Battery switch causing heat up

[Jerry_Amerson]

I put a 60 amp battery switch in line on my ground side where my two 6 volt batteries connect, hot from one side and ground from the other with switch in the middle. When I was at the races my generator got low on oil and shut off and the batteries were switched on and they kicked in until they got low and the converter shut off AC. After I put oil in the generator and it cooled down I started it up and everything was back working and it was charging the batteries. I had just cleaned the posts on the batteries before we left for the races so I wasn't expecting the problem that I got. The two #6 gauge wires connecting the switch got so hot I couldn't hold on to either one, so I don't know if that switch has that much resistance or if it just couldn't handle the current. The other two main lines were not even warm. It could also be that I need to go to a heavier gauge wire. Any good ideas from you all would be appreciated.
Thanks,
Jerry

[Sam_Spade]

Jerry Amerson wrote:
Thanks,
I will move the switch to the hot side (red), and try that.

How many wires are attached to the + red post; how many to the - ground ??

From your last post, it appears that you are ignoring some important parts of the advice you have gotten.....from more than one person.

Moving the existing switch may not help....IF it is too small.
You NEED a higher capacity switch.

And putting the switch in the NEGATIVE cable is much safer in most circumstances.

IF.....you insist on putting a new switch in the positive side PLEASE disconnect the negative while working on the switch. If you do not, grounding a tool can cause significant damage.....both to the equipment AND to YOU.

[Jerry_Amerson]

Thanks,
I will move the switch to the hot side (red), and try that. That will also make it easier for me to charge the batteries while docked with my battery charger. I will also get a #4 gauge red line because I think that's what my hot line is.

[pauldub]

Yes, you need larger wire. Typically your switch wires would be the same gauge as the wires used to connect your batteries to the house wiring. Most of the Blue Sea battery switches are rated for more than 60 amps so if yours really is a 60 amp switch you need one with higher ampacity. It looks like the smallest Blue Sea battery switch is rated for 300 amps continuous. You'll need to crimp or solder big terminals on the bigger wire or you can just order custom built cables from genuinedealz.com.

[Sam_Spade]

Jerry Amerson wrote:
What happened on this trip was the generator ran low on oil and shut off, and at that time the batteries kicked in because the converter was on and they started supplying juice for the converter to put out AC.

We need to get your terminology straight here......because it is important in understanding what is and is not happening.

First, if you used the same gauge wire(s) as was originally there when you inserted the switch, hopefully there wouldn't be a problem IF you made really good connections.

BUT THEN.....the "converter" does NOT produce AC from DC. The converter/charger goes the other way; it produces 12 V to charge the batteries and other things and is ONLY active when there is an AC input from an external source, like shore power or a generator.
When the external AC input goes dead, so does the converter.

What you are trying to describe is an INverter, which takes a DC input and produces 120 V AC output.

While it is not impossible to have an INverter big enough to run your air conditioner, it is not usually practical because of the high power requirement of the A/C. It would require a large, expensive INverter and would have a HUGE current draw from the batteries. Two would probably not be enough.

So.....is your RV really equipped to keep the air conditioner running when the external AC power fails ?? I HIGHLY doubt it.

[enblethen]

Now I see that you installed the switch in the jumper between the two batteries. Not a good idea, but it will work.
Are you sure the AIr Conditioner is routed through an INVERTER? I doubt it!
Do not confuse an Inverter with a Converter.
An inverter changes 12 volts DC to 120 volt AC
A converter changes 120 volts AC to 12 volts DC.
What size wires leave the batteries? If it is #6 then #6 would be good as a jumper. If larger then that, you need to at least equal that size or larger for jumper.
60 ampere switch is pretty light. I would have been looking for a 100 or maybe 200 ampere switch.
Make and model of converter?
Make and model of inverter if equipped?

[Jerry_Amerson]

OK folks let me explain this a little better. I have two 6V batteries in series, so there is only one hot and one ground (red and black) that are used in the system for 12V. The other hot of one battery is connected to the ground of the other battery to complete the series connection. That works fine. Then I added a blue sea switch in the circuit between the two batteries which completely opens the circuit and there is no voltage at the system when open...when closed there is 12V present at the main terminals. I'm inclined to believe I need heavier gauge wire because it works fine if the batteries don't get drained and the generator starts charging them while running the AC. What happened on this trip was the generator ran low on oil and shut off, and at that time the batteries kicked in because the converter was on and they started supplying juice for the converter to put out AC. The air conditioner was on and when the batteries drained down the converter did it's job and shut the system down. So I topped off the generator oil and restarted it and that's when the cables got hot because the generator started recharging the batteries. If I'm not right about all this let me know what's wrong in my thinking what the issue was. Everything is fine now after we got home and I put the charger on the batteries and recharged them. The generator runs fine and the cables don't get hot at all.
Make sense

[time2roll]

photobug wrote:
Anyone know of a good wire diagram to hook up disconnect? I've got dual 6v in series. should the switch cut off the positive or negative?

By convention all fuses and switches in the RV are on the positive side. I would continue with this to be consistent. Electrically it will accomplish the same effect on either side.

Wire diagram?

Remove all wires from the the positive RV battery terminal and connect to the switch. Get a new jumper from the battery terminal to the switch.

Minimum wire size should match the largest wire connection.
http://www.genuinedealz.com/custom-cables

[D_E_Bishop]

photobug wrote:
Anyone know of a good wire diagram to hook up disconnect? I've got dual 6v in series. should the switch cut off the positive or negative?

To Photobug and even applicable here,Schematics

Before I had a disconnect switch in my Bounder, I would always disconnect the battery negative terminal cable to chassis ground when in storage because it was easiest to get to. You know I haven't checked which side is switched on this one. It works and it doesn't matter to me.

[Sam_Spade]

photobug wrote:
Anyone know of a good wire diagram to hook up disconnect? I've got dual 6v in series. should the switch cut off the positive or negative?

You don't need a "diagram".

Which ever cable you pick, you effectively cut that cable and insert the switch at that point.

Electrically, it makes absolutely NO difference which cable you insert the switch into. You could even put it in the cable that is between the two series batteries.

It most often is put into the negative cable because that is the safest place to be doing the work.....while all the other cables remain connected.

[photobug]

Anyone know of a good wire diagram to hook up disconnect? I've got dual 6v in series. should the switch cut off the positive or negative?

[time2roll]

So you were running the air conditioner on an inverter?
That would be about 120 amps through the switch rated for 60?
If it only got warm you are lucky.

How big is the inverter? How big is the fuse?

[OLYLEN]

If I understand correctly you put #6 wire between the two in series 6 volt batteries for what reason. But yes TOO light of wire, should be same as the other battery cables. And what are you trying to accomplish with the switch, Isolate the two 6 volts from each other?

LEN

[OLYLEN]

If I understand correctly you put #6 wire between the two in series 6 volt batteries for what reason. But yes TOO light of wire, should be same as the other battery cables. And what are you trying to accomplish with the switch, Isolate the two 6 volts from each other?

LEN

[Sam_Spade]

Jerry Amerson wrote:
and the batteries were switched on and they kicked in until they got low and the converter shut off AC.

IF.....you really have enough battery capacity, along with a big enough inverter, to run your air conditioning......then neither your 60 amp switch nor the #6 cable is big enough.

BUT....running A/C off of batteries would be a rare setup.
Your A/C probably went off when the gen did.....but then what else would have been running to draw down the batteries ???