Hi Pete,
John describes it quite well. I used 3 ea. 1 Ohm 25 Watt surface mount resistors in series for 3 Ohms. In series with the plus 12 Volt lead to the contactor. Next time I have occasion to get in there, I'll take a picture and post it.
They also make 5 and 10 Watt devices that are usually green porcelain and have leads out both ends. These may be easier to mount especially if some sort of terminal block with several screw posts is used. Use one 3 Ohm 10 Watt or two 1.5 Ohm 5 Watt or three 1 Ohm 5 Watt resistors. Remember, the resistors will get warm to hot so mount them above the contactor if possible or far below if not.
As I think back, maybe that's what I used. Seems like the dead spots in my memory are increasing!
Hi John,
Did you give up on Texas? I did a little research and came up snake eye. Looks like we're stuck with the Trombetta or $180.00 for the Blue Sea 9112. Although the Blue Sea does have certain advantages, if you already have an Eco Charge installed, it seems a rather high price to do what is already being done.
The Cole Hersee 24059BP Continuous Duty Solenoid suggested by Glenn is only rated for 85 Amps. This probably won't be enough if the boost switch is accidentally (or on purpose) activated during engine cranking.
According to Trombetta's web brochure for the ˜Bear', they haven't done anything to the coil of the 12 Volt continuous part. It's still listed as 7.7 Ohms and with 14 Volts applied that works out to 25 Watts. After several hours of driving, it's going to get pretty hot inside that contactors housing.
Hi Monte,
I may have been misleading about the coil. The coil doesn't open up but becomes hot enough to discolor or even burn the insulation around the magnet wire. Heat is an enemy of copper wire's resistance reducing the current and hence magnetism. Heat also affects the armature of the contactor increasing the magnetic reluctance and reducing the force available to pull in the contactor. Heat also speeds up the oxidation of the contacts.
My guess would be that 99% or better of all failures of this device are a result of contact oxidation and is why your procedure of toggling the contactor works. This brakes through the Copper Oxide layer.
Silver has both a lower oxidation rate and a thinner oxidation layer. Since Silver is a softer material, when the contacts close, it's very easy to break through this Silver Oxide layer. This translates to increased reliability and reduced closed contact resistance.
Hi Harry,
I replace the Dimensions inverter with a ProSine 2.0 and have now added the spare ProSine in parallel. I'm only using one unit to invert but have both units set up to charge. They can bring my 440 Amp./Hour AGM battery bank up from 50% discharge in a little over an hour. Try that with flooded batteries and they won't last long.
I knew of the heat problem soon after we got this coach so I installed a muffin fan at the foot of the bed and ducted the air into the electrical compartment with flexible dryer exhaust hose. The return is back out the top of the compartment, under the bed and out. This doesn't provide a positive pressure, a nice feature of John's setup, but does keep the compartment much cooler when needed.
For when we hit dirt roads, I installed a reversing switch on the kitchen roof fan, reversed the outside hood, and reversed the fan blades. Opening the fan door acts as an air scoop and with the fan on high and reversed, a nice high pressure is created inside the RV that can only escape through any of the cracks in the basement compartments. This keeps dust and dirt from entering any of the compartments except for the StoreMore. Of course, the windows have to be closed for this to work but it's saved us from many dusty cleanups.
wagonmaster2
Chris is correct. And if the contactor doesn't tie the batteries together after the engine starts, the house batteries are not being charged. Unless you check it occasionally, this can go on for much too long. If the inverter is left on, this can discharge the house batteries in 8 hours much lower than they should be allowed to go and will shorten their life. If you pull into a park and check the house battery voltage right after shutdown, they should read around 13.8 Volts. If you see 12.5 or less your battery tie contactor didn't work.
