Category Bit Bucket

Miscellaneous distractions and diversions.

Battery discharge test setup

Used LiFePO4 Battery Fiasco

After more thorough testing of the used LiFePO4 battery that I described in my previous post, I’ve reached the sad conclusion that it’s essentially a worthless piece of junk. Encouraged by stories from mobile-solarpower.com and other sources, I’d hoped this…

Testing a used LiFePO4 battery

Used Lithium Battery Mysteries

My used LiFePO4 battery (lithium iron phosphate) arrived yesterday. Who buys used batteries? I do, apparently. I’ve been putting the battery through its paces to see how much of the original capacity of 45 Ah / 675 Wh still remains.…

LiFePO4 and lead acid batteries

Batteries – Lead Acid or Lithium?

What’s the most expensive component in a small off-grid solar setup? You might assume it would be the solar panels, but the cost of panels can be surprisingly low. For many people, the batteries are the single most expensive element…

Solar panel on a patio

Small-Scale Solar Experiments

While sheltering in place this week, I’ve been tinkering with a small-scale setup for solar power generation. I’ve got a 100 watt solar panel, and access to the sun. What fun things can I do with this? Is it actually…

Battery constant current and constant power discharge tables

Constant Power Battery Discharge

Recently I’ve been looking at battery datasheets, in preparation for an off-grid solar project. I’ve noticed something strange about the “constant power discharge” numbers in the datasheets of several 12V lead acid batteries. Here’s an example from a 20 Ah…

Steve holding a logic analyzer

Shelter In Place

My family and I have been ordered to shelter at home until at least April 7, to help stop transmission of COVID-19 in the San Francisco area. Many of you may already be living under similar orders, or will be…

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