Battery Boost Switch

[zzjea]

Originally Posted by loulong

K3 is the relay (solenoid) that connects your batteries together when you press the aux/start switch -OR- when the circuitry senses that one of the battery sets is being charged. K3 is not on the circuit board, it will have large battery cable sized wires running directly to each battery.

The "electronic module" on your version is circuitry integrated into the circuit board.

As I said earlier, it's NOT just the boost function that you are missing (if the relay and circuitry are not functioning properly) it's the ability to charge ALL the batteries while driving or plugged to shore power. That is really the most important function.

I can't hear a clicking near the batteries when DW tries the boost switch and can't find a solenoid anywhere. Any ideas where it might be? Why would they refer to K3 when it's not part of the circuit board? The Siemens relay is K1, but I did not find any other "K" elements on the board itself.

John

[Old Bounder]

Originally Posted by zzjea

I can't hear a clicking near the batteries when DW tries the boost switch and can't find a solenoid anywhere. Any ideas where it might be? Why would they refer to K3 when it's not part of the circuit board? The Siemens relay is K1, but I did not find any other "K" elements on the board itself.
John

Is this circuit board in a box? Are the disconnect solenoids in the same box (behind the board? Are there large cables going to this box?

[zzjea]

Originally Posted by loulong

Is this circuit board in a box? Are the disconnect solenoids in the same box (behind the board? Are there large cables going to this box?

Here are 2 pics. No box but there is more behind the CB which is part of the entire assembly. Looks the same as the pic on the supplier page you gave me.

The lower right side of the board has the generator and jack pump terminal with a heavy gauge wire attached. Behind the board (yet part of the same assembly) is something large that could be a solenoid. It is connected to the CB via solid metal strips attached at terminal points on the board. This is the only thing I can find that might be what you are talking about. You can see in the second pic that there is about 2.5-3" of space between the board and the wall it is attached to. That space has a larger device that I am referring to that is likely the solenoid.

If it is that solenoid, I hope I can find a replacement as the new CB assembly is $457.

John

[zzjea]

This is exactly what mine looks like. Probably K3 is the solenoid behind the board. The one on the right must be the computer monitoring unit.

I tried it with ignition on and press boost switch. No click in the back compartment. Maybe the solenoid is bad.

[Old Bounder]

Originally Posted by zzjea

This is exactly what mine looks like. Probably K3 is the solenoid behind the board. The one on the right must be the computer monitoring unit.

I tried it with ignition on and press boost switch. No click in the back compartment. Maybe the solenoid is bad.

Yes, the solenoid on the left is the interconnect relay (K3). The chassis battery is connected to one side (large terminal) and the coach batteries are connected to the other. The two smaller terminals on the solenoid are the control wires.

That square box to the right of the solenoid is actually the battery disconnect solenoid, K2.

If you are plugged into shore power when you try the aux/start switch, you will not hear a click because the solenoid should already be closed by the comparator circuit. You must start the check with NO battery charging going on.

Run some interior lights and the chassis headlights for a few minutes before starting the test. Perform the troubleshooting test on the fourth page of the document.

If everything works except the actual switch, fuse 32 may be bad.

[zzjea]

Originally Posted by loulong

Yes, the solenoid on the left is the interconnect relay (K3). The chassis battery is connected to one side (large terminal) and the coach batteries are connected to the other. The two smaller terminals on the solenoid are the control wires.

That square box to the right of the solenoid is actually the battery disconnect solenoid, K2.

If you are plugged into shore power when you try the aux/start switch, you will not hear a click because the solenoid should already be closed by the comparator circuit. You must start the check with NO battery charging going on.

Run some interior lights and the chassis headlights for a few minutes before starting the test. Perform the troubleshooting test on the fourth page of the document.

If everything works except the actual switch, fuse 32 may be bad.

Thanks. I will give this a test.

[zzjea]

I did not have anyone to help me today so I could not do the boost switch test to hear a click. However, I did determine that the coach and chassis batteries are charging while on shore power OR when the engine is running. I put a multimeter on them and could tell they were charging.

The K3 solenoid is pretty hot to the touch while I was there. It did not "click" except when I removed F32 and when I re-installed it. BTW the fuses have an led to indicate if they are not powered. It came on when I removed it. Is K3 supposed to be that hot?

John

[Old Bounder]

The relay will be quite hot. It is rated "continuous duty" so should hold up under the heat.

If/when you have to replace it, get one with the same continuous duty rating, but they do make some with a higher coil current rating that will run cooler and hopefully last longer.

You can get solenoids from $20 to well above $100.

[zzjea]

Does the battery boost switch when pressed also connect both chassis and house battery banks to use when starting the genset? If the house batt bank is low, should the boost switch provide chassis amps to start the gen?

[Old Bounder]

Originally Posted by zzjea

Does the battery boost switch when pressed also connect both chassis and house battery banks to use when starting the genset? If the house batt bank is low, should the boost switch provide chassis amps to start the gen?

Yes. Some BCCs only pass 12V from the house batteries to the AUX/start switch, but according to your schematic, your BCC will use either battery to activate the solenoid via the switch.

[zzjea]

Originally Posted by loulong

Yes. Some BCCs only pass 12V from the house batteries to the AUX/start switch, but according to your schematic, your BCC will use either battery to activate the solenoid via the switch.

I have had starting issues with the Generac for a long time. It will try to crank but most of the time it does not seem to have enough amps to get it going. It has started ok in the past but not now. The Xantrex battery panel shows the batteries to be full.

I have tried the boost switch with it and no change. This may indicate that the aux starting function of the BCC is not working.

I am getting a digital battery monitor that may help isolate the true condition of the battery banks.

[zzjea]

I followed the trouble shooting and shorted P1 and P14 but no click. They say they are assuming both battery banks are fully charged. I still don't know the actual condition of the batteries. I have a specific gravity tester but can't find it yet. The monitor I bought gives me volts ok but not condition. I'm not sure how to use it to get amp hours but it says it will do that too.

[Old Bounder]

Originally Posted by zzjea

I followed the trouble shooting and shorted P1 and P14 but no click. They say they are assuming both battery banks are fully charged. I still don't know the actual condition of the batteries. I have a specific gravity tester but can't find it yet. The monitor I bought gives me volts ok but not condition. I'm not sure how to use it to get amp hours but it says it will do that too.

In this case, by "fully charged" they simply mean sufficiently charged to perform their assigned functions. There is nothing in the procedures that requires detailed measurements of battery condition.