Split Charge System, Intelligent Relay Question ..

[xpress]

i noticed when reading the wiki that there's relays with "basic intelligence that wil avoid an alternator connection for your split charger".

how do these avoid patching into the alternator/no charge light? how do these patch in? i would be grateful if someone could explain this to me and maybe you might want to put it in the wiki somewhere.

here's the quote from the wiki:

"Horza:

£12 from towsure will buy you a relay with some basic intelligence that will avoid an alternator connection for your split charger".

Reference:

https://club8090.co.uk/wiki/Ca ... it_charger" onclick="window.open(this.href);return false;

[andisnewsyncro]

Have a look at this, it probably explains it better than I can.

Personally I'm not over happy with the supplied hardware as shown, and it might not be up to the amps you need, but it gives an easy explanation of what it does.

[xpress]

thanks for that, was an easy explanation and good that it comes with the fuse holders etc in a kit.

i wonder how the intelligence works out what it promises tho?

btw why are you not happy with the supplied hardware?

and in what instances might it not be up to the amps i need? thinking tho, if you add a fridge, couple of radio amps etc ..

is this a battery parallelling relay in this kit?

if it parallels both battery banks, then it might not matter where the charge comes from or which bank it's connected to. It could be the alternator, an AC powered charger, a solar panel etc?

ps . can anyone recommend a fuse box that they use with the split charge system that they use or can recommend?

pps. i just looked in the box of front brake pads and they've given me the wrong ones, i need the square ones arggg!

[Oldiebut goodie]

100 amp relay

kit

[andisnewsyncro]

Oldiebutgoodie's link shows a much better kit IMHO.

My reservations with what I linked to were about the "scotchlock" type connectors included and I'd much rather see soldered joints on the battery terminal rings with a bit of shrink wrap to insulate - perhaps being picky but I like things done properly and neatly when it comes to electrics

I think the "intelligence" is diode based, but I'm a bit rusty on that sort of stuff these days

Anyway you get the idea. As for a fuse box I just have one from a local auto electrical place for about a fiver.

[CovKid]

http://cgi.ebay.co.uk/180-100A-12V-Spli ... 414f97f300" onclick="window.open(this.href);return false;

[AngeloEvs]

The smart relays include a voltage sensing circuit that engages the charge relay when the starter battery voltage increases over and above 12.7V. Once the alternator kicks in, the voltage across the starter battery is higher (usually around 13.4V). Smart relays have an adjustment that allows the user to set the voltage at which the relay will kick in and most are factory set to kick the relay in when the voltage across the starter battery reaches around 13.4V. They relay can be slow to trip out sometimes and switching on your ZIG (when on EHU) too soon can prevent the relay from dropping out. Alternatively, if the trip voltage is set too low it takes longer to disconnect. If set too high and you have headlights, wipers and 12V fridge on then they can trip out whilst you are driving and you will hear it engaging and disengaging frequently. I set mine to kick in at around 13V.

[xpress]

thank you for this.

what relay do you have angelo? is it different from the ebay one covkid posted up? (thanks btw).

is there some kind of physical user dial inside the relay that you can use to set the voltage to your requirements?

[AngeloEvs]

The relay has a small hole and you insert a small screw driver and rotate the adjustment potentiometer left/right but try the factory setting first. The one CovKid has linked to is a conventional relay but with 100A rating (not a smart relay). Towsure sell them but the current capacity isn't very high but I it all depends on just how discharged the leisure battery is but do a search on google and you will find higher rated types available. I have a Smartcom but purchased it from CPC.

http://www.towsure.com/product/1828-Sel ... tion_Relay

[xpress]

thanks again,

i was initially going to go for a brocott kit (30amps) but then i am thinking that this set-up would take longer to charge batteries and the fridge might not function at full efficiency.

i have a small 3 way fridge, would a 30amp relay and 30amp rated wire be up to snuff for this, charging an average 95 amphour leisure battery and running internal lights, radio etc?

i have a fuse box i am looking at too, that's similarly not too heavy duty, just a plastic interconnect with 30amp wiring and accepts blade fuses.

i am hovering over the order button thinking i could trade up later or is it better going for 100amps to start with or am i likely to be ok for now with 30?

[bigherb]

Ideally the split charge relay and wiring should be matched to the maximum alternator output as you can never put any higher amps down the circuit. So if you have a 55A Alternator you would need the closest relay which would be a 60A. In practise though unless you have multiple leisure batteries only 30 to 40A would go down the split charge as some power is used to run the engine and recharge the starter battery. The easiest option is to use a small intelligent charge relay to switch a higher power standard relay for the leisure battery which can then be uprated later to any capacity.