disco_al Posted January 2, 2009 Posted January 2, 2009 Right, another electrical question I have an x-charge fitted to the disco, if i run a switched 12v feed to the orange wire (the one that goes to the alternator charge light) can i flick the switch, thus activating the relay, thus giving me a quick self jump start mode? or even just leave it for 5 mins to recharge the starter battery a bit? Quote
rtbarton Posted January 2, 2009 Posted January 2, 2009 You'll burn the wiring between the batteries out, or blow fuses if fitted, if you try to jump start. Leaving it for 5 mins may work, depends on relative charge of batteries and how easy the engine will start anyway. Quote
BogMonster Posted January 2, 2009 Posted January 2, 2009 The X Charge is designed to cope with winching current according to X-Eng - I would have thought a short burst for starting would be OK but Si might be able to comment on this? Quote
disco_al Posted January 2, 2009 Author Posted January 2, 2009 You'll burn the wiring between the batteries out Wiring should be ok as it's thick battery cable. I'll await Si's response Quote
Ben_J85JTY Posted January 2, 2009 Posted January 2, 2009 IIRC the X Charge is rated for 280amps continuous usage, which would mean that for short periods of time it will be able to handle more. If you had a standard "caravan" split charge then you wouldn't be able to do this, they are only rated for about 30amps. The only issue you may have is that sometimes if one battery is really flat, the relay won't trigger, or at least that is what I hvae found with my X Charge. Great bit of kit tho. Quote
BogMonster Posted January 2, 2009 Posted January 2, 2009 According to the site http://www.x-eng.co.uk/X-Charge.asp it is 180A continuous and OK for higher for short bursts. So I don't really think 5 seconds for starting would cause undue problems even if it is 400A or so, but there is one way to find out I was amazed to see how cheap they sell the relay, for something that can handle that sort of current! Quote
rtbarton Posted January 2, 2009 Posted January 2, 2009 Wiring should be ok as it's thick battery cable.I'll await Si's response Fairy Nuff. I didn't realise the X-Charge was that hefty, should have known better! Quote
TheRecklessEngineer Posted January 2, 2009 Posted January 2, 2009 You could always wire in a starter solenoid in parallel with the X-charge. Then you can energise that to give you a self jump start. Or just use a cut-off switch... Quote
disco_al Posted January 2, 2009 Author Posted January 2, 2009 was originally going to use a cut off key type isolator switch with more battery cable, but had a crazy "eureka" type moment last nght as i was lay in bed of using a 12v supply to the trigger wire to operate the relay, thus connecting the two batteries. Quote
PaulMc Posted January 2, 2009 Posted January 2, 2009 was originally going to use a cut off key type isolator switch with more battery cable, but had a crazy "eureka" type moment last nght as i was lay in bed of using a 12v supply to the trigger wire to operate the relay, thus connecting the two batteries. I would use a changeover switch so that you disconnect the alternator warning light feed when you switch the relay with 12v. I you used a changeover switch that doesn't latch, so that you have to hold it in the 'jump start' position, you can't inadvertantly leave it in that position. Paul. Quote
PaulMc Posted January 2, 2009 Posted January 2, 2009 I would use a changeover switch so that you disconnect the alternator warning light feed when you switch the relay with 12v.I you used a changeover switch that doesn't latch, so that you have to hold it in the 'jump start' position, you can't inadvertantly leave it in that position. Paul. If you use a switch with a centre off (ON-OFF-MOM), you could leave the split charge turned off, so that the dead starter battery gets all the charge. I don't think that an ON-OFF-MOM switch is commonly available in most ranges - I made one from the more common ON-OFF-ON switch for my 110's previous homemade centre dashboard, by dismantling the switch and removing the latch in one of the ON positions. The switches I was using were from the Arcolectric 1300/1350 Rocker Switch range, but I'm sure that you could do the same to the more commonly used Carling or Eaton switches. Paul. Quote
simonr Posted January 2, 2009 Posted January 2, 2009 Yes it will work - however! You may damage your alternator if you just connect the wire to 12v while still connected to the alternator. Use a change-over push button switch which will disconnect the alternator from the relay and instead connect it to 12v while the button is pressed. A momentary (Eg. push button) switch is the best option so you do not leave it connected longer than necessary. There is little point in disabling the X-Charge so the discharged battery gets charged first because the charge is split proportionally to which battery is most discharged. That way, both batteries will arrive at 100% charge at the same time. Current wise, the relay will handle the current required for that short duration. As you suggest, push the button for a few sec first so the X-Charge is not supplying the full current to the battery and starter at the same time - then crank! Si Quote
freeagent Posted January 2, 2009 Posted January 2, 2009 I'd put a cut off switch in parallel with the X-charge. Quote
simonr Posted January 2, 2009 Posted January 2, 2009 I'd put a cut off switch in parallel with the X-charge. Why? Quote
freeagent Posted January 2, 2009 Posted January 2, 2009 Why? Because it only costs you a few quid to do, can be used to jump start yourself when the Engine start battery is completely dead, and gives you manual control should the relay fail for any reason. If you look at a lot of marine electrical installations they do the same thing, put a manual switch in parallel with the split charge relay. Quote
disco_al Posted January 3, 2009 Author Posted January 3, 2009 Use a change-over push button switch which will disconnect the alternator from the relay and instead connect it to 12v while the button is pressed. I think i've got it, basically a switch with three positions would be best, on for running x-charge as normal, off and momentary on for jump start, so that it isolates the alternator from the starting currents involved. Excellent, cheers all. Quote
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