Batteries for long tours

[JennyB]

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.

Reviving this thread to see how technology has moved on. My 36v 15 Ah ping is doing well for long day rides of around 50 miles, but I've been thinking of getting some 12S lipo so the bike is lighter for my usual 15 mile round trip into town. Also, this summer I'd like to try an extended trip with more daily mileage. Maybe take the bus to Cork and back home the long way. I reckon I would need to have 1kWh of capacity if I was only relying on overnight charging, a bit under half that if charging on the road. At present I only have the standard Ping charger, and even the fast version takes three hours. I don't want a 15 minute charge, but an hour would be nice.

So the options are:
Get a three hour charger and learn to wait
Get another Ping and charger and put up with the weight
Get 10 ah Lipo and a slow charger. Take both it and the Ping
20 ah Lipo and a slow charger. Leave the Ping at home
10 ah Lipo and a fast charger. Leave the Ping at home

So what chargers would you recommend? :?

 

[jag]

So what chargers would you recommend? :?

Most people seem to be getting the Meanwell S350. About $50 shipped from ebay.
For your 36V Ping trim it down to 43V using the potentiometer on the back. It will output constant current at about 10A to charge your 15Ah in about 1.5h. Check with Ping if the BMS likes a 10A charge current first though. The Meanwell current can be lowered by changing a resistor inside. Setting it to <=7A will also increase the lifelength of the Meanwell, but at $50 the Meanwell is more expendable than the battery.

 

[Uncle Ron]

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.

Jag and all of the more expert folks around here,

First, I'm wondering about something here which may have no bearing on the original post or may have a lot of bearing. How linear is the charging of these various lithium chemistries, particularly with a premium faster charger with 2-3 times the amperage of a standard charger? I'm wondering if the last 10 or 15% of the charge takes 50% or more of the charge time? I realize that c-rate enters into this as well as battery maintenance for long life. For instance on an LiFePo4 Ping battery pack with a 5 amp charger which charges fully in 3 hours, would someone get 85 or 90% of the full charge in, say, an hour, and what does the shorter charge time do, vise-a-vise balancing through the BMS? If this is the case then the long e-touring equation with what battery capacity could become quite complicated, eh, if you anticipated an hour stop or 2?

Second, a little whine here. I'm surprised that no one has suggested or mentioned a bike trailer, probably single wheel, for extended touring w/campling?

 

[spinningmagnets]

Ron, I'm told the LiMn batteries (ebikes.ca sells a lot of these) are a popular chemistry in cordless drills, and one of the benefits is that the first half of a charge can be "refilled" quite fast. Of course the optimum charge rate is controlled by the BMS and smart-charger.

I agree on a trailer for cargo and an extended-range battery pack being a great option. Perhaps use a small pack on the bike frame, and a very big parallel pack on the trailer, plus a charger on the trailer for "opportunity" charging from unlocked outlets exposed to the public.

 

[LI-ghtcycle]

I also wanted to mention, if you're fine with charging at night, LiPo can get you thought the day, and a reasonable priced charger & supply can be bought for under $150 if you can charge over-night in the hostel, and it won't be a huge bulky monster.

Hyperion makes a charger with a built in 200W power supply (just plug it right into the wall) IIRC, and if you looked around, I bet you could find one pretty cheap, and you could parallel charge & balance with packs that are well matched (cycle them 10 times and get them all at about the same and you can safely parallel charge/balance them) is being done with good success by many of the RC guys.

I plan on doing what you want but in reverse, weight will not be a real issue for me, and I will be using power 99% of the time on tour( even if it is just to "tickle" the throttle enough to eliminate drag from the hub motor, but not enough to use any measurable amount of power) but I will be using the camp grounds and planning for 100 mile range, but I will have the battery for it (most likely 30AH of 14S Nano Tech LiPo).

I imagine you have covered most of the Island by now on Shadowfax? I wonder however, does it come to you when you whistle? :wink:

 

[jbond]

Reviving this thread to see how technology has moved on. My 36v 15 Ah ping is doing well for long day rides of around 50 miles, but I've been thinking of getting some 12S lipo so the bike is lighter for my usual 15 mile round trip into town.

Here's another option. Get Cellman to make up a couple of A123 LiFePo packs with his BMS and charger . A 12s1p or 12s2p in a frame triangle bag for short trips and a 12s4p or upwards to go on the rack paralleled with the small pack for longer trips. You may be able to bulk charge both together paralleled with a 5A charger. Same chemistry, same technology. LiFePo safety, plus a BMS for simplicity and a relatively High C so that even the small pack will still be ok with a low powered geared hub motor. For the big pack, you could use a Ping or similar LiFePo and save some money but still use the same charger.

For long tours with plenty of pedalling, rig up a CA with their current limit circuit used with a switch so you have an optional Economy mode.

 

[dogman dan]

My gut reaction is that a 36v 15 ah ping is pretty light. Lipo would be lighter, especially a 10 ah pack vs 15 ah. But the difference is not so big between ping and lipo, since both are pouch cells. I don't get the advantage of carrying lipo for a 15 mile ride where you'd need 10 ah of 12s. The advantage of 12s for a faster ride is a different story. More volts= more fun for many of us.

However, to carry a bit more range on longer rides, I couldn't agree more that adding a 12s 5 ah lipo pack as a "reserve tank" is hard to beat. Or even adding 12s 10 ah is still a lot more range in a tiny package. So go for a 12s setup by all means.

Don't worry so much about charge times, just do most of your charging at home still, and all of the lipo charging at home. Easy to carry enough range for most rides without needing a 1 hour charge. But at home, a 1 hour charge for 12s 10 ah lipo is not so expensive at all. About $150 for a s350, and 300 watts of charger, or chargers. My setup uses a 350 watt meanwell and two 150 watt chargers, and charges a 12s 10 ah pack in about an hour.

BTW, were your aware that a 48v 15 ah ping charges faster than a 36v 15 ah ping? 12v x 5 amps = 60 watts faster charging.

 

[JennyB]

Don't worry so much about charge times, just do most of your charging at home still, and all of the lipo charging at home. Easy to carry enough range for most rides without needing a 1 hour charge. But at home, a 1 hour charge for 12s 10 ah lipo is not so expensive at all. About $150 for a s350, and 300 watts of charger, or chargers. My setup uses a 350 watt meanwell and two 150 watt chargers, and charges a 12s 10 ah pack in about an hour.

BTW, were your aware that a 48v 15 ah ping charges faster than a 36v 15 ah ping? 12v x 5 amps = 60 watts faster charging.

I knew that, but the 36v is what I have... It seems to be turning out O.K.

At present I don't get as much time for long rides as I'd like, but I did a hilly 45 miles on Tuesday and the battery seemed to still have plenty left in it (and so did I). Sixty or 70 on an easy road does seem possible, especially as I get fitter. Let's just say I'm carrying enough extra weight to take me twice as far again if it was lithium!

So maybe by the time I'm ready for that week-long tour I'll be able to stretch out a century on a couple of hours day-time charging at 5 amps. Touring, for me, is all about taking your time and enjoying where you are. My old rule of thumb was: go as fast and as far as like, but don't plan on having to do more than ten miles in any one hour.