Tag Archives: lfp

Lithium vs Lead acid: a charge profile primer

How lead acid and lithium batteries charge

Recently I was asked if lithium batteries( lfp) accept more voltage from solar panels than lead acid batteries (fla). The short answer is No. But, they do accept more amps! You see as your batteries charge the peak voltage limit is hit and then amperage begins to taper.

The formula you need to remember is voltage X amperage = watts. In battery charging amperage is key.
The formula you need to remember is voltage X amperage = watts. In battery charging amperage is key.
Amperage is the key

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Solar tips: Why 1 watt to 1 amp

1 watt of solar to 1 amp of battery storage

I developed this basic rule of thumb about 5 years ago. When I did my initial solar research I noticed that off grid, either full time or RV boondocking, the folks who were happy with their systems typically had 1 watt of solar panel per 1 amp of battery capacity (measured at 12v/lead acid battery packs).

Lead acid. Yuck. But I've still got mine. 4 years and still chugging along.
Lead acid. Yuck. But I’ve still got mine. 4 years and still chugging along.

Those with less panel grumbled about “genny time” and worse. The consequence of lead acid battery packs: over discharge & under charge = dead batteries.

So let’s look at a small system

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LFP is King — and I have proof

Vindication is mine

Dear readers, as you know I’ve been touting the energy storage benefits of lithium iron phosphate batteries (LFP) for off grid families who need reliable solar / wind / hydro energy storage from the moment I discovered a plug and play format earlier this year.

Sharing my realization on sites other than this one, I have been attacked, yes, and slandered, by a variety of what I have come to call “leadites.” Those who cling to this idea that solar power will remain in one fixed position.

Oh the battles I could tell you about. But today, dear reader, I found scientific proof to my hypothesis that LFP is the new best solar/wind off grid storage media.

To wit:

A comparison of lead-acid and lithium-based battery behavior and capacity fade in off-grid renewable charging applications
by Elena M. Krieger, John Cannarella, Craig B. Arnold
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ USA

Mwha ha hah … take this leadites …

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LiFeP04 vs Flooded Lead Acid batteries

Post from Simon, Karrak Farms, Australia

Creeky says: I thought this was interesting, so I bring this to the attention of those who are interested in LFP batteries for offgrid power storage.

LFP compared to FLA
LiFePO4  Flooded Lead Acid
Total Operating Voltage Range 14.4 – 11.2 15.5 – 10.5
Normal Operating Voltage Range, No Load 13.8 – 12.8 (90%-20%SOC) 15.5 – 12.0 (100%-50%SOC)
Normal Operating Voltage Range, C/8 Load 13.8 – 12.4 15.5 – 11.0
Normal Operating Voltage Range, C/2 Load 13.8 – 12.0 15.5 – 10.5
Max sustained charge rate 1C C/8
Recommended sustained charge rate N/A C/10
Sustained discharge rate 1C C/8
Peukert Coefficient ~1.02 1.2-1.6
Current efficiency >95% <90%
Lifespan ~10 years ~6 years
Warranty 5 year prorata (balqon) 5 year prorata (trojan)
Cost per kWh ~US$340 ~US$130
Cost per usable kWh ($/kWh/cycledepth) ~US$523 ~US$325
Cost per usable kWh per year ~US$52.30 ~US$54.20

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LFP battery revolution changes off grid electric forever

I am weeping with joy as the Lithium Iron Phosphate battery (LFP or LiFePO4) completely changes off grid energy storage

Recently I stumbled across the Balqon LFP 9kw energy storage battery. It comes complete: battery management system, even a fuse, so it’s plug and play. The benefits look amazing, but how will it fare in comparison to my lead acid battery pack?

LFP battery pack
This Balqon LFP battery pack gives you 13 years of 4.5 kw daily energy use and you can buy it today. I’m in love.

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