Please help me with battery choice

[SamTexas]

...Besides, I like the size, weight, and flexibility of rc lipo compared to lifepo4.

I think everyone agrees with you on the advantage in size, weight and discharge rate for RC LiCo. 500 cycles is ok with you (if RC LiCo can actually live that long) but definitely not ok with me. But the main reason most people (me especially) have second thought about RC LiCo is the thermal runaway risk.

A123 (LiFePo4) is safe, has more than acceptable discharge rate and is cheaper than RC LiCo (if A123 truly has 2 to 3 thousand life cycles). The only thing it can't compete with RC LiCo is energy density. But then RC LiCo's energy density is way inferior to consumer LiCo's. It's always a compromise.

[NeilP]

To give you an idea of LiPo cycles and cost...an this is on going and getting better every charge...
My pack is 20s4p Nano Tech LiPo (the expensive type of LiPo)
It cost about $1200 US dollar to build

is now up at 316 cycles, no sign of loss of capacity and 5800 miles, so 20 cents per mile at present plus electric recharge cost..minimal. cost per cycle is expensive at present, $3.80 ...It is going to come down, but i do not see it getting much cheaper than $2.00 per charge cycle, assuming 500 plus re charges.

[SamTexas]

Good, realistic data NeilP. Man that's expensive. In my mind, $0.10/mile is the absolute upper limit for battery wear and tear.

[NeilP]

Not when you compare it to driving a car or 4x4
And that is current figures..I can easily see getting plus 500 cycles on this pack..so that will bring price down...
AND.
I bought Nano Tech LiPo, because I wasa newbie and did not do enought research and realise they were so expensive...I bought them because they were 10 s packs..If I had bought the 15C Zippy packs as I linked to earlier cost would have been a lot less. Also since I bought, I think prices have come down a bit for LiPo. So your costs will not be near mine

What size pack were you thinking of going for..we can work some prices and recommendations for you to help out..

A mate built his pack ( had it built by Jim Delgado) to the similar capacity to mine out of Headway Headquarters 10Ah cells.
He has cells in the frame and in the rear carrier...twice the size and weigh of my LIPo pack.

[SamTexas]

Not when you compare it to driving a car or 4x4

That would be apples to oranges, right? I would compare it against a small ICE scooter.

Honda CBF125 http://www.honda.co.uk/motorcycles/125cc/#!/cbf125/
Honda Innova 125 http://www.honda.co.uk/motorcycles/125cc/#!/anf125i/

What size pack were you thinking of going for..we can work some prices and recommendations for you to help out..

Just discussion and fun for me. I have more battery than I need at this moment. I do want to play with A123, but again just for fun and out of curiosity.

[NeilP]

I am comparing to what I have and what my bike is replacing.

These are my choices, electric bike, 4.0 litre diesel 4x4, small car or 1200CC Harley . My e-bike replaces my 4x4 for every day transport.

But I do get your point, but I can't compare as I have no idea and not worked out the cost of a small scooter.
But you will probably have better performance than a small 50cc scooter, and you can take it on cycle paths too, where the scooter only on the road, so even if it is more than a small scooter, in my mind, it is still a winner

[NeilP]

Just discussion and fun for me. I have more battery than I need at this moment. I do want to play with A123, but again just for fun and out of curiosity.

Sorry, I should have directed that bit about working out the costs of a LiPo pack to the OP (silentfoster)

[SamTexas]

But you will probably have better performance than a small 50cc scooter, ...

That's why I did not list a 50cc scooter. The two I listed were 125cc.

..., and you can take it on cycle paths too,

Agreed.

[NeilP]

Depends where you live too I suppose and the cost of fuel in your area.

here unleaded is $2.26 per litre so $8.56 per US gallon

.That's why I did not list a 50cc scooter. The two I listed were 125cc.

depends on how far you push your e-bike..mine out performs most standard 125's as well

[SamTexas]

$8.56 per US gallon

Even at that astronomical price, fuel cost for the 125cc scooter is still way below your battery wear and tear cost.

[SamTexas]

depends on how far you push your e-bike..mine out performs most standard 125's as well

I seriously doubt yours can outperform the CBF125 I listed above. But if yours can, good for you.

[NeilP]

Not arguing with you, I have no data on scooter costs, but i would be interested to see what the costs are that you are using to compare.

I suppose the basic calculations would include
Scooter:
Insurance,
Servicing,
Fuel
Oil
Tyres
Road tax.
Compulsory safety equipment

I suppose with the E-bike, you have to consider the battery pack purchase cost as a disposable item, as you would for fuel

If you get down to the detail it becomes complicated I guess..need to consider total vehicle life cycle, deprecation...re use of parts?

What costs do you have for your scooters per mile

How many cycles do you reckon it

[NeilP]

depends on how far you push your e-bike..mine out performs most standard 125's as well

I seriously doubt yours can outperform the CBF125 I listed above. But if yours can, good for you.

Well in our local conditions, I can..but I live on an island with 40 mph speed limit and twisty lanes, so acceleration is everything and top speed not so relevant. But i guess on a speed run the CBF would win.

The spec does not list top speed, but i certainly beat it at max power output...8kW..pah...

[SamTexas]

Well in our local conditions, I can..but I live on an island with 40 mph speed limit and twisty lanes, so acceleration is everything and top speed not so relevant. But i guess on a speed run the CBF would win.

The spec does not list top speed, but i certainly beat it at max power output...8kW..pah...

Once again I doubt it. The CBF125 is a very popular scooter, not just in England but around the world. Maybe one of your friends or acquaintances has one and you two can do a head to head, side to side comparison.

Unfortunately, you don't have 8kW output. If you did, your ebike would top out at 70mph. You have 8kW draw from your battery, by the time it gets to the rubber of your driving tire, you'd be super lucky to have 4kW or 56mph.

[NeilP]

Yes, true enough losses in the system, I see peaks of 15kW from the battery (150 to 160 amps at 100volt) so your are right there will be losses at the back wheel.

All I do know is that I can out accelerate any standard 125 I have been up against over here on the island. Tuned ones excluded, just talking about local kids I know with the standard 125's. Top speed they will beat no doubt but not ever tried that over here...trying not to be too obvious

[SamTexas]

All I do know is that I can out accelerate any standard 125 I have been up against over here on the island.

That's simply because "standard" 125 is INTENTIONALLY geared for friendly/smooth take off. A simple switch to either a smaller front sprocket or a larger rear sprocket will do wonder to acceleration. A change to both sprockets simultaneously will get the scooter to wheelie at the slightest touch of the throttle.

[NeilP]

Yes, ..have spent my life around bikes..my first when I was about 7 years old

[SamTexas]

I have no data on scooter costs, but i would be interested to see what the costs are that you are using to compare.

I suppose the basic calculations would include
Scooter:
Insurance,
Servicing,
Fuel
Oil
Tyres
Road tax.
Compulsory safety equipment

I suppose with the E-bike, you have to consider the battery pack purchase cost as a disposable item, as you would for fuel

If you get down to the detail it becomes complicated I guess..need to consider total vehicle life cycle, deprecation...re use of parts?

What costs do you have for your scooters per mile

I do. Here's one: viewtopic.php?f=1&t=24087&start=15#p349691
I have done the cost comparison between a small ICE scooter and an electric bike many times. There is no way for me to make the ebike cheaper. But as you and I know, a scooter cannot go on a bicycle path.

[wesnewell]

The total cost of my ebike was under $700. That includes everything. 66.6V 18s battery cost 7 cents to charge (660wh). At 20 mph I get a minimum of 30 miles, so that's .23 cents per mile for electricity. Conservatively, the battery pack will need to be replaced every 10K miles and it cost $200. So add another 2 cents per mile for a total fuel operating cost of 2.23 cents per mile. For a scooter that gets 100 mpg the per mile cost at $4 per gallon is 4 cents per mile. And that doesn't include insurance or registration which will add another 1-4 cents per mile. The only drawback for the ebike is legal speed limits, but if 20mph is fast enough for you, it's the cheapest route overall.

[SamTexas]

OK, let's keep the discussion going, just for the fun of it. I have absolutely no intention of challenging or "questioning" your numbers. Agreed?

Conservatively, the battery pack will need to be replaced every 10K miles and it cost $200.

Where do you find a 660Wh battery for $200? How many miles do you have so far on that pack? How do you arrive at the conservative 10K miles battery life?

So add another 2 cents per mile for a total fuel operating cost of 2.23 cents per mile.

I projected a cost similar to yours for my ebike. But my battery is practically free (recycled laptop cells), my actual paid price for those cells is less than 5 cents/wh. But I don't know how long they'll last (thus the projected cost and not actual cost). My oldest pack has about 2K miles on it.

For a scooter that gets 100 mpg the per mile cost at $4 per gallon is 4 cents per mile. And that doesn't include insurance or registration which will add another 1-4 cents per mile.

Agreed. My actual cost (everything, including depreciation) for my 24 year old 250cc motorcyle is 8 cents/mile.

[wesnewell]

OK, let's keep the discussion going, just for the fun of it. I have absolutely no intention of challenging or "questioning" your numbers. Agreed?

Conservatively, the battery pack will need to be replaced every 10K miles and it cost $200.

Where do you find a 660Wh battery for $200? How many miles do you have so far on that pack? How do you arrive at the conservative 10K miles battery life?

I got this one at leaderhobby. Six 5000mah 6s packs wired as 18s2p for under $23 each. 6x23=$138. With shipping it ws under $200. Don't remember exact cost. I've had them close to a year maybe and have about 3K miles on them and they still charge as good as new. I usually charge them twice a week at 40-50% dod. Just saved $1000 by replacing my hw heater myself, so even though I don't really need these, I bought 11 5000mah 4s Turnigy hardcase packs for under $23 each. Total was $283, but I paid about $20 extra for priority mail. And that's 814wh. Close enough to $200 per 660wh to not worry about. I estimate the 10.000 mile life as 30 miles per charge which is only 333 cycles. And I really expect to get a lot more than that out of them. That's why I said conservatively.

So add another 2 cents per mile for a total fuel operating cost of 2.23 cents per mile.

I projected a cost similar to yours for my ebike. But my battery is practically free (recycled laptop cells), my actual paid price for those cells is less than 5 cents/wh. But I don't know how long they'll last (thus the projected cost and not actual cost). My oldest pack has about 2K miles on it.

I wouldn't even pose a guess. Impossible to know their state when you put them in use.

[silentfoster]

Hello,

you guys are awesome...I haven't been able to read the whole thread yet...but thanks so much for your help.

it was, effectively my kit from cellman. I am going to star the day after tomorrow setting it up ( I am working nights). It seems a little more complicated that I was thinking, but I am sure I can figure it out.

I will read all you have posted and then decide on a battery. This sun-thing, seems pretty good...I will be checking it in detail.

other thing, I need a torque arm, any recommendation?

[Speedfreke]

Since the battery is probably the most important componant of an ebike (I'm in the market for one now) it's a shame the thread is getting bogged down. I'd like to hear more than just lipo vs lifepo4 unless that's all there is to battery choice.
Anyone have great success with a particular brand with a reliable BMS? Any suggestions to make them last longer such as wiring harness and connectors, charging habits?
Also, in the light of A123 quality problems from it's Livonia plant does anyone know if cellman's batteries are too risky to buy?