Originally Posted by jpeterman
Thanks everyone for the response. I'll change out as we are doing our upgrades.
One question I had was how did you measure the voltage drop before and after installing the LED lights. I can understand a amp drop but not volts.
THANKS AGAIN FOR ALL THE HELP. (some of us need it)
The ohms law formula is E=IR. E=voltage, I=current(amps), R=resistance. You can also use I=E over R, or R=E over I.
With a given resistance, when the voltage drops, the amps drop too.
Or you can say that with a given resistance, when the current (amps) drop, the voltage must also drop.
To measure a voltage drop is easy.
First you must have a DC voltmeter.
Then simply measure the applied voltage, in this case to a clearance light at the rear of the trailer, with the old type and then with the LEDS.
Several things can cause voltage drops, above normal.
1. Poor connections.
2. Excessive current draw.
3. Inadequate wire size.
4. Partial short circuit.
5. Corroded terminals.
6. Bad or poor grounds.
Electrical consumption can be related to water consumption.
The more water you require from a source requires that you increase the size of the hose and/or increase the water pressure.
Likewise with electricity. If you want more power, then you must increase the size of the wire (minimizing a voltage drop), or increase the voltage at the source.
This works for DC.
In the case of AC, things work a little different, since you would deal with resistance and impedance. That formula is E=IZ, Z being the resistance and impedance.
As an example, with RV air conditioners such as used by Airstream, when the voltage drops, the current draw will increase because the compressor and the fan motor must work harder.
That's why using a under rated extension cord on an RV, will cause air conditioners to not run properly, and/or become ruined, rather quickly.