CMP Electrics

Lauren Child · #1 05-01-12, 15:50

Hiya,

I've started looking at my F22's electrics. I had a dodgy horn that turned out to be not enough voltage getting to it, and then I had trouble starting her which flattenned the battery.

While I polished the contacts and got the horn working again, only about 4volts was getting through to it, which got me thinking about the sluggish starting. With the battery out for charging I've done a bit of investigating on the wires.

I've found some loose connections, but the cable used seems to be smaller than I was thinking it should be. It looks like 60mm2 (with a small section of 40mm2).

Did she have 00 gauge originally? If so that's about 70mm2.

Assuming that makes sense, and yes I'm also looking at the earth straps around the place, can I get a bit of advice?

Is the wire sizing that significant?
Is there any easy trick to getting at the switch and starter motor?
What size of ring terminal do I need for them and the engine case connection?
Is sluggish starting normal? She seems to slowly turn the engine over, with one or two moment of "whoosh" and one or two moment of "stop, I've had enough"

Thanks!
Lauren

Richard Farrant · #2 05-01-12, 19:48

Hi Lauren,

As you say, all the earthing points need cleaning for good contact, but if it is still on 6 volt, then the battery cables should be significantly larger than you would use for 12 volt. Actual cross section/area size escapes me are this moment.

regards, Richard

cletrac (RIP) · #3 05-01-12, 20:43

The battery cables should be about as big around as your little finger. What's that in metric?

Lauren Child · #4 05-01-12, 21:08

Thanks chaps, She is indeed still 6 Volt.

Little finger size is maybe a bit bigger than what she has, depending on who's pinky you are looking at

Ken Hughes · #5 06-01-12, 00:31

Hi Lauren,run a new heavy battery cable from the earth end of the battery earth chassis mount,to your bell housing near as possible to the starter motor.
I had advice from Alex Blair on this site,and it works a treat!!,just like 12v.
Do that first before anything else as that will eliminate any earthing problem.
My F30 was having the same trouble as you are having and this fixed it.

Lynn Eades · #6 06-01-12, 02:09

If you can, buy cable with lots of fine strands, rather than a cable with a few heavy strands. Welding cable is good because it employs many fine strands. It remains flexible, and with its good cross section, a great current conducter.
I suggest you follow closely what Kenny has suggested. It is well known that many Jeeps(amongst others) have suffered this same problem.