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General => General Discussion => Topic started by: Bird on December 12, 2012, 11:51:15 AM

Title: Interesting Battery Discussion
Post by: Bird on December 12, 2012, 11:51:15 AM: its a few yrs old, but a good ~~laugh~~ read on $8000 ($2kea)batteries for campers.

lithium iron phosphate (LiFePO4) batteries (http://caravanersforum.com/viewtopic.php?f=55&t=17543)

and you thought our electrical threads went off.
Title: Re: Interesting Battery Discussion
Post by: chisel on December 12, 2012, 12:06:35 PM: Price of lifepo4 batteries is coming down rapidly. Almost to the point where you'd consider them for camping duty soon. Should not be much more than twice AGM prices, I thought.
They can be repeated cycled to 80% DoD and are a lot lighter than equivalent AGMs. So arguably a better option if weight is an issue and they are frequently being cycled heavily.
See the Green Tech forum on Whirlpool for some more discussion (mainly discussion about going off-grid with solar using these batteries as a battery bank)
Title: Re: Interesting Battery Discussion
Post by: Bird on December 12, 2012, 12:11:56 PM: Quote from: chisel
Price of lifepo4 batteries is coming down rapidly. Almost to the point where you'd consider them for camping duty soon. Should not be much more than twice AGM prices, I thought.

http://www.alibaba.com/showroom/120ah-battery.html (http://www.alibaba.com/showroom/120ah-battery.html)

http://www.hollyhockbatteries.com.au/12V_100Ah_SSB_Li-ion_Deep_Cycle_Battery.html (http://www.hollyhockbatteries.com.au/12V_100Ah_SSB_Li-ion_Deep_Cycle_Battery.html) $1300ea

Edit:
some interesting figures here
http://www.allpurposebatteries.com.au/product_info.php?cPath=39&products_id=333 (http://www.allpurposebatteries.com.au/product_info.php?cPath=39&products_id=333)

Average Weight 15KG (appealing)
Cycle Life 3000-5000
Continuous Amp Draw 200AMPS
Title: Re: Interesting Battery Discussion
Post by: chisel on December 12, 2012, 01:08:48 PM: Couple of other options
http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=92 (http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=92) $620 for 100AH

http://www.evworks.com.au/index.php?product=BAT-LP12V90AH (http://www.evworks.com.au/index.php?product=BAT-LP12V90AH) $535 for 90AH

So about twice the AGM price, but you can safely use more of the quoted capacity and they are about half the weight of the AGMs.
Title: Re: Interesting Battery Discussion
Post by: KingBilly on December 12, 2012, 01:11:20 PM: As my batteries sit on the drawbar, the half weight is what interests me. Price just has to come down.

KB
Title: Re: Interesting Battery Discussion
Post by: Bird on December 12, 2012, 01:29:58 PM: Quote from: KingBilly
As my batteries sit on the drawbar, the half weight is what interests me. Price just has to come down.
get some from China! LOL!
Title: Re: Interesting Battery Discussion
Post by: Mandrake on December 12, 2012, 02:18:13 PM: I have been looking at these Lithium Iron jobbies and most if not all I looked at showed the C/5 rate not our C/20 rate - So a battery showing 110 aH COULD be at the C/5 rate and only 27.5 aH at the C/20 rate - Does that then become a problem for us camper folks - Drivesafe might know a bit more about that ... Steve
Title: Re: Interesting Battery Discussion
Post by: Bird on December 12, 2012, 02:34:21 PM: Quote from: Mandrake on December 12, 2012, 02:18:13 PM
I have been looking at these Lithium Iron jobbies and most if not all I looked at showed the C/5 rate not our C/20 rate - So a battery showing 110 aH COULD be at the C/5 rate and only 27.5 aH at the C/20 rate - Does that then become a problem for us camper folks - Drivesafe might know a bit more about that ... Steve
any subtitles for the numpties in the crowd like me?
Title: Re: Interesting Battery Discussion
Post by: Mandrake on December 12, 2012, 02:46:46 PM: Sorry Lost - I'm no battery person I'm not even sure if it makes any difference to the battery's capacity to discharge - hopefully Drive safe can enlighten us ..Mandrake
Title: Re: Interesting Battery Discussion
Post by: Mace on December 12, 2012, 02:46:57 PM: 5 hour and 20 hour discharge rates in Amps!

I had to google it. i am a numpty too.

http://www.scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf (http://www.scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf)

I think Mandrake was alluding to the specification data provided by the battery maker and not being able to make comparisons with it to what we may currently use?
Title: Re: Interesting Battery Discussion
Post by: chisel on December 12, 2012, 02:51:12 PM: Quote from: Mandrake on December 12, 2012, 02:18:13 PM
I have been looking at these Lithium Iron jobbies and most if not all I looked at showed the C/5 rate not our C/20 rate - So a battery showing 110 aH COULD be at the C/5 rate and only 27.5 aH at the C/20 rate - Does that then become a problem for us camper folks - Drivesafe might know a bit more about that ... Steve

C5 capacity is usually lower than C20 capacity, for AGMs anyway.
http://www.fullriver.com/products/hgllist.htm (http://www.fullriver.com/products/hgllist.htm)

I'd be surprised if the C20 capacity for these Lithium jobs is not higher than stated capacity. But I'm no expert.