Anyone used this type split charge relay

[sciroccotune]

Hi guys any one used on of these? Looks to be a good product to help protect both batteries.

http://www.ebay.co.uk/itm/SPLIT-CHARGE- ... 830wt_1062" onclick="window.open(this.href);return false;

Cheers

[California Dreamin]

Voltage sensing split charge relays are pretty popular nowadays. They simplify the wiring no end by nagating the need for any switching circuit from the alternator.
The only downside (in my opinion) is that this 'so called' heavy duty relay is just not man enough and you need to be looking at a similar relay but one that can handle at least 40 amps.
Something like:
http://www.ebay.co.uk/itm/Split-Charge- ... 35b23f84d7" onclick="window.open(this.href);return false;

Martin

[Oldiebut goodie]

You can use the Smartcom to switch another larger standard relay such as an 80 amp one. Easiest way out of it as voltage sensing relays for 50 - 100 amps are thin on the ground and bliddy expensive when you do find one.

[Hacksawbob]

or the Durite one, not that expensive.
http://www.thetoolboxshop.com/0-727-33- ... 8096-p.asp" onclick="window.open(this.href);return false;

[Oldiebut goodie]

The only thing that I have against those relays is that the switching voltage is preset not adjustable like the Smartcom (as I found with my 180A one)

[sciroccotune]

Thanks guys I like the look of the 60amp one - that should be enough right?

Cheers once again

[California Dreamin]

60 amp is big enough but as I've just spotted this one at the same price you might as well go for the extra capacity and never have to worry.

http://www.ebay.co.uk/itm/Split-Charge- ... 33729cbfdd" onclick="window.open(this.href);return false;

Martin

[Oldiebut goodie]

Take note that the above one will only switch in at 13.3v though - if your alternator regulator is running lower than this it will not work. That's why the Smartcom + another in some cases is preferable as you could set it lower to suit your voltage.

[California Dreamin]

Take note that the above one will only switch in at 13.3v though - if your alternator regulator is running lower than this it will not work. That's why the Smartcom + another in some cases is preferable as you could set it lower to suit your voltage.

Sorry mate....but if your regulator is only charging at 13.3 volts then it needs ditching anyway. A regulator set this low isn't going to be much use in charging 150 amps PLUS of batteries so if this is the case it really is worth paying £10 - £12 for a new regulator brush pack.

The original Beru and Bosch regulators had a charge tolerance from 13.9 - 14.2 volts and when you buy modern aftermarket replacements they are closer to 14.5 volts (the 3-4 I have tested have all been between 14.2 and 14.5 volts) by virtue of the fact that modern batteries based on newer core materials need a higher charge voltage. Manufacturers of these regulators have recognised the needs of newer battery types and have deviated from the original charge specification as a result.

I would go as far as to say any regulator not hitting the lower spec of 13.9 volts (measured at the starter battery) should be changed if you want reliable charging from you setup.

Martin

[Oldiebut goodie]

That's why I said 'in some cases' - let's face it we don't all have everything running as it should! (I have just replaced my regulator and that runs at 14.2v also)
I use mine to switch the solar panels output to the leisures after the starter so being able to vary it has its uses.

[bmouthboyo]

Can i ask do you have to mach the relay amps with the battery amps? So for instance i have a 150ah battery, do,i need to get at least a 150 amp relay? Also do i need heavy duty wiring?

[CovKid]

No, but when the voltage on a battery falls, as it would if you used it heavily while camping, when the engine is running again and the relay kicks in, the draw can be higher than normal. MIne (including connecting cables and simple relay) is rated at 80amps - well in excess of whats needed to be honest but some of the cheaper 'kits' are often 40amps which is just on the lower end of acceptable. If you were drawing 150amps, you'd be using some serious amount of power and beyond the scope of a a leisure battery or indeed a circuit like this.

[bmouthboyo]

Thanks formthat cov, what amp relay woukd you recommend?

I cant image running the battery flat too oftwn tbh, ill have stereo, some led lights, laptop etc. in future maybe a propex. Would a 100amp be safe?

[California Dreamin]

The decision about what sort of relay and wiring to use is based on current flow (amps) between the two batteries (Leisure & Starter)
A typical split charge setup on one of our vans would be using batteries of around 60 - 70ah for the starter and 70 - 110ah for the leisure (Note* the leisure might just be a high capacity starter battery if situated in one of the under seat battery boxes)
With this sort of setup owners (who have tested amp draw) have reported around a 40amp 'initial surge' with a heavily discharged leisure (amp reading flowing between the two batteries).
This 40amp draw appears to quickly fall (5 - 15 seconds) to around 25amps and slowly tail off there after.
Baring these figures in mind, 40amps is the likely maximum current flow and only ever going to occur with a very discharged leisure battery.
Therefore, the recommended minimum relay rating is 40amps. However, to give headroom for long term reliability, one of the higher capacity 60/70amp relays would be a wise choice.
Of course there is nothing wrong with going even bigger (100/120amp relays) but based on these figures there is nothing to be gained unless more batteries or much higher capacity batteries are being used.
The other issue around going 'very high capacity' 70 amps plus...is that cables/terminals/fuse holders are large/expensive and difficult to make without special crimps etc.
Whatever you choose, make sure the circuit is fused at a lower rating than your weakest component.
70 amp relay/45amp main wiring/40amp fuses......something along those lines.


Martin

[CovKid]

Agree completely with that. 40amp is enough for what you want. I ended up with 80amp because thats what I had available (free) at the time. Plus thicker cable is a pain (and expensive) to route. I recently switched to a big lorry battery instead of a leisure battery and rather glad of the better cable/relay in the charging circuit now but my system is really overkill. Its not the norm. Besides, when you think about it, there needs to be consistency on all the heavy current carrying cable - ie alternator to battery, starter etc if you're upgrading.