and they will also cost you more. I don't know what plans EVT of America have for supplying a LiFePO4 battery for their bike (and that's why I still suggest you keep an eye on the post I mentioned above).
John H.
Blue XM-2000
Ann Arbor, MI
http://www.revevllc.com - Authorized X-Treme dealer
`DonCristobal,
You question has been sent to Fernando.
Peace Out,
Gman
What is your vision for the future our growing community?
Peace Out,
Gman
`
You are welcome to use these photos for V for Voltage.
Fernando
Peace Out,
Gman
What is your vision for the future our growing community?
Peace Out,
Gman
andrew,
I notice you are a EV Tech Advisor here, just by looking at the spec sheet, what are your thoughts on the EVT Battery?
I think these are on the low end in terms of comparability to other 35 ah AGMs for high rate performance. Take a look at these 35 ah AGMs from B&B battery here. To try and provide as close as I can to a direct comparison:
At the 1/2 hr rate the EVT batteries can do about 28 amps at a nominal voltage of 12v so thats 336 watts or 168 whrs.
AT the 1/2 hr rate the B&B BP35-12 can provide 471.6 watts (from the power timetable from the spec sheet above) or 235.8 whrs. Thats 40% better on paper, for the B&Bs, but there are a lot of AGMs on the market that I'm sure perform worse than the B&Bs.
The EVP35-12 B&B batteries that I use in my bike can do 508 watts for 1/2 hr or 254 whrs which is over 50% better than the EVT batteries.
So the EVT batterie's high rate performance is not very good, and I'd bet you could get an improvement in range just by switching to EVP batteries like the kind I use in my bike once the stock batteries go.
If these are KLB (or Kung Long Batteries) I remember a lot of EVT owners had early battery failures with them. I don't know if their quality has improved, or if maybe the EVT setup caused battery imbalance.
In any case I recommend buying balancers immediately for your Z20 unless you are prepared to replace the batteries after about 1/4 of their expected life.
Usatracy may be right about his dismal range projections from the data I see. But take this fact: I ride my motorcycle KZ750 conversion with two eteks fast. I can hold 40-60 for much of the riding and the drive system is not as near efficient as a direct drive hub motor. I'm using 7 of the EVP35-12 batteries and I get 10 miles safe range and 11-12 if I stretch it, and even more if I nurse it back home. Just FYI I can draw over 550 amps from them and they are still fine. I don't think 90 amps will hurt the batteries. What will hurt them is battery imbalance and overcharging and overdischarging. I strongly suggest battery balancers, and monitor the batteries with a digital multimeter on the first charge!!! If any of the batteries go over 14.5v than you will know they will gas some. How much over 14.5v is how severely they will gas and how much their life span will be shortened.
---
Avatar taken from http://www.electricmotorbike.org/
My KZ750 Project: here
andrew - I doubt that a 10Ah battery pack would match a fresh set of 35Ah AGMs. My factory fresh Electier's handled 23 miles at high speed for a week or so.
However, the question is after say 100 cycles of "high speed" commuting (when did 35 - 40mph become high speed? if my friends could see me now! ) what will things look like? Even with balancers my Electier Silicones are down to around a 12 mile range with less than 1000km on them. If a 10Ah pack could start out at a 15 mile range and reliably stay there for 800-1000 cycles and if they are more robust with a BMS and charging system then I'd say that a 10Ah is better than 38Ah of Electier's. Until I see some real life data on AGMs installed in a similar EV usage pattern I'd expect them to be closer to silicones than LiFePO4s.
Just my 2 cents worth.
John H.
Blue XM-2000
Ann Arbor, MI
http://www.revevllc.com - Authorized X-Treme dealer
`andrew
Thanks, maybe I asked Fernando the wrong question.
Fernando
We have had them made in accordance to our specs and they are very well made. We have been testing them at top speed and the range has been better than acceptable.
You of course can change the batteries if you wish, as long as they have the same power and dimensions. In doing so I believe that you would be trading down in quality. Simple as that.
Peace Out,
Gman
What is your vision for the future our growing community?
Peace Out,
Gman
Very good point jdh. But what you are not factoring in is if you used AGMs which are very comparable to silicons in cost than you would get your full range for >70% of the pack life. AT your 23 miles range the EVT batteries should provide 200 100% DOD cycles (from their cycle graph) so you would get 4600 miles even before the range began to decline. Thats almost 7500 km. These silicons may be total crap. AGMs have been proven and used much longer for EVs.
For more range calculations (bear in mind this is from the EVT spec sheet which could be wrong):
If you draw constant 50 amps to maintain 45 mph (just a guess) than you will get 15 min out of the batteries or 11.25 miles.
If you draw a constant 28 amps, maybe doing 30-35 (just a guess) than you will get 30 min out of the batteries or 15-17.5 miles.
This is just my guess on range. Someone care to do the full calculations?
---
Avatar taken from http://www.electricmotorbike.org/
My KZ750 Project: here
I would like to just give a word of caution to anyone who believes that 10ah lithium battery is going to come close to a 35ah agm battery in performance. Let me state that either battery when operated at EV discharge rates of 1C or greater will not retain all of their rated capacity. For example a 40 amp discharge rate will be about 1C for the AGM and give about 60-65% of the stated 20hr-rate capacity (~23ah.) The same discharge rate for the lithium battery will be about 4C and will likely give a capacity of about 90-95% of the rated capacity (9.5ah.) This is due to something called the Peukert effect which varies between battery chemistries and manufacturers. The situation changes dramatically when discharge rates go down say if you chose to ride at one-quarter to one-half throttle (8-15 amps). The AGM battery will give a much longer range than the lithium pack.
Lithium is a little tricky in performance too because unlike agm the discharge curve usually is pretty flat. If you don't keep track of how much juice you are using the battery can die quickly without as much warning as a lead acid battery. Also, the BMS may not let you limp home on a deeply depleted battery as well. There is also a big warranty concern and the danger of charger failure. A failed charger can ruin batteries and there are some pretty low quality chinese charger out there. My original charger prematurely killed my first set of scooter batteries. The thought of this happening to over a thousand dollars worth of batteries makes me cringe.
I will be monitoring the forum to see how the lithium pioneers do with their chinese lithium phosphate packs, BMS, and chargers. Hopefully, they will get quality items and keep us updated.
`
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jbird and andrew - you make good points.
First off - I'm not expecting the Li 10Ah's to give the range of well tended top quality 35Ah AGMs. However I am expecting them to be a good real world contender as replacements for 35Ah Z-20 AGM batteries or 38Ah XM2K Silicones as provided "out of the box". To state it another way I'm expecting that over the life of the batteries the smaller Li's will prove a better bet because all I need is a reliable 12 miles per charge at 35-40mph cruising.
These bikes don't have enough speed/power (for my usage pattern) to ride at less than WOT in most cases - so I'm likely looking at a 1.5C(ish) rate for the Z-20s and a 5C rate for the Li. Furthermore you also need to factor in around a 100lbs (about 20%) reduction in overall weight advantage for the Li's - this in turn will help improve the scooter range because it will take less energy to shift it. Granted at cruising speed weight is of less concern - but my commute is about 50% city riding and 50% out of town cruising. So I expect the in city stuff to consume less watts (however, I might just end up accelerating more quickly and using the same amount of watts in the end). All this seems too complicated to model reliably (at least for my little brain) - so my plan is start with 10Ah lithium pack and if it works for my commute great! If it doesn't I'll add another 10Ah pack in parallel and see if that works.
BTW, The flat discharge curve of Li is also a big advantage in terms of ride performance - the 15th mile is almost as good as the 1st. Granted the 16th mile is non-existant! A state of charge meter becomes more critical (and has to work with finer tolerances) - the simple volt meter setup on the XM won't cut it. If the Z-20 has a SOC meter already it also will be no good because it will be calibrated for the Z-20 AGMs.
What would be interesting would be a three way comparison of all costs, ranges and expected life of (1) batteries as provided, (2) top quality AGMs, (3) LiFePO4s. If I have time I'll mock something up in editgrid and people can play with the numbers.
usatracy - if you read this and if you are still conversing with Sam ask him for the Peukert constant for the various cells you're considering. Also note my paragraph about the state of charge meter - is there a way for you to factor that in to your dealings with Sam?
John H.
Blue XM-2000
Ann Arbor, MI
http://www.revevllc.com - Authorized X-Treme dealer
Andrew's power figure for 30/45 mph seem about right based on some measurements I've done. I have a spreadsheet that I made a while back to calculate torque and power curved based on speed measurements on various slope percentages and flat ground - or it can be used backward to calculate the mechanical power requirements for various speeds or hills. I've sent it in to be placed in the download library.
My e-max has eight BB EB20-12's 48 volts at 40 AH plus a single 20AH guineng silicone "booster" battery under the seat for selectable 60 volt usage for more speed when needed. It will reliably go 20 miles on a charge in hilly urban and inner-suburban riding, or 25 miles if you can avoid any hills in the last 5 miles. What helps the range is that, for the sort of urban usage these scooters are is intended for, the average speed is probably not much more than 25 mph. Even the Vectrix will not go too far if run at a steady 45 mph or faster. Remember power requirement increases with the square of the speed. It takes 325% more power to go 45 mph than 25 mph.
The wattage rating of the motor itself is not much of a factor in power consumption - it is how much power that is being fed into the motor.
` :?
So what question do I ask Fernando to clarify range or speed?
Peace Out,
Gman
What is your vision for the future our growing community?
Peace Out,
Gman
Deafscooter is Here...
Craig Watch what you talking the branded batteries packs on EVT Z-20 / R-20 E- Scooter...
Deafscooter do 
<== on Silicones or other branded batteries
=
=
=
Simples...
Here and You Get HAWKER AGM Batteries !!!
============================
andrew,
Thanks for the information.
Range are mostly depend on efficiency based on the same size battery,the point is to find out the dymo data of EVT motor
First a little background about me, I have a good background with batteries having a solar PV system for over 12 years now. My first batteries were, nice "marine" batteries, they lasted 2 years. My second bank consisted of 8 Trojan T125's (slightly better cap then regular T-105's). They lasted 8 years, and now I am running eight Deka AGM 8A8D's (12v@240A each) and I really like them, much less standby loss, less internal resistance, no off gassing, no mess no watering.
So my thought is when my batteries go in my Z-20 I plan to replace them with hopefully with the closest Deka AGM's. I don't know much about EV's, yet, but batteries and battery maintenance and battery care I am fine with.
My second thought is can you get a 5th battery in the "trunk"? Would the controller freak out? I know I would have to charge them some other way. Personally I can't image a "good" charger to work with 4 batteries in series, keeping them balanced and all, especially with less expensive batteries. Also I wonder if the standard charger would damage the AGM’s since they don’t like to go above 2.4v per cell.
Brock,
The Z-20 in it's current form is a 5-battery 60 volt scooter.
But a far as over-volting a controller, it can be done but is risky. As a minimum you need to open the controller up and look up the numbers, get the spec sheets and voltage ratings the power circuit components - notably the filter capacitors and MOSFETS.
The e-max controllers (also used in "Kaseas" and "e-motos" have been successfully over-volted to 60 volts, in at least three cases I know of (two of them mine) with just the replacement of five capacitors.
Ahhh, thanks, I guess that only makes since to start with 60v. I guess time will tell how they hold up and if we could add a 6th battery. I will let someone who know more about the electronics tell me it's ok :)
Personally I can't image a "good" charger to work with 4 batteries in series, keeping them balanced and all, especially with less expensive batteries.
I can't either. If I was buying a Z20 I'd buy a battery balancing system or individual chargers for each battery first thing.
Also I wonder if the standard charger would damage the AGM’s since they don’t like to go above 2.4v per cell.
Did you find some specs on it? I'd expect it to be designed for AGMs, and have the CV charging stage set at no more than 2.5 vpc.
- Kudo (2)
Yes, I agree - big kudos to EVT for making this sort of information available. I hope that we can use that PDF as a template to gather the same information for other batteries. This would then give us a good basis for comparison.
Now, if they'd just pony up and buy the PDF software instead of using the "for evaluation only" version...
John H.
Blue XM-2000
Ann Arbor, MI
http://www.revevllc.com