Zig cf8 curiosity.

callum · Post by **callum** » Tue Dec 29, 2015 10:54 am

Hi folks,
In the process of building my conversion and i'm looking at using a zig cf8 unit. The reason being that i do not have split charge set up at the mo, but i want it. I have tested that it works on a bench, but not sure about the charging aspect as my meter is locked up at work.
The only thing that is troubling me about it is the wire from the starter battery.
When flicking the switch to "touring" and with engine running, it should start to charge the battery. But, in bold it says you shouldn't leave it in this position permanently as it can drain the starter battery.
Now...
My confusion is this...
Why would it drain the starter battery if the feed is taken so that it is only live with ignition on?
Many thanks!

Post by **g8dhe** » Tue Dec 29, 2015 9:06 pm

As I recall the CF8 simply parallels the batteries, rather than using a Relay to switch when the voltage is high enough or by the a ignition switch position, so if you forget to manually switch it the two batteries will remain in parellel and hence drain both.

callum · Post by **callum** » Tue Dec 29, 2015 9:41 pm

Thanks for that.
I do believe you are correct yes.
So it isn't a concern about day to day running then as such, it's if i happen to have something connected from it that i accidentally leave on (a light for example) it will drain both batteries. I'm not really worried about doing that as i trust myself to remember to switch it to "on site" when we're camping etc.
Also, the live feed from the starter battery, could i not just fit a standard relay of suitable amps (30amp should do as fuse is rated at 25amp) from between battery and zig with a signal wire from ignition on?
This should mean that it can't draw power from starter battery when parked up whether it is in "touring" or "on site" and therefore stops the issue of draining the starter?
I really just wanted a split charge set up, but my in-laws had the zig on offer for £20, so made sense to give it a go. So i'm mainly interested in making sure the leisure battery get's charged up.
Thanks again for your input.

Post by **g8dhe** » Wed Dec 30, 2015 7:39 pm

Yes that is the way I prefer to operate the SCR, use the IG2 feed as this ensures that the LB is disconnected during cranking.

Far right fuse on the middle row is the best source of the signal to control the relay.

callum · Post by **callum** » Wed Dec 30, 2015 9:01 pm

That's a great help, thanks very much, i shall have a gander at it.
As a pointer, if you please, how do i draw a feed off the fuse you have mentioned? Will it just involve removing the fuse box and seeing which wire comes from that? I've only ever piggy backed off wires or made fresh ones, direct from the fusebox confuses my mind a tad as i'm more used to the wiring of Morris Minors and such like!

Post by **Bob** » Wed Dec 30, 2015 9:03 pm

You can get Piggy Back fuse holders, just plug in.

callum · Post by **callum** » Thu Dec 31, 2015 9:35 am

Bob, that's my kind of thing! Thanks very much for that, just purchased one!

Jim the Box · Post by **Jim the Box** » Sun Jan 03, 2016 11:52 pm

I would switch mine to towing to maintain the charge on the leisure battery however when I got home and parked up I always switched it to on site, If I did not the starter battery would be flat in about 10 days.

callum · Post by **callum** » Mon Jan 04, 2016 12:45 am

Hey, thanks for that.
We use the car daily, so no real parking up is done. But certainly something to think about if we did go away without the van.

callum · Post by **callum** » Tue Jan 19, 2016 4:50 pm

Just for information.
I wired the zig in and was able to test it yesterday.
They 12v charger now works, tested by volts with engine on and off.
I did wire the SB via a relay. With the zig set to "touring" there are 12v being sent down the wire to the relay from the zig, i assume this is drawing the power from the leisure battery to activate that as i removed the fuse on the SB this disconnecting that power, and the 12v was still going through the wire.
There is pleasingly resistance at the relay that i fitted and an audible click at the relay when the ingnition is on.
So i do believe i should now not draw any power from the SB, which is nice.
So thanks for the help, saved myself a bit of money in the process too, which is good. I haven't retested the elec hookup yet, but it should work fine as it did on the bench test.
So i have a converter, charger and distribution centre for £20, which is a nice thing!

mikeonb4c · Post by **mikeonb4c** » Tue Jan 19, 2016 6:04 pm

One huge benefit of having a leisure battery isolated from starter battery when engine off, as I have discovered twice, is that the leisure battery can be used to revive a flat starter battery just enough to allow you to crank the engine and start it. To do this, you connect the batteries using jump leads, leave them connected for a few minutes, remove jump leads (ideally) then crank the starter motor. Worked for me and no demonstrable damage to leisure battery from high charging the SB for a few minutes.

jordanruby · Post by **jordanruby** » Tue Mar 01, 2016 2:17 pm

Im new to all this. We use our Bongo as our main car. Should I switch to towing all the time so it constantly charges the leisure battery? Its all very confusing to a camper van double battery virgin!!!!

Post by **g8dhe** » Tue Mar 01, 2016 4:07 pm

It depends on the control panel that has been fitted!
When travelling you want the Split Charge Relay to operate putting the two batteries in parallel, but once stopped you need to release the relay, some Zig units operate the SCR when in touring mode, if you leave this on (inadvertently) then you will discharge BOTH batteries, its much better to wire the SCR to the circuit shown above (IG2) then when you take the ignition keys out the batteries are isolated!

philpdr · Post by **philpdr** » Wed Mar 02, 2016 12:04 am

mikeonb4c wrote:One huge benefit of having a leisure battery isolated from starter battery when engine off, as I have discovered twice, is that the leisure battery can be used to revive a flat starter battery just enough to allow you to crank the engine and start it. To do this, you connect the batteries using jump leads, leave them connected for a few minutes, remove jump leads (ideally) then crank the starter motor. Worked for me and no demonstrable damage to leisure battery from high charging the SB for a few minutes.

Did exactly the same when my starter battery died.

Zig cf8 curiosity.

Zig cf8 curiosity.

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