Comparison Li-ion vs Lipo4

[Old Timer]

On my aurora I have the original battery( 10Amp li-ion) at the rear and my Chinese 15amp lipo4 in one of my front panniers. Anyway, today whilst out and about I was running on my lipo4 and reached down to switch over to the li-ion to give them both a run ready for a recharge. I thought I noticed a slight better power with the original battery

So! on a flat section of road near where I live with no wind to speak of today I did a both ways run on high power and just throttle.
Results= The li-ion original was 1mph faster over the measured distance although a slightly extended run saw the lipo4 catch up to the same max. I put that down to the fact that the lipo4 being at the front and being connected to the controller box via a 1mtr extended kettle type ext lead with the extra connections for my in line fuses + 4 actual kettle plugs (one on the small patch lead from the controller, one from the battery and one each end of the 1 mtr extension lead running down the bike and of course the lipo4 lands up at a lower voltage after charging.

Any Thoughts?

Dave

 

[Orraman]

Do these batteries not have different nominal cell voltages?

On my bike the 26V Panasonic battery illuminates all 3 handlebar lights but the Cyclone 8 cylindrical LiFeo4 illuminates 3 for a few seconds before dropping to 1.
Subjectively it provides similar power and duration to the Panasonic with power dropping off shortly before the 1 light starts to flash.

I would guess that this could be due to the Panasonic controller controlling the power output rather than current.

Dave

 

[Old Timer]

Do these batteries not have different nominal cell voltages?

On my bike the 26V Panasonic battery illuminates all 3 handlebar lights but the Cyclone 8 cylindrical LiFeo4 illuminates 3 for a few seconds before dropping to 1.
Subjectively it provides similar power and duration to the Panasonic with power dropping off shortly before the 1 light starts to flash.

I would guess that this could be due to the Panasonic controller controlling the power output rather than current.

Dave

Yes Dave, they do have different volts but they were both still well charged.
I did a similar test today and there isn`t an awful lot in it, when actually switching whilst on the move there isn`t any discernible lurch or fall back so I put the small difference down to the multi connections and longer run of the cables to the lipo4. From working out the difference in voltage and using the lipo4 battery on a bike made for li-ion there will be the situation where the lipo4 will not get down as low as it could before the controller cuts it out but to be honest at the price paid for the lipo4 (£180) which included a decent bms and a fan cooled charger I`m quite happy and will probably land up with something like the equivalent of a 13Amp battery and who knows not running the lipo4 down very low each time might give me more months of use. I use the original battery and the lipo4 on the Aurora which gives me an estimated 60 miles on medium power and probably near to 40 miles on high power.

Out of interest, I ride the bike every day when the roads are not covered in ice or snow and am very pleased with it`s performance so far and with the recently fitted Marathon Plus Tour tyres and the large frame and weight of the bike with the extra battery and full set of tools it just plods right through the mud and crud in the local lanes at this time of year. It has become my winter bike of choice now and I`ve even reverted back to the original supplied saddle

Dave

 

[jbond]

In the cheap LiPo thread, these LiFePo 12s3p batteries seem to have a 41v fully charge and a 36v cut off. The Aurora's LiOn battery has a 42v full charge and a 31v controller cut off. I think but am not sure that the LiOn BMS has an LVC below 31v so the controller LVC takes precedence. I seem to lose power without the controller resetting itself and doing it's startup sequence so I don't think the battery cut out.

That looks to me like with nearly complete discharge the LiFePo battery's BMS will cut off before the controller's cut off, so you should get the full capacity available. There's not much difference in the fully charged voltage so performance should be similar. There's a narrower voltage range so there'll be a period at partial discharge where the LiFePo voltage is higher than the Li-On so performance should be better. This will all be modified by the voltage sag under load and internal resistance. This is almost certainly different but I don't know how.

The 4 LED battery state display is probably linear between 41v and 31v. When my LiOn cuts out I've got one LED lit. So I'd expect the LiFePo battery to cut out while say 2 LEDs are still lit and the controller to turn off. If the battery recovers enough to turn back on, I'd expect the controller and LEDs to go through their startup sequence.

What's also still unknown is exactly how 15AHr is measured. Is it a theoretical cell capacity, or is it the capacity between fully charged and BMS cut off, assuming that the BMS protects the cells by preventing the last 20% (say) from being used.

One last thing. Does anyone know what cell chemistry the Phylion cased batteries use, as supplied by Alien and many others?