Club 80-90 Forums

Two points....

1. The Xplorer conversion with the viking roof had a switch and indicator lamp mounted on the dash to the right hand side of the steering wheel. This was used to connect the fridge in place of an automatic relay so if you switch that off when the engine isn't running your leisure battery won't get flattened by the fridge.

2. Zig units were designed for caravans not campervans hence the 'touring' option (caravan being towed and plugged into car so car charged caravan battery when on the move; just like a split charge system does except via the Zig). I just leave the switch permanently in the middle 'off' position since I have a split charge relay fitted.

ghost123uk wrote:Many folk (including me) use a thing called a LVD (Low Voltage Disconnect) that cuts off the leisure battery when the voltage falls too low LINKS HERE

OK, I've looked into a few LVD units. Obviously they route the load through the LVD and control when that load is connected. I have two wires connected to my leisure battery's +ve terminal: one from the split charge relay, and one from the ZIG.
- The one from the split charge relay isn't a load, so I assume it should not be switched out under low voltage conditions. But would it be better to route it through the LVD anyway, to avoid the two batteries trying to equalise when the split charge relay connects them?
- The one from the ZIG is both the load and the mains charging connection. If I disconnect it with the LVD, how can the ZIG charge it? Are the LVD units configured so that a +ve voltage on the load side reconnects the load circuit?

1664 wrote:1. The Xplorer conversion with the viking roof had a switch and indicator lamp mounted on the dash to the right hand side of the steering wheel. This was used to connect the fridge in place of an automatic relay so if you switch that off when the engine isn't running your leisure battery won't get flattened by the fridge.

Ahh, that was some of the 'redundant' wiring I pulled out yesterday! That warning light was the one I 'repurposed' as my relay tell-tale. The previous owner told me it was something to do with the tow hitch electrics, and since I only have a 12N socket and all of the pins work without this wiring I thought maybe he'd been referring to a 12S socket that had been removed. Oh well, on balance I think I prefer automatic operation, provided I can get the 'automatic' part reliable.

1664 wrote:2. Zig units were designed for caravans not campervans hence the 'touring' option (caravan being towed and plugged into car so car charged caravan battery when on the move; just like a split charge system does except via the Zig). I just leave the switch permanently in the middle 'off' position since I have a split charge relay fitted.

My ZIG doesn't have a middle position - it has to be either 'Touring' or 'On-site'. With the split charge system in place, I think I don't need to touch any of these switches - I can leave them all 'down'.
- So the 'Mains' switch will always be on, but this only has an effect when the hook-up is connected, in which case I can't see when I'd ever want mains off.
- The 'Touring' switch will always be set to 'on-site', so the main battery is kept isolated from the leisure battery and the separate split charge system takes care of charging the leisure battery. If I need 12V in an emergency when the leisure battery is flat I can switch this to 'Touring' and draw from the main battery.
- The 12V switch is always on, but this doesn't matter provided all the 12V loads are turned off.

MidLifeCrisis wrote:...not very relaxing! although there is no prob real danger in the batteries staying connected when there is no drain on them ..... but it still made me nervous...

Yes, this is my concern. I have some previous experience with this that makes me doubly cautious. We have a vehicle at work that is fitted with several high capacity 'leisure' batteries that can be chained in parallel. We used to have an intelligent high current (40A) charger installed and permanently connected, so that whenever the mains hookup was connected the bank of batteries would charge in parallel. One Monday morning we came to use the van and it was full of white smoke/steam, and the two batteries that were in the chain were massively swollen, and very hot to the touch. Their seams had not given way, but I believe they weren't far from exploding. The only explanation we could come up with was that the state of charge of the two batteries was sufficiently different that although one had reached full charge over the weekend, the other was still low, and therefore the 'intelligent' charger thought that the pair still needed a high current charge, even though the full one only needed a trickle charge at that point. So the charger was still putting 40A into the full battery. It was either that or the charger malfunctioned somehow, but either way, I'm quite wary of parallel charging systems now.

Thanks for all your inputs and links everyone - there's obviously a wealth of knowledge on this forum.

CJH wrote: Before I get a new voltage regulator for my alternator though, can you confirm that measuring the voltage across the main battery terminals is the correct way to measure the output of the alternator? I can't see another way to do it, but it seems like the battery might be acting as a bit of a sink so I won't get a true reading.

Chris

Best to measure the voltage by putting your red probe on the big terminal on the back of the alternator that usually has a little rubber boot over it and has a thick red wire attached. Mind you, once the van has been for a short drive, the voltage there should be the same as at the +ve of the battery.

Re LVD, leave the split charge wire directly onto the leisure battery. Then connect a short bit of wire from the +ve & -ve of the leisure battery to the appropriate inputs of the LVD, then connect the output of the LVD to the "load", be that the leisure input of the Zig or a distribution fuse box. If you end up with an LVD that comes in a see through blue plastic case, the instructions are a bit vague, but I can send you a simple "how to".

E D I T =

Are the LVD units configured so that a +ve voltage on the load side reconnects the load circuit

No. If you think about it, there cannot be a +ve voltage on the "load" (ie lights etc) side when the unit is in "disconnected mode" can there.
It switches back on when some charge has gone back into the leisure battery and raised the voltage to a reasonable level again.

ghost123uk wrote:

Are the LVD units configured so that a +ve voltage on the load side reconnects the load circuit

No. If you think about it, there cannot be a +ve voltage on the "load" (ie lights etc) side when the unit is in "disconnected mode" can there.
It switches back on when some charge has gone back into the leisure battery and raised the voltage to a reasonable level again.

I can see that, provided the 'load' wire is purely a load. But the connection from the ZIG is both the load AND the charging wire. The ZIG draws the 12V load from this wire AND it provides the (mains) charging current, so if the LVD disconnects this wire, how does the ZIG provide a mains charge? If this wire is disconnected it seems like the only way to reconnect it to the ZIG is to drive around for a bit until the split charger tops it up. What am I missing?

Ah, I see your point. My Zig is a lesser model and is just a simple distribution panel. At this moment, without complicating things with Diodes and a relay, I cannot see a simple solution then. Someone else might have an idea though.

Thought = the one I have (in the blue see through case (from REUK iirc) has a normally closed terminal on the output relay. This terminal is not normally used and closes when the voltage falls below the level you have set it to. This terminal could be used to make a buzzer sound when it gets too low.
Example of suitable buzzer = HERE

Blue one from REUK with extra normally closed terminal = HERE

CJH wrote:

1664 wrote:1. The Xplorer conversion with the viking roof had a switch and indicator lamp mounted on the dash to the right hand side of the steering wheel. This was used to connect the fridge in place of an automatic relay so if you switch that off when the engine isn't running your leisure battery won't get flattened by the fridge.

The previous owner told me it was something to do with the tow hitch electrics, and since I only have a 12N socket and all of the pins work without this wiring I thought maybe he'd been referring to a 12S socket that had been removed.

I'm pretty certain it was the switch for the fridge - Holdsworth conversions use a similar set up. I'm going to stick my neck out here and postulate that you can't (as in not allowed to have) a manual switch to isolate your towbar electrics; besides which what would it isolate? Brake lights? Indicators? Rear lights? Just wouldn't work really as it's only a simple one way switch.

ghost123uk wrote:Ah, I see your point. My Zig is a lesser model and is just a simple distribution panel. At this moment, without complicating things with Diodes and a relay, I cannot see a simple solution then. Someone else might have an idea though.

Thought = the one I have (in the blue see through case (from REUK iirc) has a normally closed terminal on the output relay. This terminal is not normally used and closes when the voltage falls below the level you have set it to. This terminal could be used to make a buzzer sound when it gets too low.
Example of suitable buzzer = HERE

I'll keep investigating - there seem to be various LVD units out there, and I suppose there may well be one that would reconnect the load side when a charging voltage is detected. If not I'm open to suggestions including diodes and relays

1664 wrote:I'm pretty certain it was the switch for the fridge - Holdsworth conversions use a similar set up. I'm going to stick my neck out here and postulate that you can't (as in not allowed to have) a manual switch to isolate your towbar electrics; besides which what would it isolate? Brake lights? Indicators? Rear lights? Just wouldn't work really as it's only a simple one way switch.

Yes, my apologies, I wasn't suggesting you were wrong, just that the information the previous owner had given me was misleading. Your suggestion seems the most likely, since the wiring from that switch ended up (unconnected) in the main battery compartment, along with the fridge 12V feed (also unconnected), so I assume that they were connected at some point in time. There was also a relay in there (not connected, and broken), so maybe the manual switch was replaced with a relay by a previous owner.

I think this thread has set a new record for the amount of words per post ever

billybigspud wrote:I think this thread has set a new record for the amount of words per post ever

I was thinking that a bit earlier on

BREVITY

billybigspud wrote:I think this thread has set a new record for the amount of words per post ever

I'll be brief then - I prefer longer posts!

It's just occurred to me that your Zig charging is likely only when on the Mains hook up. I am guessing you have a normal split charge relay for charging off the engine when on the move.

So, if an LVD has isolated the leisure battery, due to low volts, you are correct, the way it is wired the Zig mains charger cannot "reach" the leisure battery. However, if you fire up the engine for 2 minutes (or less) the LVD will close and then the Zig's charging current can get to work. There is no problem with the Zig charger "back feeding" the LVD by the way. This solution would work fine. But it should be noted that the circumstance would be unusual anyway, because if you are on a mains hook up, your leisure battery will not be doing the "supplying" anyway as it will be constantly being charged by a mains charger which acts as the "supply", so it won't go flat, (as long as the load is less than the capability of the mains charger) and the LVD won't cut off.

ghost123uk wrote:So, if an LVD has isolated the leisure battery, due to low volts, you are correct, the way it is wired the Zig mains charger cannot "reach" the leisure battery. However, if you fire up the engine for 2 minutes (or less) the LVD will close and then the Zig's charging current can get to work.

Thanks, yes, I agree it's an unlikely situation. An LVD will only disconnect the leisure battery when I'm without a mains hookup, so I'd probably have to drive to another site with a hookup anyway, in which case the split charger will do the job. But if not (let's say I forget to connect up to a nearby mains hookup, then connect up after the LVD cuts in), running the engine will be the only way to reconnect. Maybe I just need an LVD with a manual override for this rare situation - I'm pretty sure I saw one of those.

E D I T: I can make a manual override quite easily I think, with just a switch to bypass the LVD.

CJH wrote: E D I T: I can make a manual override quite easily I think, with just a switch to bypass the LVD.

ghost123uk wrote:

CJH wrote: E D I T: I can make a manual override quite easily I think, with just a switch to bypass the LVD.

OK, well now the challenge seems to be to find an LVD with a high enough current rating. That one from REUK is rated at 16A, but with suggestions that there may be more than 30A going down these charging wires that's clearly not enough. OTOH, I won't be DRAWING 16A, so I suppose those high currents only come FROM the charger when the battery is really flat, which a) I'm now avoiding, due to the LVD, or b) the high current would go through the manual override switch.

So just a double check with those that know - if the LVD keeps the battery voltage above, say, 11.5V, would the mains charging current ever exceed 16A?