Rotronics Duel Battery System?

[Boxhead]

have got a Rotronics system in my Patrol it was put in 1998 pros and cons on this system.

[RaginRover]

Well translated I think you mean what are the pros and cons the system ?

Pros.

1. Once installed correctly it should provide a years of good service
2. No switches to remember to flick it looks after itself

Cons.
1. Has trouble recharging a dead flat marine battery, it will take a fair while and struggle, it can also shock the marine battery while it is trying.

2. Make sure you have a good alt that doesn't mind the work ... bosch comes to mind and keep the alt cool so it doesn't cook the diodes

3. The top two terminals can get hot and will melt things that touch them, so make sure it is not touching the bonnet lining (if you have any)

4. They need to stay relatively dry, I mounted my old one is a plastic
container (like an electrical container) and put a vent hole in it.

They are good but you need to keep you eye on the other battery so you can see when it is struggling, make sure you install a voltmeter for
the secondary battery so you can watch it

Tom

[Boxhead]

Thanks for your advice Tom. Why does it struggle to charge a deep cycle battery and whats the story with shocking the battery.

[RaginRover]

sorry mate,

I missed your reply.

It only struggles from dead flat. If you have a meter on the dead marine battery you will see it sitting at a really low voltage as you are driving along - then the rotortronis will start to charge it and you see it apply a
fairly high current (probably 20A) to the battery and you then see the meter start to rise - after a few seconds it seems to draw too much power trying to recharge so it drops the input and thus less current is supplied
and the marine battery charge rate drops.

I believe while the controller is trying to figure out what to do it could damage a weak battery, this large application of current and then drop in that current followed by the whole cycle starting again is what I refer to as "shocking" the battery. If you have huge cables this can also work against you as that can transfer more current and give a higher shock load to the battery.

If I ran my marine flat and I had a large highway drive home (like over 1 hour) I would let the rotortronics re-charge the battery by itself but if I only had a short trip home I will disconnect the charge circuit and use a battery charger when i got home.

Hope that helps

Tom