: hi all when i connect the 2 batters together in the center i get an ark it is little is that
normal or is it from the box above the batters that equalizes the batters
There are two different possibilities. If the batteries are not at the same voltage, an equalizer will cause a current flow between the batteries. Even if there is no equalizer, when you make the last connection to a battery, there will be a small (or large) spark as current flows to whatever is drawing current. There is almost always some small permanent loads (clocks, radio memories, computer memories, etc.) that will make a small spark. If you have left the bus light switches turned on, you will get a significant spark.
In almost all cases the ground connection should be the first cable removed and the last connected to a battery, unless some piece of electronic equipment specifies a different method.
Glenn,
To add to what Stan said, on my Vanner equaliser it recommends/states that the ground on the equaliser should be the first wire removed and the last connected.
Cliff
the main reason for removing the ground cable first and connecting it last is safety. Any slip of a wrench when working on a hot battery terminal, when the ground is connected, can result in an enormous arc (think arc welder size) and possible battery explosion.
To meet specifications like the Vanner Equalizer, I would completely disconnect the Vanner prior to doing any battery work and reconnecting it after the battery work is finished. Since the Equalizer is hooked up with relatively large cables, you have to be very careful when working on the bolt type connections. Recently I have seen ads for insulated tools to use when working on battery terminals.
"...ground on the equalizer should be the first wire removed and the last connected."
only applies to the older model Vanners (family 1 & 2) like the 60/50a
not to the new models (family 3 & 4) - doesn't matter with them
Another major exception to diconnecting the negative first is with at least some inverters being controlled by a Link. The Link manual warns against disconnecting the negative first.
We failed to follow that advice when working on an older Heart and it killed the inverter. Since it was a 32 volt model, Xantrex declined to repair it, so it was a total loss. We wound up having to go to 24 volts, and it was a lot of work.
A better procedure is to remove the fuse first.
For what it's worth.
Tom Caffrey