battery charging question

[Patricia D.]

I need to use a battery charger to charge the deep cell battery in my trailer. Can I leave the various cables attached tot he terminals while charging or is it best to remove them?

[Raspy]

Leave them connected.

[Patricia D.]

Thank you. I know it must seem straight forward for most people but I was just not sure.

[Steve L.]

+1 for leaving them attached.

[Patricia D.]

When I charged the battery (not enough obviously) outside the trailer before putting it in and attaching everything up, I put a battery cable on the negative post and attached the negative to that, as directed in the battery charger manual. Do I do the same at this point?

[John in Michigan]

Yes, charger negative to battery negative, charger positive to battery positive.

[Raspy]

Patricia,

Try not to let your battery voltage get below 12.2 volts before you re-charge it. If there is a small constant load that runs the battery down when you are not using it, you can pull one of the cables off to hold the charge.

You can also get a battery tender that will keep it charged up when not being used. This will save your battery and allow it to remain hooked up.

[Wayne Collins]

A smart charger will automatically cut back the charging amperage to maintain the full charge without over charging.

Another trick is to add a battery disconnect switch in the negative cable so the parasitic loads don't drain the battery while trailer is in storage. ( I did that because the battery in our Parkliner is inaccessible without removing the LP tanks.
If yours is easy to get at, just disconnect the negative, or ground, cable. - assuming you have negative ground system -
Any time you are disconnecting the battery, ALWAYS do the (-) post first.
that way, even if you touch your wrench to metal, while undoing the + post, it won't short out.

[Byron Kinnaman]

Originally Posted by Wayne Collins

A smart charger will automatically cut back the charging amperage to maintain the full charge without over charging.

Another trick is to add a battery disconnect switch in the negative cable so the parasitic loads don't drain the battery while trailer is in storage. ( I did that because the battery in our Parkliner is inaccessible without removing the LP tanks.
If yours is easy to get at, just disconnect the negative, or ground, cable. - assuming you have negative ground system -
Any time you are disconnecting the battery, ALWAYS do the (-) post first.
that way, even if you touch your wrench to metal, while undoing the + post, it won't short out.

I don't know why the negative lead should come off first or a disconnect switch in the negative when according to Kirchhoff's law it doesn't matter. For automobiles the frame is use to conduct current via the negative terminal which would cause a problem if the wrench used to disconnect a terminal managed to touch the frame while undoing the positive terminal while the negative is still attached. In case of fiberglass trailers it's not an issue.

Once the loop is broken that it.

[Raspy]

Fiberglass trailers have metal frames. Often the batteries are located too close to the tongue jack, which is metal and bolted to the frame. Or next to steel propane tanks that are sitting on metal brackets bolted to the frame.

Did Kirchhoff have any particular opinion about a grounded steel propane tank shorted to a positive battery terminal with a wrench?

[dmad1]

Recently bought an upright charger with wheels from Sears before they shut down. The instructions now say to hook and unhook the positive cable first. I guess their thinking is that there is less chance of the battery being grounded when you hook up the positive first.

I have heard stories of mechanics grounding out their wedding rings while using a wrench on the positive pole and the wrench coming in contact with the frame.

[jerrybob]

Originally Posted by Wayne Collins

A smart charger will automatically cut back the charging amperage to maintain the full charge without over charging.

Another trick is to add a battery disconnect switch in the negative cable so the parasitic loads don't drain the battery while trailer is in storage. ( I did that because the battery in our Parkliner is inaccessible without removing the LP tanks.
If yours is easy to get at, just disconnect the negative, or ground, cable. - assuming you have negative ground system -
Any time you are disconnecting the battery, ALWAYS do the (-) post first.
that way, even if you touch your wrench to metal, while undoing the + post, it won't short out.

I agree Wayne....the battery disconnect is a great idea. Our trailer is on site here on our property....I keep her plugged in all winter with the battery disconnected. About once a month....I turn the switch and let the battery charge for 5/6 hours from shore power....this process keeps the battery fully charged and ready to go at any time. Been using this method for years and get many years out of the battery.

[Iowa Dave]

Originally Posted by Raspy

Fiberglass trailers have metal frames. Often the batteries are located too close to the tongue jack, which is metal and bolted to the frame. Or next to steel propane tanks that are sitting on metal brackets bolted to the frame.

Did Kirchhoff have any particular opinion about a grounded steel propane tank shorted to a positive battery terminal with a wrench?

He told me personally it was the quickest way to meet my maker should there happen to be a leak in the propane system.
Iowa Dave

[gordon2]

Originally Posted by Byron Kinnaman

I don't know why the negative lead should come off first or a disconnect switch in the negative when according to Kirchhoff's law it doesn't matter. For automobiles the frame is use to conduct current via the negative terminal which would cause a problem if the wrench used to disconnect a terminal managed to touch the frame while undoing the positive terminal while the negative is still attached. In case of fiberglass trailers it's not an issue.

Once the loop is broken that it.

B.K... get your voltmeter out, touch the positive lead the battery positive post and the negative lead to any bare metal on your trailer's tongue. Really.. do that before commenting further. If reading is zero, then you are correct for you.. it does not matter which terminal you disconnect first.

But for me, and most every Scamp owner out there, there will be 12 volts on the meter.

There are many people on this board who are newer and have not read many of your posts, and therefore don't know that your advice, equipment and camping (RV) lifestyle rarely is applicable to the majority.

Removing negative post first (or positive if pos ground system) can never hurt, but removing the positive post connection first with a negative grounded frame can hurt. I've grounded a wrench that way and once is all it takes to understand the common sense of removing the ground connection first.

[Raz]

Originally Posted by gordon2

But for me, and most every Scamp owner out there, there will be 12 volts on the meter.

There are many people on this board who are newer and have not read many of your posts, and therefore don't know that your advice, equipment and camping (RV) lifestyle rarely is applicable to the majority.

Removing negative post first (or positive if pos ground system) can never hurt, but removing the positive post connection first with a negative grounded frame can hurt. I've grounded a wrench that way and once is all it takes to understand the common sense of removing the ground connection first.

As the only valid reason for connecting the negative side of the battery to the frame is to use the frame as a conductor, I can only assume Byrons point is that most fiberglass trailers don't. I can't say if that is true or not but my Trillium does not. I guess Scamp uses the frame for the electric brake connection, a common source of brake issues, apparently. I'm not sure about Casita or Escape. As far as Byrons camping lifestyle rarely being applicable to the majority, did you take a survey? While he may be a little blunt, many of his posts ring true with me. I'm an each to his own kinda guy, so I seldom comment.

[Jon Vermilye]

If your trailer has electric brakes & a breakaway switch, the negative of the battery should/must be connected to the trailer frame since that is what majority of trailer brakes use for the negative connection.

When the breakaway switch is pulled, the Trailer battery supplies the current to the brakes. Without a negative connection, no brakes.

[Raz]

Originally Posted by Jon Vermilye

If your trailer has electric brakes & a breakaway switch, the negative of the battery should/must be connected to the trailer frame since that is what majority of trailer brakes use for the negative connection.

When the breakaway switch is pulled, the Trailer battery supplies the current to the brakes. Without a negative connection, no brakes.

Again, my Trillium uses a second wire instead of the frame for the return path and the breakaway switch works fine as I installed and tested it. So I guess what you are telling us is that Escape also uses the frame as a conductor. Good to know.

[Jon Vermilye]

Originally Posted by Raz

Again, my Trillium uses a second wire instead of the frame for the return path and the breakaway switch works fine as I installed and tested it. So I guess what you are telling us is that Escape also uses the frame as a conductor. Good to know.

Since the tow vehicle ground powers the trailer brakes while driving, even if you have a separate ground wire from the converter ground going to the brakes, the two negatives are tied together at the brakes. A short between the battery + and the trailer chassis (or anything tied to it such as your propane tanks, etc) will result in the ground wire from the brakes carrying the short circuit current.

[John in Santa Cruz]

Originally Posted by Raz

As the only valid reason for connecting the negative side of the battery to the frame is to use the frame as a conductor, I can only assume Byrons point is that most fiberglass trailers don't. I can't say if that is true or not but my Trillium does not. I guess Scamp uses the frame for the electric brake connection, a common source of brake issues, apparently. I'm not sure about Casita or Escape. As far as Byrons camping lifestyle rarely being applicable to the majority, did you take a survey? While he may be a little blunt, many of his posts ring true with me. I'm an each to his own kinda guy, so I seldom comment.

both my Casita and my Escape have the chassis grounded to both the 120VAC ground wire, and the battery negative.

[Raz]

Originally Posted by Jon Vermilye

Since the tow vehicle ground powers the trailer brakes while driving, even if you have a separate ground wire from the converter ground going to the brakes, the two negatives are tied together at the brakes. A short between the battery + and the trailer chassis (or anything tied to it such as your propane tanks, etc) will result in the ground wire from the brakes carrying the short circuit current.

I guess I'm missing something here. If there is no continuity between the coil wires on each brake magnet and the magnet housing, how will the return wire become part of the circuit.