LiFePo4 battery w/ decent mAh rating?

[Cheeseburger]

Seems LiFePo4 batteries are widely suggested for buggy kits like the Tamiya DT-03. I'm keen to try one, but I can't seem to find any with a decent mAh rating... all are in the 1600 - 2000 mAh range. Maybe i'm misunderstanding how LiFePo4 works, but compared to NiMH with a rating of 2000 mAh - it's just not enough.

If you can link me up any (reputable) vendors you know that sell high mAh LifePo4 packs i'd be most appreciative.

Also - 2S vs 3S LiFePo4... can a TBLE-02 handle 9.9V? Will a 3S pack fit in a DT-03 cavity? Or just stick with 2S?

[Origineelreclamebord]

I know one supplier, but they're hideously expensive... Maxamps sells these 6750mAh 90C LiFe packs:

http://www.maxamps.com/Life-6750-66-Pack.htm

And it doesn't even have a hard case around it

Also, with the TBLE-01 I know for fact that you should keep it at 2S (also for LiFe) - with the TBLE-02 I'm not sure, but it should state in the manual up to what voltage it can go. Stick with that and your ESC should stay happy (using more would probably void the warranty, too)

[Percymon]

I really fail to see why this technology exists, why Tamiya want to go Li-Fe when the rest if the world is the far superior (power wise) lipo technology is beyond me.

[alfagta]

hi , try hobbyking , they have a vast selection , if you want one to fit the terrible tamiya hole in m chassis and older cars then it might have to be a tamiya life battery , but if its just for the dt03 you can get 2s1p or 2s2p 4200 mah for peanuts , i use them in my dt-03 and HL tiger 1 tank , very robust with no memory effect that lipo can suffer from ,

I really fail to see why this technology exists, why Tamiya want to go Li-Fe when the rest if the world is the far superior (power wise) lipo technology is beyond me.

hi Percymon, i was of the same opinion , i love lipo, however life does seem more robust when mistreated , the metal cells tamiya use are far safer for air shipping than any soft cell lipo and can stand up better to partial discharging and recharging that a young kid may be likely to give them ,

all in i find it is the technology we should have adopted before li-po as if it had the same surge in take up we would by now have a safer and easier to ship battery tech .

[Cheeseburger]

I really fail to see why this technology exists, why Tamiya want to go Li-Fe when the rest if the world is the far superior (power wise) lipo technology is beyond me.

I've investigated LiPo, but for my circumstances LiFe batteries seem to offer the greater benefit:

- I don't want to have to buy another ESC (with an appropriate voltage cut off)

- virtually last forever

- sympathetic to abuse, and greater safety margins

- handle storage conditions better

- fast charging times, and no need for supervision

My buggy is just a fun basher, and I only need enough performance to keep the carpark races between my brother and nephews interesting. I'm happy enough running NiMH batteries, but while i'm in the market for a new battery (due to my last NiMH failing after a few charges), I might as well try for a LiFePo4 battery which will be a plug-and-play upgrade. As long as I can get a battery in the 4000+ mAh range (which is about 20-30 min runtime in my hands).

At worst, if the go-fast bug bites I can overhaul my Neo Frog to LiPo and stick the TBLE-02 and LiFePo4 pack in my older Frog.

[GregM]

The trouble with LiFe is they deliver significantly less nominal voltage with 6.6V compared to NiMH (7.2V) and LiPo (7.4V). This affects acceleration and top speed. If you want to retain the same speed with a LiFe pack, you'll need a higher reving motor than usual.

[Cheeseburger]

I have a 17.5T 2600kv Tekin brushless on the way. We'll see where I stand after I install that.

From the performance graphs i've seen they seem to indicate a NiMH will initially be superior to LiFe (for the first five minutes of driving I guess), then LiFe wins out with its flat-line voltage output. LiPo is in another league, but that is to be expected.

BTW - I only just discovered the Hobby King website... reasonably decent mAh LiFe batteries can be found for $20 - that's half the price local hobby shops are selling equivalent NiMHs for. Looks like i've found my new favourite online shop

[alfagta]

if you go for hobby king for batteries , when the pack/s arrive there is a warranty code on the side of them , go to your HK account and find the order in your account , next to it you need to input the code for the battery or it wont be warrantied ,

gregm makes a worthy point about the voltage reduction over lipo but with nimh only around 1/3 of usable capacity is above LiFe output , the other 2/3 are at the same or below what life can output through 90% of capacity ,my dt-03 manages to wheely around with 13.5 and 19t pinion with ease ,,

if you do want the oomph of lipo , an alarm only costs a few dollars and most can be connected to the lipo balance lead so no soldering or messing about is required ,

i personally am rather taken with life technology , i plan on getting some hard case life packs for my m chassis cars too , especially the FWD 03/05 kits benefit from reduced voltage and turning up the timing on the motor to reduce wheel spin but increase top speed and all with lower temps ,

less can sometimes be more .

have fun with whatever you choose

[Cheeseburger]

Got one of these on the way... hopefully doesn't turn out to be a dud. If so - nothing ventured, nothing gained.

http://hobbyking.com.au/hobbyking/store/__14068__ZIPPY_Flightmax_4200mAh_2S1P_30C_LiFePo4_Pack.html

[GregM]

Softpacks?

[alfagta]

the dt03 doesn't require hard case packs due to the well protected monocoque chassis so no worries there , charge it at half 'C' (2.1A) for the first 2 or 3 charges , always do this if the pack is stored for more than a month without use , beyond that they have been bullet proof , absolutely no swelling , no memory effect regardless of repeated partial discharge and recharge and the life packs also run cooler than lipo when run with hotter set ups or charged at high rates , i love em and as i mentioned i am hunting for hard case versions for use in rounded battery compartments . if you do notice the tiny reduction in top speed just run higher gearing , the voltage reduction means everything in the car runs cooler so gearing up isnt an issue .

enjoy

[Cheeseburger]

Thought i'd follow up on this with my observations - I've had a 4200 mAh pack installed for a couple of runs now. I have noticed a little less top end speed (maybe 5 - 10%), but I have a Tekin brushless motor on the way so hopefully that'll blind me to any speed loss. On the plus side the speed seems very constant over time, it also seems to be more torquey, and the pack generates no heat at all during charging. And it's a very rigid casing for a soft-pack. And 4200 mAh is giving me a really long run time. My only gripe - not sure if it's a voltage thing or a setting error in the tx - it seems a little more hesitant to hit reverse from a full-brake-stop.

Initially, i'm pretty happy. I guess only time will tell if it was a good purchase decision.

[GregM]

Please try adjusting the throttle endpoint and neutral throttle settings of your speed controller, as well as the throttle E.P.A. or dual rate settings of your transmitter.