Safe's Electric Bike Project #001

[safe]

Was this parts from a "Toys are Us" bicycle that wore out?

Shocking huh?

That "Toys R Us" would allow their bikes to be sold with such low quality hub cups! :lol:

Just kidding.... yes, you buy cheap parts and they often wear out. But I can guarantee you that had I bought the expensive stuff it would have been a lot more expensive overall.

One day when I have all the ideas figured out I'll "throw money at the problem" and use all expensive stuff. But that future bike will probably cost $2000 to build while this one cost something like $750.

In late 2006 (when I built this bike) I knew so little compared to now. Had I blown all kinds of money back then I might have given up because the hobby would have gotten too expensive. This way I'm starting off spending less and then adding as I learn more. In 2006 I would have had no idea about using an RC motor, but that will be my Project #004 bike. (still not even started yet)

3,800 miles is pretty damn good for "Toys R Us" parts. :wink:

 

[safe]

Just Peachy!

Downright peachy keen in fact!

After a few hard rides I've gotten about 30 miles on the new "upgraded" hub. Everything seems to be working well and it's actually quieter and smoother since there is no more rattling coming from the hub. I figure that I was probably losing 100 watts just based on added friction.

So the "Toys R Us" hub still survives... it took a little tender loving care, but it's still working.

However, a new "runt" is developing within the batteries and battery number one always drains faster than number two. Numbers three and four are new and always end very strong. So it won't be too long and I'll probably want to replace the two older cells with two 18 Ah smaller sized ones. That will drop the weight (and the range) and leave me with nothing but a speed bike. That's okay at this point... (I can always switch back to range if I felt like it)

I'm at 3,835 miles right now, so maybe I'll wait until 4,000 miles to do the switch... maybe 5,000 miles.... we'll see.

Everything is feeling really dialed in at this point and the tires are well broken in so that they give goobs of traction. I've also been riding it long enough to know what it can do and so as a rider I'm able to use it better. This is probably the best this bike will be. (well, maybe the lighter weight batteries will improve things a little)

 

[safe]

My Top Speed Returns

Approaching my biggest hill from below I managed to get up to 45 mph and then I kept a lot of that speed so that I crested the hill at about 27 mph. When I used to run 36 volts I would crest the hill at only 16 mph.

Going down the same hill I'm back up to my old record speed of 52 mph.

...so for the last month or so I was unable to go any faster than 50 mph. The new cup in the rear hub means that the rear wheel is finally spinning without all that drag and at the higher rpms it seems to show the most effect. With the derailler in it's sixth and smallest gear the chain is pulling on it really hard and that was where the bad cup was located (chain side), so all the friction there was really holding the power back.

I'm able to stick the bike into sixth gear now and get the full power out of it, where before I was losing too much power because of the friction in the old cup.

 

[safe]

Watching The "Runt" Die...

It's sad to watch the weakest cell slowly dying.

Every ride is showing that the ending voltage of the "runt" cell gets lower and lower compared to the strong ones. This time I started with an even 13.0 volts for everything and at the end of 8 miles I found that:

Number One: 13.0v - 11.3v
Number Two: 13.0v - 12.1v
Number Three: 13.0v - 12.4v
Number Four: 13.0v - 12.4v

...and to make matter worse when I charged Number One it was very warm on one side of the battery and completely cold on the other. My guess is that one side is completely "gone" and not even participating anymore and the other is trying really hard to carry the slack that the other can't deliver.

So it's looking like I'll struggle to get to 4,000 miles before I finally need to replace the last of the original batteries. Seems that you can only really expect about 3,000 miles out of a set of SLA's before you begin to have to think about replacement. These old cells are still working, but even though they are 38Ah they are actually delivering LESS than the capacity of my new 18Ah. So I've worn them down to less than half of their original capacity... I've gotten my money's worth... but at this point they are at least 50% dead lead doing nothing for me. (about 30 lbs of excess weight)

The only way to get more out of SLA is to lower the "C" rate further... that's the only way to get more mileage while causing less wear. I'm now pulling 2.2C which violates my rule that suggests 1C or lower is the ideal.

But what the heck... it's been fun.

 

[Toorbough ULL-Zeveigh]

Seems that you can only really expect about 3,000 miles out of a set of SLA's before you begin to have to think about replacement.

That's what the 'smart crowd' has been trying to tell you all along. 8)
If you recall this prediction to your drunken boast;

It would be great to get 10,000 miles out of the batteries if that's possible.

"Dreaming is free."

- Deborah Ann Harry

http://endless-sphere.com/forums/viewtopic.php?f=7&t=857&p=23347
10,000 miles... that fibreglass resin is really wicked stuf!

So what have you learned from this?
I'll tell you what I think & sorry if it sullies your precious thread.
I think xyster was right when he tried to warn you that discharging to 12.0V is not shallow.

12.0 volts is not shallow.

(from same thread as above)

Also the main reason I was following your SLA saga was that my PbAs always died prematurely from sulphation whereas you had meticulously taken steps to prevent that (with only the one slip-up in that regard) & was curious to see how much it improved the lifespan or if it even made any difference.
So the big thing I learned, actually more like confirmed what I suspected is that sulphation is just one half of the one-two life-killing combination punch that will getcha one way or the other.
The other major flaw that drastically restricts the calender life is grid corrosion, so even if you do everything right, which you nearly did, the plates will still fall off as their support structure deteriorates & this trumps any & all efforts to maximize their lifespan.

Gee, who would have thought that dipping metal into a corrosive acid would dissolve the battery's internal structure?
That is one of the 'innovations' behind the Firefly/Oasys battery, that they simply replaced the vulnerable metal bits with graphite to support the plates so that they won't deteriorate with age.
Wow! That was reel difficult to figure out & it only took over a hundred years of the same old same-old to do it because it's more profitable to have batterys that wear out & require regular replacement.
That's the beauty of capitalism that you so admire, so I hope you learned something there.
With the other Firefly off-the-shelf innovation of using foam microcell plates I am even so optimistic that lead-acid could finally be a reasonable alternative now that I'm eager to vote with my money if they ever show up here.

The other thing I hope you learned but I doubt your ego will allow it is that this one test was worth 10,000

of your opinions.
I hope you learned that there are other intelligent & even not so intelligent people in the world besides yourself that shouldn't be so readily dismissed when trying to help you & the thing that counts way more than intelligence is someone's direct hard won personal experience that they've taken the time to share with the rest of us.

 

[TylerDurden]

He will live in our hearts forever...

...like a plaque, but a realllly smart one.

 

[safe]

The Lesson Learned

My original motor was this:

...and it's rated amps were only 27.4 Amps.

Unfortunately I was curious about this motor and took it apart and noticed that the area that the brushes touch was dirty so I did something really dumb and SANDED them. It was only a short time later that the motor literally burnt up. (as in fire inside near the brushes) The circumstances where such that part of the blame was overheating in an extreme test, but it was really because I tinkered with it. So anyway, the motor gets replaced at 500 miles and all of a sudden I jump to the 1000 watt motor:

...which I've used without problems ever since. The only difference is that it's rated load is 35.6 Amps.

I can recall looooong (slow) rides in the 25 miles range using the original motor and then less to more like 15-20 miles with the newer one. I also was originally running an alternative gear where I could switch from a 14 tooth to a 22 tooth when I wanted. That meant that I could do a speed test OR be able to climb the steeper hills, but not both.

Now I've got a 2.2C setup where I'm pulling 40 amps out of some 18Ah SLA's at 48 volts.

So it's hard to say how things "might have been" if I stuck to the original less than 1C configuration.

My "guess" is that since most of the riding was done with the 1000 watt motor and it's "sweet spot" is naturally higher that I tended to use the power it gave.

"Power is seductive on an ebike... it corrupts absolutely."

The moral of this story is that I'm someone that started with a configuration that very well might have made it to 5,000 or even 10,000 miles, but that I've increased the "C" rating (and power) something like a factor of 3 or 4 from where I started.

I've radically altered the original design.

I firmly believe that if you use SLA at less than 1C and you exploit gears to their fullest that 10,000 miles is possible. I stand by it as something that is possible to do. (it's probably the far edge of the possible though)

Also, at first I didn't really think of the bike as being the full blown "Road Racer" as I do now. It wasn't long on the bike that I truly realized:

"Hey, wow, I could really pull this off and get something that is really, really, fast."

...at first I just didn't believe it could be so good. I pretty much surprised myself at how fast I've been able to go.

 

[TylerDurden]

I firmly believe that if you use SLA at less than 1C and you exploit gears to their fullest that 10,000 miles is possible. I stand by it as something that is possible to do. (it's probably the far edge of the possible though)

Under what other conditions:
what bike?
what batteries?
what motor?
what location?
what timeframe?
etc.?

 

[Lessss]

Tyler, why don't you change your avatar to something more appropriate to what you do here?

 

[TylerDurden]

Tyler, why don't you change your avatar to something more appropriate to what you do here?

Bite me... those are real questions.

 

[Link]

Tyler, why don't you change your avatar to something more appropriate to what you do here?

Eh, he's got a point. He was pushing the limits of how long SLA can last in an EV as it was, and it took a custom frame to haul around enough battery to do it.

 

[safe]

The Range to "C" Rate Relationship

Here's a profile of a 18Ah battery:

0.1C Drain Rate - 2 amps - Peukert loss 0% - Actual 18Ah
0.6C Drain Rate - 10 amps - Peukert loss 35% - Actual 12Ah
1.0C Drain Rate - 18 amps - Peukert loss 50% - Actual 9Ah
2.0C Drain Rate - 36 amps - Peukert loss 65% - Actual 6Ah

...these are approximate numbers of course.

So the secret to getting long range is to SLOW DOWN and use as many gears as is necessary to be certain to be running your motor at it's optimal rpm all the time. If you can carry all the weight you need (like 100 lbs of SLA) and go really slow so that nothing breaks (20 mph or less) and you can climb any hill because you have the granny gears to do it, then I don't see any reason why you couldn't expect longer than 5,000 miles and potentially as much as 10,000 miles in a "pure range" machine.

My bike has drifted away from long range and long battery life toward high speed and short battery life. The question becomes "what do you want to do?" and if you are okay with a bike dedicated to range at slow speed then it can be done. Not only do you get more range out of the same battery when you use less power it also will wear out the battery more slowly.

Would anyone really want a bike that was:

Slow
Heavy
Long Range
Long Battery Lifetime
...but very Boring?

 

[TylerDurden]

Would anyone really want a bike that was:
Slow
Heavy
Long Range
Long Battery Lifetime

http://www.endless-sphere.com/forums/viewtopic.php?t=2334

 

[safe]

Just passed 3,900 miles today...

 

[Link]

Here's a profile of a 18Ah battery:

0.1C Drain Rate - 2 amps - Peukert loss 0% - Actual 18Ah
0.6C Drain Rate - 10 amps - Peukert loss 35% - Actual 12Ah
1.0C Drain Rate - 18 amps - Peukert loss 50% - Actual 9Ah
2.0C Drain Rate - 36 amps - Peukert loss 65% - Actual 6Ah

...these are approximate numbers of course.

That would be positively AWEFUL performance from SLA. The crap 4.5Ah batteries I used to power my BD36 with were being punished with 30A (nearly 7C) through them, and they still gave me about 2.3Ah (~50% loss).

 

[safe]

The crap 4.5Ah batteries I used to power my BD36 with were being punished with 30A (nearly 7C) through them, and they still gave me about 2.3Ah (~50% loss).

My guess is that with "sag" you really aren't pulling the full 30A out of your controller. I know that from the beginning to the end of my rides the performance progressively drops due to sag as well as motor heating. With that said... getting 2.3Ah out of a 4.5Ah SLA battery seems very good. My calculations are for "generic" batteries and I based them off of the manufacturers data for "C" rates and the Peukert Effect. The data source was from a larger battery (38Ah) and I then extrapolated backwards, so there could be some error.

It's possible that there is a sort of "maximum loss" that Peukert can inflict because the sag prevents you from actually pulling more than a certain current.

...so "sag" might be the answer.

 

[Lessss]

That so sag... lol

 

[Link]

The crap 4.5Ah batteries I used to power my BD36 with were being punished with 30A (nearly 7C) through them, and they still gave me about 2.3Ah (~50% loss).

My guess is that with "sag" you really aren't pulling the full 30A out of your controller. I know that from the beginning to the end of my rides the performance progressively drops due to sag as well as motor heating. With that said... getting 2.3Ah out of a 4.5Ah SLA battery seems very good. My calculations are for "generic" batteries and I based them off of the manufacturers data for "C" rates and the Peukert Effect. The data source was from a larger battery (38Ah) and I then extrapolated backwards, so there could be some error.

It's possible that there is a sort of "maximum loss" that Peukert can inflict because the sag prevents you from actually pulling more than a certain current.

...so "sag" might be the answer.

Nope. The Doc Wattson doesn't lie, and it says I was drawing exactly the controller's limit: 31.25A. Granted it also said that this 48V pack was sagging down as low as 30V before they were dead. Yeesh.

 

[safe]

Nope. The Doc Wattson doesn't lie, and it says I was drawing exactly the controller's limit: 31.25A. Granted it also said that this 48V pack was sagging down as low as 30V before they were dead. Yeesh.

So these were new batteries right? That's another possibility, that maybe when new they work the best and then decline. Do you have the battery manufacturers name? I'd like to research this battery and check with their technical documents. My big 38Ah batteries were the "cheapo specials" and probably the bottom of the line as far as quality. It does suggest the better SLA cells might matter... especially when dealing with micro sizes. (Sub 12Ah is "micro" in my book)

The big cells allow enough room between power "needed" and power "available" so as to work for a long time without any problem.

 

[safe]

New Batteries Ordered

I passed 4,000 miles today.

But I've also gone ahead and ordered the smaller SLA cells (two more 18Ah) so that I will have a lighter weight bike while at 48 volts. (30lbs less) This means that with the higher "C" rate the lifespan will go down... but that's fine, after 4,000 miles I'm at the point where I just want the bike to run and run fast.

 

[recumpence]

You should move to nicads or nickle metal cells. Now would be a good time to do it. I know are designing your other bike for them anyway.

You would not see sag like you do with SLA and your bike would drop alot of weight.

Matt

 

[safe]

You should move to nicads or nickle metal cells. Now would be a good time to do it. I know are designing your other bike for them anyway.

I've got two bikes that will be NiCads.

This bike is thoroughly "debugged" and tested, so I'd rather keep it as an SLA bike just because I have less work to do that way. The cells actually assist in the frame strength... the space frame tubes use the strength of the batteries as a "stressed member" and that's why it's been so strong while still being fairly lightweight. If I didn't have SLA cells to press against the frame it might all of a sudden start flexing in places it never did before.

At 30lbs lighter it will be even quicker... so SLA deserves a showcase for what it can do too.

This bike still whips most everything else out there. Many people are just trying to get past 30 mph for a top speed while this bike can hit 40 mph on the flat, so this still stands as an impressive "historical artifact". And it's a "road racer" design, so while others might be timid in a turn I'm able to zip through the corners at full speed.

My newer bikes are going to make this bike seem slow though...

 

[safe]

Riding In Extreme Heat?

Summer is really kicking in out here in Missouri with the high today expected to be 95 degrees. I tried riding #001 earlier with basically shorts (not a real ride, but just to putt around) and it was hot. Then, just now, I tried a high speed athletic type ride while fully decked out in my leathers. It seems to me that the leathers actually prevent the "wall of heat" from getting to you as much. Inside your leathers you sweat a lot and it stays with you and so it actually feels deceptively cool. I suspect that if you rode long enough you would go into heat exhaustion which actually doesn't feel so bad because your body tricks itself into thinking it's cool.

Anyway... it actually seems better to wear the leathers on the really hot days if it's a short ride. (less than 1/2 hour) Eventually the heat will drag you down though.

 

[recumpence]

Yup, 90+ here today too.

I ran flat out 38mph for 6.5 miles. My motor only reached 130 degrees, though. I am glad. 8)

Yes, leathers are cool on a hot day for a short time. It is good to unzip the jacket and let air get inside occasionally.

Matt

 

[johnrobholmes]

Fellow missourian here too. What part of the state are you? Im dead central.