Dual Battery Wiring Mistake
- Thread starter chartrock
- Start date
Thanks for the pic Ants. I will have a look at their web site later and see if i can get more info. But for the
moment here is what i think has happened.
To disconnect your service battery from your start battery when the engine is not running the d250 uses an internal
VSR (voltage sensing relay) circuit. This will disconnect when the voltage measured on your start battery side drops bellow a pre set limit. I don't know the setting but for our example lets say 13.5v. Now dumb alternators usually run at around 14v so the ctek will have no problems and connect as it is meant to do. Smart alternators however will more often than not sit at around 13v so your ctek will think the engine is not running and disconnect, leaving no charge going to your service battery.
Most modern VSR's allow you to adjust the cutout voltage so you can set their threshold voltage lower when connected to a smart alternator. I have no doubt that we will soon see a new ctek that will have the same feature. Untill then if you have a smart alternator you will have to use their "work around" and fit an extra relay.
The solar input of the ctek is unlikely to have any sort of cutout so you will need to fit the relay (If you have a smart alternator) whether you have solar fitted or not. Otherwise your service battery will remain connected to your start battery all the time and you don't want that. Make sure the relay is switched by your ignition circuit as shown and not the accessories circuit and though they don't show it in the circuit a fuse will be needed in the supply line.
I must say i am a little disappointed with ctek's position on this, they have a product that appears not to be compatible with some modern alternators yet instead of marketing it so they offer up a kludgy work around which will severly impact anyone with solar connected.
Hey @boots33 thanks for that description that makes sense. Im certainly not on the technical side of this one its all a bit over my head.
I know that when I read about the Pajero, that there were reports that the smart alternator in it can dip the voltage down to 12.1 volts which was below the modern VSR's that you speak about (from my research. I however could not get any clear indication from anyone - Mitsubishi included (I had the Pajero at their workshop after purchasing it and they couldn't even install the relay?), about a good solution for a dual battery setup and hence went with the CTEK even though I lose the ability to be able to start the car from my secondary battery if required. The Redarc equivalent i think was just too expensive. I would however now be upset if someone was able to tell me that there is a VSR that would be able to achieve my desired outcome as a VSR IMHO is a far less complicated solution.
Anyway, the CTEK is the way i have gone and carrying a set of jumper leads to solve the other issue is not a bad solution I think. And the kicker of this solution is probably better charged batteries anyway.
So I will now organise (from yours and others @navmatt advice greatly appreciated) to get the car to an auto sparky to setup the wiring for me and get this setup finished.
cheers guys
Ants
I know that when I read about the Pajero, that there were reports that the smart alternator in it can dip the voltage down to 12.1 volts which was below the modern VSR's that you speak about (from my research. I however could not get any clear indication from anyone - Mitsubishi included (I had the Pajero at their workshop after purchasing it and they couldn't even install the relay?), about a good solution for a dual battery setup and hence went with the CTEK even though I lose the ability to be able to start the car from my secondary battery if required. The Redarc equivalent i think was just too expensive. I would however now be upset if someone was able to tell me that there is a VSR that would be able to achieve my desired outcome as a VSR IMHO is a far less complicated solution.
Anyway, the CTEK is the way i have gone and carrying a set of jumper leads to solve the other issue is not a bad solution I think. And the kicker of this solution is probably better charged batteries anyway.
So I will now organise (from yours and others @navmatt advice greatly appreciated) to get the car to an auto sparky to setup the wiring for me and get this setup finished.
cheers guys
Ants
