AMperage meter question whilst driving

martyc5674

Hi ll,
Another newbie question :-)
When driving if i switch on the power in the MH the needle on the amperage meter goes a good few amps into the red...it is charging the battery fine but just wondering why it appears to be "drawing current"?
When i hooked up to 240 for the first time this weekend it went into the green for a little while then levelled off.
Everything works fine just wondering if i should or should not have the power switched on while driving and why it goes into the red if switched on.
Cheers,
Marty

peasant

The alternator would usually charge the main battery first while driving and only when that is fully charged, the leasure battery gets its fill. If you're drawing power from the leisure battery while driving this could be the reason for what you see. It would take a bit of driving before the leisure batt is getting any charge.

martyc5674

Cheers,
No not drawing any current in the MH while driving..just goes into the red if i switch it on..batt seems to be in better shape voltage wise after a drive, only new to this so not sure if this is only the scase when MH poered up or not(thought there would be diodes to prevent MH supplying the regular batt @ any time)
Does your own go into the red if you switch on your console without drawing power whilst driving??
Cheers,
Marty.

peasant

OK ..I don't really know what's going on there, but just to explain further:

These guages don't normally show amps, just voltage. Then there normally is a switch to switch the display between main battery and leisure battery so you can check the charge of either.

These are just guages, not scientific instruments. Shortly after charging the battery or after drawing a current, they may read wrong.

What may be going on is that your guage is set to show the state of the starter battery and after turning over the starter motor (big current draw) it may read low for a while.

If you want to be sure that everything is ok, go to a car electrician and get you batteries measured, as well as the alternator to make sure it's charging correctly.

chrisblack

Hi Marty

I have a toggle switch on mine, which I can swap betwwen leisure and engine battery.

This switch shows me:

1. when the engine is off, how many volts are in the batteries and
2. when driving how much power the alternator is pumping into the batteries. Dependent on the engine speed, the needle goes into the red when driving.

I had it checked a while ago by a mechanic, who told me not to worry and that the alternator appeared healthy.

Chris

When I'm driving along, dependent upon the speed of my engine, the needle on the guage can pop up into the red...

martyc5674

Cheers lads,
Just being inquisitive really...my meter shows volts when you toggle between each battery ion the battery check.
It also shows current draw when you switch on appliances(on the same scale)

When i turn on a few lights it goes a little into the red indicating current draw...when i hook up to the mains it goes a little into the green indicating that current is going into the leisure battery.
Its just when im driving im wondering why it goes into the red...wouldnt like to find out ive used my leisure battery to top up my car battery @ the end of a long journey!!
Cheers,
Marty.