The Ideal Diode / Leisure battery switch, charging thingy

[John and Kim]

OK, Looks like I've got myself a project (too much time on my hands at work!) and have thought about this 'Problem' before.

How to connect the leisure battery to the alternator permanantly whilst;

1, allowing the Main battery to be fully charged first.
2, not allowing current to flow in the 'wrong' direction, i.e from Leisure to Main, or from Main to Leisure whilst engine not running.
3, lots of other things I probably haven't thought of yet!

Well there are the usual voltage sensing relays and the like (and this has been covered in depth on here before) but this is I think rather crude and there are more 'Modern' solutions.

Without getting even slightly technical (I'm an Electronic Engineer) I'd just like to gather a list of requirment of what this 'Device' must do.

It will be very easy to install, only having an earth tab and a connection in from the Main and connection out to the Leisure.

Ideas please.......................

JnK.

[mikexgough]

I looked into this myself but have settled for one of the excellent kits made up by willinton on ebay, I have the one with the battery tray.....it's all there apart from your leisure battery.......does what I want it to do without being too techie......

[John and Kim]

Don't worry 'bout the 'Techi' bit as it's only got two wires!

I mean I don't want too techi in explaining how my device will work.

But I do need to know what it must do, in case there is something I have not thought of?

[daveblueozzie]

intelligent split charge relay, charges your main battery first then charges you LB .
when engine off the relay stops the LB drawing power from your main starting battery.
no need to cut into any wires from the alternator.
willinton best bit of kit around.
the one you fix on your alternator sometimes puts a warning light on your dash and you may need an extra bit of kit to stop it lighting up.

[MountainGoat]

Messing about with the alternator when installing a leisure battery is a no no where Bongos are concerned, they just don't like it. The setup which my converter installed gave me no end of grief. Always flattening the starter battery over a few days and even overnight when using a hook up on a campsite. I also went through about fifty fuses, most of them when I limped home from the Western Isle last year via half a dozen jump starts and call outs. Since installing one of Willintons Intelligent split charging wiring looms myself just over a year ago I have yet to have a problem, even after camping for three nights without a hook up.

[John and Kim]

Just a relay, two resistors and a transistor then? (I'm getting technical now!)
Not a very clever circuit but it doesn't need to be either and maybe I'm trying to be unnecessarilly ?

I don't see why anyone would be inserting anything in the alternator cabling (I certainly won't!)

What is the benefit of using these here;

http://www.power-store.com/view-item.as ... 501&id=248&

As this is the kind of thing I'll be making.

Any ideas anyone???

[Bin Bongoed]

Just a relay, two resistors and a transistor then? (I'm getting technical now!)
Not a very clever circuit but it doesn't need to be either and maybe I'm trying to be unnecessarilly ?

I don't see why anyone would be inserting anything in the alternator cabling (I certainly won't!)

What is the benefit of using these here;

http://www.power-store.com/view-item.as ... 501&id=248&

As this is the kind of thing I'll be making.

Any ideas anyone???

Just buy from Willinton, he's virtually on your doorstep anyway, got a good reputation, and cheaper than that.

[John and Kim]

I can't find his ad on E-Bay.

I'm developing something myself and will be adapting it for any battery system up to 280A.

It'll drop less volts than a relay contact and bit a bit more intelligent (not much, just a liddle bit!)
Should be scalable to charge multiple batteries too. Any relay system will allow current to flow either way between batteries which is something mine wont. It will work exactly like a diode without the associated volt drop and power loss and be able to sense, under and over voltage conditions and other such problems and give an indication of such a fault. I think that's all it has to do?

I'm still looking for a list of requirments from anybody who uses a leisure battery setup, max current etc.

JnK.

[MountainGoat]

Here is Willinton's ebay shop for you.

http://myworld.ebay.co.uk/willinton&ssP ... X:SELLERID

[scanner]

Here is Willinton's ebay shop for you.

http://myworld.ebay.co.uk/willinton&ssP ... X:SELLERID

Willinton's in Bristol as well, so it could be worth contacting him to see if he'd be willing to have a chat about your idea.

If anybody knows what's needed he does.

[Aethelric]

Just a relay, two resistors and a transistor then? (I'm getting technical now!)
Not a very clever circuit but it doesn't need to be either and maybe I'm trying to be unnecessarilly ?

I don't see why anyone would be inserting anything in the alternator cabling (I certainly won't!)

What is the benefit of using these here;

http://www.power-store.com/view-item.as ... 501&id=248&

As this is the kind of thing I'll be making.

Any ideas anyone???

Standard Diodes suffer from the voltage drop, up to over a volt on high currents, and 0.7V even at low currents. FETs are great at low currents but are resistive and this will limit the charging current. They don't state the resistance of the FETs, but it can't be negligible as they would not need such a chunky heatsink. I'd distrust any data sheet that said output wattage is 100 amps

Dave

[g8dhe]

FETs are great at low currents but are resistive and this will limit the charging current. Dave

Huh ? If you think you need to charge a L/B at greater than 95A then this one won't be adequate! but you will need to generate an adequate Vgs I guess or use a P channel FET instead like this one which will handle 40Amps which might just be rugged enough.

[hogggman]

hi,
i work for a company called Autosparks,and purchased this excellent relay kit:

http://www.autosparks.co.uk/product_inf ... ts_id=1709

for £15 or for £26 all in,you get the relay,terminals and all cabling required.it actually connects to the starter solenoid,not the alternator,so may be much more suitable for a bongo.
when fitting i actually found that my bongo already had a relay fitted,but was missing a fuse,so i ended up getting my money back on this relay kit,but i think it`s well worth considering.if youy phone up for advice,ask for paul,as he`s an auto electrics whizz,and say that jamie told you where to go.
thanks
jamie

[missfixit70]

hi,
i work for a company called Autosparks,and purchased this excellent relay kit:

http://www.autosparks.co.uk/product_inf ... ts_id=1709

for £15 or for £26 all in,you get the relay,terminals and all cabling required.it actually connects to the starter solenoid,not the alternator,so may be much more suitable for a bongo.
when fitting i actually found that my bongo already had a relay fitted,but was missing a fuse,so i ended up getting my money back on this relay kit,but i think it`s well worth considering.if youy phone up for advice,ask for paul,as he`s an auto electrics whizz,and say that jamie told you where to go.
thanks
jamie

Why?

[corblimey]

What about this one http://uk.farnell.com/international-rec ... dp/8648018

162 Amps and RDS is only 0.004Ohm. Surely that package can't handle 162A