Dual Battery Setup

[whoneedsbitumen]

Anyone here know anything about Rotronics charger/isolator that is fitted to our HJ60 sahara
Wouldnt start the other day and after calling out racq the guy said that the 2nd batt died and drained the main, is this possible with this rotronics box?

Was talking to a guy at work who thinks i should get rid of this rotronics thing and just have a isolator swithc somewhere?

Thanks

[MissDrew]

This is more a general electrical question then a toyota question. Its getting moved

[bazooked]

in the experience with dual battery systems ( i do the rac battery run) i have seen alot of different duel battery system not work properly, usually if 1 battery dies it drags the other 1 with it causing 1 toasted battery and 1 flat 1.

[-Scott-]

Anyone here know anything about Rotronics charger/isolator that is fitted to our HJ60 sahara
Wouldnt start the other day and after calling out racq the guy said that the 2nd batt died and drained the main, is this possible with this rotronics box?

Was talking to a guy at work who thinks i should get rid of this rotronics thing and just have a isolator swithc somewhere?

Thanks

The whole point of a dual battery system with an isolator is to allow the 2nd battery to discharge without draining the starting battery. If the second battery has caused your main to flatten too then I'd say your isolator is defective, so you should get rid of it.

A switch is simpler, but it's not automated. Somebody (i.e. the driver?) needs to open the switch to prevent the starting battery from being drained, then close it again to permit the second battery to be charged. As soon as you forget to open the switch you've lost the benefit of an isolator. As soon as you forget to close the switch, you've lost (some of)the benefit of your second battery.

I don't see how a dead 2nd battery can cause your starting battery to die - unless it severely loaded the charging system, preventing it from charging your starting battery. If this was happening, the RACQ guy could have explained it a little better.

Good luck,

Scott

[kirragc]

Im a bit of a novice when it comes to electrics. Ive got a kill switch mounted between the cranking battery and a deep cycle battery.

When parked I hit the kill switch this isolates the cranking battery.

Thats it really. the deep cycle lasts ages for lights fridge etc.

In the morning hit the switch and start car.

Cost about $15 bucks plus battery.


What is the risk as Im struggling to workout why I should pay $100 clams plus for a hi tech isolator/power managment module.???

[mickyd555]

i have a rotronics and a install guide/manual. it covers a few different models, which one have ou got and i will dig up some info for you to make sure its installed correctly.

[whoneedsbitumen]

i have a rotronics and a install guide/manual. it covers a few different models, which one have ou got and i will dig up some info for you to make sure its installed correctly.

Thanks mickyd555 ill look in the morn didnt really pay much attention to the model this afternoon if u have some info would be greatly apreciated as i looked for some this afternoon with no luck.

Thanks

[whoneedsbitumen]

[mickyd555]

ok, youve got the big rotronics box. From what i read here it should not drain the main battery fully, unless of course there is something wrong with the Rotronics. If the aux battery has drained the main, there is something wrong, the unit should only discharge between the two batteies while the car is off when the main battery is not fully charged.

Things to check: is the green LED on while the car is off?
Have you got it wired up correctly?

i can send the wiring diagram to you if you dont have it.

[cookiesa]

For those with non electronic controlled injenction systems an easy way to gaurd against forgetting to "switch" your aux on/off is to use a solenoid (?) to isolate your aux.

One of the main advantage is that unlike the voltage sensing ones that allow some drain from the main is that once you switch off your ignition or whatever switching method you use the two batteries are completely isolated. These are about $20 from supercheap (you can buy dearer "better" ones but for most people these will be reliable enough)

They are simple to install.

One point about dual battery systems is that if your cranking battery is dead ie dropped a cell when you connect the two together (which most dual battery systems do when you crank or select to jump start) the dead battery can flatten your good battery and leave you with no go and dead batteries. (If this is wrong I am sure someone more knowledgable will crrect me)

Whenever I have had or come across someone with a dead main, we have always first removed the dead main and started using the aux battery in the main cradle with no dramas. The main can then be put in the aux side to attempt charging and assesing if it was just flat or dead

[Trusa]

I am thinking of setting up my solenoid (which is currently operated by the ignition) with the following setup. So when ignition is turned on it will start from only the first battery, not connect them instantly as it does now, but will still disable the solenoid when turning off the vehicle. Cheap too!

What do people think?



MOM is a momentary switch meaning the default when the ignition is turned on is the batteries being isolated, unlike an on/off switch which would create the same setup I have now if switch is not turned off. Good idea or not?

[-Scott-]

I think your concept is good, but your "latching" arrangement (as drawn) won't allow the relay to turn off. And I'm a little confused by the LED - what's it intended to do?

[Trusa]

LED indicator in cab next to switch, sorry picture was drawn only for my own reference!! Yeah, 12+ power will need to come from the ignition in order to turn off.



This should work a little better! Reckon it's not a bad idea, no chance of leaving batteries connected, cheaper than automatic solenoid.