Batteries for long tours

[JennyB]

I've got one of Terry's Mini-Mite hub motors for Shadowfax, my touring bike, and now I'm looking for a suitable battery.

At present, I am thinking of a 36v 15 ah Ping. I don't want anything that will weigh more than about 12lb, because I want to be able to ride unpowered, carry other stuff and still lift him without unpacking.

So, how far can I get on a battery that size?

That's a nominal 540 watt hours, but when you account for depth of discharge and motor and controller efficiency, would 270 watt hours be a good estimate of what actually hits the road? In my touring days 50 miles was about the limit of what I would want to do day after day on the roads I like to tour, and I would figure that cost 600 watt hours in energy. So I should expect a 40% increase in range - 70 miles for the price of 50. There are very few parts of Ireland where I could not find somewhere interesting to stop and recharge within that distance.

Is that realistic - and if not, what are the alternatives?

 

[swbluto]

I've got one of Terry's Mini-Mite hub motors for Shadowfax, my touring bike, and now I'm looking for a suitable battery.

At present, I am thinking of a 36v 15 ah Ping. I don't want anything that will weigh more than about 12lb, because I want to be able to ride unpowered, carry other stuff and still lift him without unpacking.

So, how far can I get on a battery that size?

That's a nominal 540 watt hours, but when you account for depth of discharge and motor and controller efficiency, would 270 watt hours be a good estimate of what actually hits the road? In my touring days 50 miles was about the limit of what I would want to do day after day on the roads I like to tour, and I would figure that cost 600 watt hours in energy. So I should expect a 40% increase in range - 70 miles for the price of 50. There are very few parts of Ireland where I could not find somewhere interesting to stop and recharge within that distance.

Is that realistic - and if not, what are the alternatives?

Were you ever on the motored bicycling forums? If so, then, I assume you know of gasoline and wonder what's stopping you from gasoline propulsion?

If you want to stick with electric propulsion, you could possibly bring along a tiny generator (Like, maybe 200 or 300 watts), and then recharge during your "rest" breaks. You could also slow down and pedal harder to increase your total electric range. A change in the vehicle design (Say, a streamlined recumbent) would significantly reduce the aerodynamic footprint which could substantially increase your electric range, though if the bike is acting like a cargo bike, it might be hard to keep the aerodynamic footprint small with paraphernalia hanging off the side.

The smallest I could find out there was a 350 watt generator and here's a link of honda generators at http://www.tappedin.com/hop/html/litegen.htm . I can't seem to find anywhere where it's sold, though. Good news is that it only weighs 19 pounds (Well, sort of good news ).

If you had some serious skill, you could make your own generator out of a 6.5 pound 25cc honda engine. http://www.honda-engines.com/engines/gx25.htm . I'd guess you could get the generator weight down to 10 pounds, and it could probably output somewhere around 300 - 400 watts.

 

[NeezyDeezy]

I have the ping 36V 20AH battery and I can get 40+ miles out of my 9C without pedaling. Your geared motor will be more efficient, and you probably weigh less than I do. There's other factors, but I based on my experience your estimate for watt hours is on the low side.

Edit - If your controller has a speed limit (normally reduces current) function, you can substantially increase your efficiency with pedaling.

Ping's C rate is 1.5, which means they will take a long time to charge safely. You would have to look into charging it overnight every night. Is this something you can consistently do on tour?

 

[John in CR]

Jenny,
With weight being a big consideration you should really look at some of the RC lipo. eg 14 of these packs on sale for $18.21/ea would come in under your 12lb limit and give you 800wh of capacity http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8853. Plus being so small they would be easier to fit to your bike, and the great price gives you money room for charging and monitoring equipment. Yes you would need to get up to speed regarding proper handling of Lipo (eg never over charge or over discharge), and you'd need to do some tedious wiring to make balance charging convenient, but you just can't beat the price and weight, and in addition they can be charged much quicker, so while touring you could stop for a quick lunch and still be able to do a nearly full bulk charge. Then do your balance charging at night.

 

[seanreit]

Jenny,
With weight being a big consideration you should really look at some of the RC lipo. eg 14 of these packs on sale for $18.21/ea would come in under your 12lb limit and give you 800wh of capacity http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8853. Plus being so small they would be easier to fit to your bike, and the great price gives you money room for charging and monitoring equipment. Yes you would need to get up to speed regarding proper handling of Lipo (eg never over charge or over discharge), and you'd need to do some tedious wiring to make balance charging convenient, but you just can't beat the price and weight, and in addition they can be charged much quicker, so while touring you could stop for a quick lunch and still be able to do a nearly full bulk charge. Then do your balance charging at night.

Can you tell me how you found out about that deal? I don't have the money to invest in those batteries right now, but when a similar deal comes up in the future, I want to be able to find out how to be notified. Was it an RC site, or their monthly deal memo?

 

[itchynackers]

This sounds good to me to, but don't you have to carry a bigger charger, and also a power supply?

 

[John in CR]

Itchy,
RC stuff is small, but yes the charger/balancer generally run on a 12V power supply that is separate. A Meanwell 650W power supply that would power a full charge in about an hour is 11"x5"x2.5", which can't be much larger than a Ping charger, though it probably weighs more.

Sean,
I just check HobbyCity.com once a week or so, click on the 2nd category line which is batteries, and then on all lipoly. Above the detailed list are thumbnails of the Flash Sale items. The one I linked above is by far the best price I've seen at 32cents per watt-hour, and it's good for 192 more hours. Don't worry if you miss it, because prices have continued to fall with quality going up for the past year, so waiting is likely to save you money. eg Here's some 40c packs for 51cent/wh, and you couldn't touch that stuff for less than about 3 times as much a year ago http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=9939
You can also register as a customer and they'll send you some info on specials, and sometimes a further discounted price. You still have to go look for the best deals.

 

[Rassy]

Wow, ask a simple question and get a bunch of diverse answers. I think your plan is right on, and I agree with NeezyDeezy in that you will get close to the rated AH from a Ping battery. It will take over 7 hours to fully recharge with the 2 amp charger that comes with the battery, but it sounds like you are prepared for that.

Good luck with whatever you decide, and let us know how the tour works out.

 

[veloman]

Man, those LiPos are so cheap!! For each watt-hour, they are 1/3 the cost of my Fatpacks, and weigh only about 65% as much!

I must invest my time in learning LiPo!


As far using a gas engine as a generator - wouldn't it make a lot more sense to just use the gas engine directly? You negate most of the benefits of electrics buy charging with an ICE.

 

[swbluto]

As far using a gas engine as a generator - wouldn't it make a lot more sense to just use the gas engine directly? You negate most of the benefits of electrics buy charging with an ICE.

It would ASSUMING gas propulsion isn't a high legal risk. As far as I know, it seems to be high risk in a few places outside of the Americas, especially Europe and Australia. However, if you were to use the generator as a charging source, I'd assume that wouldn't be illegal unless generators are illegal in those countries.

As far as battery chemistry is concerned, lipo would give you the most energy for weight. So, yeah, if you're limiting yourself to 12 pounds or whatever pounds of batteries, lipo is going to give the greatest energy capacity and thus distance you can get circa 2010.

 

[ryan]

Whoa! That's awesome. Can you combine these LiPo packs with other LiFePO4 packs? I have 72v20Ah of Headways that I'd love to supplement with an extra 10-20Ah. I'm a little iffy on the math as well. How do I calculate how many packs it would take to add 20Ah? And should I look at the largest LiPo packs available to minimize the charging/balancing hassle?

Not to hijack the thread, but I'm very interested in long tours as well. I'd love to double (maybe triple) my max unassisted distance.

Man, those LiPos are so cheap!! For each watt-hour, they are 1/3 the cost of my Fatpacks, and weigh only about 65% as much!

I must invest my time in learning LiPo!

 

[auraslip]

I feel the need to interject here.

A) LIPO is for hobbyist. There is no plug and play option that would be suitable for a touring bicyclist. Consider that you will have to spend big bucks on a BMS solution AND a separate charging system. All of which requires plugging and unplugging and figuring out wiring. Not something you want to do after a fifty mile ride. Oh and it might blow up if you plug it in wrong. Oh and the batteries only last ~500 cycles. It's not cheaper in long run.

B) You can charger the 15ah ping with their 5 amp charger. That is a 3 hour charge time. I ride between 20-50 miles a day with my 20ah ping, and have never had to worry about running out of juice.



I do want to say that ping is essentially a 1c-1.5c battery. This sucks, but it sounds like you want range over speed. Limit it to 7 amps with drain brain and you should still be clipping along at around ~15-~20mph for two hours. Truthfully though perhaps a 20 ah ping would be better.

Also an option are some of the new vendors selling headway packs. I think they weigh a bit more, but have a higher C rating. You could recharge a lot of faster with these.

 

[dogman dan]

You want to use a pingbattery for touring, and 15 ah is the smallest practical size. Smaller, and you risk the battery not lasting so long. Get the 5 amp charger, and you will charge in 3 hours, though a fully balancing charge does take longer. Using larger motors, I can reliably get 35 miles from my 36v 20 ah ping, but if you pedal without the motor on any, then that will obviously extend your range. Using power 100% of the time, you could easliy get 30 miles in the morning, charge 3 hours, and then do close to the same distance in the afternoon.

Lipo is great stuff, but the charging out on the road is not so easy. For my long distance touring needs, I have a 36v 20 ah ping and a 48v 15 ah ping. Carrying both, My range is about at the upper limit of what my body can take. 70-80 miles at 20 mph.

 

[JennyB]

Were you ever on the motored bicycling forums? If so, then, I assume you know of gasoline and wonder what's stopping you from gasoline propulsion?

I think you misunderstand my intent. For someone who is reasonably fit and in no hurry can 50 miles in a day on a bare bike. Not easily, perhaps, but it doesn't take long to reach that level. Longer distances are much harder. In my time, I have cycled up to 130 miles in a day, and if i wanted to go that far purely for pleasure, I would get myself a proper motorcycle. But for the normal tourist with access to electricity, a relatively small battery can provide a significant increase in range.

 

[dogman dan]

Yup. Others that are very fit and like to pedal get unbelievable range from small batteries. For you to double what I get running the motor 100% of the time wouldn't suprise me at all.

 

[JennyB]

You want to use a pingbattery for touring, and 15 ah is the smallest practical size. Smaller, and you risk the battery not lasting so long. Get the 5 amp charger, and you will charge in 3 hours, though a fully balancing charge does take longer. Using larger motors, I can reliably get 35 miles from my 36v 20 ah ping, but if you pedal without the motor on any, then that will obviously extend your range. Using power 100% of the time, you could easliy get 30 miles in the morning, charge 3 hours, and then do close to the same distance in the afternoon.

That's what I was hoping. I'm lucky to have two long-distance cycle trails passing close to my front door. My plan is to research and then publish suitable charging stops. Back in the '30s (long before my time) people who cycled into town from the country used to leave their bikes with the local blacksmith. I'm sure there are a lot of businesses who would be willing to provide a similar service.

Lipo is great stuff, but the charging out on the road is not so easy. For my long distance touring needs, I have a 36v 20 ah ping and a 48v 15 ah ping. Carrying both, My range is about at the upper limit of what my body can take. 70-80 miles at 20 mph.

That's about my limit too, these days!

just one more question: what difference do you find between those batteries on the same motor. I expect 36v would be more suited to my purposes, but i'm just wondering.

 

[dogman dan]

Basicly, amps x volts = watts, so at 48v it's a higher wattage motor that the same kit at 36v. Top speed increases 4-5 mph, and the grade of hill the motor is comfy with goes from 7% to 10%. So I get a bit more performance out of the 48v battery. Both batteries have the same number of cells, and weigh about 15 pounds. With a higher top speed, I get home a bit quicker with a 48v battery. Some of my bikes have been 36v only, but nowdays they all can take 36 or 48v.

 

[toaroa]

Me = long time cycle tourer; recently converted to the religion of ebiking (as a commuter).

I've tried to conceptualise ways of putting those two together, but I can never get passed the weight issue in my mind and come up with a sensible strategy. I tour on the light compared to some, but as I usually tent while touring (albeit at camp grounds where I could charge the battery) I can't get my kit below two larger, ortleib panniers on the back, two medium-small ortleibs on the front (low rider rack) and a handlebar bag. Other stuff like water can add up too. Taking all those matters into account...

- with the weight from touring kit + motor/battery/controller/charger, the mechanical soundness of the rest of the bike will be suspect (racks, rims)

- mounting batteries in the frame triangle might be crucial to making this work

- front hub motor seems sensible to evenly distribute the weight, but with all the weight you'd need to add more weight with cromoly for the forks (and even then potential for fork breakage is high because of all the torque you'll need to pull the weight uphill)

- aiming to come up with the capacity to merely pedal assist for a whole 100-120km day might be an unachievable goal. Yep, it can be done for one day, but with all the weight for touring??? (I doubt it)

- perhaps it's better to aim for 'strategic' assistance: e.g., low voltage chain drive motor (or perhaps small, geared hub) and high C, low Ah lipo for hills only, preserving leg power for the flats in between? (reliability of both chain drive and geared hubs is questionable, especially with all that weight)

=> I might be waiting for zinc-air or lithium-air miracles before putting these pastimes together!

 

[dogman dan]

Yes. My "touring" has been local enough to not need to carry camping gear. Perhaps I should have more correctly called it daytripping. Typical is carry the bike to the mountains on a car, and ride there.

But just one 15 pound pingbattery or other lifepo4 could still carry you quite a ways when used at low speeds, like 15 mph on the flats. A long lunch for a 3 hour charge and off for more. The main reason I carry two is that here in the western deserts of the US, you could easily have 70 miles between electric plugs you can use. I might have to carry a gallon or more of water, so depending on climate it could be close to a hyperlight camping load for a bike with one battery.

 

[JennyB]

Yes. My "touring" has been local enough to not need to carry camping gear. Perhaps I should have more correctly called it daytripping. Typical is carry the bike to the mountains on a car, and ride there.

But just one 15 pound pingbattery or other lifepo4 could still carry you quite a ways when used at low speeds, like 15 mph on the flats. A long lunch for a 3 hour charge and off for more. The main reason I carry two is that here in the western deserts of the US, you could easily have 70 miles between electric plugs you can use. I might have to carry a gallon or more of water, so depending on climate it could be close to a hyperlight camping load for a bike with one battery.

That's not a problem I have in Ireland! :lol:
I was thinking more of a hostelling/B&B tour. I'm not sure that a full camping load would work too well, unless you are willing to forgo the contents of the front panniers.

OTOH, given the right topography, the idea of sub-24-hour overnights is quite appealing. Use the batteries to get you up into the hills in the evening, and gravity to bring you back down in the morning. You could make an extended tour out of it by altenating with more civlised overnights for balance charging. 8)

 

[toaroa]

Yeah - I've been impressed with the distances I can get out of a 12Ah lifepo4 and the smallest bafang front hub. I think Jenny has it right though: if you want to tour your ebike, paid/indoor accommodation and not carrying all the food and cooking equipment might be the way to go. Then you could get around the charging problem by disconnecting the battery and charging it in your room overnight.

 

[zap]

I've tried to conceptualise ways of putting those two together, but I can never get passed the weight issue in my mind and come up with a sensible strategy.

Kepler's lightweight set up might be the answer to your weight issue.
http://endless-sphere.com/forums/viewtopic.php?f=31&t=20491

 

[jag]

Personally I enjoy riding a really lightweight bike the most. Light batteries and frequent stops would suit me better than large capacity and one overnight charge. The problem is that there aren't good alternatives for high power chargers..

On most stops one can find a standard 110V outlet. In Canada they are omnipresent because in the winter cars use them to plug in their block heaters. Many of these are left powered year around.

A standard 110V outlet provides 1500W. That would charge a small 36V 10Ah pack of high-C rate cells (e.g. A123) in 15 min = quick stop for a snack. The problem is that to do 1500W one needs 4 Meanwell S350 = 4kg = ridiculously heavy for onboard charging. This doesnt' seem to be a technical limitation. 1500W ATX computer PSU for PC's weigh less than 1kg, so it should be possible to make a 36 or 48V charger < 1kg for about the price of a PC PSU, less than $100. (less since only one voltage is needed)

 

[dogman dan]

Yup, lots more places to charge where all cars have to plug in. Here in the desert, there might not even be a house for 30 miles, let alone a convenient, unguarded plug you can poach. Lots of places like a city park might have a plug, but it's switched off till somebody pays a fee to use the spot for a wedding or civic event. Wallmart has a plug out front nearly always, but towns may be 70 miles apart. Any multiday touring I do will involve a motel room or freinds house where I can charge.

It would be real nice to have the plugs everywere, and be able to just carry enough lipo for 1 hour of ride, and then charge fast, like 15 min. But then you run into the problem of that much charger needing more than 15 amps at the plug. A pair of 10 ah pings with two 5 amp chargers would charge in 2 hours though. so you might get into a ride 2 hours, charge 2 hours cycle.

 

[jag]

It would be real nice to have the plugs everywere, and be able to just carry enough lipo for 1 hour of ride, and then charge fast, like 15 min. But then you run into the problem of that much charger needing more than 15 amps at the plug.

Actually no problem to charge 15min to ride 1h: 15min = 1/4h of 1500W = 375Wh = 1 full 36V 10Ah battery.

With most setups this would allow you to ride 1+h.

E.g. I use about 16-18Wh/km when riding mostly WOT with my 9C at 40-50km/h. The 360Wh in the battery would give me give me about 1h of riding to go 40ish km.

At around 20mph/30km/h one can probably ride for 2-3h on 360Whr

So 15 min charging could be practical if a small, lightweight and inexpensive 36 or 48V 1500W charger could be found. Unfortunately the BMS battery 1500W charger weights 5.5kg, so more than the 360Wh battery back in LiFePo4, and twice that of a LiPo pack. So for now it makes more sense to carry the weight in batteries.