LiPo VS. LiIon - THE BIG DISCUSSION

DasDouble

100 kW
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Hello world! Im planing to build myself for 667,35 Euro a 3.5kWh batterypack with 15 LiPo-Packs from hobbyking: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=66309

In the beginning of my Vector-Built which I am on at the moment, I was thinking about buying a ready to use, plug and play Panasonic 18650PF Li-Ion 2.5kWh batterypack from Vector for 1300 USD, which is ~1141 Euro.

Some informations: I will use it together with my 14kW Motor and my Max-E Controller, a Charger from Allex, and have planned to drive about 60km/h in average.

So far, so short... Now I have some questions:

What do you guys think about my idea of using liPo instead of LiIon, while saving about 473 Euro?

Will the LiPo charge same fast, will it get hotter then LiIon? Some oppinions?


-Cheers, Elias

##EDIT:

-I use Adaptto BMS, 30A Coil, and have planed to go with this on an everyday ride, which is each way 22 kilometers, + some fun-kilometers in forest.
 
The problem with radio control airplane batteries isn't their chemistry, which is pretty standard, or their performance, which is very good. It's poor quality control and the potential for fires resulting from thermal instability. Yes, they are cheaper-- but the flip side to that is not only the chance of accidental fire, but a much larger chance that you'll get packs containing defective cells. You'll have to buy extra packs to replace the defective ones as they appear.

I thought Germany was too tightly regulated to allow the kind of bike you're talking about. Can you get it registered as a motorcycle?
 
As Chalo mentioned you will have to monitor the pack for lousy cells. Is this a daily driver bike? Or just for fun?

How much is your time worth? I know for me I don't use lipo often anymore because once i factor in the extra maintenence time, I'm not saving any money.

A lot of guys will push lipo hard here. And they are nice and cheap. But most of those guys are retired. I can spend time monitoring a pack, or riding and with my wife and family. Yes its only 5-10 minutes here and there, but often thats enough to ruin a ride. Only so much time after work.
 
If your running the Adaptto BMS checking and ensuring correct voltages won't be much of an issue, however I've looked at this option and with a little SketchUp of the internal area of my vector frames you can only fit 12 of those packs, taking into account the cable mess involved with H/K connectors and XT/JST etc... Unless you've the fatboy sidepanels in which case ignore :).

With a pack that size it's ideal for long life no matter what chem you choose, yes 18650 will last a little longer, however having 40+Ah means all your riding is going to be fairly sedate to the battery compared to guys running 10-20Ah packs. H/K are hit and miss as others have said, however if a pack goes down its only 35Eur and a quick disconnect, whilst 18650 failure means a learning a new skill set, a battery spot welder and a lot of time and patience.

Also, think about the weather conditions you'll be riding in, atm 0-10 deg C is frequent here in the UK (5 in the morn) so I end up losing around 40% capacity and battery sag is bad even with decent A123 20ah cells. Because of ease, german weather, vdroop and price if it were me I'd go LiPo.

*Edit, as for temps the low C rating used due to the high Ah capacity should mean you don't need to worry too much about heat. CHarging in 0.5C would be ideal and only take around 2.5 hrs from flat with Adaptto charging your using with the Eaton.
 
Have edited something on my main-comment
 
The lipo should outperform the li-ion in every way except one. It is more prone to thermal runaway, so you will definitely have to take precautions with the lipo. Because it's pouches, you have to take care the cells don't get dinged or chafed or dropped. Because it's touchy, you have to take care about over discharging or over charging. Because it's cheaply made, you have to take care to sort out any defective cells. FWIW, the last defect cell I bought was in 2009. But you still have to watch em.

But much of that also goes for Li-Ion. It's not safe to over discharge them, drop them, let a chafe short the wires. etc. And you'd be sorry if you got a defect cell and built it into a pack permanently.

But I still feel safer with li-Ion. I won't go to sleep with lipo on a charger, not even a short nap. But it's cheap, I just bought 48v 20 ah of new 20c turnigy.
 
dogman dan said:
But I still feel safer with li-Ion. I won't go to sleep with lipo on a charger, not even a short nap. But it's cheap, I just bought 48v 20 ah of new 20c turnigy.

Two things:

1.) Everyone is talking about "turnigy". Is this a "turnigy"-Li-Po? http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=66309

2.) What happens if I put them all in a big steal-box with ventilationsystem, which gets cut off, if they get on fire? I would use some special Fire protection material which is also used on the construction for fire-protecting. Would you sleep with such a stealbox and charge it at the same time? Or isn´t that useful?

Chalo said:
I thought Germany was too tightly regulated to allow the kind of bike you're talking about. Can you get it registered as a motorcycle?

Well, I think it´s for me as a private person just too complicated to get it registered. So I would say I will have to pedal "under the radar";) I have no idea if it has to be LiIon or LiPo..

Grizzl-E said:
How much is your time worth? I know for me I don't use lipo often anymore because once i factor in the extra maintenence time, I'm not saving any money.

.... Yes its only 5-10 minutes here and there, but often thats enough to ruin a ride. Only so much time after work.

Im still a student, so I think I would have enough time to repair a single li-po pack. I think you just have to dissconnect and connect the new one.. right? :)

ccmdr said:
H/K are hit and miss as others have said, however if a pack goes down its only 35Eur and a quick disconnect, whilst 18650 failure means a learning a new skill set, a battery spot welder and a lot of time and patience.

How will it looks like when a pack "goes down"? Will it inflate and changes it´s volume? If so, what happens with all the other battery-pack when they are already squashed together to fit in the Vector frame? I want to install 15 of them inside the frame to get 3.552kWh..... :roll:


ccmdr said:
Also, think about the weather conditions you'll be riding in, atm 0-10 deg C is frequent here in the UK (5 in the morn) so I end up losing around 40% capacity and battery sag is bad even with decent A123 20ah cells. Because of ease, german weather, vdroop and price if it were me I'd go LiPo.

Yes that´s a thing I will have to think about. I have already thought about installing an electric blanket inside the frame, which goes on and off via adaptto when the inner temperature is too cold / hot. Also I´ve already thought about installing some damm-materials inside to save the warm air inside better.. :roll:
 
Both are Lithium Ion...

One is in a rectangular pouch, one is rolled up and stuffed in a can.

The question is whether you require RC model level C-rates for your vehicle to deliver the performance you need. If you don't, then no reason to deal with RC toy level mfg QC related drama to save a few bucks IMHO.
 
Even if you dont need those C rates ( and infact he does!), its hard to ignor the us$200 per kWhr, that the Multistar packs offer.
Test cycle the crap out of them before pack assembly, get refund/replacements for any substandard packs, treat them with respect, ..and have fun.
 
Because I am associated with the RC industry flying large RC aircraft and drones handling high power Lipos are not a problem for me. I would use a Li-ion pack on the my E-bike except the Li-ion pack would be a bit large and have to be mounted high on a back rack. It take some time to understand the use of Lipo. Having higher end Lipo chargers, I'm able to charge 8 of my 5000 Mah lipo packs (20AH) in less than 90 minutes. I would go to Li-ion if all you are going to use it only for the E-bike.
 
I have thought about this a long time now and have decided to buy 5 of these LiPos Packs to test them for 222 Euro and have planed to add more and more by adding them in parallel by time. What do you guys think about that? so first I will have 1.1 kWh. Later on more and more.
 
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