Anyone actually got 500+ Cycles out of a Lipo ebike pack?

[el_walto]

Has anyone on this forum actually got 500+ cycles out of an ebike lipo pack?

 

[dogman dan]

For many, that would be at least two years use. I think a few that run very conservative discharges and charge to 4.1v have at least come close to that, several years use. But climate could mean it's not 500 cycles.

All my lipo is in the fun budget, so I get plenty of fun for the dollar out of em in just a few months. I'll pay a lot more for big fun than for a ride to work.

 

[Ykick]

I'm getting close and maybe passed it. 'have a very regular commute with at least 8 charge cycles per week since April 2009 on 15S 20C Turnigy. I sometimes goto 12S 15C Zippy"s for a week every once in a while but the 15S perform the bulk of my commuting miles and that doesn't count many, many joy rides and chharge cycles around NYC during my days off.

15S2P capacity is still around 8Ah although there seems to be a little more sag than when new. I follow the 4.1-4.15V/cell and regular DOD of 50-60% regime but every once in a while do attach alarms and drain 'em close to empty to see how they're doing.

I really dunno what to expect when they die? I assume they'll just sag really bad and maybe puff?

 

[el_walto]

I really dunno what to expect when they die? I assume they'll just sag really bad and maybe puff?

I've also wondered about this. If one used a lipo pack with BMS for 3000 cycles, would it gradually reduce its capacity to %5 and still be "safe", or after enough cycles would it eventually blow itself up?

 

[Spacey]

I'm at just over 260 cycles of Lipo at the moment.

 

[grindz145]

I really dunno what to expect when they die? I assume they'll just sag really bad and maybe puff?

I've also wondered about this. If one used a lipo pack with BMS for 3000 cycles, would it gradually reduce its capacity to %5 and still be "safe", or after enough cycles would it eventually blow itself up?

As the impendance goes up, the chance of balooning under load is going to go up. Capacity is probably going to be less than 80 after around 350-400 cycles.

That being said, since the impedance is so low to begin with... they might not baloon up and fail for over 1000 or more if you're only charging up for 4.1 volts anyway (which is maybe 85-90% soc) which I highly recommend if you can afford the capacity.

 

[liveforphysics]

Capacity is probably going to be less than 80 after around 350-400 cycles.

That's a really hard statement to make these days, some LiPo technology is in the 10's of thousands of cycles at 95% DOD to 80% capacity. Some LiPo is as poor as 50cycles of only 80% DOD to 80% capacity, and it's just awful performance for that 50 cycles.

This is truly something you can't generalize, the difference between some ebay RC packs and stuff a Tier1 EV provider is using is just a massive massive difference in lifespan.

 

[SamTexas]

So where do Hobby King RC LiPos fall in that range?

This is truly something you can't generalize, the difference between some ebay RC packs and stuff a Tier1 EV provider is using is just a massive massive difference in lifespan.

 

[Ykick]

Hey Luke, is it safe to assume old Lipo will sag more and more as it's nearing the end? I've lost a bit of capacity and I'll be watching more closely as winter cold rolls in but if all my RC Lipo died tomorrow (it doesn't look like they will) I'd still be thrilled with the amount of work/use from 'em. Way, way, more cost effective than SLA and so much less sag than NiMh...

Thanks Luke, for inspiring and showing us the way!

 

[Arlo1]

I got 440 cycles on my turnigy 6s5000mah20 packs before I pounded mine into the ground <1v on high load on 2 or more cells, and now I got two cells that are overcharged very fast and go dead very fast, but I must say.
MY LIPO LASTED GREAT UNTILL I frocked UP! AND MY LIPO WOULD STILL BE >80 CAPACITY IF I DID NOT frock UP! Non the less i got some of methods miracle lvc hvc boards on their way!

 

[liveforphysics]

So where do Hobby King RC LiPos fall in that range?

This is truly something you can't generalize, the difference between some ebay RC packs and stuff a Tier1 EV provider is using is just a massive massive difference in lifespan.

Far from a Tier1 EV provider. I would say, about as far from a Tier1 provider as they are from the Ebay garbage LiPo.

 

[John in CR]

I got 440 cycles on my turnigy 6s5000mah20 packs before I pounded mine into the ground <1v on high load on 2 or more cells, and now I got two cells that are overcharged very fast and go dead very fast, but I must say.
MY LIPO LASTED GREAT UNTILL I frocked UP! AND MY LIPO WOULD STILL BE >80 CAPACITY IF I DID NOT frock UP! Non the less i got some of methods miracle lvc hvc boards on their way!

It sounds like you really beat them with a belt or a chain and sprocket instead of "frocked them up".

 

[grindz145]

Capacity is probably going to be less than 80 after around 350-400 cycles.

That's a really hard statement to make these days, some LiPo technology is in the 10's of thousands of cycles at 95% DOD to 80% capacity. Some LiPo is as poor as 50cycles of only 80% DOD to 80% capacity, and it's just awful performance for that 50 cycles.

This is truly something you can't generalize, the difference between some ebay RC packs and stuff a Tier1 EV provider is using is just a massive massive difference in lifespan.

I have seen little data on this and I don't even work in the battery field anymore, so I'm sure Lukes got a better idea. My cycle-life knowledge is based mostly on "laptop" batteries for the military.

What type of cycle life would you expect on a nanotech and or lower grade lipo, cycled at low C rates (2C or lower)?

 

[Arlo1]

I got 440 cycles on my turnigy 6s5000mah20 packs before I pounded mine into the ground <1v on high load on 2 or more cells, and now I got two cells that are overcharged very fast and go dead very fast, but I must say.
MY LIPO LASTED GREAT UNTILL I frocked UP! AND MY LIPO WOULD STILL BE >80 CAPACITY IF I DID NOT frock UP! Non the less i got some of methods miracle lvc hvc boards on their way!

It sounds like you really beat them with a belt or a chain and sprocket instead of "frocked them up".

Dude this was my first ebike. I dont even own a lipo charger. Just 2 350w meanwell clones and some HK 3in1 battery medics. And other then your bikes this was the only hub motor bike luke was even happy with! Im ok with wrecking the first set of lipo as long as I learnt from it!

 

[neptronix]

500+ cycles out of a RC lipo pack is easy if you baby the pack.

+ Don't keep the battery stored at over 60% charge for a long period of time. Storing these at 90%-100% is particularly detrimental; they do not cope with that well at all and could vent gas if charged to full and let sit for weeks. These batteries like hanging around mid-charge ( 3.8-3.85v/cell ) when they're not being used.
+ Don't ever let the cells go below 3.0v. Easiest way to prevent this from happening is to stop discharging at 3.5v/cell, where there is only ~5% of the storage left anyway.
+ Charge lower than 4.2v/cell; 4.15-4.10v is good, and won't sacrifice most of the charge, as there is little energy above 4.10v.
+ Charge at the low-spec C rate.. IE, if your batteries say they'll charge at 1C, or 2C MAX, charge at 1C.
+ Discharge at 1/3rd-1/4th the rated C. C rates on batteries are often exaggerated, and if you actually discharged at those rates, you will get massive voltage sag and your batteries will get quite hot. Even at half the C rate, a lot of batteries will turn some of the stored energy into waste heat. What you want ultimately, is a battery pack that never rises above ambient temperature, and doesn't sag more than say, 3 volts for a 36v pack - 6 volts for a 72v pack.
The good news here is that even 10ah of cheap 20C lipo at 5C will produce 50 amps constant without breaking a sweat.

Follow these tips and you get optimal life out of your RC lipo pack.. a thousand cycles or more is possible.

 

[GCinDC]

Has anyone on this forum actually got 500+ cycles out of an ebike lipo pack?

i'm on 569 cycles with current pack (made up of 5s Turnigy 20c) which, by god, is almost exactly a year old! i've been balance charging to 4.16 1x/wk and bulk charging to 4.08, and probably 5 times have let the cells dip below 3V under load.

balance is pretty good, but i'm starting to notice a bit more sag (could be weather too tho), about 5-6V of sag under 50A load.

when i charge to 4.08/cell, i've got 7.5Ah max of the '10Ah'. charging to 4.2, i've got a little more than 8Ah before cells start to go over the cliff, 69V for my 20s.

if i baby it more, i should have several months left. i'll probably pay for higher C rate next time tho and will expect them to last longer if treated nicely.

my last pack lasted only about 600 cycles IIRC, but i was a bit careless with it, driving it down further more often, and i abandoned the pack because of a couple cells, tho the rest probably could have gone longer.

 

[neptronix]

At that point, you should invest in some A123 if you're killing a battery within 2 years. multiple thousands of cycles.. that will pay off

6-7v sag on a 72v pack is not too bad.. 15ah of the 20C stuff would perform better and live longer tho.. IF you can fit it on the bike... may want to consider that.

 

[999zip999]

I recommend a kite trailer for an extra pack as long as at speed what's the problem.