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Old 12-20-2012, 06:36 PM   #261
_cy_
Beastly Adventurer
 
Joined: Sep 2011
Location: Tulsa, Oklahoma
Oddometer: 5,257
Using Heated Gear with LiFePO4 batteries

heated gear don't understand PB/EQ. they draw real amps. Almost all LiFePO4 battery mfg like to use amp equivalents to lead acid batteries. that may be valid for starting requirements. but heated gear don't care... they draw regular amps.

listed amp/watts for Gerbings micro wire. even if you don't have Gerbings, amp draw will be real close. amp x volt = watts

1. Jacket 6.4 amp/77watts
2. Vest 4.5 amp/54watts
3. Pants 3.6 amp/44watts
4. Gloves 2.2 amp/27watts
5. Grips 3.0 amp/36watts

let's say you've got a heated jacket, heated gloves and heated grips = 11.6amp draw

let's say your LiFePO4 battery has an actual Amp Hour capacity of 6 amp hour. this means your battery will support your heated gear for about 1/2 hour before going dead.

then let's factor in alternator output and amp draw from rest of bike. on short rides using heated gear, it's quite possible to use more amps from your battery than Alternator has a chance to replenish.

when you put your bike away for the night after that short cold ride. your 6 amp hour battery may not be fully charged.

next morning it's say 30f degrees ... you go to start your bike with a half dead battery.... fail ... one automatically blames the battery. when the fault is putting bike away with a half charged battery.

this is where LiFePO4 batteries with BIG reserve capacities shine. Lithium batteries internal resistance goes way up with battery gets cold. this means substantially less amps will be delivered. cold start procedures calls for a load to be placed on LiFePO4 battery. this heats up battery reducing internal resistance, allowing more amps to be delivered.

ahhhh... but there is a catch... heating a cold LiFePO4 battery takes amps... battery must have enough reserve capacity to heat battery up and start your motorcycle.

clear as mud... nah.. it's not that hard to understand. Adventure bikes must have some of the hardest demands on a battery. if you've got a R1200GS and you are planing on climbing the Andes mountains and camping out.

go with an AGM or if saving 10lb+ is worth the trouble... go with largest LiFePO4 motorcycle battery available.

one year old Shorai LFX36 next to new Earth-X ETX36C

_cy_ screwed with this post 12-26-2012 at 02:21 AM
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