Hooking Up Batteries-Getting a Spark Help

[BW1]

Nice day outside and decide to hook up batteries from winter storage.

I hooked red trailer wire to Positive of first battery, then hooked connecting wire to it and Positive red to other battery and tightened wing nuts.

Went to put black trailer wire on Negative of opposite battery first and got a spark. Stopped everything disconnected all positive wires and came in the house.

Inverter is plugged into the wall. Should it be unplugged?

What am I doing wrong?

These are the instructions I have written down from last year…LOL!

[HowieE]

Getting a spark while connecting batteries is not uncommon. That just indicates that some thing in the trailer is turned on and draws current as soon as it is available.

An inverter, and I assume you do not mean converter, is a 12 volt device and if connected to a 12 volt line as you connect the batteries it would draw current. The converter is hard waired to the batteries on it's output side and will not draw current from the batteries.

If you are concerned disconnect the inverter, the carbon detector and any think else that may be turned on. However this is not necessary.

Yes you always want to connect and tighten the positive terminal first. Failure to do this leaves you open to one hell of a spark if you ground out the wrench while tightening the positive terminal.

[BW1]

I will disconnect converter and check for anything on. Maybe I forgot to turn fuse panel to all 'off' positions, I will check.

So when I get this little spark with the negative black trailer wire, will I get another one as I attach the black connecting wire? Will it hurt while connecting with the sparks going..lol!

Thanks for your help

[HowieE]

You do not need to disconnect the converter as it is not a load on the batteries and thus can not draw current.

The little spark one sees while connecting batteries is nothing to be feared.

if your trailer has a master switch, commonly referred to as the storage switch, you can just turn it off before making the connections. That will isolate the batteries from the trailer and thus anything that may be turned on.

[Rich Jenkins]

As above. ^^^

I would only add, check to make sure your propane is off. Good way to get new set of eyebrows.

[BW1]

Hi Folks,

Thank you for giving me the confidence that, I would not blow everything up... and get new eyebrows!

All went perfectly, just a little spark and everything is beautiful!


Thanks again!

[Tincampers]

They aren't really sparks, just happy beams from the trailer waking up after a long winters nap.

[TomKirk]

Two possibilities:

1) Some 12 volt appliance is turned on.

2) You've got a short somewhere.

Pull all 12 volt fuses, connect batteries, and see what happens.

A) If you still get spark when you connect batteries, you've got a dead short; possibly a bad ground or a grounded positive wire.

B) If you get no spark when you connect batteries (with fuses pulled), plug in one fuse at a time, then connect batteries. That's one way to isolate continuity in individual circuits.

Tom

[lewster]

I get a bit of spark almost every time I connect a battery ground after the positive is on. There are many scenarios that would cause this bit of electrical jump, from circuits being completed to capacitors engaging.

If your system is healthy and was operating properly prior to the disconnect, usually nothing to worry about.

One more reason for a marine battery disconnect switch at the battery box. With the switch off, you won't get any spark and simply engage the switch to power up the trailer when your terminals have been tightened.

Also, it's a great idea to dump those wing nuts in favor of flange nuts. ABYC standards limit the use of wing nuts to trolling motors with a maximum wire capacity of 8AWG. Your trailer's battery cables are either 6AWG or 8AWG.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

[Davidwantz]

I have been reading the thread about the spark and agree that grounding a wrench is a bracing experience. I have heard conflicting info on which side to unhook when you'll be away and not want the batteries to get sucked low by the voltage vampire LP detector.

Negative lead seems to be the top vote getter for the disconnected battery.

Thoughts?

Dave

[Tincampers]

Remove all rings and metal watches and then remove the negative cable first. If you remove the positive cable first and inadvertently make contact with any metal part of the trailer would will make a huge spark and could even weld the wrench to the trailer. I've seen it happen. A large crescent wrench melted about a third of the handle. Fortunately the idiot doing the work was wearing the proper gloves.

[lewster]

[QUOTE=lewster;1778464]I get a bit of spark almost every time I connect a battery ground after the positive is on. There are many scenarios that would cause this bit of electrical jump, from circuits being completed to capacitors engaging.

If your system is healthy and was operating properly prior to the disconnect, usually nothing to worry about.

One more reason for a marine battery disconnect switch at the battery box. With the switch off, you won't get any spark and simply engage the switch to power up the trailer when your terminals have been tightened.

Also, it's a great idea to dump those wing nuts in favor of flange nuts. ABYC standards limit the use of wing nuts to trolling motors with a maximum wire capacity of 8AWG. Your trailer's battery cables are either 6AWG or 8AWG.

CORRECTION!

Airstream battery cables are either 6AWG or 4AGW. Sorry for the mis-type in the post.