Batteries

Almost all combat robots are powered by batteries. Although compressed gas or internal combustion engines are occasionally used (especially for weapons), batteries are always required.

There are too many batteries to choose from to make any meaningful list here, so we list some criteria to consider when choosing a battery.

Roger's Hobby Center has a really good guide to lipo batteries.

Battery types (chemistry)

Nowadays (2021) nearly all combat robots run on lithium polymer (LiPo) battery packs. This is because they give the highest power density and are widely available. For safety, childrens' toy robots usually use a different type, generally NiMH. Transmitters often use other types.

Series and parallel cells

Battery packs are generally formed of more than one "cell". These are put in series or occasionally parallel.

Series cells = more volts Parallel cells = more amps

Be careful with series or parallel cells - it is usually better to buy a ready made pack with the correct number / size of cells.

Safety

See Roger's Hobby center (link above). Rules of thumb:

• Use the right charger type (and settings)
• Don't use parallel charging boards
• Charge in a lipo bag
• discard damaged / puffy packs

Connectors

There are too many annoying connector types which aren't compatible :) we could put a picture of some of them here.