How much of the battery you actually use before recharging. LiFePO₄ tolerates deep cycles, so usable capacity is high — but cold reduces it.
Usable capacity is not the same as rated capacity. Depth of discharge is how much you actually take out before recharging — and it drives how big a bank you really need.
It feeds directly into bank sizing: a higher safe DoD (lithium tolerates deep cycles) means you need fewer amp-hours for the same usable energy, though cold cuts it.
Design your van, boat, cabin or RV system in Wattonomy and it sizes the bank around an honest depth of discharge and the cold-weather capacity hit, not the sticker rating — from the appliances you actually run, sized to the recognized standard for your region. You see it on the wiring diagram, in the sized parts list, and in a plain-English build pack that explains the reasoning behind every choice. No account, no email — about a minute to a complete, validated design.
Lithium tolerates deep cycling — often 80-90% usable — far more than lead-acid. Wattonomy sizes to an honest figure so you are not buying capacity you cannot use.
Yes — cold reduces usable capacity and charging is restricted below freezing. The tool factors a climate allowance into the bank size.
It takes about a minute. No account, no email.