electrical help - do a need a 2nd battery?

I have added a ton of accessories to my truck...LED lights, SPOD, twin compressor, compustar alarm, amp and subs etc and a winch coming. at what point do I need a 2nd battery? the alarm I had installed shows battery voltage through an app. what is too low? I will not do much with the truck when its not running - primarily I just don't want to have a starting problem. the LED flasher that shows the alarm is on makes me cringe but they installer says its no problem . thoughts? is there a minimum size for battery? if I need 2 batteries how do I set it up? thank you for any help!

 

You don’t need a second battery really. The only time it makes sense is if you’re going to be powering stuff from the truck while it isn’t running. Better off getting a portable jump pack if you’re worried about not being able to start.

 

What is the function of the battery?

It is a reserve storage of energy used to “start” the truck. Once running the alternator turns with the engine and generates electricity to fill the “reserve”energy in the battery back to full. This is to make sure the truck starts next time.

While the truck is running, yes the electrical system is taking energy from the battery to power everything but at the same time the alternator is generating new energy to put into the battery. The battery is really just a middle man “storage tank” for energy while the truck is running.

The key here is you always have to make sure the battery level is full to start the truck/kick the system on and get it going.

You really only need a second battery when the amount of power you are consuming out of the battery continuously is more than what the alternator is putting back in. IE your reserve is being depleted even while the truck is running.

For your case almost none of your systems should be running while the truck is off minus the alarm. These are generally low power consumption and a good battery can power that security LED for a LONG time. It being on and flashing while the truck is off is not a concern.

The real question is how many of your added systems will be running at the same time while the truck is on? The winch and compressors, although high power consumption, will probably only be used for short periods of time. The LED lights really are not a concern assuming you don’t have like a thousand of them. LEDs are much lower power consumption that older incandescent light bulbs.

The radio could be a issues depending on how much/how big the load is. It runs basically 100% of the time the truck is on.

It really depends on how many of them systems you are running at the same time for extended periods of time. I personally would think if you have a good battery and correctly working charging system you are not in a position where a second battery is needed. However you can always add one for extra insurance.

Generally you want at least 12v in the battery to start the truck. Getting down in the 11v range and lower is the danger zone. A good fully charged battery will be 12-13v with almost 14v going in while alternator is running charging it.

Long story short as long as you are not running all these systems with the truck turned off you are probably fine.

If you really want to get into calculating load and power consumption of each added circuit you can. This would just give a better idea of how much you are actually using vs what is needed