10cm 25 mm2 250 Amp Heavy Battery Cable

Roughly the maximum is 10 amps per mm2 of copper at 20°C, so 16 mm2 carries 160 amps, 25 mm2 250, 50 mm2 500 and 95 mm2 950. That figure is on the spec table above for this cable.

That is the heating limit and it is not usually what limits you. On a DC run the voltage drop over the length is the restriction, not the raw current carrying capacity, so a cable that will not overheat can still be far too small for the job.

It depends on three things: the current, the length of the run, and what the cable is feeding. A charging run wants about 1 percent voltage drop or the battery never finishes its absorption stage. Battery to inverter about 2 percent. A non-critical light will live with 7.

Put your own numbers in and it will tell you which size holds up.

Open the DC voltage drop calculator

16 mm2 is AWG 5, 25 mm2 is AWG 3, 35 mm2 is AWG 2, 50 mm2 is AWG 0 and 95 mm2 is AWG 000. The AWG number for this cable is on the spec table above.

The two systems do not line up exactly, so the nearest AWG size is always a little larger or smaller than the metric one. 1/0 AWG is 53.5 mm2 and the cable you buy is 50 mm2.

See the full AWG to mm2 conversion chart

A pair, one red one black, for anything needing a positive and a negative: a battery to an inverter, a bank to a busbar, a controller to a battery.

A single where you are only bridging one leg, which is most often putting a circuit breaker, a shunt or an isolator into a circuit that already exists.

The eye terminals are 8.2 mm and take up to an M8 bolt, which covers most battery posts and busbars on a system this size. Measure your stud if you are not sure.

For this job, yes. The flexible cable we sell by the metre is welding cable: a high strand count so it bends into tight spaces instead of fighting you, with the same copper cross section as anything else at that size.

It is what we use ourselves for battery to inverter runs and for getting power out of wind and hydro turbines.

Every connection adds resistance, and resistance on a high current DC circuit turns into heat and lost volts. Soldered connections are what make a low loss, high reliability cable that will serve you for years without degradation, corrosion or wear.

They cost more to make. It is the reason they last.

As short as you practically can. Voltage drop is proportional to length, so halving the run halves the loss, and it is usually cheaper to move the inverter than to buy the next size up in cable.

If the length is fixed, size up and check the number rather than guessing.