When should a diesel truck battery be replaced?

The average life of an automotive battery is three to five years. If your truck is older than that, and there is a possibility of being stranded somewhere remote where help might be a long time coming, you might want to replace the batteries just as a precaution.

Do I need to replace both batteries in my diesel truck?

Glowplugs in diesel engines are used before the engine even starts to preheat the combustion chamber and they consume a fair amount of electrical energy to do that. However, if you have a diesel truck with two batteries and one needs to be replaced, you really should replace both batteries at the same time.

What kind of battery does a diesel truck use?

Diesel starting batteries, like most 12 volt RV battery systems, are wired in parallel, so any readings you take with the batteries still connected to the truck are misleading, you’ll get the same readings on each battery. Anyhow, the voltage readings I got on my work bench at home were very interesting, though not surprising.

How do you know if a diesel battery needs to be replaced?

By taking separate voltage readings of each using a multi-meter or battery analyzer after removing them from your truck. Yeah, I know doing this is a pain, but it’s important to do this in diesels because removing them electrically separates the batteries from each other.

How long does a diesel engine battery last?

What makes the sticker shock even worse is that diesel engines require two rather than one. Automotive starting batteries typically last about five years, but the triple-digit heat here in Arizona reduces their life expectancy to three to four years at the most (mine lasted a little over three years).

Why do you need two batteries to start a diesel engine?

Some of you may be wondering why two batteries are needed to start a diesel engine. There are two reasons. The main reason is that it takes a lot of amperage to turnover a high-compression diesel engine.