Good Batteries?

Hi, I'm wondering what the latest reliable 48v battery might be. Longevity? I searched but I didn't find a thread on this most important subject--any clues?

Thanks,
A

Most batteries are OK now, but I'd avoid the cheap Chines ones wrapped in gaffa tape.LiFePO4 has a longer life, but is heavier. Batteries with the modern Panasonic, Samsung or Sony 18650 cells are probably the best for Ebikes now because they give high energy density and the cells are good quality.

Also, don't forget an important aspect of the battery which could become overlooked. Battery placement. May not be an issue if you have 10Ah worth, but the more battery you have, the importance of its placement will be a priority if you want to keep your bike's handling. Some battery makers & electric bike manufacturers are becoming wiser to this and actually designing the battery to be optimally placed so you do not lose the ability to ride like a bike. If your electric bike feels like a regular bike, then you've done something right. :wink:

Reliable used on what? Some of us have bikes that can quickly ruin a battery that would last 4 years on a low wattage bike.

Nimbuzz said:

Hi, I'm wondering what the latest reliable 48v battery might be. Longevity? I searched but I didn't find a thread on this most important subject--any clues?

Thanks,
A

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I think you should specify the wattage you want to use, this way we give an advice that is a bit more precise. To give you an example for a few hundred watts @48V I'd go for a ping lifepo4 or an em3ev NMC; for a few thousands watts maybe something R/C - a few LiPoly in parallel/series.

Nickel Iron has the longest life time of 50+ years and is the most reliable battery. Not long ago, a large bank had been in use for ~100 years someplace I don't recall. Then there's lithium titanate, good for 20+ years and 9000+ cycles. And then there's what I use, rc lipo (LCO). The smallest lightest, most powerful type you can buy. Good for 2 to 6 years under a very heavy load. And then there's the hyped lifepo4. Good for small amp loads. Heavier, bulkier, with a supposed 10 year life cycle, while most are dead withing less than half that time. Some within a year if over loaded. Take your pick. For the limited space on an ebike, nothing beats rc lipo for power to size/weight.

wesnewell said:

Nickel Iron has the longest life time of 50+ years and is the most reliable battery. Not long ago, a large bank had been in use for ~100 years someplace I don't recall. Then there's lithium titanate, good for 20+ years and 9000+ cycles. And then there's what I use, rc lipo (LCO). The smallest lightest, most powerful type you can buy. Good for 2 to 6 years under a very heavy load. And then there's the hyped lifepo4. Good for small amp loads. Heavier, bulkier, with a supposed 10 year life cycle, while most are dead withing less than half that time. Some within a year if over loaded. Take your pick. For the limited space on an ebike, nothing beats rc lipo for power to size/weight.

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If range, at the expense of speed and torque, was the most important factor for your ebike, would you still choose lipo?

99% of my riding now is done at ~12mph and I use lipo. The speed doesn't really matter. It's the amount of watt hours I can fit on the bike, and the fact I can suck as many amps as I need out of the pack. When you find an 88V 10ah pack that can do 200A for $0.31 per wh, why look for anything else.

It could be, that you can simply afford a bigger battery with RC lico. Or maybe the cheap thing for you is free laptop cells.

You can definitely carry a bit more ah of lico in the same space than lifepo4. But my experience has been that since the pouches are squares and the bikes are triangles it may not be that easy to carry more in the frame space of a particular bike. On my cargo bike, I can fit only 48v 15 ah of either one. No more. But in the panniers that are squares I can definitely fit more ah of lico in a pannier. And lico is lighter. So carrying a huge pack can be 5-8 pounds less weight.

I do like lico best for the short trips on the trail bike. It's a joy to go for a ride carrying only about 4 pounds of battery. A 5 ah pack can run a 25 amps controller with ease.

Bottom line, it's very very important to tailor your battery choice to your exact needs, and your exact motor system. A mismatch can either make the bike an un ridable crashmobile, or murder the battery in weeks.

If you don't need to go the cheapest possible route and want a good, reliable, power dense, energy dense and safe solution I would recommend Sony 18650 V3 or VTC4 cells, depending on he power and weight requirements you may have.

I advise against LiFePo4 because of the excessive weight and the need for a strong balancer and against the use of LiPos because of the dangers.If you've ever witnessed a LiPo fire, you'll share my opinion.

"Bottom line, it's very very important to tailor your battery choice to your exact needs, and your exact motor system. A mismatch can either make the bike an un ridable crashmobile, or murder the battery in weeks."

I do understand this dogman. However, there seems to be many opinions on what constitutes your bottom line. Like most things, it's a real task to filter through all the opinions and come up with my own opinion. Trial and error is not in my budget, so my first stab at this might be my only stab. I'm considering an 18650 laptop build, because of the initial cost, the fact that I can fit a lot of them in the space I have available, and some fairly successful builds seen on this forum.

There are so many factors that need to be considered, and prioritized in the proper place, or in the place that I want/need to prioritize them, such as my ability to acquire and put together the cells required, if I am to build my own battery.

Not only is everyone's bike/use different, their financial situations and skill levels are also very different, so this makes it a real challenge. However, I'm continuing to read the forum and learn as much as I need to know, in order to be able to make those decisions.

Thanks for these many and informative replies! Some (drebikes) asked for more detail of my uses. I have an 1100 watt motor but it goes through a 14 speed derauler so it is not a hub motor with that draw BUT I do ride usually in steep hills but keep the cadence high at around 90 so the motor is spinning well and only gets slightly warm even after a long climb.

Some years ago when I had hub motors I killed a number of expensive batteries so I'm checking in on the latest battery tech.

I seem to see that the more substantial batteries like All Cell (USA) and what Justin at bikes.ca has are still at about $800 for 48V and around 10ah. Friends in RC have been trying to get me to get some hobby King packs but the reviews say the quality of individual cells is inconsistent. These peeps in RC are recommending these;
http://www.hobbyking.com/hobbyking/store/__18210__Turnigy_nano_tech_8000mAh_6S_25_50C_Lipo_Pack.html

With this charger
http://www.hobbyking.com/hobbyking/store/__20613__Turnigy_MEGA_400Wx2_Battery_Charger_Discharger_800W_.html

If these could last say 100 cycles the 10 ah packs are only $250 for 48V and a charger that can do two packs and balance is another $130.

Any more ideas are welcome and links are helpful. This thread should be useful for anyone shopping for the latest packs.

Thanks again.

If you're considering a battery made from recycled laptop cells then remember to figure in the equipment you'll need to test the cells and then join them together.

I'm not looking for a project to build. I'm looking for ready made--though I do have a CBA & etc
Thanks

Nimbuzz said:

Thanks for these many and informative replies! Some (drebikes) asked for more detail of my uses. I have an 1100 watt motor but it goes through a 14 speed derauler so it is not a hub motor with that draw BUT I do ride usually in steep hills but keep the cadence high at around 90 so the motor is spinning well and only gets slightly warm even after a long climb.

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I'm at work and can't provide you links , but here's what I'm thinking:
*the motor is rated for 1100W
*I'll assume a conservative 80% efficiency if the motor is a brushless (typical low speed and/or steep hill)
*also assume 95% inverter/controller efficiency, again conservative
==> so to power this you'd need 1100/(0.8*0.95) == 1450W
*@48V you'd need a bit over 1450/48 == 30Amps continuous current

...as such, if let's say you're looking at 10Ah batteries you'd need it to discharge @ 3C sustained; you could have blips over 3C as at the moment you're starting from standstill the motor efficiency is actually lower.

I'll assume you can't limit DC current in the controller to any specific value, so the battery will take the hit whatever the motor/controller asks from it. Then you'd need a chemsitry that does 3C sustained and 4-5C peak. You can lower the necessary C-rating if you get a higher capacity battery (say 20Ah will half the required C-rating vs a 10Ah) or if you can limit the DC current in the inverter - Infineon controllers (and others I don't know if) allow this.

I have no pretention of being exhaustive and some manufacturers may apply the chemistries in different ways, but here are some very general guidelines:
*LifePo4 may be borderline for 3-5C; most LiFePo4 on sale don't like more than 2C in the sense that their internal losses can jump if over 2C for a long time. (as an aside, I use at work LiFePo4 with 200C rating so anything is possible, just unlikely on the market to get such outliers)
*NMC (ex. cell_man batteries based on samsung 18650) - more likely to accept continuous 3C than LiFePo4
*NiMh - don't really know
*LiPo - R/C pouches more than able to do the 3-5C; they would be ok from the performance standpoint, but as stated above one can have issues with dispersion of characteristics between cells and risk of fire
*LiCo - I'd say similar to LiPo, but other's opinions are welcome

I think you grilled battery packs because they were undersized, so to avoid this you can compute the necesary current and get the pack that can do that current. Be careful with the specs, some sellers tend to be very optimistic about their products and if pushed as far as advertized it can't go well for long. So choose the proper battery and if the seller has a reputation for quality batteries you should be fine.

Are Golden motor batteries good ones?
Top Quality LiFePO4 Battery Pack for Electric Bikes 36V12AH
http://www.goldenmotor.com/batterypack.htm


Or I can throw a coin and buy cheap one.
http://www.ebay.com/itm/NEW-DIY-36V-15AH-LiFePO4-Batteries-5A-Charger-BMS-E-Bike-Powerful-Rechargeable-/141095186967?pt=AU_Car_Parts_Accessories&hash=item20d9edb217&vxp=mtr
http://www.ebay.com/itm/36V-12AH-LiFePo4-battery-Lithium-Electric-Bicycle-Scooter-EBike-Rechargeable-/281224016313?pt=US_Rechargeable_Batteries&hash=item417a41f1b9

drebikes,

Now that you mention it I guess that's the main thing I'm asking here = " if the seller has a reputation for quality batteries you should be fine."

What sellers have a reputation for quality batteries? Everyone please chime in with good & bad purchases in the past 2 years & how the packs have been used and how they held up.

Thanks,
A

My em3ev battery pack works fine after two months, but I've done only 1.5 full cycles. So far so good and they have good reputation. Ping batteries also has good/great reputation on this forum. Any pack pased on A123 cells should be ok (except if fake A123 cells). I have noticed that there's close to impossible to find lower prices per Wh than what em3ev/cell_man and ping ask, so I haven't looked any further.

*Edit: typo

jerrypa said:

Or I can throw a coin and buy cheap one.
http://www.ebay.com/itm/NEW-DIY-36V-15AH-LiFePO4-Batteries-5A-Charger-BMS-E-Bike-Powerful-Rechargeable-/141095186967?pt=AU_Car_Parts_Accessories&hash=item20d9edb217&vxp=mtr
http://www.ebay.com/itm/36V-12AH-LiFePo4-battery-Lithium-Electric-Bicycle-Scooter-EBike-Rechargeable-/281224016313?pt=US_Rechargeable_Batteries&hash=item417a41f1b9

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hightly recommend sunthing

Just got my sunthing battery 36v15Ah today... Took the slow shipping 7-8 weeks option. initial voltage was 38.5V...4hrs charged up to 41.5V. Took it for a quick spin and now charging overnight.

I really don't get the different opinions.

How do you judge whether a battery is good?

Power-to-weight ratio?
Energy-to-weight ratio?
Cost per watthour?
Internal resistance?
Safety?
Ease of use? (BMS required or not)

I don't see, why in 2013 you would use LiFe'Po4 (much too heavy, difficult handling), LiPos (too dangerous, difficult handling), laptop batteries (too low power-to-weight ratio), or cheap Chinese Li-Ion packs (internal resistance, power-to-weight ratio, wrong claims on energy content...)

In my view, the way to go is very clear. I don't know a single e-bike manufacturer that uses LiFePo4 or LiPos in their bikes.

Melbourne said:

Just got my sunthing battery 36v15Ah today...

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Can you post a few pictures

schwibsi said:

How do you judge whether a battery is good?

I don't know a single e-bike manufacturer that uses LiFePo4 or LiPos in their bikes.

Click to expand...

Safety
Ease of use
charge cycles

Maybe Lifepo4 are too expensive to use and they are not so easy to use (in line).

Re quite a few posts back.

We have no clue what Natural Path needs. But we can in general say that if you use a cell with a .5c discharge rate, then it takes a lot of them paralleled to get to a capacity that can handle 20 amps at .5c. It may be that you will ride such long range that you will have a huge capacity pack anyway, or it may be that you will not use any more than 10 amps. Figure out what you need, and build a pack big enough to do it. One clue. Whatever the maximum discharge rate for a cell is supposed to be, build so that when you cruise at full speed, you only use half of that. No battery likes to be used at it's max rate, as others just said.

Nimbuzz has told us generally how much amps he might be pulling.

IMO, a 15 ah size pouch lifepo4 pack should be enough size to meet his needs. It will handle brief 30 amps spikes, and it sounds like he does not ride in the wrong gear causing him to pull full amps all the time. People say too heavy. But really it's not that much heavier in pouch cells than other types. It IS larger by a lot though. So the larger physical size can make it hard to fit where you want your battery carried.

In the various limn types available, there should be enough amps with a 12 ah size. But unless the very very best discharge rate cells are used, I would hesitate to recommend a 10 ah pack. But if a 10 ah pack can put out 20 amps at half it's c rate, then 10 ah should work fine. It depends on your actual controller amps setting.

In lico, even a 5 ah pack can power a bike to 1500w. The cheapest types are said to be 20 c. We know that is total bull hockey, but even if you cut the c rate of lico to 25%, the cheap 20c lico can still go 5c discharges without killing it. So the hobby king stuff is definitely always a contender when you want the highest c rate for the least size. I love carrying only 4 pounds of battery on my off road bike. The downside of HK lico batteries are many. It can catch fire easier than other kinds. But a dead short on any battery can burn a house down. Don't do that. The vendor is not the greatest, but in general, you do eventually get what you ordered. The cells are low quality, so if you need 8 packs, I highly recommend ordering 9. And you have to add your own bms, if you want a bms. The number one reason to use lico, is you need the c rate to power a huge motor. The second might be that you want the lightest possible battery, yet still need to have a moderate power battery without going to 10 ah size.

Who to buy from? It's just about the same list as you would buy the motor from, Grin, EM3ev, E-bikekit, Electric Rider, High Power Cycles, etc. Others that just sell batteries that you might look at are Pingbattery, and Sunthing, for lifepo4.

This vendor list is far from a complete list of vendors I'd recommend. But I will say this, Golden motor isn't on it. That does not mean you will not be happy with a battery from them. It just means they have not had many people come to here, and rave about how good it was. We had lots of complaints 4-5 years ago about GM batteries, but not lately. I only mention GM because somebody asked.

dogman said:

People say too heavy. But really it's not that much heavier in pouch cells than other types. It IS larger by a lot though. So the larger physical size can make it hard to fit where you want your battery carried.

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What's the Wh per kg and W/kg of the LiFePo4 cells?
The Sony V3 cell has 193 Wh/kg and can deliver 860W/kg
The Sony VTC4 cell has 180 Wh/kg and can deliver 2581W/kg

dogman said:

The number one reason to use lico, is you need the c rate to power a huge motor. The second might be that you want the lightest possible battery, yet still need to have a moderate power battery without going to 10 ah size.

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I disagree. You can do that without all the LiPo downsides (especially the fire hazard)
Look at realistic W/kg ratings and at the sacrifices for what little higher power density you can get

dogman said:

Who to buy from? It's just about the same list as you would buy the motor from, Grin, EM3ev, E-bikekit, Electric Rider, High Power Cycles, etc. Others that just sell batteries that you might look at are Pingbattery, and Sunthing, for lifepo4.

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Again, I disagree. If you can spotweld yourself, get high quality cells and make the pack yourself, I can't speak for other countries, but in Germany there are quite a few shops now that make excellent high quality packs.

dogman said:

That does not mean you will not be happy with a battery from them.

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That all depends of what you have to compare them to. If you've never driven a BMW or a Mercedes, you may be happy with a Lada, too. It doesn't make the Lada something I'd recommend.

jerrypa said:

Safety
Ease of use
charge cycles

Maybe Lifepo4 are too expensive to use and they are not so easy to use (in line).

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LiFePo4 are safe. But that's it.

They are absolutely not easy to use, as you said, in line (which is what we always need) they're the worst cells to deal with. Extreme drift, you have to divide up the pack and check individual cells all the time and you need a stron balancer.

Sony cells? you pack them together, set the LVC right on the controller and use a bulk charger. Nothing else to do.

The Sony cells lose 10% capacity after 500 full (!) cycles. How many years of life is that on an ebike? And even after those 10% are gone, the energy- and power-density are a lot higher than of LiFePo4.

Things have moved on with batteries. The latest 18650 and larger cells from Sony, Panasonic and Samsung have higher power density than your average licos. They also have good C rates, which now makes them a viable alternative to licos. You can now get ready-made bottle and rack batteries with 11.6 aH that can give 20 amps continuous and 40 amps peak. They're also pretty reliable unlike the old leaking 18650 cells of years ago. It gets better all the time.