Battery Always Dies

[Ziiii]

Hello! I have a 2004 Ford e450 shuttle bus and I installed a battery disconnect switch to Help with battery drainage but it's not working. The bus also has an auxiliary kill switch but that doesn't seem to help the suitation.

Does anyone know of a heavy duty kill switch that would help me not run through batteries left and right?

Or happen to know what's causing this battery draining

Or what fuses I can let go of. I use the A/C & Door opening switch.

[nikitis]

My advice is to put a battery disconnect switch on the negative ground like right after the battery.

There are a lot of positive items plugged into the battery, but everything that can drain goes through that ground. Plus ground is better against surges as surges can dissipate better into the ground plane, when you turn it on.

I've had good luck with the cole hersee model:

https://www.amazon.com/Cole-Hersee-7...s%2C102&sr=8-3

[Rucker]

Are your existing batteries recent? I ask, because it may not be a case of battery drain but rather just a good pair of new batteries.

I had a similar problem after I finished my build. (I have a similar rig to yours, by the way). The battery would die after a week of not running the bus.

I put two new batteries in, and figured if they drain I'd have to systematically trace every circuit; but the batteries held a charge even after a month of not running....

For battery drain, I'd use a multimeter and check the ohms of the load side of each fuse (pull the fuse, confirm which is the battery side by checking for 12VDC, then check the other side to see if there's anything other than zero Ohms between that and battery ground). You should be able to identify the short pretty quick.

If there's a short between the battery and the fuse panels, that's a little more difficult to check. I'd start with the above first.

Let us know how it's going.

[Ziiii]

I'm not sure what you mean by the load side of the fuse. Are you talking about the fuse box under the steering wheel/hood/right or passenger entry?

And I the 12 VDC is a setting in the multimeter? Forgive me I am VERY green in this area.

When I got the bus I bought two new auxiliary batteries and a new ignition battery.

[ewo1]

Originally Posted by Ziiii

I'm not sure what you mean by the load side of the fuse.

Load/field side means the output side of the fuse, not where power comes in but goes out to the device you are powering ....

[demoman]

I had a problem with a semi truck where the batteries would drain down over a short time and the shop I had it at just said oh they all do that because the computer draws continuously. I didn't accept it so I took the ground off and put a multimeter set to current across negative battery to the lead. With the key off and door closed I saw how much draw there was and had a helper pull out and replace the fuses one at a time to see which one was carrying the load. I found one that had a continuous draw of about half an amp but nothing enough to account for a dead battery in a couple days. That's probably your easiest way to narrow down the source of the draw.

[nikitis]

Originally Posted by demoman

I had a problem with a semi truck where the batteries would drain down over a short time and the shop I had it at just said oh they all do that because the computer draws continuously. I didn't accept it so I took the ground off and put a multimeter set to current across negative battery to the lead. With the key off and door closed I saw how much draw there was and had a helper pull out and replace the fuses one at a time to see which one was carrying the load. I found one that had a continuous draw of about half an amp but nothing enough to account for a dead battery in a couple days. That's probably your easiest way to narrow down the source of the draw.

There are continuous draws from your ECM, he's right about that, where he is lazy is he didn't check for 3rd party aftermarket installs of devices that could be parasitic because the installer of such devices was lazy and tied them to a main line and not behind a key on circuit.

[nords]

Be sure the top of your battery is completely clean. That film of dust, grime, oil, and whatnot can pass enough current to drain the battery slowly, even with nothing connected to the terminals. In a shop class I took, the instructor put a meter on the plus terminal and showed us a voltage from that point as he slid the other probe across the top of the battery.