Having been through @matty thread on leisure electrics there are a few dead links so I thought I would ask he to make sure I order the right stuff for techenders. So I think I need one of these http://www.vehicle-wiring-products.eu/product.php/666/fuse-box-for-ceramic-fuses And these http://www.vehicle-wiring-products.eu/product.php?xProd=643 Do I need one of these ? http://www.vehicle-wiring-products.eu/product.php/651/interlocking-relay-socket Will need one of these http://www.vehicle-wiring-products.eu/product.php/580/battery-earth-cable What else do I need cable wise also what size battery should I be looking for ?
Righto- The fuse box. I like the style you've selected, it's in keeping with the original and you've probably got a bag of ceramic fuses anyway. What I would do, though, is fit fuses at either end of the charging cable. This is especially important if your power cable is going to pass through any bodywork (my leisure battery is inside the van, for instance- meaning potential shorting through where the cable passes through the bodywork- always fit a grommet for this reason) Normally, if you were wiring up, say, lights, you would fit one fuse. In case of emergency ( for instance- power feed to lights shorts against body, draws lots and lots of current, then everything's on fire) the fuse will blow and your power to that problem area will be cut. However with a leisure battery, you have a source of power at either end of your cable. That means that if that cable earths to body and draws lots of power, the fuse will blow, disconnecting the system from, say, the leisure battery. HOWEVER if you don't have a fuse on the starter battery side too, then your short circuit will draw all the current it can from that starter battery, and potentially cause a fire. So- what I'd do- fit that fuse box close to your lesiure battery. Designate one fuse- 30A is fine- for current going into the battery. Use all the other fuses for whatever you want to run on 12V from the leisure battery- Lights, radio, etc. Then, close to the starter battery, I'd fit another one, a twin fuse. I'd use one of those fuses for the big fat power lead going to the leisure battery, and the other one for the "signal" wire to the relay from the coil/alternator. Second line- the relay itself That one's fine- and you could use the integrated fuse for one of the "starter side" fuses I mentioned above. I'd be tempted to use one without the integrated fuse, though, as ideally you'll be using two fuses in that area- so it makes more aesthetic sense to me to keep the fuses together, near the relay but seperate. Personally I'd probably go for the below: http://www.vehicle-wiring-products.eu/product.php/642/12v-4-blade-relay Only 40A, but your leisure battery is not going to draw that much ever, and if it does it'll just blow the fuse. Relay holder Makes it look nicer, doesn't it. Easier to get the relay out as well, without messing around labelling wires and such. Battery earth cable That looks fine to me Other cables Right, you're probably going to want 30A fuses, to I'd go for any cable rated at over 40A @12V. Preferably a red one! or maybe red with a tracer of your choice. Doesn't matter. The only cable I could find on vehicle wiring products is proper battery cable at 110A... Might as well use that, it looks correct, even if it is overkill. http://www.vehicle-wiring-products.eu/product.php/1030/battery-starter-cable You could also use 35A cable: http://www.vehicle-wiring-products.eu/product.php/982/35-amp-4-5mm-sq-65-0-30 but with tolerances and fire risk and all sorts of things like that, I'd be tempted to go higher than 5A over fuse blowing. Not that it'll ever happen, but it's nice to know that everything's overspecced rather than underspecced... Of course, there are other suppliers out there. Other than that, you'll need "some cable" for the signal wire that turns the relay on and connects the leisure battery to the alternator. Honestly, a relay draws about 0.2A maximum, so really what you're looking for is "big enough to fit a connector properly" as some really small wires like you'd find on modern electronics would have problems being "gripped" by the connector, and soldering them on can make them brittle and break off over time (not that it's not common practise) Boggo cable, far more capacity than you'll need but looks normal and you won't break it in half by breathing on it: http://www.vehicle-wiring-products.eu/product.php/1020/8-75amp-1mm-sq-14-0-30 Other bits You'll want battery terminal clamp connectors- quick release ones are a good idea, I personally didn't bother and used standard ones since I've usually got a spanner handy. You'll want big ring terminals for your power line and big spade terminals for where it goes into the relay. You'll probably also want to get a bag of terminals, I like these: http://www.vehicle-wiring-products.eu/product.php/429/female-blade-with-latch as they've got a little latch mechanism that clicks into the hole in the male terminal. And because you're using relays and fuses, where the terminals are quite close together, you'll probably want some kind of insulation on the connectors. These are good: http://www.vehicle-wiring-products.eu/product.php/442/plastic-holder-for-female-blade But they may be a bit bulky, so you might want to get some of these too: http://www.vehicle-wiring-products.eu/product.php/433/female-blade-insulation Battery This depends on what you're using the van for. I lived in mine for a while, and had a 110Ah battery. I powered lights, radio and a normal sized laptop for about a week. No hookup but a long drive once a week to top them up and visit t'mrs. You can work out your capacity requirement, if you like, by adding the current draw of each item you want to use and how long you'll want to use it for. 110AH=110 amps for an hour, or 1 amp for 110 hours. That's the idea. You shouldn't need to pay more than £90 for a 110Ah, obviously they get cheaper if you don't want as much power.
Just a quick intervention but blade fuses every time for me. Much better than torpedo type! (which can melt on a constant overload and damage the fuse box, and indeed sometimes melt the plastic and not actually blow)
Yes blade fuses are better and less troublesome but can still melt. Use separate Maxi blade or or preferably the better and neater Midi fuses (which can tolerate a surge current without blowing) at either end of the split charge cable. As a rule the split charge cables and fuses between the batteries should be the near or above the same rating as the alternator output.
