LiFePO4 BATTERIES

[jmensa]

I bought 2 Ping batteries for my Travelscoot. A 20ah and a 10ah. I asked Ping about fast charging and he said that the maximum rate should be 5 amps because of the electronic battery monitoring system attached to the batteries.
Has anyone purchased any yet as I would be interested in your findings. I have a TGA Supersport with a range of 32 miles on 100ah batteries and wonder if the LifePO4 would extend that.
Thanks
Jonn Morris

[Burgerman]

>>> I bought 2 Ping batteries for my Travelscoot. A 20ah and a 10ah.

Why 2 and why different sizes? What voltage are your packs? 12, 24?

>>> I asked Ping about fast charging and he said that the maximum rate should be 5 amps because of the electronic battery monitoring system attached to the batteries.

Lithium batteries are very good at high charge rates as long as the correct 3.6v max cc/cv charge algo is observed (for A123 or LiFePO4). And not a fraction of a volt over that 3.6v per cell. He sells them with a simple circuit that can "sink" or waste any extra energy so as to prevent the cells being over charged. So you can actually feed them more. But too many amps and you will damage the circuit. The real answer is a proper charger for Lithium Batteries, which includes cell balancing such as the ones we model heli people use and dispose of the cheap BMS system.

But 5 amps on a 10 amp hour battery is already 2C which means its fast now. Or 4 hours on the 20 Ah battery?

>>> Has anyone purchased any yet as I would be interested in your findings. I have a TGA Supersport with a range of 32 miles on 100ah batteries and wonder if the LifePO4 would extend that.
Thanks

I have SERIOUSLY considered it. But to replace two 70 Ah group 24 powerchair batteries means a huge expense and only an increase from 70 to around 100 Ah because LiFePO4 batteries are not very compact. So a big expense for minimal gains although weight is also a benefit as they are about half as heavy. So so far I didnt bother.

LiPo Lithium Iron Polymer offers about 6x better energy density than lead batteries though. Unfortunately it burns rather violently and I cant get off the powerchair! So again not dared do that yet...

You also gain about 20 to 30 percent range because of the peukert effect on capacity as well though. Which almost makes the swap worthwhile.

Unless you mean as an ADD ON to extend range? That works! http://www.wheelchairdriver.com/extende ... rchair.htm

[jmensa]

I bought 2 as the 10ah only weighs 5lbs and being disabled I need as light a bag as possible to carry onto a train or coach. Although weighing 11lbs the 20ah is (as you can appreciate) a bit heavier. Also for distance use it extends my range.
In fact Ping supplied me with a 24v 6 amp charger.
Have a look at Travelscoot.com and you will see what it's all about.
John Morris

[Burgerman]

Ah, so you are doing this then http://www.wheelchairdriver.com/extende ... rchair.htm

Or are you using it instead of the stock lithium battery?

Then it will work great! It may work great in parallel to it as well if its the same TYPE of lithium iron battery.

There are lots. The main three are Lithium Iron Phosphate, safe. Lithium Iron, mostly safe..., Lithium polymer very unsafe! But best performance and price by miles... But you cant mix these.

[jmensa]

As I originally said I purchased 2 batteries from Ping . Both are Lithium phosphate. I do not wish to do "marathons" at 70 but like the reassurance of having a backup battery to get me home. The Travelscoot is not a long distance scooter, as you will see, but having been stranded with flat sla's on a Cameo I want the security I know LiFepo4 will give me. In USA these scooters have a cult following of extremely obese people for some reason and I am in touch with a large circle of interested parties who do not appear to have any mechanical knowledge whatsoever. As a Mobility engineer my aim is to give them the best advice I can and that is why I went on your site. We can't all know everything can we?
Unless you look at the site you will not appreciate the benefits these scooters give to the disabled regarding travel on Rail, buses, planes, coaches and overcoming travel companies restrictions.
John

[Burgerman]

Yes I looked at them before and umderstand the build quality and lightness.
I read their battery page too. Still dont know what type of lithium ion battery they offer? Only the size... And that its not lipo as the voltage is wrong.

The Ping batteries work well when they work according to electric bike enthusiasts. Some people have problems though usually with the very cheap BMS system boards and dead cells because of it. And scarily there are a few reported fire problems which is a little worrying! Especially if you are intending to recomend them to the very people that are mechanically/electrically ignorant.

Did you see this for eg?
http://visforvoltage.org/forum/9360-my- ... aught-fire its not a one off it sometimes happens.

Its ok for you, as you know it can happen - at least now you do! And you know whats going on.
I have decided that I dare not sit on top of 100Ah of pings batteries.
These LiFePO4 batteries are/were supposed to be safe!