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Author Topic: Cole Hersee 48530 smart isolator alternate wiring options  (Read 364 times)


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Cole Hersee 48530 smart isolator alternate wiring options
« on: January 21, 2018, 03:40:32 PM »
I purchased one of these smart isolators to replace three relays that were on my rig.
1 of the relays was controlled by the ignition switch. Whenver ignition on, the batteries were connected.
1 of the relays was controlled by a momentary switch for help starting.
and the last relay was controlled by a toggle switch to force them connected.
I ripped all that out, taking care to mark the wires. All relays were grounded locally and the switched wire came in with 12V.
Quite a complicated custom setup. While disassembling I noticed the 3 chassis batteries, connected in parallel were connected in the simple unbalanced way, which I corrected, by making sure the main ground connection was on the furthest battery away from the main power connection.
While dissembling I also noticed the 12V for the fridge was hardwired to the chassis batteries as well so I moved that back to the fused 12V distribution panel on a lightly loaded line. Not sure why it was hardwired to chassis
I order the 48530 and wired it in. But one thing I didn't like is that if I use the purple "override" and apply 12V to it via the momentary switch, after releasing the momenrary switch driving the purple override, the relay doesn't disengage. This doesn't seem right.
But I think I have a solution. The 48530 is actually two combined products. There is what appears to be their standard 200A continuous duty relay, and a mounting bracket with the "smarts" in an enclosed module underneath it. The module monitors the voltage on either side of the battery connections of the relay, the purple override wire, and it has two wires that are connected to the control inputs of the relay. Measuring the voltages it appears that the control module just sends 12V to one of the control connectors and then actually controls the other connector by grounding it through a control transistor. I surmised this because I get about a .6V difference between battery GND and control connection on the relay, and there is virtually no difference in voltage between the other control connection and 12V on the batteries.
So instead of using the momentary switch to send 12V to the purple wire, I could just hook the momentary override switch to GND on one side, and the other side to the GND control side of the relay, essentially bypassing the control module.
So with this setup, when cranking the motor, if I think I need a boost to start the engine, I can just hit the override, and only while I have the momentary switch pressed, will the relay be connected, and as soon as I release the switch, the batteries will get isolated. This will allow the alternator to first charge the chassis battieries up, before connecting the house batteries. At least thats the way I thought the SMART isolator should work.
Anyone else try this?



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  • Posts: 5
Re: Cole Hersee 48530 smart isolator alternate wiring options
« Reply #1 on: January 21, 2018, 03:42:14 PM »
Oh ya, my rig was built in 1995 or so and it looked like all the relay isolators where original. So I was also thinking that replacing them might just be a good ideas as well.