Hi there,

I have a HJ60 TLC, 24v, with an optima dual battery. I want to run a split charge relay from the 24v system to charge the 12v battery. So this requires 2 components - the relay and the voltage convertor.
The problem is that I'm not sure which way round they should be wired up?
It could either be:

OPTION 1:
24v Source >> 24v voltage sensing relay >> 24v to 12v convertor >> 12v Aux Battery

OPTION 2:
24v Source >> 24v to 12v convertor >> 12v voltage sensing relay >> 12v Aux Battery

In the first option I dont know if the convertor bewteen the relay and the aux battery will effect the 'voltage sensing'. In the second option I dont know if its a bad idea having the convertor directly wired to the 24v source, always connected, risking running the battery down.

And then just to add to it, i dont know what specification the convertor should be to handle running an engel fridge etc.

I've spent hours searching the web about this - if anyone has any ideas or comments it would be very much appreciated. This 24v business is driving me bananas!

Many thanks - Andrew

Thousand ways of doing this... and generally nobody agrees on what's best ;-)

This is how I did it, and works best for me:

24volt starting batteries (2 x 12v battaries in series) --> smart relay --> 24volt auxiliary batteries (2 x 12v batteries in series)

This setup will require an additional battery, but in my opinion this is best. Converting from 24v to 12v always means a loss and a convertor that can cope with the amperes that your alternator generates is not exactly cheap.

The smart relay I'm using is the Victron Cyrix (http://www.baintech.com.au/Victron_-...Separator.pdf_ and cost me about 90euro's. It prevents the aux batteries from draining the main batteries and automaticly charges the aux's when the main batteries are charged enough. Nice piece of kit, and a hell of a lot cheaper then the split charge systems they sell in overland shop (national luna, ...)

Now, you still have 24v at your auxiliary batteries, but that shouldn't be a problem. Your Engel fridge is perfectly happy to run on 24volt and will run a LOT more efficient too! Try to run as much as possible on 24v (spots, ...) and use a smallish (15a is most likely enough) to run the 12v equipment like a radio, ...

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2006-2007 overland expedition: Brussels - Cape town - Tokio - Brussels

http://www.radiobaobab.be

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2006-2007-2008 : Brussels - Cape town - Tokio - Lubumbashi - Brussels

http://www.radiobaobab.be

I made a diagram of my setup:



As explained above. The emergency switch allows me to start the engine with the auxiliary batteries if my main batteries would fail.

__________________
2006-2007-2008 : Brussels - Cape town - Tokio - Lubumbashi - Brussels

http://www.radiobaobab.be

Originally posted by Moodoo:
Andrew

Someone please correct me but I expect that the HJ60 should have the same 12V/24V setup as HDJ80. This means you need not to worry about the 24V component because 24V is supplied only to the starter motor. All the other bits always get 12V.

If you just want to split charge a single deep cycle battery for the fridge, consider a setup as would be normally applicable to a standard 12V only installation.

If you want to backup the main batteries, things become complicated and you need two split chargers configured in a particular way.

Let me know which one you want and I'll make a diagram for you.

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Roman (UK)
www.overlandcruiser.com

[This message has been edited by Roman (edited 13 February 2006).]

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Roman (UK)

Hi Roman,

Some 60 series did come with a 24volt system throughout, which is what these guys are referring to.

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Cheers,

Julian
Euro Landcruiser Owners Club
http://www.landcruisers.info/lists/

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Cheers,

Julian Voelcker
Overland Cruisers - Specialising in Land Cruiser preparation and servicing.

I would go for option 1.
I had to make the same decision and choosed wrong (option 2)... our 24v to 12v converter gives about 13.8v, the smart switch (as mentioned earlier) has a switching point of 13.7v... ergo, it stays on/open.

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bart



[This message has been edited by Sophie&Bart (edited 14 February 2006).]

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bart & sophie

Hi. Just take your 12v supply from one of the batteries, if you are using a NL split charge system connect ALL the pos things to the pos of one of the 12v batteries, and connect all the neg things to the neg of the same 12v battery (NOT earth).
As long as the split charge system is issolated from the vehicle (the vehicle being 24v) it'll be fine.
Cheers,
Matt

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www.mattsavage.com
VIAIR - 12 & 24 volt compressors and systems. Tyre levers, Land Rover parts, Sand Tracks, Allisport Intercoolers, Overland Prep, and much more...

That's what I thought kills your batteries rather quickly because of uneven charging/discharging.

There are some alternatives discussed on the forum though (second alternator, solar panels, 24V->12V convertor...)

Thats what I thought as well, would have thought it would be safer to use a voltage dropper to run a charging circuit from the 24v to 12 v. I believe all H60 have full 24 volt electrics, mines a 1990, last of the H60 and thats all 24v, except for the radio which runs off a 12v circuit. what about running a feed off this? Not quite sure why you would need a split charge given the size of the twin batteries, bit belt and braces. If your worried about draining them then as someone else suggested, one of the small foldable solar cgarges may be the thing to get you out of a fix.

cheers
Andy
land 101fc ambie
TLC H60
1968 morris minor traveller

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1990 Landcruiser H60. Full rebuild completed 2014

Thanks everyone for all the ideas.
Think we will have a play around with the relay and the convertor (option 1, cheers Bart), and if that looks dodgy then we'll either go for the 2 battery 24v aux option (thanks v much for the diagram 2cvfred) or maybe a 12v alternator mounted on the unused air-con pulley.
Definitely dont want to run everything off the two 12v batteries alone as we've already had problems getting enough cranking power out of them to bleed the engine.
Will update this thread to let you know what we do in the end. Thanks to all again,
Cheers Andrew

Moodoo, if you have this option I would go for the extra altenator. The relief/comfort of a totally independent system is a bonus.
In my experience (HJ60/6 months in N-W Africa) a separated powersystem gives a lot ease of mind, because you can totally forget about it.
We use a small solarpanel (±45watt), 2 extra batteries 'parallel' connected, giving 12v with enough amps to keep our compressor running long enough to fill our tyres and powerup all our gadgets (torches/gps/phone/laptop/etc). Never run out off power (though we don't have a fridge).
The idea was to use the 24v>12v (cyrix>converter>batterie) connection for the days without sunshine. Because of all sorts of lastminute decisions I started to connect all this electricall stuff when we were a few weeks on the road... after I found out I followed the wrong way (Moodoo OPTION 2) I searched a while for a batterieswitch (in Morocco)to make a manual connection (didn't find a marinesupliesstore in Figuig with a new cyrix) but in the end give up all because the solarpower was more than enough to keep our gadgets happy.

The 2 extra batteries (deepcycle) are specially made for solarpanels-electrical systems but can be used as starting batteries too (surf/ask around in marinesupliesstores). The benefits of these deepcycle batteries are that they are build for the job, and can be totally emptied (e.g. forget switching off your fridge) without harm, something that's not recommended with your traditional accid type starting batteries.




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bart

http://www.woestijnzand.nl

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bart & sophie