Stock Battery Limitations

Hi everyone,

I searched the forums but couldn't get to the answer i'm seeking. I have a 3rd gen tacoma with the stock battery. I'm trying to better understand the current draw of LED lights and the limitations of the stock battery.

I'm in the process of installing a 40" BD OnX6 light bar & 4x BD rock lights on the roof of my truck. I'm okay with the wiring of it all, however i'm nervous the OnX6 is going to push my stock battery to the limit. I've tried to research what # of amps can be asked of the battery before it begins to outpace the charging from the alternator, but I haven't been successful. In addition to these added lights, I also have an HID retrofit setup for my headlights.

40" BD OnX6+ = 26.8A (high power) or 22.4A (dimmed)
BD Rock Lights = 0.40A each
Kustom 54 Lighting AB6 HIDs = ??A

Questions:
1) Assuming the battery is at full charge, how can I calculate how long the battery would last with the engine off with all four rock lights turned on? With the OnX6 turned on?
2) What amount of amp draw would be required in order to outpace the charging from the alternator?
3) I do not have any other accessories or gear requiring power. What would be a reasonable battery upgrade above stock to help manage the current draw from the lightbar and the rock lights?

Forgive me if my understanding of these mechanics is off. I'm relatively new to wiring/electrical practices and am trying to learn.

Thanks

 

Reserve power is calculated using a 10A draw so multiply your battery’s reserve power # by 10 and divide by the actual current, the result should be a number of minutes but don’t use them all or the truck may not start. 1.6A for the 4-rock lights and 26.8 for the bar. Personally I wouldn’t use the bar for very long without the motor running, it draws more than even both your high beams. If you need auxiliary lighting for camping get something specific to that need. An upgrade from a Group 24 to group 27 or even group 31(all available in agm which can offer deeper draw but cost more and weigh more) or addition of one if these as a second battery might be a good idea if you’re planning for extended outings or adding solar. Not sure I’d want to go off into the boonies planning to run a lot of lighting with the engine off and no backup battery.

 

This is helpful. For clarification, I do not plan on running the lightbar with the engine turned off. I was just trying to get a sense of perspective for how much power this light bar demands vs the capabilities of the stock battery. I would entertain the idea of running the rock lights with the truck off as long as it wouldn't kill the battery in <20min or so. I don't think I have the need for a dual battery setup yet, i'll look into potentially upgrading to a group 27 AGM battery.

Still a bit uncertain: will running the OnX6 on the stock battery with the engine on drain the battery faster than the alternator can recharge?

 

No, but if you add more high drain circuits you might want to consider the HD alternator installed with the tow package. Probably more critical to your immediate decision is the higher voltage requirement for AGM batteries, your current system can’t charge them completely without a separate plug-in charger to top it up regularly because 3rd gens can’t accept the mod used on 2nd gens. If you’re willing to add that bit of cost and maintenance time then fine, otherwise you’ll probably be happier with a standard battery in group 27 or 31.

 

Used to run 4 100w halogens off the ancient dodgy battery in my old 86.. you could hear the engine step up and the dash lights dipped when they all came on. I wouldn't let it sit with all those light on but it was fine for 12 years running them with the engine on.

LED use much less, I run two squadron sport (2A ea) and two Squadron Pro (2.9A ea) for around 10A when they are all lit and it doesn't mind a bit.