Quote:
Originally Posted by Padgett
Mist admit I'd be concerned about putting 28vdc on the TM 12vdc system. 15v ok but not 28.
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I will prepare and attach a corrected diagram later tonight. There are
three Relays within the Trailer. The "Detector Relay" power circuit is connected to a 12V Trailmanor lead, un-switched. On the output side, this lead becomes the "control circuit" for two other 5-pin Relays (with 12V coils), and then connects to Frame Ground - creating the voltage differential to activate
both coils when
12V is present on the "control" wire.
The Bargeman "battery charge +" input is connected to both the "Detector Relay" Control, AND to the common POWER input of Relay "1A" (the missing Relay). When 12V is
not present on Relay "1A" coil control, the common POWER lead is connected to a fused battery link. (The TM thus has a direct connection from Bargeman to Battery, through a fuse). But, when that Relay is switched - the alternate "POWER" path switches into the other connection.
That connection hooks into the second Relay, on the "connected when coil IS powered" switched power lead. As Kevin's diagram correctly shows, the "common" power lead goes to the Solar Controller, and the lead "connected when Coil
IS NOT powered" goes up to Solar Panel "output "+".
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When the GMC Tow Vehicle isn't connected, and when the GMC (or other "TV") supplies only 12-15 volts on the Bargeman "Battery Charge +" power lead, the "Detector Relay" doesn't connect the 12V TM supply line to the "control circuit" output wire - the "control circuit rests at zero volts (TM Ground), and the 5-pin Relays Coils are not powered. The "unpowered" State is: Bargeman "Battery Charge" (Shared lead) connects to a battery terminal through Relay "1A", and "Solar Controller PV +" (Shared lead on Relay 2) connects to the genuine Solar Panels.
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But now Kevin flips the switch. The Bargeman Voltage goes up to 24V, and the "Detector Relay" makes the connection, putting 12V power on the "coil control wire". Relay 1A disconnects the battery (activating "24V Bargeman Power" into Relay 2);
and Relay 2 switches the Solar Controller "PV + input" from the "genuine Solar Array", over to the "24V Bargeman Power" connector.
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For a very short time (while the coil of Relay 1A gets "pulled in"), the battery might be connected at 24V. But the battery can absorb that power for a short time. (It is therefore important that Relay 1A be reliable.) On Relay #2, it is also possible to have "24V Bargeman power" connected to Solar Controller input for a short time, before high voltage actually becomes present on that wire. Zero input power results at the Solar Controller.
Because the hold-in Voltage within a "24V" Relay,
after it has switched, can be less than 12V, the Tow Vehicle switch (back to "12V mode" might not cause the TM to switch back. (The genuine Solar panels don't get connected, and the Solar Controller receives only "12V" from the Tow Vehicle.) To force switch-back, just disconnect the Bargeman Adapter at the "TV" hitch for a moment, and then plug it back in. (Or simply turn the "TV" off for a moment.)