After having to get a jump every single time i wanted to start my truck this winter, i went out and bought an optima yellow top in march. I havent had any trouble with it until just the other day. I drove up from Houston and then parked my truck for just about 2 weeks (dont drive it too often here in Austin since most things i need are pretty close). Anyway, go to start her up and she just doesnt have quite enough juice to turn over, came close though... I have my amp hooked up to a switch turned off that runs from my head unit which was also obviously off. Then my KCs are run via relays through switches next to that same switch for the amp, which were off as well. Then there is my security system, which is really touchy. You get close and it will warn you pretty easily, but just the short warning chirps. So, im just wondering what drained it? I guess if i have to in order to have a working truck, ill just run over weekly and start her up and let her run for a little... Just a little perplexing since i thought i fixed this issue with the new battery.

 

Might want to start with having the battery & Alternator load tested to see if anything is going on there. Could be the new battery is having an issue, not unheard of.

Next would be to see if there is a drain on the system, aside from the truck's normal range.

Idle in a paring lot will not charge the battery, you would need to have it at speed to have it charge. You can drive around at 40 MPH ( or around that speed depending on the gears ) in 2nd gear, that would keep the RPM up high enough.

 

1) Optimas (& other AGM batteries) are not good. Their only advantage is that they don't leak if you puncture them or mount them upside-down. A high-quality wet cell (MotorCraft, Interstate MTP, Sears DieHard Gold) will outperform an AGM of the same BCI group in every way.

2) The alternator isn't a dead battery charger, and shouldn't be used as one. It damages the battery & the alternator. Use a real battery charger (5-40A). If you need to maintain the battery's charge level during periods of disuse, get either a solar charger or a household trickle charger (0.5-3A).

3) The typical spec for maximum parasitic draw on the battery is <0.05A (<50mA), but normal draw is closer to 0.01A . You can measure yours with a cheap digital multimeter that has a 10A setting. Disconnect the (-) cable from the battery, touch the black meter lead to the battery (-) post, and the red to the cable end. If it shows less than 0.2A, you can switch to the 200mA range for a better reading. Read the meter instructions.

 

If your parking it for prolonged periods you may want to consider the use of a battery tender to overcome the parasitic draw of electrical juice needed of the pcm, security, and anything else that needs it when the truck is shut off.
Or......
If an outlet is not available where you park.
You could use a swap method of switching batteries before you use the truck.>>keep a battery where you live on a tender and just keep rotating them.

 

Real simple fix - disconnect your battery when you park it for long periods of time.

Don't connect your meter when the battery cables are disconnected. As soon as you make contact, your headlights will flash and blow your 10A fuse in your dmm. What you need is a battery knife switch. Install the switch between your batt neg and cable neg. Connect your red lead to the neg cable side and black lead to batt negative post. When your interior lights and all other loads are off, then disconnect the battery with the knife switch and any current will now flow thru the meter.

 

but it needs to be connected in order for my security system to run... after thinking about it though, having the prox sensor running for 2 weeks straight prob puts a good amount of strain on the battery. i guess ill just have to run out ever few days to make a small trip around the block to keep the charge up.

 

well, I finally got to o'reilly to have them check the battery. ended up I melted the core, so it got replaced for free. only 6 months old. I went ahead and bought a "Battery Brain Type IV" to help prevent draining it so much that I cant start it... we will see how that works.