Seeking The "Most Cost Effective" Battery

[Drunkskunk]

Lipos are great for me. I ride with 10 pounds of the strapped 6 inches from my arse.
But I'm crazy. I wouldn't recomend them to anyone who doesn't have experiance with them, and a real good understanding of electronics. A Ebike sized Lipo is deadly.

TrueRC is a great source for them. I've been running his packs in my planes for a couple years. they are almost as good as thunderpower, and better than every other brand i've tried. They are half the size and weight of LiFePO4.

500 cycles to 80%. The up side is most give 100% of rated capacity, so it takes 800-1000 cycles for them to drop to SLA normal capacity.

But Cost effective? Not so much. LiFePO4 has 2 to 3 times the life expectancy, for about 20% more cost. Its also dangerous enough to be disqualified.

Here's a 4 ouncer blowing up. Notice only 2 cells let go.
http://www.youtube.com/watch?v=KpUXuEg3fNE
and a few more tiny ones.
http://www.youtube.com/watch?v=SQ0SNESIkWk

 

[safe]

But Cost effective? Not so much. LiFePO4 has 2 to 3 times the life expectancy, for about 20% more cost.

You meant more like 200% or 300% right?

For the same watt hours the LiFePO4 are multiple times more expensive than SLA even after factoring in the Peukert's Effect.

For example, the low priced Lipo that was talked about a posting ago:

...translates to about one dollar per Watt Hour compared to the more cost effective deal they have on those NiCads that are running about 50 cents per Watt Hour. Both should last about the same time and the Nicads are half the price. (but a lot more weight of course)

 

[TylerDurden]

But Cost effective? Not so much. LiFePO4 has 2 to 3 times the life expectancy, for about 20% more cost.

You meant more like 200% or 300% right?

For the same watt hours the LiFePO4 are multiple times more expensive than SLA even after factoring in the Peukert's Effect.

He was referring to LiFe v. LiCo.

 

[stew007]

That was connecting a lipo into the mains I have never seen one catch fire in normal use, only slightly puff if too many amps were drawn.

I have seen reports of Nimh and NICad cells violently exploding too, some with so much power they would have been deadly, metal shards everywhere, like a grenade going off, this was charged on a normal charger, not plugged into the mains, supposed to be more common on the cheaper ni cells. So it's best to never be complacent with any type of battery, always be around when your charging a battery, unless it's nicd/nimh c/10 or less trickle charge.

Where Lipos shine is less bulk and less weight, they will make for a neater installation, plus the bike should handle more or less the same, they can handle lots of amps, and are quick to charge, thats the reasons im going for lipos

 

[safe]

Where Lipos shine is less bulk and less weight, they will make for a neater installation, plus the bike should handle more or less the same, they can handle lots of amps, and are quick to charge, thats the reasons im going for lipos

All good reasons... but if "Cost Effectiveness" is the criteria they don't have any advantages over something like NiCad if you can get a good price on NiCad.

I suspect that NiCad's are selling for a little less right now because they are being ignored. They are heavier than NiMh and they require recycling because they are toxic to the landfills. So while they are still a good technology they won't allow you to profess your "Going Green" status with the same vigor as something like LiFePO4 which can be simply thrown away.

There's little doubt that LiFePO4 prices will come down eventually... but for the here and now you are still paying that little extra for it.

Maybe if these Duct Tape packs (which have no track record) turn out to actually deliver long life then it might be worth it to try one. They seem to be closer to competitive in price compared to the other options. (a little scary to make such a deal however)

 

[stew007]

yes some really good deals on nicads at the moment, I am tempted, I found these http://www.batteryjunction.com/r1ed-gd7000.html
I got 10000mah nimh d cells form here before, for a golf trolly I built, the cells were ok, but i'd guess they were actually around 8000mah, and quite low current, they didnt like to be charged at anywhere near 1c so I resorted to c/10, 2 years on still going good. but the D size cell is not easy to conceal on a bike, it's quite a bit of bulk there sitting on the back if going for 40+ volts

Im sticking with the lipos until the next leap in technology comes, watch out for lithium sulphur http://peswiki.com/index.php/Directory:Lithium_Sulphur_Batteries and a whole load of other chemistries in the pipeline 10 years time lipos will probably be like the nicads of today :lol:

Stew

 

[safe]

For some reason it's the SubC cells that have the highest "C" rates. Some have said that there were lawsuits about the "D" cells from some long ago issue and so the focus on "high tech" has been the SubC's. RC's use these and they demand the highest performance.

But it does appear that NiCads are being neglected right now as the other options are taking over.

Their loss (excess inventory) could be our gain...

But it depends on your application... I've got a bike that needs something like this because it's designed to place cells inside the frame, so it's right for me.

 

[stew007]

wow, I like your idea, cells inside the frame, that would be the ultimate way of concealing them. How would get to access them? I would imagen a pump action shotty style of layout, with an access hatch and spring loading to keep the cells tight together with good contact, many possibilities there

 

[safe]

cells inside the frame

The big "fad" in pack design these days is the solderless tube. What you do is place the cells into a tube and then spring load the ends. I've got a custom built frame for this. I'll use some PVC pipe inside the frame itself so as to provide an insulation layer. Batteries have thin skins... if they rupture they could short to the frame.

Better "safe" than shocked.

 

[fechter]

I don't think you'd get shocked, but if the cells shorted out, it might turn the tube into a battery cannon! Hmm... that might be cool.

 

[safe]

I'm sticking with the lipos until the next leap in technology comes, watch out for lithium sulphur...

"A unique feature of Li-S technology is its liquid cathode. This provides exceptionally fast transfer of charge and offers two benefits. First, a wide range of power delivery can be accommodated. When a surge of power is required, as in power tools or vehicle acceleration, the liquid cathode provides a rapid flow of energy. Second, low temperature operation has less effect on energy availability. The liquid cathode's high-energy transfer rate provides at least 65% of ambient temperature rated capacity at temperatures as low as -40°C."

"In addition to much higher gravimetric energy density, this unique chemistry has an inherent overcharge protection mechanism providing an additional layer of safety to the cells. For high power applications in power tools and appliances, Li-S is nearly the same as nickel cadmium and nickel metal hydride in its rate capability, but having only one-third to one-fourth the weight."

This is the first time I've heard about this. Very interesting... probably not "Cost Effective" right away, but very promising.

The Company's (Sion Power) technology is secured by over 51 US issued patents and over 48 applications pending worldwide protecting various enabling aspects of Sion Power's intellectual property.

 

[Link]

Safe, I think I know what you could use: nickel-iron. It has cycle life comparable to LiFePO4, but all the drawbacks of SLA :lol:.

 

[TylerDurden]

^^^ :lol: :lol: :lol: ^^^

 

[safe]

You guys forget that I still hold the record here on this forum (unless someone can prove otherwise) of the currently in existence (in other words real life) most "Cost Effective" bike.

I've just passed 3,500 miles on what was originally $138 worth of batteries.

So that's why I've "set the bar" to clear at 3,000 miles which happened last summer before that one cell went bad on me. The other two are also in decline and we will see how many pennies I can pinch from them. (that works out to 4.6 cents per mile for the first 3,000 miles)

It's generally not smart to criticize the guy that's actually winning... :wink:

(though in the Ping thread we're all watching to see if someone can beat the "old champ")

http://endless-sphere.com/forums/viewtopic.php?f=7&t=4002

Update: I just noticed that there is a "5,000 Mile Club" thread and so there is some dispute about who is the champ. We need some numbers (original pack price) before we can declare a true winner.

This is fun... a new type of contest... who can be the cheapest...

 

[TylerDurden]

a new type of contest... who can be the cheapest...

I keep my house @ 45F in the winter to save fuel. (no electric blanket, btw)

I wipe my ass with BK napkins.

Beat that for cheap.

 

[OneEye]

Eating at BK to get napkins disqualifies you for the Cheap Ass award.

 

[safe]

Everyone's a comedian these days... is there any chance we could at least try to keep to electric bike technology?

At least make the attempt...

TylerDurden is one of those people I'd like to be able to have filtered out of a thread. See the "Feature Requests For The Webmaster" thread:

http://endless-sphere.com/forums/viewtopic.php?f=1&t=4343

 

[OneEye]

Fair enough, Safe, althought the off-topic banter is hardly limited to hijacking your threads...

So have you arrived at a decision on what you are going to do? Your #1 build with its huge lead acid batteries is certainly one end of the high weight / low cost spectrum, and I'm not sure the cost aspect is beatable yet with the lighter chemistries.

I'd certainly be interested to see how you approach a massive small-cell build and attach parallel charging with the nickel based cells you posted about.

 

[Link]

You guys forget that I still hold the record here on this forum (unless someone can prove otherwise) of the currently in existence (in other words real life) most "Cost Effective" bike.

Which is EXACTLY why this is pointless. You are an OUTLIER. Nobody else is going to come close, because there are no frames around that can handle the weight of enough batteries to get decent range and still keep the batteries healthy. Even you had to build one expressly for that purpose. Not everyone has a welder, you know, and the "average" ebiker either won't be able to or won't want to hassle with working out such a system. In the spirit of "most cost effective", they can't have someone else do it, either, since that would offset the cost of better batteries by far.

 

[safe]

So have you arrived at a decision on what you are going to do?

I ordered these this morning:

24V DC Battery Pack Charger With Tamiya Connector (8) $10.99 USD $87.92 USD

96 NiCd Sub C 2400mAh Batteries for PowerTools Flat Top (3) $119.99 USD $359.97 USD

Subtotal: $447.89 USD
Shipping & Handling:$56.45 USD
Total: $504.34 USD

That's $1.25 per cell. (very cheap)

These batteries will power Project #002 and #003.

 

[safe]

In the spirit of "most cost effective", they can't have someone else do it, either, since that would offset the cost of better batteries by far.

I have real sympathy for what you are saying.

Yes... it's true... the choices people have right now are limiting and so what might be most "Cost Effective" in the abstract is not the same as what is valid for the consumer.

However, there are low priced WalMart electric bikes that do use SLA and get good mileage out of them. What they do is limit the motor to 250 - 350 watts and that way you don't waste the battery.

My bike is sort a "proof of concept" bike... it shows that you can use regular SLA and go 40 mph and get 3,000 miles. It's showing what's possible.

Maybe you could create a thread that deals with "consumer only" options and try to figure out which consumer products fair the best?

Title it something like:

"Most Cost Effective Consumer Ebike"

...and then focus on specific products and not just batteries.

(remember this thread was about batteries alone)

 

[TylerDurden]

Eating at BK to get napkins disqualifies you for the Cheap Ass award.

I don't eat there... they leave em out at the turnpike service-plazas.

 

[fitek]

What exactly are the specs on your bike Safe? Maybe others know them, but I don't... and you have quite a few posts to wade through when using the forum search hehe.

I remember you have a 3 speed hub or something...

 

[safe]

What exactly are the specs on your bike Safe?

86 lbs of lead. A 1000 watt motor that is being overvolted some of the time to 48 volts and an "effective" 18Ah. (two of the cells are older 38Ah) 6 speeds through a regular derailler.

So peak power is about 1400 watts at the rear wheel... 38-40 mph top speed on the flat, 50 downhill, 20 uphill, 25 average. 10-12 mile range. (at speed)

 

[inspron]

Sorry for this total newbie question:

I have this: http://www.walmart.com/catalog/product.do?product_id=5662772

Lets say I get 3x12V SLA and install it in series on my bike. http://cgi.ebay.com/ebaymotors/12-Volt-7AH-Rechargable-Battery-Gas-Electric-Scooter_W0QQcmdZViewItemQQcategoryZ10066QQihZ012QQitemZ220242466825QQrdZ1QQsspagenameZWDVW

or some Sub C or even Lithium cordless drill batteries.

How would I charge them? Do I have to charge each SLA at a time? or can I buy a special charger to charge them all at the same time? Could I use my existing charger that comes with the bike?

Thanks!