Thought I’d resurrect the above diagram from another thread as it wasn’t loading anymore. I am very interested in implementing this wiring diagram to achieve charging of both batteries whilst driving and on hook-up. Also isolating the fridge from startup...but I assume that’s only an issue if the Zig is switched on. The PO has done some funky wiring throughout my camper so I’m struggling to figure it all out and then correct. Being new to all of this I’m hoping the Bridging Fuse and Relays can work in tandem with my current (more like being worked on) electrics setup... (Probably another thread needed for Inverter and Consumer Units) It looks like there are a few differences I should address. Currently I’ve... •No fuse on the Vehicle Battery + wire to the Zig •My Leisure Battery - currently goes directly to the Zig, as per the Zig manual. Wondering what the reason (I’m learning) is for taking the Leisure Battery negative to an Earth point instead? Should I go ahead and do the above? The guy who sold me the Fuse Box suggested its Neg wire go to the Neg on the Leisure Battery and not to an Earth (for reasons I don’t know but it works) To implement the Relay setup, as there is no info on the diagram, I’m wondering about the following: •Relay amps rating has been suggested to be 30a, but are they Make & Breaks? •Wire sizes for all of the Relay electrickery, suggested as 50a, but I don’t know what the wire sizes from Zig to the two batteries are supposed to be because it’s not in the manual. •The Relays can go in a module and mounted on my redundant Air Filter stand (have Twin Carbs), which puts them close to the Alternator...I assume heat won’t be a problem with the module, but what do you think? It comes with a cover. Now for the Bridging Fuse: •Wondering if this “12v 240v Resettable push button thermal circuit breaker” can be used? Looks like it might act like an MCB and pop out if forgotten. I’m thinking I could probably squeeze it in to my Electrical Panel... Unfortunately I have a few more specific questions I’ll have to ask once I know I am on the right track with the above. Many thanks all! Sent from my iPad using Tapatalk
As an electronic engineer, all I can say is that the setups you are proposing .. seem complicated. Sometimes while it is nice to use all of the kit you already have, leaving some of it behind and buying a few bits new may make it simpler. For instance replacing the double relay with a voltage sensing relay with a 30 amp fuse between starter and leisure battery takes less wiring and is smaller. That would replace the need for the bridging fuse. Which will forever be blowing if you start with a well charged leisure battery. The thermal breaker would just pop and then you would find it wont go back in if either battery gets flat. But when both batteries are reasonably well charged it will go back in. Then you only charge the leisure battery off hookup or solar and the main battery stays connected to the alternator. The VSR deals with topping up the 'other' battery when the battery you are charging is pretty full. The RM123 needs to be connected to a relay that closes to the starter battery when the engine is running. So that the 7 amps it needs can only be drained when the engine runs. When you are on hookup then you run it on 240v directly . Later on it can join Snottys EMPI pile when you get an efficient compressor fridge that can be left on the domestic battery because it uses 1/4 of the power. Fuses need to blow before the wire downstream melts : they are for the wiring not the equipment.
Thanks for taking a look at this and making suggestions. You’ve sold me the idea of using a VSR instead of the Bridging Fuse: “Dual sensing operation. Charges from starter battery to leisure battery when alternator is running and charges from leisure battery to starter battery when mains charger is connected.” - 12voltplanet Sounds perfect! I think it also eliminates Relay 1 on the diagram, but I’m not sure of that. I think the origin of Vanorak’s diagram is Zig’s recommendation of using RM14 Relays (still available) to split charge and isolate fridge from startup, in 1995. It also eliminates the standard Zig instructions which encorporate a 12s Plug connection between caravan and car. But for the fridge I still have some questions and/or confirmations. I think it needs isolating due to internal Zig wiring connecting the Fridge to the Main Battery (an assumption based on forum threads). Zig suggest wiring the RM14 Relay as follows:- #85 to Earth/Chassis (does it need its own or can it piggyback an existing one?) #86 to Alternator (I assume D+ as both Relay 1 & 2 do in the diagram) #30 to Main Battery+ (but should it be Alt B+ as both relays do in the diagram?) #87 to Pin 6 on 12s plug, which is Ignition Positive. #87 on the new diagram goes back to #11 on the Zig (which is +IN) so I assume I should I take it to there and replicate #12 on Zig (+OUT) to the Fridge 12v? •Does the above mean only ‘Relay 2’ is required for the Fridge, or is ‘Relay 1’ on the diagram still needed? There are some other differences between Vanorak & Zig diagrams: •Wiring... -On the Zig unit... —#11+In to Leisure Battery via Relay & Alternator...not direct to Fridge as Zig suggest —#12+Out to Fridge +...not to Ignition Positive via 12s Plug as Zig suggest •Batteries... -Leisure Battery- to Chassis...not #3 on Zig as Zig suggest Basically I think I just need to be told what to do with the relay setup haha Many thanks for your patience and feedback Sent from my iPad using Tapatalk
