Lithium LFP batteries becoming affordable

Submitted: Friday, Feb 15, 2013 at 13:02

ThreadID: 100564 Views:4165 Replies:2 FollowUps:4

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Member - Gerald V

Dropped a couple of these into the camper late last year...

http://ev-power.com.au/webstore/index.php/12v-lifepo4-batteries/12v-lifepo4-batteries/12v-4-cell-040ah-lfp-battery-module-1.html

Direct drop in replacement. Charges well off alternator as well as solar via standard SLA solar reg. Used it over summer with a few camping trips and was very pleased with the performance. The price is also a welcome change from what I have previously seen LFP batteries selling for in the past.

The only problems that I have found so far are:
1. Due to the voltage holding above 13.2v when charged, my dual battery controller does not cut out and the LFP battery 'discharges' into the vehicle lead acid battery (haven't swapped this one yet). Added an extra ignition switched relay to solve this.
2. They do not respond well to 'over discharge' (then again neither do SLA, but these are worse) so you may need to add a low voltage cutout on your equipment.

Disclosure: I have absolutely no (zero, none, nill) affiliation with this company, I'm just happy with the product, and thought others might benefit.

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Reply By: chisel - Friday, Feb 15, 2013 at 15:27

Friday, Feb 15, 2013 at 15:27

Needs to be a bit cheaper for most users. AGM (or other deep cycle) at $250-ish for 100AH is half the price and will do the job for most. Yes lithium is going to last longer and weighs half as much or less but for irregular use the AGM is still cheaper if looking at a 5 year lifespan.

AnswerID: 504815

Follow Up By: Member - Gerald V - Friday, Feb 15, 2013 at 16:13

Friday, Feb 15, 2013 at 16:13

Hmmm... possibly debatable, but I'm not sure I agree... LFP has 2000 full discharge cycles (ie dod down to 0%) for 80% remaining capacity with a calculated design life of 10 years. Also, given that they happily may be discharged to 0%, a 60Ah may be used in place of a 100Ah AGM (assuming a recommended 40% max discharge for the AGM).

Admittedly, reducing weight is a bit thing for me (trying to keep it down), but the other factors (overall cost per cycle, design life, higher operating voltage, small operating voltage range, tiny voltage sag) swayed me.

I guess the only true test is to operate both side-by-side under the same conditions and see which one wins over 10 years - but I guess no-one will be prepared to do that!

Either way, it's nice to see LFP's starting to compete.

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Follow Up By: chisel - Friday, Feb 15, 2013 at 16:57

Friday, Feb 15, 2013 at 16:57

For many users who may only discharge their batteries deeply on a handful of occasions throughout a year of occasional camping, the extra discharge cycles of lithium-based batteries are a bit of a waste. If you are on the road full-time then yes, I think they would be great.
I still think they are possibly worthwhile primarily based on weight for myself, but only if the price drops by 20-30%.

FollowupID: 781727

Follow Up By: Member - Keith Berg - Friday, Feb 15, 2013 at 20:06

Friday, Feb 15, 2013 at 20:06

I think the big plus with LIPO4 batteries is that you can draw the amp hours down a lot lower than you can with an AGM. A 100 AH AGM is only good for about 50 AH if it is to have a reasonable life. If I understand correctly, a LIPO4 battery can be taken down to about 10% of full charge. That means that a 60AH LIPO4 is as good as a 100 ah AGM and is maybe a third of the weight and less than half the size.
They sound like a good idea and are getting cheaper all the time.

FollowupID: 781730