Lithium v AGM

[mcp 19]

If you are interested in the size differences and electrical differences of lithium Iron Phosphate and Lead Acid AGM batteries,  I have started to put my battery compartment together this weekend.

On the left is a Vision FM100 AGM battery, 100ah @ 12v nominal,  which is my start battery [currently running the fridge and lights] and on the right are 12 x 150ah LiFePo4 cells, 450ah @ 12v nominal.  

On the left the AGM weight is 32kgs and on the right the LiFePo4 pack weights all up 34kgs.  

On the left we have 30ah usable @ the recommended 30% depth of discharge and on the right we have 360ah usable @ the recommended 80% depth of discharge.

On the left its costs $395 on the right $2800 [included in this price is $895nzd of shipping]

On the left cost per usable ah = $13.16 and on the right cost per usable ah = $7.77

On the left lifespan/cycles 500-700 and on the right 3000-5000 [or more, but there's a caveat to this].

On the left charge efficiency 85-90% and on the right 98-99%    

[vesper1 2]

That's so cool, I recently did a delivery on a yacht with lithium iron batteries and what astounded me was the rapidity of the recharge the yacht had electric auto helm and electric fridge and I definitely felt the lithium iron was a disruptive technology same as H. F. Radios are being displaced by Sat phones.

[CarpeDiem 5]

9 minutes ago, mcp said:

On the left cost per usable ah = $13.16 and on the right cost per usable ah = $7.77

Nice.

What battery management system / charging solution are you using? Is that per ah cost inclusive of the BMS? 

[Clipper 192]

I'm very interested in this. Which brand, how are they managed, what charging system you use etc.

And if all that's shipping cost, you obviously bought these overseas from somewhere, not local. Whereabouts?

[MartinRF 10]

Where did you get those efficiency numbers from? The reason for asking is I looked into this (for non-vehicle reasons) a few years ago and what I found then was not that high.

/Martin

[Adrianp 33]

Very interested in seeing the finished system and how you do it as this is on my to do list. There seem to be many many ways to approach this!

One of my mates has just imported 900ah of Winston cells and REC BMS for a roll Royce system.

Another has imported some other cells himself and is just starting the build.

And another mate got a 400ah 24v system from Blue Cars on Waiheke, who seem to have pretty good pricing on cells they have in stock. https://bluecars.nz/shop/206ah-module/

My AGMs are dead so it's time to upgrade. All my chargers are Li ready too now so I really have no excuses.

[Island Time 728]

If you are going to build your own banks, may I suggest that this is MUCH more difficult for you to get right than many believe.

It can be done, but PLEASE tread carefully! It can also fail, sometimes spectacularly, and cost you your investment, your boat, or more.

May I respectfully suggest that you START your reading here https://marinehowto.com/lifepo4-batteries-on-boats/ and do a lot of research before you commit.

[Dtwo 92]

And read this series of articles.  This is quoted by many people as extremely useful in understanding Lithium technology.

[Adrianp 33]

I've read that Marinehowto recently and there is very useful info contained within its poorly formatted and repetitive page! Worth the effort though.

There is a interesting facebook page that is useful too: https://www.facebook.com/groups/427372107686109/ 

[Dtwo 92]

19 hours ago, Dtwo said:

And read this series of articles.  This is quoted by many people as extremely useful in understanding Lithium technology.

Woops

 

http://nordkyndesign.com/category/marine-engineering/electrical/lithium-battery-systems/