Technical resources
These guides are written for the person who has to sign off a specification, not for a search engine. Each one explains what the decision actually turns on and where the common mistakes are made.
Written from failure analysis
Most of what is on these pages came from examining packs that came back. A pack that fails at eighteen months instead of five years tells you something specific about how it was specified — usually that one parameter was assumed rather than calculated.
The guides are deliberately blunt about trade-offs. Where a cheaper solution is genuinely adequate, we say so. Where an option that looks cheaper costs more over the life of the system, we quantify it.
What is covered
- Chemistry selection — LiFePO4 against NMC and against lead-acid, on cost per usable kilowatt-hour and on safety.
- Pack sizing — how to get from a load list and a duty cycle to a capacity and a current rating.
- BMS specification — what to check on a BMS board before you buy a thousand of them.
- Certification — what UN38.3, IEC 62619 and UL 1973 actually cover, and which one your market requires.
- Cycle life and warranty — how cycle life is measured, and why the datasheet figure and your application will differ.
Technical guides
Battery certification, explained
Certification rarely fails on the test. It fails because the report describes a build different from the one being shipped — a cell substitution, a BMS change, a modified enclosure — and nobody notices until customs or an audit asks.
Read guideCycle life and warranty, honestly
A 6,000-cycle rating is not a promise for six thousand of your cycles. It is a measurement at a defined depth of discharge, temperature and charge rate — and if any of those differ, the number does not transfer.
Read guideHow to size a battery pack
Most undersized packs are undersized on current, not on energy. Working through the five steps below in order avoids the two mistakes that account for most specification failures.
Read guideHow to specify a BMS
The BMS is the pack's operating envelope — cut-offs, current limits, balancing, temperature derating and the data your controller sees. Two packs with identical cells and different BMS configurations are different products.
Read guideLiFePO4 vs NMC vs lead-acid
The comparison that matters is not energy density on a datasheet. It is cost per usable kilowatt-hour over the life of the system, which depends on depth of discharge, cycle life and how the chemistry behaves at the temperature it will actually see.
Read guide