Lipo vs LiFePO4

[dougnutz]

I am still new to the entire battery tech (read n00b) so I’m looking for a little guidance on a battery pack. My main question is why are Lipos so popular? Is it just peak output?
Here is what I am considering. 4 6s20c Lipo packs from HK for a pack producing about 44v and 10 ah, or a 10ah 48v Ping.

The Lipo’s would weigh about 8lbs and the Ping would weight about 10 lbs. The Lipo’s would be about 94 sq in the Ping would be 191 sq in.
Ok so far 80% the weight and roughly half the volume. The volume savings is more appealing than the weight savings for my application at least.

Now price the Lipo’s are (44.2*4)+charger(159)+power supply(39)= about $375, Plus it seems that there should be low voltage alarms for(3.50*4) =$14 for a total of $389. The Ping costs $348 (including charger)

Now if I want to upgrade I can just add cells to the Lipos which is nice. For sake of argument let’s say I want 20ah. Lipos (44.2*8)+charger(159)+power supply (39) and alarms(3.5*8)=$579. This is still using one charger, which for 8 battery packs is starting to be a nuisance but doable. There may be a better option for charging. Anyway the Ping now costs $598. The Lipos are now slightly cheaper (unless I buy additional chargers in which case the Ping is cheaper again).

But now comes the confusing part to me. Many people seem to recommend that you don’t charge Lipos all the way and that you don’t discharge them all the way either. So in my rough approximation it seems like you should use about 75% of the available output. Making it a 15ah battery (effectively) This doesn’t seem to be mentioned for the Pings.

Then there is the safety issue. The Lipos require careful charging and preferably a fireproof charging station. Plus if you discharge them too far things can get really exciting.

So if I understand it the cost is comparable, the weight and size favor the Lipos but at the cost of much more trouble to charge and the fire hazard that seems to necessitate caution. Now one thing I did admittedly leave out is the current. The Lipos have easily 20c+ discharge but for me 20amps is all my controller will handle anyway.
I can see the appeal in a race type application where the extra current would be really handy and the rest of the system is probably up to the challenge but for an average or even above average commuter build the Lipos just don’t seem worth the trouble.

Again I am admittedly a n00b here so please school me if I am missing something.

 

[neptronix]

The LiPo packs can discharge a hell of a lot more power. A ping puts out 1c or 2c, a singe lipo pack can put out from 10c-100c!! LiPo batteries will dump out amps like mad; so if you want to upgrade to more power later, it is not a problem.

Many people have problems with the pings because they draw too many amps. Also, the BMS is lackluster. If you look around you'll see a lot of threads about ping BMS's acting naughty.

Another thing about lithium batteries is that their internal resistance grows over time. Eventually your ~2c you can pull will fall to 1.75c.. 1.5c... etc. There just isn't enough headroom in a ping. It is really cutting it close.

The equivalent LiPo pack is also much lighter. It also costs a hell of a lot less to ship.

Yeah, charging and safety are a downside. The question is, can you live with it?

 

[Samba]

There is a difference in longevity as well. The LiPo's you're looking at are modern while Pings are older LFP thats maybe 500 charges on lipo vs 1200? on the ping? Older LiPo's got 300, many LFP claim 2000.

You can get LFP in RC packs too - more expensive than the LiPo but with 30C rates and the safety and lifespan benefits - I've only seen smallish packs though like 2-4s.

You mentioned square inches in your volume calcs, should be cubic inches so I looked at a spreadsheet I keep.
Pings are roughly 104 Watthours per KG and 160WH/Liter.
For LiPo's 150WH/KG and 300WH/liter is pretty typical.

 

[dougnutz]

The LiPo packs can discharge a hell of a lot more power.

Current output from the battery isn't really a question. No doubt the Lipos far exceed other types such as LifePo4. But in my application with a 20a controller a 48v battery at 20 amps is 960w vs a 44.4 v Lipo at 20 amps =888w. So in this case the Lipos don't offer any more power, actually less. This would obviously change with an upgraded controller, upgraded motor wiring, etc...


As far as bms issues I'm sure you right but It seems like BMS issues trump charging issues (and explosions)

You mentioned square inches in your volume calcs, should be cubic inches so I looked at a spreadsheet I keep.

true. I typo'd that but the calculations were right

 

[Samba]

Rated Discharging Amperage: 10 Amps
Max Continuous Discharging Amperage: 20 Amps
Maximum Discharging Current: 40 Amps

ping 10AH

1C, 2C, 4C? I always regarded them as 1.5C. There must be a thread here somewhere where you can find out how they do at 2C.

I found out why the hobbyking densities varied so much - because I had their LFP's and LiPo's mingled together. I updated the volumes in the prior post.

 

[neptronix]

Current output from the battery isn't really a question.

Actually, it is. Look at the maximum wattage rating on the 48v ping batteries; the 20ah pack is what you need since the 15ah pack will run only 'up to 800w'. The 20ah pack is 22lbs and comes out to $743 with shipping.

A small pack would be fine for a very low power 250w kit. Other than that, forget about pings unless you are okay with buying a very high capacity one.

You can output more power than that with 3-4lbs. worth of LiPo.

 

[AussieJester]

There is a difference in longevity as well. The LiPo's you're looking at are modern while Pings are older LFP thats maybe 500 charges on lipo vs 1200? on the ping? Older LiPo's got 300, many LFP claim 2000.

I believe this to be incorrect...This figure for cycles on the lipo is based on use in rc application with one lipo being discharged from full to empty in ~6 minutes (thats how long mine lasted in my rc heli doing intermediate 3d flying) Now when you bunch a heap of them together as we do in e-bike application your not taxing these packs anywhere near their rated specs, IMHO and that of many more experienced people here that will see the number of cycles of the lipo greatly improve. This is using quality lipos not the cheap crap often flogged off on fleaby.

KiM

 

[999zip999]

Hay, Love my ping. Love PING O.K. .I had put my Ping on a 40amp controller before E.S. told me to turn it drown to 22a.(Dogman) (LI) So what I would have not learn from this is priceless information from Dogman. I hate going 25mph now.But my ping is not in test zone, For Now Les then 34mph on my little ping of 2 years 20ah is getting peaceful. My test days are over larbor intence and I can't ride if at 40amps for very long. or .... months. It worked. And is.

 

[999zip999]

Sorry, Will read the post first I have abusding my Ping and he still loves me for ALL parts and support, But as said I would have brouth headways. But NO love there. Knot like PING...EVER!!!!!!!!!!!!!!!!!!!! Good news. Boat time. No 7-11.

 

[jondoh]

Pings are a good value. No doubt about that but Lipos are well worth the premium if only because they have much higher C ratings (that is, current discharge ratings).

Theoretically, LiFePO4 should last longer than lipos-- however in practice, both will probably give about 2 years of service.

LiFePO4 life gets shortened often because they're pushed past their C rating. This is less of a problem with higher C rated cells (headway, psi, lifebatt, thunder sky, calb, high power, etc).

Lipo life gets shortened often due to over discharging. This can happen due to faulty charging, wiring problems or problems with monitoring circuitry. You know they are in trouble when they puff up.

Lipos have the possibility of catching on fire if mistreated. You'll find threads regarding the care and feeding of Lipos. Don't over charge or over discharge and you'll be fine. LiFePO4 are more forgiving in this respect-- especially the higher C rated ones.

If you are a true total noob with absolutely no experience with batteries at all, you should probably go ping. There's a lot of wiring in a lipo battery. The balance leads need to wired a certain way to get all the cells to charge at once. With a Ping battery, Ping takes care of you. With a Lipo, you're pretty much on your own since you do your own wiring.

 

[neptronix]

^--- what he said.

LiPo is the best battery for the buck ( and size/weight )for eBikes right now. It is a pain in the butt to manage, however.

If you are dead set on a ping, buy one that is appropriate for the *peak amps* you'll be putting out. Then the amp draw will be spread out across more cells, preventing the shortening of the battery's life.

 

[dogman dan]

I own two pings and two sets of 72v 10 ah lipo. Love em both. Wouldn't dream of doing the commuting at 20 amps job with lipo. ( charging is complicated, or risky) Wouldn't dream of trying to ride 40 mph with the pings. (would be either too heavy or would kill em if smaller) Both are great solutions to the problems they slolve but neither is the ideal solution a really good A123 lifepo4 combined with a really good bms and charger would be.

Unfortunately the battery bits and peices haven't quite come together in ideal form for ebikes at affordable and easily bought form. But it won't be all that long till it does. Soon as it's there I bet Ping will start selling it among others. As I see it, one of the big holdups now for lipo is just that the chargers are all aimed at lower voltages. Once we have a 20s balancing charger the appeal of lipo will be huge for those looking for 72v power. A 14s charger that plugs into the wall, and 10ah 14s pack would be ideal for commuters.

At this point, my advice remains a 48v 15 ah ping and a 20 amp controller for a ridden on the street sort of bike, such as a commuter. Despite the fact that a problem with a bms can be catastrophic, mostly the pings have held up when used at 30 amps or less. It's not ideal, but 20 ah is big and heavy, and 48v will get you up a fairly steep hill. Later on, then build your faster bike with lipo or better lifepo4.

As for lifespan, in a few months my first ping will be 3 years old, with an estimated 600 cycles. Still works fine, but gets unbalanced if discharged till the bms trips.

All chemistries should be discharged no more than 80% So there is no advantage to any chemistry in that respect. But discharged 100%, lifepo4 has potential to last longer than lipo.

 

[Doctorbass]

Here is one convincing advnatage of LiFePO4:

You could leave your LiFePO4 ebike battery pack alone in the garage or the house for charging Everyday Without any doubt!! :wink:

I'm sure doing the same with LiPO is a bit more complex and risky in your mind!!! :wink:

Never ever wonder WHY lipo are not so present in the commercial ebike application??



Oh... BTW.. Ping battery are excellent.. I only had problem with their charger and BMS.. but the cells do the job! I use them burst at 3.5C no prob

Doc

 

[steveo]

Here is one convincing advnatage of LiFePO4:

You could leave your LiFePO4 ebike battery pack alone in the garage or the house for charging Everyday Without any doubt!! :wink:

I'm sure doing the same with LiPO is a bit more complex and risky in your mind!!! :wink:

Never ever wonder WHY lipo are not so present in the commercial ebike application??



Oh... BTW.. Ping battery are excellent.. I only had problem with their charger and BMS.. but the cells do the job! I use them burst at 3.5C no prob

Doc

I have a nice video of a123 cells exploding into flames when shorted... i personally don't think any chemistry is really safe...

i'll say a123 is safer the most chemistries....

3.3v 11p row shorted with jumper cables...

(don't worry no good a123's where damaged in the video)

i'll try to post it when i get the chance..

-steveo

 

[Doctorbass]

Here is one convincing advnatage of LiFePO4:

You could leave your LiFePO4 ebike battery pack alone in the garage or the house for charging Everyday Without any doubt!! :wink:

I'm sure doing the same with LiPO is a bit more complex and risky in your mind!!! :wink:

Never ever wonder WHY lipo are not so present in the commercial ebike application??



Oh... BTW.. Ping battery are excellent.. I only had problem with their charger and BMS.. but the cells do the job! I use them burst at 3.5C no prob

Doc

I have a nice video of a123 cells exploding into flames when shorted... i personally don't think any chemistry is really safe...

i'll say a123 is safer the most chemistries....

3.3v 11p row shorted with jumper cables...

(don't worry no good a123's where damaged in the video)

i'll try to post it when i get the chance..

-steveo

Steveo.. it'S normal that short to cells can make fire :wink: .. I was talking about NORMAL USE.. like ebike use charge-discharge.. not shorting cells.

Post that video.. 11P a123 is like above 1500A availlable for the short!.. no doubt that fire is close to that!

Doc

 

[dogman dan]

Yep, that's why the pings get used on the daily grind to ride to work. As long as I don't place the charger on something flamable I'm good to go. No worries. I've had lots of chargers for the pings go tits up, often my bad though putting a connector on a charger backwards or something even stupider.

Shorts worry me, that's for sure. But that worry is the same whether sla or whatever.

I don't worry much about charging my lipo, but I do make sure I'm there and awake, and my charge station is a tile fireplace hearth. I'm definitely not ready to trust bulk charging them, but I have no worries about using my lipo chargers inside in a fire resistant place. I have a couple puffies that I do cover with a metal lid when charging them.

I do wish ping sold an A123 pouch cell pack that did 10c or so.... with a bms that has the diodes built in etc. Good for 100 amps or so. But I expect that would be pricy.

 

[dougnutz]

I currently have a liMn pack that manages 20amps most of the commute. I haven't been able to find the C rating but the retailer claims the pack is rated for 25 amp discharge, (probably max, but I don't know). It's pretty small though (8ah) . According to my CA I use 6.5-7 ah most days. It is enough to get me to work and back but not much beyond that. Based on what I read, and suspected already, there really isn't a significant advantage using Lipos for commuting if you are limited to 20 amps. As I am. Even though the Lipos would be capable of much more, my controller isn't. Plus for the "daily grind" of charge and go,Pings seems to offer the advantage of simple, and safe charging. I wouldn't want to devote an hour or more every night to babysitting my batteries while they charge.

For me I think a 10 ah battery would probably be enough, considering I only use 7 ish anyway. But based on the output (2c max) of the Pings I would be better off with 15ah pack. So that I am not running it at it's max all the time.

One apealing thing about the Lipos is that it seems like you could carry a backup battery pretty easily. One 6s 5ah pack at 2 lbs would be enough to limp home. 2 would get me there fast. So as a backup or random use they seem really apealing.

 

[AussieJester]

I don't worry much about charging my lipo, but I do make sure I'm there and awake, and my charge station is a tile fireplace hearth. I'm definitely not ready to trust bulk charging them, but I have no worries about using my lipo chargers inside in a fire resistant place. I have a couple puffies that I do cover with a metal lid when charging them.

If when you finally go with bulk charging you will see that lipo is as hassle free as any other chemistry. You keep telling people its tricky or complex that's totally incorrect Dogman, just because you decide to complicate things using multiple chargers and connections doesn't mean others want to follow your example. If you charge the entire pack with one charger it is no different from charging your ping pack, its beyond me why you fart around rewiring your pack to charge with multiple chargers in the first place, you make it much more difficult than it needs to be.

KiM

 

[neptronix]

i understand his caution; didn't you have an episode with puffing some packs yourself doing the whole bulk charge thing?

 

[jondoh]

Lipos are funny in that they come in a range of quality. Sometimes you get a batch and they're well balanced and matched and sometimes they're not.

While i can agree that bulk charging works for packs that are stable, balanced and matched, the issue with lipos is that if there's a problem, they can catch fire.

 

[AussieJester]

i understand his caution; didn't you have an episode with puffing some packs yourself doing the whole bulk charge thing?

Absolutely did had nothing to do with bulk charging had everything to do with me not having ANYTHING
at the time to check the individual packs... I built it charged it never checked a pack... If you monitor your packs and
balance them prior to building them & check them regularly bulk charge IMHO its the best way to go. Theres alot
here doing it i bought it up as i have seen Dogman in a few posts now saying lipos are fiddly and more complicated its simply not the case IMO
and it could put some people off using them. I meant no disrespect to dogman i have utmost respect for the man his
input in this forum is an acet.. Apologies if i offended anyone.

KiM

 

[liveforphysics]

Here is the difference.

Late last night, Methy and I took ebikes out together to tear around the city, and hit some trails afterwards.

His bike's controller was setup to draw 120amps, my bike was setup for 65amps, I was running a little 74v 10Ah pack, he was running a 88v 15Ah pack, and we both tore all over town and up and down trails and crap, and the packs stayed cool to the touch the whole ride, had barely any voltage drop under full load, and when we got back home, he plugged in with a 30amp charger, I plugged in with a 20amp charger, and it about 20mins, the bikes were topped off and ready to ride again for another hour (but Methy's bike's hubmotor melted again! )

That's the sort of experience that a Ping pack simply cant provide. Not looking for that sort of experience? Then go with whatever you feel most comfortable with.

 

[dogman dan]

Pehaps I should clarify a bit.

For one, Jesters posts where he lost a lot of lipo bulk charging did scare me. I didn't mean to warn against bulk charging lipo. I just mean to tell people that if you configure a commter bike battery right, using the lipo chargers is not so bad. A 12s ( 42v nominal) pack would only need two good chargers to charge pretty fast and easy. The hangup with a commuter is only that you may need to charge at work. So plugging in a lifepo4 charger gets a bit easier then. But you can also pack quite a bit of range onto a bike with those tiny lipo bricks too. So a 12s 25 ah battery would not be so huge.

For two, I'm nowhere near as smart as some of you guys who are bulk charging, so I'm just sorta waiting for a 20s lipo charger to come out. For me at this time, it is easier to charge 4 sets of paralelled packs with two lipo chargers. My setup is slow, but I can still charge one of my 20s 10 ah packs in about 2 hours. 20 min charging would be nice!

For three, My needs are not to use the lipo every day. With luck, I may race my bike a couple times a year. I'm working now on a 72v dirt bike for next summer, but that will not get used much more than twice a week. And I have two 72v 10 ah batteries, so If I build my bike for a quick battery change, I can have 5 min to be riding more.


I can't agree more, that if you want more than 20 amps of 48v you'd be stupid to use pingbatteries. Well maybe not stupid if you just want 20 amps of more volts and already own a ping.

But no doubt about it, for a perfomance bike where low weight and high power is the goal lipo is currently the only thing that makes sense. Now if you happen to already own a pile of headways or A123's, great! But I wouldn't go buying them now unless a bargain was found. The lipo is so easy and so powerfull even an electronic moron like me can handle it. A stupid simple 20s lipo and hubmotor setup easily blew away half the gas bikes at the last race in Tucson. Imagine a REAL fast bike there. The 40 mph club is super easy now with lipo. Even the 50 mph club is not too hard to join.

I totally agree that for a light weight low volume "gas can" pack nothing can beat lipo. A pair of 5s or 6s batteries in 5 ah fits in your hand, and if you ride slow could extend your range as much as 10 miles. You just can't beat that for an easy to carry emergency back up battery. Nor can you beat that for a superlight battery for a pedalers bike. Something like a tiny cute, or a friction drive on a 20 pound road bike, and you can have motor help on hills on a bike that still weighs only 30 pounds.

 

[The Mighty Volt]

LiPo
Better power to weight ratio than LiFePo4
Available in a wider range of qualities and Ah capacities thru the HK/Turnigy/Zippy range, wider range of discharge rates, voltages etc.
Pound for Pound is cheaper
Does not forgive errors in charging or discharging
Will not tolerate shorting
Relatively few cycles, 800-1000 or so.
Turnigy Nano-Tech is boss when it comes to high C rates.
Easier to arrange into packs thanks to the manner in which they are sold.

LiFePo4
Inferior power to weight ratio
Available in a narrower range of qualities- you either have basic or you have very good, with not much in between. By qualities I mean power. Ping makes a good battery with a low discharge rate. A123 make the only {accessible} LiFePo4 battery which can hang with LiPo in terms of pfp power.
Pound for Pound is more expensive
A123 cells will take a dead short across the terminals without you wishing Barack had got that health care bill passed.
Tolerates overcharging and overdischarging without the catastrophic consequences of LiPo
Harder to arrange into packs but A123 new cell is changing all that- if you have the $$$$

 

[AussieJester]

r (but Methy's bike's hubmotor melted again! ).

BWAHAHAHAHAHAHAHHAHA make him make it piss Luke you no Cali mofo

Just got home...my ESC didnt fail nor the HV160 or my lipos...if i haven't
broke me ankle i will be amazed...i went over on the cruiser for the 2nd time
the linear actuator failed :-( I also didnt make it past the second sentence of Dogmans dribble... but that post Luke..made me smile ...lipo forever...waffle waffle waffle Dogman ...ah man....ill come back to it tomorrow if i continue now YPedal Man will have to get involved...u have used lipo for 5 minutes dogman...get a fuckin clue dude and stop "advising" people about it stick you shit ass pings and the piss poor frock motors you wank over ever second post



KiM