Battery types: starter, deep cycle, traction and stationary

Every battery here is described by the figures that actually decide a purchase: voltage, capacity in Ah, cold cranking current, case size, terminal layout and chemistry. Start with the job the battery has to do, then filter by those numbers.

Starting a vehicle, powering a caravan, moving a forklift or backing up a server all need a different design, even when the voltage matches.

Four families, four ways of using energy

Batteries differ less in their label than in how they are discharged. Choosing the right family first avoids most premature failures.

• Starter batteries deliver a very high current for a few seconds to crank an engine, then get recharged by the alternator. See our starter batteries for cars, motorcycles, trucks and boats.
• Deep cycle batteries release energy slowly over hours and tolerate repeated deep discharges: caravans, solar systems, wheelchairs. Browse deep cycle batteries.
• Traction batteries move electric machines every working day, including 2 V PzS/PzB cells for forklifts. Find them in traction batteries.
• Standby batteries stay on float charge and only work when the mains fails: UPS, telecom, alarms. Go to stationary batteries.

The data sheet, line by line

Voltage (V) must match the system: 12 V is the common case, while 2 V, 6 V and 8 V units are combined in series for higher voltages. Capacity (Ah) tells you how much energy is stored; for cycling use it is usually quoted at a 20-hour rate. CCA or EN measures cranking power at −18 °C and matters only for starting. Dimensions and terminal position decide whether the battery physically fits and whether the cables reach.

Lead-acid, AGM, EFB, GEL or lithium

Flooded lead-acid is the simplest and most widespread design. EFB strengthens it for frequent restarts. AGM holds the electrolyte in glass mats, is sealed and accepts more cycling. GEL is the most tolerant of slow, deep discharges. Lithium (LiFePO4 or Li-ion) is far lighter and keeps its voltage stable, but needs a compatible charging profile; check our battery chargers before switching chemistry.

Frequently asked questions

Can I use a starter battery for a caravan or solar system?

It will work for a short time, but its thin plates are not built for deep discharges and it loses capacity quickly. A deep cycle model is the sensible choice for that use.

Is a higher Ah figure always better?

Only if the battery still fits and your charging source can refill it. An oversized battery that is never fully charged ages faster than a correctly sized one.

Where do I find the data of my current battery?

On the label: voltage, Ah, CCA or EN and often a reference code. Measure the case and note which side the positive terminal is on before comparing.