Guides
Guides
The reasoning behind the calculators — battery chemistry, common sizing mistakes, reading a datasheet, and what actually happens to a battery in the cold or over the years.
Can you charge LiFePO4 batteries in cold weather?
Why charging below freezing causes permanent lithium plating, what a BMS low-temperature cutoff does, and how to keep a bank charging safely in winter.
6 signs your solar array is undersized for your battery bank
The battery never reaches full charge, autonomy shrinks every cloudy stretch, and five more diagnostic signs your array can't keep up with the load.
How to read a battery datasheet (without getting misled)
Nominal voltage, rated capacity, C-rate, cycle life DoD qualifiers and continuous vs. peak current — the numbers that matter and how manufacturers dress them up.
7 common mistakes sizing an off-grid battery system
From confusing nameplate Ah with usable Ah to ignoring inverter idle draw — the recurring errors that leave a system under-built or overspent.
How long do LiFePO4 batteries actually last?
Cycle life vs. calendar life, why depth of discharge is the biggest lever you control, and a realistic lifespan estimate instead of a marketing number.
Series vs. parallel battery wiring: what's the difference?
Series wiring adds voltage; parallel wiring adds capacity. How to tell which you need, and the series-parallel configurations most banks actually use.
MPPT vs. PWM charge controllers: which do you need?
PWM controllers are cheaper and simpler; MPPT controllers extract more power from the same array. How to choose between them.
Continuous vs. surge watts: sizing an inverter correctly
An inverter sized to continuous load alone can shut down the instant a motor starts. The difference between the two ratings, and how to size for both.
Round-trip efficiency: what it means and why it matters
Every charge-discharge cycle loses energy to heat. What round-trip efficiency means by chemistry, and how it changes how big an array you need.
How many days of battery autonomy do you actually need?
More autonomy days means a bigger, pricier bank with diminishing returns. A practical way to pick a number instead of defaulting to 3 days.
Building a DIY LiFePO4 battery pack: cells and BMS basics
What it takes to build a safe DIY LiFePO4 pack from cells: series counts by voltage, BMS matching, and where DIY makes sense versus buying assembled.
Understanding C-rate: what "1C" means and why it matters
C-rate describes discharge current relative to capacity, not an absolute number. Why a big battery isn't automatically safe with any load.
Peak sun hours explained: why location changes array size
Peak sun hours, not daylight hours, drive solar array sizing — why the same daily load needs a very different array in different climates.
12V vs. 24V vs. 48V: choosing the right system voltage
Higher system voltage means lower current for the same power, which means thinner, cheaper cable. How to pick between 12V, 24V and 48V.
Sizing a backup generator for an off-grid solar system
A generator sized to run the house directly is oversized for recharging a battery bank. How to size around charger capacity instead.