The EV Tech 37V LiPoly pack review and discussion

Paul Knox wrote to me last week,

Lipo is the future for all electric vehicles; its the best we have.
And if the price keeps dropping and the specs keep going up,
we're all on to a winner.

Click to expand...

An interesting statement, that.
The attractions of lipoly cobalt include

=greatest energy density of all lithium types.
=highest voltage per cell of any lithium type
=most compact form factor, owing to flat cell construction, usually in pouches.

There are some detractions to LiPoly. We'll talk of them later.
This thread is for newbies and also old hands.

In particular this thread will review the 15Ah nominal capacity 37V pack
offered by EV Tech of Addison, Texas.

Why? Because I am buying their pack this week.
I'll document the battery here in this thread.

Let's look at their ad copy in the next form:

Am recovering from a disappointing purchase experience from BatterySpace
--their first lipoly pack was defective. Initial reports back from them
said that they could find nothing definitely wrong with the pack.
There was something definitely wrong---the pack cut out at half its rated drain rate
The end result: BS refunds my credit card this week.

I'm ready for some other firm's pack.
I want it to just plain work.
I want a couple of years' service.
I don't want to prototype or build my own pack of this nature;
I want something with a past, with expertise behind it.

The EV Tech pack has good user reports, just learned this recently.
I couldn't have known these things by reading their presently-poor ad copy and empty review page.

Aside from the all-caps ad copy, miserable product illustration
and the stiff pricing, this is what really put me off months ago:

On sale since 12/05 without user reviews at all.

For these reasons I did not consider the EV Tech pack for purchase in the first place.
And that result was no mistake of mine---what else was there to go on?
Confusion, as it turned out.

And so in ignorance, when BS offered their new lipoly pack,
I jumped on that item. The price was right enough, but,
the pack did not work out well. I had to return it for repair or refund.

Now I am back to square one again.
This time I know more about the EV Tech pack
and that's why I'm buying with full confidence.
That's why I'm electing for refund instead of a new pack from BatterySpace.

I'll apply the money instead to the EV Tech pack purchase.


.

I first spoke to Doug Canfield on Sunday.
Today, Tuesday, I had a second talk by phone.
Gave my CC information and addy and finalized the purchase--which will go through when I know for sure that BS has processed a refund to my card.
So, probably on Wednesday the pack may be shipped.

My bike is in pieces for frame repair and repainting.
No rush here.

Doug Canfield has some documentation on the safety of the cells in the EV Tech pack
I"ll put that stuff in the slot below when it becomes available.

_____________________


In the meanwhile,
Any EV Tech pack users here?
Please share your impressions and reviews.

_____________________


Go ahead folks, please,
talk about batteries and whatever that's relevant to the topic.

8)

That Doug Canfield guy
sure is on the ball. Just checked email, and whoa!

Date: Tue 04/17/07 06:37 PM


Attachments
Name Type Save View
Part 1 text/plain Save
lipolyspecs.pdf application/pdf Save View

Reid,
This is the info we talked about on the phone. If you are shooting for a
BSEE it may be of interest. Nice pictures though.
Will get the battery out tomorrow.
Doug Canfield
EV TECH
4310 Wiley Post Rd. #217
Addison,TX 75001
w ww.ev tech.us
1-866-370-9990
972-851-9990
Fax 972-851-9993

Click to expand...

space for Doug's data.

edit:

Doug sent me a PDF file.
I'm on Vista. Adobe does not yet support Vista.
I can't open his file.

Maybe one of you TF guys here can open the file at the TF forum (in the file section), and screenshot or quote its pictures and texts.

Or I'll ask Doug to do this.

Sorry for the delay.

Funny--I can open PDFs on line usually, but some always fail to open "corrupted file" but it's Vista,
which also locks up all open browsers while I try to download any PDF file
Most online PDFs will open but some will not.

Reid Welch said:

space for Doug's data

Click to expand...

No doubt these packs have some Lightweight Value! They would have a better value if you got a co op going to get them at a DECENT PRICE. these 16ah packs do NOT cost over $250. FOB China. Just like you can get 450 watt Chineese hub motors direct from china at $40.each by the 100s. even at $500. a pack these would be fun to use for 150- 200 cycles if they constantly lasted that long? A lot depends on the users discharge rates and if all the batteries and bms could handel each users punishment.

Reid : I will gladly remove this if requested.

250 $ FOB + Charger + Duties + Brokerage + wait time..... = ?

As far as chinese hub motors, at least crystalytes i can GUARANTEE is not 40 $.. even if you buy 100 lot or more.. ( hub only ) -- much more...

Then add , spokes, rims, labor to assemble them properly....

NO free rides in this country.. Why do i know this ? Because i'm doing it. Yes.. I have done my homework.. and i've invested my money in the best possible way i could justify.

At 750 $.. Dougs Lipo's with charger/BMS etc.. is not a bad deal provided with support.

I gladly await updates, we can then compare with my 2 x 36v 20ah Forsen LiMn packs.

I agree that the present price is too high to allow the packs to be affordable to most of us here.


Randy, complaining again: if you are fair you will now launch invectives against Kokam USA for their $1500 price for equal capacity, no charger included. You trumpet for Kokam as if you were their agent.
So--tell us why we should not feel Kokam's 100% doubling of cost for equal capacity is so sweet? It's not sweet here.

Anywho, they don't even include a charger
EV Tech's present $750 price includes a 3.7A charger.
______________________________
___________

On the bright side, Doug Canfield and his partner, Bob Smith USN retired admiral with great connections---
they are hoping to drop the price of their product soon. We hope so too.
Then the battery packs will fly like China Clippers.


______________________________
___________

Cycle life: The packs have BMS management which cuts them off at 33V,
which is a realistic balance to strike a conservative discharge level
to allow a 500 cycle life (so far as I know at this time of writing; I'll ask)
before the pack has lost 20% capacity. We'll see and I'll update on this important point.

The packs in real life usage deliver not 15Ah, but only 11 to 12Ah.
The first of the first generation packs did dish 15Ah
because Doug and Bob spec'd cutoff at 27V. They soon realized that would lead to higher internal impedance and great voltage sag and greatly reduced cycle life.
So they raised the cutoff point for reasons already noted.


The EV Tech packs as they are today are projected to give 80% of their initial capacity at 500 full-depth (to 33V) discharges.
They are configured as a vertical stacking, 10S2P of 7.5Ah cells, potted in an immobilizing wax-like substance (I'll ask Doug just what it is) and encased in a light gauge aluminum box with lead outs.

The next crop of EV Tech packs, due in a few weeks or so, will differ in these two ways:

=The connections will be sockets on the case end, no more leads
=The prismatic pouch cells will each be sleeved in individual aluminum containers; like playing card boxes.
The reason for this just to make the cells fully modular for easy swap out, and.... you know, the TidalForce bikes have NiMh battery cells in the big front hubs? The EV Tech team wants to make LiPoly an option for the TF hubs. The aluminum sleeved cells will allow configuration within a TF front hub.



Cheers,

Reid

Buzzz/Gaston up above, your post is great and makes good points.
I just started this thread because the first one had been hijacked in a bad way and
it wasn't going to fix itself.

You guys know me, that I too I jack threads temporarily for comic purposes at times;
I do it a lot! But this thread should be kept reasonably clean.
It's got an important goal to meet: To find and promote the truth;
to find us a reliable and affordable LiPoly pack. To build buyer confidence,
dispel rumor, innuendo and lies.

At this time of writing,
the truth is that EV Tech (and also Team Hybrid in the UK) are handling a pack---the pack in question---and
the packs are working well and customers are happy, with very few exceptions.

I'll tell you about one of the unhappy exception who did not feel his EV Tech pack gave good-enough service. I'll tell the story tomorrow. It's funny and makes no bad reflection on the pack. So hold on for that tale. It's stupid.

We'll talk about warranty too.
We'll talk about responsible vendors.
I think EV Tech is a responsible vendor---you too, Buzz
because you support your customers and you will make things over and over again
until they are right.
Generation III EV Tech packs are on the way.
I could've had one. I elected for Generation II instead because it's a tadpole shorter in height
(the III's sleeved cells add a bit of bulk, you see).

The height of the present pack is about ideal for my bike's installation space.

It will stand atop the cubby of the brush motor controller,
fastened to the seat tube---where the old Currie SLA box once stood.
I'll bend an aluminum L, and bolt this to the frame
and double-stick tape the Point 1 pack to the L and it will stay put,
believe it.




frame stripped for truing, detailing, repainting in safety yellow.

--Am sorely tempted to badge the tank, TOXICITY
and have this too, perhaps on the pack:

A partial quote from the TidalForce forum, where in
http://groups.google.com/group/Tidalforce/browse_thread/thread/341a816adb0bf31/20c80f235eb1393b
deerfencer wrote as an aside, in response to members' ride-impressions of the Optibike demonstrated last weekend in S.F.

....A separate point that goes back to the discussion bemoaning the lack
of battery choice/advancement: Craig has told me they tested MANY
lithium packs over the past few years and all were problematic--until
the Point One's showed up.

Not to beat a dead horse, but finding a dependable, high-powered, safe
lithium-based battery is a huge step forward for any e-biker looking
for both performance and weight savings, and I am still in awe of the
extra power and range these batteries have given my bike every time I
ride...

Click to expand...

So, the Optibike, the world's most sophisticated production e-bike,
and probably best produced, and certainly the most costly e-bike at this time,
employs the EV Tech pack as an optional upgrade-supplement to its standard NiMh pack.

http://www.optibike.com/

For the price, lithium ought to come standard.

I think that's the next plan. I think Craig of Optibike was just taking his time to make the best choice--
the battery has to be reliable and it has to be safe. And it is both safe and relatively reliable and long-cycle lived, according to all inputs so far received here.

As someone there said in the thread, some tens of thousands of roadie bikes command Optibike prices.
Why, just two days ago at the LBS I "marvelled" at a pair of unmounted in the open box carbon fiber roadie wheels.
How much? Two grand.
People in that mindset of wanting the latest and lightest, they pay.

The benefit of a high-end e-bike with rich-appeal is that it will sell to wealthy people, make presence, be cool, desirable
and help to expand the entire e-bike market out of the kid zone, out of the DIY zone, into the gotta-have-one zone.

It aids us all, that Optibike. It's inspiring.

Here's silent video Devin made of the EV Tech-equipped Optibike 600t in San Francisco last week:
http://video.google.com/videoplay?docid=-1183422343998123844
This is the 600W Optibike version with extra battery power
--that's the EV Tech pack on its seatpost rack.

____________

screenshot from the Optibike site:



___________

Refer to the top of this page if you will: note the poor EV Tech review page screenshot?
"No reviews yet".
Huh?

The EV Tech people are not pushing this product at all. Not at all.
The pack is selling itself to a smallish group of people who buy based on word of mouth.

And now this same Point One is on the world's most costly and sleek production e-bike.

Here I'll paste more TF Group quotes. This is the latter part of deerfencer's remarks first quoted above; from the same posting:

...Being able to do extended (5-mile) stairstep climbs in turbo X/cruise
control @ 22 mph+ average speed (24 mph with a skinny front tire) is
truly wonderful, and the extra range lets me ride for close to an hour
at near maximum power--at least on the climbs (I usually try to rest
the battery a bit on the downhills). I'll shut up now, but youreally
have to experience the extra oopmh of the lipos to appreciate them--as
we've documented, running voltages (and consequently average speeds)
are close to 10% higher than NIMH due to low sag.

Click to expand...

and that was written just yesterday.

more quotes as I find them:

Exampling honesty: plasmadust is Doug Canfield of EV Tech. See the thread for the full context.

plasmadust
View profile
More options Apr 15, 2:45 pm
From: "plasmadust" <dcanfi>
Date: Sun, 15 Apr 2007 11:45:51 -0700
Local: Sun, Apr 15 2007 2:45 pm
Subject: Re: Li-Ion 36V trouble. Battery or Charger?
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
Henning,
We have had a few problems with the BMS wires getting loose inside the battery.
What you can do for the time being is charge the battery directly through the main leads.
See if this pumps the volts back up. This will tell us if it is the BMS.
You cannot over charge the battery with that charger. We have tested the cells at 3X cell voltage for 72 hours and nothing happened,
so putting 42V across the pack will charge it if the cells are good.
We haven't seen any bad cells yet, but there is always a first.

DC

Click to expand...

The climbing stairs @ 22mph for 5miles part reeks of BS to me.
It rips to shreds what I've determined to be the current world record:


The record for the most steps climbed on a bicycle is 1,374 by Xavi Casas (Andorra) at the Eiffel Tower, Paris, France on May 26, 2004.

<embed src="http://www.youtube.com/v/qvSsN0BTuI0" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350"></embed>

Mathurin said:

The climbing stairs @ 22mph for 5miles part reeks of BS to me.

Click to expand...

Larry is a noncommercial member of the TF forum.
I imagine that he'll read what you wrote.
Could be rephrased better.

Agreed though: I can't see the pack alone climbing stair grades for 5m at 22mph either.

He would also have, they all have there, the stock TF front hub battery pack of 13Ah.

So that's 13Ah of NiMh plus 11Ah of low impedance LiPo,
and that's enough to do that run for sure, yes? And pedals and gears too, if that's cheating????

__________
____

PS: The Eiffel tower biker cheated. Yes, he did!
He pedaled zee whole





times up, Math.

Ask Doug for the REAL SPECS in the fine print.I would bet that these are the same cells tested for cycle life and capacity using a 0.2 C and 0.5 C discharge rate.The wax on the inside of the packs starts ozzong out using a constant 1.5 C discharge rate.Anything more for too long the aluminum packs split the seams and a short cycle life is not far behind.Baby them and they might be good for 9 months.. Until you get 500 cycles any testing is bacicaly moot unless you cop to what you really find out in a few months If you don't keep your eye on heavy discharging.Another thing you may ask Doug.. Is How many 4 ah cells are in parallel ? There should br 4 to make up the 16ah pack.And how do you replace the cells eaisly when the tabs are soulderd and encased in wax?
http://www.sh-sungod.com/w2-1.htm
The GMB Company also uses the same cells or is the same company.
※Typical Capacity
Typical capacity refers to the median value of the capacity when a battery is discharged to the cut-off voltage with the current of 0.2 C5 mA at 20°C±5°C.

http://tinyurl.com/2aflws
http://tinyurl.com/2xtg9k

FWIW,

My first interpretation of "stairstep climbs" when I read the quote, was five miles of ascending switchback roads or trails.

:?

If he was riding on roads, it's misleading to say it was stairs, isn't it?

I've seen motocross go all the way a long flight of stairs, somehow I don't see that happening with the massive tidal force hubs regardless of the battery. My own best on a bike is a shallow 8 stair flight near the church, but I can imagine no longer feeling much of anything beyond my elbows after a few mins...

Note that the Spanish champion had a solid front fork.
Makes sense. Note his arms. He picked up the front end to climb;
hundreds of jerks. A shock fork would've wasted his muscle power.
He didn't shock his elbows, I don't see why. All muscles in tension.

That was worth the watching.
So--OK, now it's clear: Larry meant (surely meant) switchback trails,
not literal stair steps.
_______________

___________

Randy,
Here are the published specs.
here are the specs for the pack
I can't read the data or see the pictures of him shorting a cell to flatline, because the PDF won't open on this Vista computer.

Have set up an introductory thread at the TidalForce forum


Check it out for testimonials... and humor too of course

I never miss a lick.

Thanks to the crew at the TidalForce forum:

From: deerfencer1 <deerfenc>
Date: Wed, 18 Apr 2007 18:55:39 -0700
Local: Wed, Apr 18 2007 9:55 pm
Subject: Re: Buying an EV Tech pack--request for review helpr

Welcome aboard, Reid, and thanks for the post about that great local
shop of yours. So refreshing to hear of a shop that doesn't turn its
nose up when the guys encounter a situation like yours involving a
pedestrian frame in need of a good tweaking. Can't believe they did it
gratis as well--buy those boyz a six-pack at least!

If you search the archives here you'll find I was one of the first to
try--and rave about--Doug's lipo packs. I run two 15Ah 37V packs in
parallel on my S750X and have been tickled with their performance--and
this after a couple thousand (fast) miles and about 11 months time.
Even took the gold in the Tour de Sol one hour range race last May in
Saratoga, NY--in fact this was my first ride on the packs (Doug got
them to me literally the day before the race!). Feel free to copy and
paste my reviews-- a search here of "Doug's 37V lipos" should turn up
a slew of results.

Joe, Richard, and I are all co-hosts here, and I'm familiar with the
Endless Sphere site through our good friend Knoxie, who has been
testing the Point one and other lipos for Mark @ Team Hybrid UK.

Doug's latest lipos (3rd gen now I think) sound even better than the
ones I've been riding, so I think you'll be in awe of their
performance. They leave NIMH packs in the dust, and there's simply no
going back once you ride them. They have truly brought out the beast
in my Uma (my pet name for my SeX machine <g>): see my reports from
Block Island last summer, when I was routinely blasting into town at
33.5 mph avg speed (skinny high-pressure front tire)--and this on a
bike that is rated at around 25 mph max! Fun is an understatement.

Best,

Larry

Click to expand...

From: Nimbuzz
Date: Wed, 18 Apr 2007 20:55:29 -0700
Local: Wed, Apr 18 2007 11:55 pm
Subject: Re: Buying an EV Tech pack--request for review help

Reid, Sure use any of my 'celebrations' of my EV Tech pack. I think
anything on a site like this is quoteable

Uncle L, I think Doug recently said that it is currently the second
generation. The first one (of your "three") was Richard's 'beta'
version that wasn't quite up to snuff, experimental and not a real
'version.'

Unc A.

Click to expand...

That's right--the generation III packs are not quite here yet.
Thanks now for Al and Larry and all at the TF forum.

Many EV Tech pack discussions in their archives

_____________________


Thoughts as they occur (will be updated):

-The package arrived last night.
-It was well packed, padded with styrofoam. No damages at all.
-The pack is indeed fresh: it smelled of the connectors' RTV's acetic acid as the cover was removed.

-There is a slight up-down shake of the pack inside the welded-shut light-gauge aluminum box.
I will fix that after first consulting with Doug Canfield.
A bit of injectable polyurethane foam or Gorilla Glue mixed with water (more expansion), perhaps. Must consult first with Doug.
-The main box is totally welded closed. The grommet holes are not sealed.

-Will surely take some simple steps to splash-proof the pack.
A strip of duct tape all the way around the perimeter will do that.
Plumber's putty, or an inverted mounting, will take care of grommet holes,
Rubber washers under the four acorn nuts will make them watertight.

-The fit of the pack to my bike's battery box space will be so tight that I must make frame adjustment...

it fits with with the BMS panel removed


...perhaps move the OEM carrier backplate rearward, so far as tire/fender clearance may allow.
OR cut/notch the cross-tube about one-third of the way through; nest the pack to into the notch.
I see no structural problem in doing that, if it comes to that; do you?



-The bike is all apart for frame mods and repaint.
It will be a couple of weeks at least before I run this pack.


It looks great. I'm satisfied.
At this time I'm staring at this picture again

and I think to cut off the protruding top of the carrier, and cut the tube width-wise to get the depth needed,

and then have the metal shop bend an L of sheet aluminum, the width of the pack, and tall enough to meet up with the sliced cross-tube, in which the pack will nest, where the L will be attached with screws and epoxy.
The base of the ell will be screwed fast to the top of the controller cubby. The pack will then attach to the ell/carrier with doublestick foam tape.


A false top will contain the power switch and a 30A blade fuse (am planning to use a 25A controller) and possibly a key switch which would work the controller's brake-cutoff connection.
Power on, turn key to ride.

The wiring will all be hidden.

I think this will all be a go.

Think now, think.

Hmmm....

How about turning the pack wide-ways and adding material to the carrier/frame, instead of cutting?

Pack removal could be out the side, rather than out the top.

Yaay, Lithium!!

Is there enough clearance for the crank arms to spin if you turn the pack wide-ways?

Could we see a snap of the chargers' spec tag?


Happy day, -S