my 84/87 toyota, the battery seems to drain down over a few days. How do i go about finding what is draining it. It's a good battery, to double check i'm gonna swap batteries out of my every day truck and see. But how does one check to see if something else is draining it. It has no radio, cb, lights or nothing i know of on the truck.

One trick is to connect a current meter between the batt and the cable. See what the draw is with everything turned off. Then, pull fuses one by one, until the meter drops to zero. That will pinpoint the circuit giving you drain issues. Haven't needed to do it myself, but someone will chime in for a better understanding of the meter hook up.

Here is a link:
- http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

Basically you want to put your meter on the amps/current range and hook the probes between a battery post and the cable that attached to the post. This way the current flows through the meter and it'll read the current (use the highest current scale it offers to start with). Normal drain (for clock, computer, radio, etc.) is maybe 20 mA (0.020 amps) or less. Current flows much higher than that indicate something is amiss. To find out the cause, start pulling fuses to find out which one feeds the offending device(s). Then track down what is connected to that fuse and disconnect things until you find the current draining device. I had a case where it was a radio standby memory circuit that was pulling ~40 mA. I had wired the radio such that it had power all the time and with power to it's power input, it pulled that much current when it was off. I re-wired it so that the main radio power was switched off with the engine and only the memory power was constant. That nearly eliminated the current drain. Note that 40 mA drain will discharge a battery in 2 weeks or so. Higher drains = faster discharge time.