Easy Amps

Simple ammeter for your car;

Most amateurs belabor the fact that many of the present day American cars come equipped with those questionably functional "idiot lights." The average amateur, not qualifying as an idiots finds them extremely difficult to read in determining how much current his rig and other accessories are drawing from an already overloaded battery.

The generally accepted method for monitoring current in a vehicle so equipped is to mount an ammeter somewhere in or on the dashboard, break Ihe dc line at an appropriate place, run a pair of heavy leads through the firewall and connect them to the meter

This has many disadvantages. The last time I tried this using No. 10 insulated copper wire a voltage drop of approximately 0.7V under a load of 18 to 20 amps was noted, not to mention the job of knocking a large size feed-through hole in the firewall. When installing the old rig in a new car, I decided to take a iazy-type approach to this problem of remotely reading current.

This was accomplished by the simple expedient of inserting a zero center 30-0-30 microammeter from the negative battery terminal to any point on the body of the vehicle where a good ground can be obtained, This has the effect of reading the voltage drop across the negative battery cable which is directly proportional to the current flow. In my case, I found that the meter reading was slightly higher than the actual current. This was proved by inserting a standard 0-30 ampere meter in the dc line and observing the current when the lights or

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