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Remember those Cyrix split charge relays?


Super Moderator
Feb 24, 2010
Country Flag
Guys, need to get around to getting my aux battery linked up to my charging system and I was just wondering how the rest of you had got on. It sounded as though program 2 was the best all round in terms of setting, but what did you do in terms of positioning. As they are not weather proof, I would prefer to put it inside next to the battery, but the destructions say that it should be sited near to the main battery. If you put yours under the bonnet, did you find a waterproof enclosure?

I know that there were several of us who bought them, but no one has really put up much of a post on them.

That's probably because most of us still have them sitting on the shelf :lol:

My intention is to mount it on the bulkhead or inner wing on the driver's side and contain it in a in a weatherproof box and grommet the cables - nothing fancy just a modified Tupperware or similar.

It will probably depend where people have their extra batteries My suggestion above is because I'm planning a rear mounted battery under the floor.

You may have a better idea but I'm thinking that I'll just attach the cables to the main battery and allow the 24v start relay to do its job as intended. That way the Cyrix can allow charging of both vehicle batteries until they're full and then switch to the aux, but the 24v will still do the series/parallel swap for starting. I don't know though if that will allow enough boost from the aux if required to 'jump' start :think:

I've wired my winch to the driver's side battery only for that reason too.
Dave, precisely what I have planned. Battery is behind rear seats jammed in with the dog guard at present. I plan to put the battery itself on one of the big Anderson connectors with about a foot of 50mm2 cable so that it can be taken out in an emergency and used with my HD plug in jump leads or perhaps used to power a winch off the vehicle - all plans in my head. The rest of the system really doesn't need 50mm2 to charge it does it? I would have thought that given my consumption and limited use of the battery even 35mm2 would be overdoing it. But that's what I plan to use. There will never be any significant draw down the cables from anything running from the battery.

Anyone want to buy my one, decided not to use it after all. Still in the box
Paul said:
Anyone want to buy my one, decided not to use it after all. Still in the box

I'm looking into split charge systems at the moment. PM me what you want for it.

Are you also the Paul that was selling inverters? Do you have any left?
I mounted my unit in a round plastic tub - old ice-cream one, as couldn't find a tupperware the perfect size.
it is bolted onto a "L" bracket which i riveted to the bulkhead inside the engine compartment between wing and brake fluid reservoir in front of driver in my LC90.
I used profile 2. I also fitted a switch to manually link the two batteries using the option it had. i also have two LED on dash to indicate whether or not the device has batteries are connected. You can easily hear the relay "clonk" as it engages about 20secs after starting the engine in the morning and driving off.
sometimes it doenst always disengage if you stop say at a fuel station, and when i come to start the engine again, the starter motor is noticeably faster - showing that batteries are both in parallel still. but if you have the engine off and left a radio on in the car etc, or a door open (interior light on) that current draw is enough to drop the voltage in the batteries and make cyrix disengage.

I used 50mm2 cable to link the batteries and the Cyrix together, as when winching etc the winch will be drawing from both batteries.

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I have mounted mine under the bonnet in a box with one end open as I could not find one small enough. I have been through rivers, 300km of huge potholes and puddles (even the roof was dirty after that run) and it is still working as it did when first installed. I have mounted the 3rd battery under the bonnet but I will need to modify the tray as the batery is rubbing against the bonnet.

I have set mine to profile 2 and it usaully turns off within a minute after turning the engine off but I can hear it clicking on and off a couple more times after that. No idea why this is happening but I think it may have something to do with all the batteries leaking from the inspection holes in the top due to all the potholes...