2nd Gen Non-Engine/Transmission Battery isolator questions

[Wasilla Rod]

Just steped up to a 9-6 Northern lite camper from a basic sleeper with no bells or whistles. Looks like I need to install a battery isolator to charge the house battery and keep the starting battery from being drawn down or otherwise abused. Any hot tips or suggestions on size or brand.



96 -2500 with no frills

 

[dresslered]

I went a real simple route and just installed a solenoid switch. It is rated somewhere around 100-amps and is switched on/off with the truck's ignition (there is also a manual override switch). I also rewired the truck's trailer harness and really beefed up the ground and power lines which run directly to the battery for minimal voltage drops. There is an inline 0. 01-ohm shunt for monitoring the current flowing into and out of the camper batteries while I'm on the road. I also put in a secondary Pollack 7-pin connector switch inside the bed just for the camper. It keeps the connector lines very short and frees the one on my hitch for towing.

 

[SBall]

For my Lance camper, I elected to mount a voltage-sensing relay IN THE CAMPER rather than mount a relay or solenoid in the already crowded engine compartment. Being a relay, it doesn't impose any voltage drop typical of the diode isolators, and it works like a charm. The sensing circuit closes the relay automatically only when your engine is running, completing the charging circuit to your house batteries. Sometimes also called "battery combiners", I sourced mine from West Marine. I also installed an E-Meter in the camper to monitor house battery amp-hours which also has worked extremely. I like Dave's installation of the ammeter in the truck with the calibrated shunt. That's a neat idea that would save me having to climb in the camper to monitor whether the camper batteries are charging or not.

Steve

 

[Desert Proven]

I use one of these. I previously had a solenoid type and ran into problems. This is working better for me.



http://www.hellroaring.com/bic75150.htm



Dressler, I like your ammeter in cab. Can you provide some more details as to how that is set up?



thanks

 

[dresslered]

Merek, the Hellroaring battery isolator is definitely the best way to go. It is solid state (reliable) and with the FET technology, they have virtually eliminated all diode voltage drops and heating. The only advantage to the solenoid switch is a very low price in comparison. So far, I have had no troubles with the solenoid switch.



There's really nothing tricky about my ammeter set-up. It is basically just a voltmeter that measures the slight voltage drop across the inline shunt resistor (this is the method that most ammeters use). By using a . 01-ohm shunt, I drop 0. 1V for every 10-amps that flows. I programmed the ammeter (voltmeter) to slide the decimal over two places so it reads 10. 0 as well rather than 0. 10. As the batteries are charged, the current is reduced thus the voltage drop diminishes to a negligeable amount. These type of voltmeters can by purchased at almost any electronics store. I got mine at http://www.datel.com. Also, make sure that the wattage of the shunt accomidates the amperage that you can potentially pull. A 100-watt shunt is good up to 100-amps.



Lastly, I connected my shunt on the return (ground) line rather than the battery supply line. This shows the total sum of all voltages being used. Remember, there are several power lines going into the camper (blinkers, lights, etc. ), but only one return coming out. I then have a clear indication that my turn signals, etc. are working as well as the battery charging.



P. S. As an afterthought, I ran a twisted pair (sense leads) from the shunt to the ammeter for better noise immunity.