Yet another split charge one......

ive read most of the split charge stuff and have fitted a few too but something Id like opinions on is this :

Can one/is it worth using a smartcom voltage sensing relay of the caravan type (which doesnt have the capacity needed) to trigger a heavier relay,like 180a or more to split the charging?Im not looking at using this vehicle,a 300tdi auto with EDC, for heavy winching,more caravanning and general use.I want to be able to run some 12v lights and tools off the truck and envisaged a couple of auxillery fuseboxes,one ignition switched,with outlets in the cab and at the back.Also inclusing a heavy +ve to +ve battery link with a heavy rated cutout switch to give a big start charge when needed.

I have all the cable already,and a new smartcom relay left from another job plus a spare battery.Anyone think of good reasons that I shouldnt do this,or got any alternatives?

Thanks guys!

shocksi

Well as usual things didnt go quite to plan......looks like whoever fitted the tow electrics 12s socket didnt use a split charge or any sort of relay as the pins for the fridge and and charge are on permanently,not ignition switched.

So....tomorrow will have to remove the rear seat and side and see just what IS in there.

I opened up the Maypole Chargecom split charge unit that I have on the bench and it consists of two 10a relays linked on a board.....hmmmm.I think I will use it to trigger some 40a relays for the fridge and caravan trickle charge.Still,at the same time I can run a line back up to the front from the "aux battery charge" output and use that to trigger a 120a relay at a later date.

Why not just fit one "good" split charge relay that will cover everything you throw at it.

Even a 180A relay is NOT enough for "heavy winching"

Have another look mate,NOT using for heavy winching...but thanks for replying.

One good split charge relay....for caravan attachments,does such a thing exist?All the ones Ive seen have 20a or even 10a relays in a fancy box.If it was just for a secondary battery,easy.But for a fridge and a leisure battery trickle charge?The old way was to have a relay for each triggered by an ignition feed,but I like the idea of either an alternator or voltage sensing trigger on them.

I have always used 40A relays triggered by the ignition warning light terminal on the alternator which ensures that the engine is running before the split charge/fridge relays kick in.

shocker said:

Have another look mate,NOT using for heavy winching...but thanks for replying.

One good split charge relay....for caravan attachments,does such a thing exist?All the ones Ive seen have 20a or even 10a relays in a fancy box.If it was just for a secondary battery,easy.But for a fridge and a leisure battery trickle charge?The old way was to have a relay for each triggered by an ignition feed,but I like the idea of either an alternator or voltage sensing trigger on them.

Click to expand...

Sorry missed the "not".............

rubythursday said:

I have always used 40A relays triggered by the ignition warning light terminal on the alternator which ensures that the engine is running before the split charge/fridge relays kick in.

Click to expand...

^^ What I do, but used a £10-ish 180A relay (as used by X-Eng!) instead ^^

180 - 100A 12V Split Charge Relay 100 AMP 12 V 180 kit on eBay (end time 16-Jun-10 09:00:27 BST)

In case anyone was wondering (yeah,right!) The route I chose was to run two 79 strand cables ,fused, from the battery and a lightgauge one from the alternator down inside the body,under the carpet,to the rear of the vehicle where the plug in tow electrics are normally found.Instead I found a birds nest of bloody scothloks and all the 12s power supplys bodged into one contant battery feed - god alone knows what would happen if I'd have put a full caravan loading on that,no relays at all and light cable.Fire most likely.

Went with a pair of 40a relays for the fridge and battery charge,powered by the fused lives I rean in and switched by the alternator, and wired the single constant to the single constant in the loom.Relays at the back,new little fusebox next to the fitted fusebox under the drivers dash.Hopefully this should do the trick.

Next up is to use a 70a relay ,ignition switched, powered off the new fusebox,for a 4 way 12v socket fixed to the centre console.

Im still enamoured by the idea of voltage sensing for the proposed secondary battery though,so the charge is switched over when the main battery reaches 13.5,or thereabouts.Any ideas on how to go about this other than using a caravan-stylesmartcom relay?

Following mburton2's link I found that the same company do a "dual sensing self switching split charge relay" rated at 100a/180 peak for under £50....that should do the job.A bit costly........