SonexBuilders.net

Andy Walker wrote:Someone on the Yahoo Groups asked about batteries, so I did a search on lightweight batteries and found that Lithium-Ion batteries are starting to become available that have the same capacity as conventional batts but weigh less than half as much! For example:

http://www.shoraipower.com/p-210-lfx36l3-bs12.aspx

540 Cold Crank Amps, and 36Ah reserve capacity...for under five pounds!! Expensive, yes ($350), but you are shaving 5-8lb off your overall and FWF weights for that money, which is not insignificant.

Here's a thought. You can buy this battery for $110 http://shoraipower.com/lfx18l2-bs06-p98
Buy two of them and put them in parallel. You still have 36 amp/hr and 540CCA at a total weight of less than 3 lbs and save a $100.

radfordc wrote:Here's a thought. You can buy this battery for $110 http://shoraipower.com/lfx18l2-bs06-p98
Buy two of them and put them in parallel. You still have 36 amp/hr and 540CCA at a total weight of less than 3 lbs and save a $100.

I don't think that would work out. They are 6V, so they'd have to be wired in series to make 12V, right? The CCA and amp/hour ratings would stay the same as one of these 6V batteries, (270 CCA, 9AH: same number of amps but twice as many volts=twice as much actual wattage as a single battery). If I've got that right, then using two of these 6V batteries in series would save $100, but the CCA would be 1/2 of the battery in the OP, and the total capacity would be just 1/4 of the 36 AH of that battery.

Oops...missed the voltage part. Too good to be true.

What about this battery: http://www.batteryspace.com/LiFePO4-Pri ... t-PCM.aspx

12.8v; 20aH; 6.6 lbs; $124.00

Same price as an Odyssey PC625 at half the weight.

I'm glad I don't have a lightweight battery. I left my master switch on this week and ran the PC625 down to under 9 v. I recharged the battery and took it to the auto parts store for a check out. It tested out better than spec!

radfordc wrote:I'm glad I don't have a lightweight battery. I left my master switch on this week and ran the PC625 down to under 9 v. I recharged the battery and took it to the auto parts store for a check out. It tested out better than spec!

You would have been welcomed with open arms into the Flying Paperweight Club.

Andy Walker wrote:

radfordc wrote:The Shorai battery shown in the first post is a "lithium-IRON" battery...not a lithium-ION battery.

I'm noticed that too...I'm assuming it's an Asian company and that is a typo.

EDIT: whoops, from post above I am dead wrong.

A lithium iron battery is a type of lithium ion battery.

chrisyk wrote:
A lithium iron battery is a type of lithium ion battery.

Technically they are very different: http://www.brighthubengineering.com/pow ... n-battery/

No one ever refers to a Lithium Iron battery as a "Lithium Ion".

radfordc wrote:Technically they are very different: http://www.brighthubengineering.com/pow ... n-battery/

Thanks for the link. For our use, the Li-Iron sounds pretty good (safety, longevity, cost). And, even though the weight of a Li-iron battery might be more than Li-ion, it should still be less than 1/2 of lead acid.

Specific energy (watt hours/kg)
Lead acid: 41
Li-iron: 90-110
Li-ion: 100-250

In theory, it sounds good to lose 6 lbs of battery weight, but right now that big chunk of lead up on the firewall is helping my CG situation when I'm fully loaded.

You are correct. A lithium iron battery is very different from a lithium ion battery. I'll rephrase my comment. A lithium iron battery is in the lithium ion battery family. A lithium ion battery is rechargeable as opposed to a lithium battery which is not rechargeable. Some types of lithium ion batteries are:
Lithium ion manganese oxide battery (IMR)
Lithium ion polymer battery
Lithium iron phosphate battery
Lithium–sulfur battery
Lithium–titanate battery
Here's a quote from wikipedia.
"The lithium iron phosphate (LiFePO4) battery, also called LFP battery (with "LFP" standing for "lithium ferrophosphate"), is a type of rechargeable battery, SPECIFICALLY A LITHIUM ION BATTERY, which uses LiFePO4 as a cathode material."

This is on the internet so it must be true.