Lithium vs FLA batteries

[grizzley]

Are Lithium batteries worth the investment?

we have an off grid system where i need to replace the FLodded Lead Acid batteries.  The question is with what.  we have currently a 48v 420 AH bank that need to be rplaced and most likely increased to doubble its size.  We are using Midnite Classics 200 as cahrge controllers (one for solar one for wind) and are powering the house through 2 Magnum MS-PAE 4448 inverters.  What are your thoughts in general and any particular battery recommendation wheather for lithium AGM or otherwise?

Thank you

[Ron Swanson]

Our research indicates Discover AES seem to "get it" the best for a system that you install and it Just Works.  Simpliphi also looks pretty good but small units and more finicky installation requirements.  Many on here have home brewed their own.  Experience is limited in "set and forget" applications but the manufacturers have published charge/AGS settings so they should work, they supplied them.

[mike90045]

Don't forget, the ability to recharge Li cells below 40F, degrads rapidly until 32F, at which point, recharging is not feasible till the battery is warmed ( yes I know you can recharge at 1% of battery C, but how feasible is that ? )

[grizzley]

So is it in your sense worth going after the Lithium batteries or should we look for other option?  On a quick check to replace a string of my L16 HCXC FLA batteries (420 Ah 48V) would run about $2000.  The Discover AES you mentioned would run $7200 for less than have but of course the Li4PE are more efficient.   The not of caution about the temperatures, although timely given the polar vortex  , is not a concern for me as the batteries are in a temperature controlled environment.

[Westbranch]

Grizzley, I assume that you are on-grid... based on your statement that the batteries are in a temperature controlled space.  Is  that in the basement or a heated power shed?

In my case I am still  being cautious when evaluating LiFePO4 cells as I can not be assured that the batteries will not be needed after the temp drops below freezing when no one is home...  Still using Lead.... but a propane space heater for backup or days away will probably change that...

[ClassicCrazy]

If you go with flooded lead acid get the bigger heavy duty forklift type batteries - 2v cells . They are better batteries than L16 and can take a lot of use and abuse.
Larry

[grizzley]

Westbranch - we are off-grid but basement is the right call.

Sounds like you are sticking with Lead any preferences there?

[grizzley]

Larry - looks like from your system description you use both lead and lithium.  Do I read you correct that you would recommend lead over lithium?

[ClassicCrazy]

I have sealed gel type lead acid  - type called lead crystal . Got them cause they have good performance in unheated area which is good since it is  minus 16 F now and still dropping.  They claim they don't sulfate even if discharged very low- just hoping they live up to their claimed longevity .

I also bought a small lithium set - 100 AH of Calb 48v to experiment with - didn't put any bms or low voltage cutout - mistake . If some of the other lithiums mentioned above were on the market then I would probably have gone with them.
Lithiums are not as forgiving as lead acid which can take some abuse and  not get destroyed.
Not using the lithium now because too cold and a cell got ruined - my fault basically .

Larry

[RossW]

I'll just wade in and say that I've been 100% off-grid for only 15 years.
I had some used, end-of-life AGM.
I had a brief flirt with some FLA.
I had a bigger, not-quite end-of-life AGM bank.
Then 5 years ago I went LFP.
I have 900AH at 52V. My battery room is burried 5m underground and temperature never gets below about 14 deg C.
These LFP have met or exceeded my expectations in every regard, every day since.
If I had my time over again, I'd go the same way, only years sooner.

[grgdgreek]

I'll just wade in and say that I've been 100% off-grid for only 15 years.
I had some used, end-of-life AGM.
I had a brief flirt with some FLA.
I had a bigger, not-quite end-of-life AGM bank.
Then 5 years ago I went LFP.
I have 900AH at 52V. My battery room is burried 5m underground and temperature never gets below about 14 deg C.
These LFP have met or exceeded my expectations in every regard, every day since.
If I had my time over again, I'd go the same way, only years sooner.

+1
George

[grizzley]

Hi Ross and George,

since you both seem to have good experiences with lithium and would recommend them, may I ask what batteries you are using/would recommend?

Thank you and stay warm

[RossW]

since you both seem to have good experiences with lithium and would recommend them, may I ask what batteries you are using/would recommend?

I'd probably suggest the ones to avoid.

Avoid ones that are stacks of massively-paralleled 18650 or similar cells.

Avoid (as a general rule) the packs that say they "include integral protection", often combined with "balancing". While not all of them will be, lots seem to be cylindrical cells spot-welded together into packs.

Avoid ones that look like they've been made of scrap pieces.

Avoid ones that have tiny little terminal posts and/or tiny little studs or bolts to hold your hardware on.

Avoid pouch type cells. I have little faith in their lifespan and a great distrust of their safety.

My original bank were 300 amphour, LFP (LiFePO4) (prismatic) cells with a "nominal" terminal voltage of about 3.2V.
When I went back to expand my battery, the manufacturer seems to have been bought up and no longer supplies to the public. I had to find another supplier. Ended up with 200 amphour packs, in 3P arrangement.

There are lots of manufacturers now. Pick a cell that you can handle yourself (ie physically small and light enough). Pick a cell that will fit with your space, without hanging over the edges or wasting too much of your shelf/plinth/floor space. Pick cells that are your required capacity, or a convenient integer sub-multiple thereof. EG, if you want 600AH capacity, then 200 and 300AH cells are a good choice. 400 doesn't work, and 100 makes too many of them.

Pick cells that will stack nicely - where the terminals line up usefully, and ideally get proper interconnects from the same supplier. I would probably avoid stainless steel because of its higher resistance.

DO use both flat and spring washers, and DO use a torque wrench.

Thank you and stay warm

Easy for you to say! We had 48.2 degrees here a week back.
That's 48.2 degrees C.  (118.8F)
More difficult to get COOL than stay warm!

[grizzley]

Thank you Ross.  That is very helpfull as I continue my search for our next battery.

If I could I would send you some of our cold to cool you down  We are digging back out of the arctic cold (it was a toasty -8F (-22C) this morning a warmup from yesterday and nothing like the north central US has/had0

[grizzley]

One of the suppliers that I use, Northern Arizona Wind and Sun, are pushing the Discover AES batteries.  They make good points but they are also VERY expensive. 

Is their BMS capable of communicating the the Midnite Classics for state of charge etc?