Monday, Apr 28, 2003 at 19:13
Hi All.
I'm gonna give you all my Two Cents worth of Advice..
I am an AutoElectrican and a Competent one.
If you are trying to Charge your Battery in your Camper you need to make a few checks.
In your post above, You mention that your batteries in your vehicle are charging at 12.93 volts.
Well My Friend, Thats not enough. You need to be charging your batteries at 13.8 to 14.5 volts. Make sure you make your Voltage Checks with the Engine running at 2000rpm or more.
Calcium Batteries will take a higher Voltage charge. I think to 15.5 volts.
Amperage is not as critical as most Car Batteries can take almost as much current as you can throw at em but only to the suggested voltages.
If your Battery was dead falt and you Jump Started your Vehicle and The Alternator on your vehicle was rated at 80 amps, That's what the Battery would be charged at. Thing is with batteries is that the resistance is not fixed. As the battery charges to 13.8-14.5 volts, The resistance becomes higher. This reduces the load on the Alternator. At 13.8 volts, The battery may only be drawing 1amp to keep it that level.
The trailer plug cannot handle the current that may be required of it. I would seriously suggest that you fit a seperate socket that would be rated to at least 50amps. You must also understand that you do get a voltage drop through the length of wire that you are using. The more current that you would pull through the wiring, the more voltage drop. Depending on the size of the wire.
Have you ever noticed that the wiring on Vehicles is getting thinner? That's because of the current being drawn. Let's take a Tail Light Bulb. Ok, You do not need a 4mm wire to power up the Tail Lights. This is because the total amount of current that would be drawn by the tail lights is easily handled by a thinner wire and the Voltage drop that would occur is negligable for the Tail Lights to work. Now, What if we were to run the Headlights with that wire?
Well, We would then get a severe drop in voltage because now we are drawing more current through the wire than what it's capable of delivering. The wire is now becoming resistive to the load. The wire may even start to get warm or even hot.
It's a pretty complex subject once you really start to get into it.
E.g: Think of your wire as a hose. How much water will come through a small hose as to a large hose. The Larger the hose the more water you can put through it.
For the people who are thinking about Buying Battery Isolators for $125.00 or more, Did you know that a $30.00 solenoid can almost do exactly the same thing? It may even be more reliable.
Regards to you all, I hope this helps. If anyone would like any information on anything to do with Automotive Electrics or Electronics, Please Email me at, damian007@optusnet.com.au
I'll be only to happy to help if I can.
Damian Mueller
AnswerID:
18617