LiFePo Vs Nimhy

[VidPro]

Li-Ion has a huge weight advantage over ni-mhy, and power for size.
but what about li-fe-po?
if extreeme amps were NOT needed
if the voltages were relative (meaning the voltage is not an issue)
if recharging is needed, and capacity for size/weight is important
if there will be overcharge, although very limited and slow
if weight was a big issue?

does a similar wattage total of li-fe vs ni-mhy weigh less or more or very similar?
would a similar wattage of li-fe vs ni-mhy handle overcharge worse or better?

 

[gSPIN]

when u say 'wattage total' reading between the lines do u mean 'watt-hours'?
doing a simple divide of watt-hours into basic cylinder volume & weight:

......... Elite 23430 5Ah NiMH ......... A123 M1 26650 2.3Ah LiFePO4

capacity ............. 6 Wh .................... 7.36 Wh

volume .............. 17.9 ml ................. 34.5 ml

weight .............. 67 g ..................... 70 g

Energy Density .. 335 Wh/L .............. 213 Wh/L

Specific Energy ... 90 Wh/kg ............. 105 Wh/kg


subject to peer review.
do not know about overcharge capability cuz i'd rather just avoid it altogether.
i hope this is what ur askin4.

 

[VidPro]

yes it is thank you.

so what you have here is pretty similar in weight vrses "power"?
that is what i needed to know. because i have ni-mhy working fine in the situation, and li-fe-po popped into my head , i thought mabey it could save weight.

 

[Eugene]

I assume your talking about NIMH since there isn't such a thing as nimhy?

Same things as any of the other lithium based, lower overall life span, more complex chargers, etc.

 

[rmteo]

Here is a comparison table with other chemistries as well:
http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=1272

Lithium Iron Phosphate (LiFePO4, LFE) is new generation Li-Ion rechargeable battery for high power applications, such as EV car, Power Tool and RC hobby. LFP cells feature:
high discharge current, non explosive, long cycle life ( >2000 ), but its energy density is lower than normal Li-Ion cell (Li-Co) (higher NiMH cell). LFP cell has 3.2V nominal working voltage and shall be cut-off power at 3.6-3.8V per cell during charging. Please see the table below to see comparison between LFP and other rechargeable batteries. LFP battery has the lowest cost if considering its long cycle life.

 

[VidPro]

hmm, that chart shows a much better weight for the li-Fe.
although i was (sorta) asking in the forum, to get "user" input, based more on reality, and what the actual avilable Cells to us are.
you know just a , i got these and they arent light, or they weigh a lot more than li-ions.

so i looked further into , then found this

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4053

very new, and the pic seems to be just a photoshopped one of these
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3483

so i dont think a lot have been purchaced yet.
and as you can see its not immediatly available.

but i compare it directally to the similar li-poly, and the weight differential isnt to bad, ON PAPER guess i will have to get one and see what is real.