Turnigy LiFEPO4 packs

[lutach]

Originally Posted by Unsullied_Spy

Any particular reason for needing a LiFePo4? I don't buy anything from MA just on principle.

Safety is the main reason.

[johnrobholmes]

LiFe chemistry doesn't go into thermal runaway. The packs can still catch fire if they overheat (overcharging), but won't keep burning like magnesium and lipo does.

[fastbaja5b]

Precisely, safety. My Mini is what usually gets put in the boot for vacations, in the family ride thats behind where my 7 month old sits, in my "bunky" that's up against an LPG tank.

Neither are areas you want unstable packs. Also babys get into things, chew on things etc, Lipo pack + teeth?

As much as I enjoy this hobby, Safety has to be my #1 thing now, that's why the Savage Flux runs on Lifepo4 and why I want the Mini to as well.

Fastbaja5b, I'm in the same boat in terms of safety being a big concern with a small child getting into everything along with the fact I'm new to rc. What kind of setup are you using for the flux? I have the truck NIB waiting to be run when I can get some more ideas as to batteries, charger, any tray mods, run time, etc. Are you generally satisfied running liFe? Thanks.

[jpoprock]

So guys... what can I expect from two 2s 4500mah Life Packs by Turnigy if sticking them in my Summit or Emaxx for winter driving? Both trucks have a single Titan 775 and the EVX2 ESC's.

I understand that Lipos don't like cold weather, and it's COLD here. But I can wrap them in a "blankie" to keep them warm if need be, since they are so thin.

What would be my run time and torq expectations when running the Life packs vs 2s 30C Turnigys, vs a 7 cell NiMH pack that is comparable? If the Life packs I'm looking at really won't give me good run times, or will be wicked slow, than I'll just stick w/ the Lipos and take my chances. Either pack is about the same price. I'm wanting runtimes for winter driving, because I don't want to have to mess with coming in and recharging all the time. Cuz once I come in from the cold, I won't want to go back out! And really.... 30min of snow driving is long enuff for me to get my RC fix for the day anyway.

Thanks!
jason

[Unsullied_Spy]

LiFes should be just fine. With a brushed motor I would expect that you're going to get the same power, they don't put enough load on them to make a difference. I don't think the Titan pulls enough amps to keep the batteries warm on their own, so I guess that it's possible that they could get too cold even when cozied up in the Summitt's battery compartments. Might want to go with the LiFe packs just to be safe, plus you can charge them faster if you need to get your fix a little more often (if not in the Winter, you can sure use this in the Summer).

[jpoprock]

Thanks. are the run times as long as an equivalent Lipo, or more like a NiMH pack?

Well fooey... HK is now out of stock! Maybe next order...

[Unsullied_Spy]

I'd guess you should get similar run times to a lipo. The discharge characteristics of a LiFe pack are more like a NiMH though, they stay pretty solid with some voltage drop across the run but at the end they straight-up dump and you KNOW it's time to stop.

[jpoprock]

Thanks for the info. I'll probl pick up a couple packs on my next order, which could be a while. But there are some things from there that I'd like to pickup when they come back in stock.

Jason

[simplechamp]

Just got my order in for a pair of them before they went out of stock. Planning on using them in my TC3 indoors this winter.

How does charging the packs at high rates affect the pack's life? I have heard that the larger charge rates can cut the packs life by half or more, but that 2-3C is pretty safe.

[simplechamp]

Wikipedia says that rapid charging will shorten the lifespan when compared to trickle charging, but it doesn't say anything defining "rapid" as far a C values, and doesn't have any source cited.

I'm probably going to charge my 4500mah packs at 9A. I'll be happy with cutting charge time in half compared to my lipos, and hopefully with swapping the two packs back and forth in my conservatively setup TC3 I will have little, or possibly no downtime in between runs.

[lutach]

I don't know if it's true or not. I talk with people that makes way more powerful batteries and the current one they have is capable of 400C continuous and can be charged in 2 minutes at 150A. Now they say fast charging may impact life of the cell, but they have done so far over 3000 cycles and this particular cell still have over 80% of its capacity. I just wish I could get my hands on a few .

[sikeston34m]

Originally Posted by lutach

I don't know if it's true or not. I talk with people that makes way more powerful batteries and the current one they have is capable of 400C continuous and can be charged in 2 minutes at 150A. Now they say fast charging may impact life of the cell, but they have done so far over 3000 cycles and this particular cell still have over 80% of its capacity. I just wish I could get my hands on a few .

I do believe there are advances in battery technology that are still in the beta phase testing phase.

I've had a few talks with one individual about a "AA" size Lifepo4 cell that the manufacturer claims a 1600mah capacity on.

This energy density is much greater than the former 450-500mah "AA" sized Lifepo4 sized cell.

If they can get the energy density this good, regular lipo chemistry may become a thing of the past.

[lutach]

Originally Posted by sikeston34m

I do believe there are advances in battery technology that are still in the beta phase testing phase.

I've had a few talks with one individual about a "AA" size Lifepo4 cell that the manufacturer claims a 1600mah capacity on.

This energy density is much greater than the former 450-500mah "AA" sized Lifepo4 sized cell.

If they can get the energy density this good, regular lipo chemistry may become a thing of the past.

There are 2 types of LiFe battery. One is the Power cell that has less capacity, but offers higher C rating. The other is the Energy cell that has more capacity, but offers very low C rating.