Add extra battery

How many batteries do you have now? What kind of truck?

 

Look at batteries, you’ll see there all connected. Simply add another in the chain, as close as possible. Positive to positive, negative to negative. You’ll need 2 new cables. If there’s room in the battery box, good, If not, you’ll need cables long enough to reach the others. Good time to clean up all the batteries connections, and coat them with dielectric grease, or some permatex ( or similar) battery terminal protection spray.

 

It's very easy if you have room for an extra battery. You can buy the short cables to connect to the other batteries from a heavy duty truck parts store. Having more batteries won't hurt anything. It will also make your truck easier to start in the winter months

 

Your not adding voltage just capacity. Think of going from a 3 gallon bucket to a 4 gallon.

 

One or two batteries won't have much of an effect. Four or six more, like for an electric APU , then you need more alternator capacity.

 

No, won’t hurt a thing.

 

No offence but adding an extra battery for extra lights is not a smart move. Let me explain:

Batteries are for starting the truck, acting as a "shock absorber" for voltage spikes from the alternator and as a temporary backup supply when electrical loads exceed alternator output (ie alternator fails).

So do yourself a favour and upgrade to a higher amperage output alternator because if you run your current alternator at full capacity for extended periods you WILL cook it.