Thread: Dual battery system or Solar panel

Originally Posted by PhilipA

I have a dual battery controller from ABR which cuts at 12.4 volts which I personally feel is safer than 12.0 volts like Drivesafe's In my application. This contributes a share from the starting battery but not as big as Drivesafe's does.

Hi Phillip and because your cranking battery is most likely not going to be in as higher state of charge as what a cranking battery is going to be with one of my isolators in the system, you are not likely to get any useful assistance from your cranking battery.

Originally Posted by PhilipA

The voltage reading for the starting battery is taken from the behind dash fuse box so may not reflect the voltage at the battery, however the batteries do separate at 12.4 reading on the second battery , which is taken from near the battery, so it's not too far out.

This is another reason that I personally feel safer with a 12.4 cutoff than a 12.0 cutoff with a D2 diesel when using a relatively small but high CCA Optima starting battery.

Phillip, your isolator works just like any other ordinary isolator.

While you may not understand the full operating implications of how my isolators work, and contrary to your thinking that they are not as safe as ordinary isolators. Quite the opposite is the case.

First off, with my setup, if the cranking battery is still low when you turn your motor off, the auxiliary battery will reverse charge back into the cranking battery, continually raising the cranking battery's state of charge.

Your isolator and all other isolators can not do that.

Next and another concern of yours is that my isolator does not separate the batteries when starting.

That is actually a major advantage and for a number of reasons.

Firstly, by keeping the batteries connected, you have a higher CCA available while cranking, than the cranking battery by itself, can provide. My isolators are specifically designed to keep the batteries connected for up to 10 seconds while you are starting the motor, even when the voltage drops bellow 12.0v

This means it is easier to start the motor but you are not working your cranking battery as hard while starting your motor.

It also means, because at least 10% of the energy needed to start your motor is coming from the auxiliary battery, once the motor is started, the cranking battery does not need as much energy to be replaced, and this means the cranking battery is going to be RECHARGED in a shorter driving time.

So with one of my isolators, not only do you have at least 50% more battery capacity available to run your accessories while the motor is off, without having to actually add additional battery capacity or the weight and space needed for that additional battery capacity, as you would have to do with your setup.

You are also charging and maintaining your cranking battery far better than any other dual battery system can.

Contrary to your concerns, my systems are literally win, win, win dual battery setups. And there are a lot more feature available with my system that are not available with any other DBS.

First off, Tim might be a little off the money depending on which ARB isolator you have, if its one of the all singing all dancing ones that features the letters dcdc or bcdc in the title then hes on the money, if you have one of the antique ones that is a solenoid driven unit then the system will still back charge but thats about as far as it goes.

I'm personally prepared to allow Tim a lot of leeway when it comes to how he advertises his product in comparison to others because
a, the capability he talks about from his product is on the money,
b, there are a lot of older competing systems, obsolete systems and odd ball configurations its a little unfair to expect him to compare all of those systems in one go to his products and
c, for the info he gets "wrong" about the systems hes comparing to in probably more than 50% of the cases their capability claims are even further from the truth.




when you read what Tim just wrote about the capacities of the batteries in his system it can sound like smoke and mirrors, and it sort of is right up until you know how its done. Mr Peukerts has the spoilers in wiki.

Hi Dave, and thanks for the buildup and I agree with your comments about "ARB" gear.

But Phillip has an ABR isolator, not an ARB.

The use of the letters, ABR was done deliberately to cash in on the well known brand name of ARB.

just checked em out...

huh, just exactly like the vintage ARB one...

First off, with my setup, if the cranking battery is still low when you turn your motor off, the auxiliary battery will reverse charge back into the cranking battery, continually raising the cranking battery's state of charge.

My batteries stay linked down to 12.4 volts so the second battery does charge the starting battery. I have never seen the starting battery low on shutting down and imho it is not possible on a D2 under normal circumstances.

You are putting words in my mouth. The only point I was trying to make talking about the batteries separating on starting was to observe what looks like a quirk of the D2 ie a very heavy load on ign on, which means that if the battery is at 12 volts then the voltage drop could be a problem. I don't really see how linking a flat battery , which the house battery is likely to be, to the starting battery while starting helps anything.

I have the ability to link the batteries if necessary with a dash switch but I have never had a situation where the second battery is higher than the starting battery.
As I said it works for me.
Regards Philip A

Hi again Phillip and I was not putting words in your mouth, I was simply correcting the false information you had been fed.

If you measure your two batteries after a few days of not running the motor, you will find your cranking battery and auxiliary battery will be at different voltage levels and they will be bellow 12.4v.

Your system DOES NOT share the load because the 12.4v setting is far to high to allow the batteries to equalise before the cut-out level is reached, unless one or both were charge with a battery charge.

Further more, even when driving, if you do a couple of short drives, when you turn off your motor, your cranking battery will quickly settle bellow 12.4v and even if your auxiliary battery is in a higher state of charge, because you have to have that isolator mounted close to the cranking battery, as the cranking battery is in a lower state of charge than the isolator's cut-out voltage level, the cranking battery will pull the voltage down at the isolator, causing it to turn off.

So once again, you will not get any benefit from that isolator, and the info you have been supplied about it is nothing but false advertising.

Even when you first turn your motor off, there will be a surface charge on the batteries, but put a small load on them, like a fridge, and within a short period of time after applying the load, your isolator will turn off.

From many years of research and development, I have found that any cut-out setting much above 12.2v offers no real benefit, because the cranking batteries can easily settle down to 12.2 or 12.3v in normal use with just a small load like a fridge running and those levels will negate the sharing of energy with the auxiliary battery.

Look I don't want to get into yet another of these never ending threads where you aggressively defend your system and call into doubt the quality and or intelligence of anyone else.

Suffice to say that NONE of the things that you claim apply to my experience.

I keep an eye on my batteries and I keep them both above 12.5 to reduce sulphation. If the batteries go below 12.5 I charge them and I have an LED readout on the dash to monitor them. My batteries always stay connected for several days at the least and in practice are connected most of the time.

I use the system I do from long experience with what works for me not from what anyone tells me or claims. I have had dual battery systems since 1990, and have designed and run a 2 alternator system in my RRC successfully with separate circuits for starting and house. .

It may well be that your system works well but mine also works well.

My reluctance to use your system is

1 12 volts is <= 50% SOC, and the draw from ancilliaries like opening doors etc could reduce this further over a few days, after the batteries have separated. My fear on a D2 is that this could become marginal for starting as the ECU cuts off at AFAIK about 11.5 volts and the house battery will probably be that low anyway.. As one is "up the creek without a paddle with an auto with a flat battery" I prefer to be conservative.
Regards Philip A

Hold your horses Phillip. You make unsubstantiated claims about my products, based on nothing more than your ignorance.

You had no real idea how either system works and you specifically stated that your concerns about my system were based on nothing more than your opinion.

Then, when I explained how both your system and my system worked, you accuse me of "putting words in your mouth"

I am not sure what you based your decision on when you bought that brand of isolator you have, and while you seem only to happy to make unsubstantiated claims about my products, yet you have bought the most unreliable isolator on the market and if you care to do a bit of research, you will find plenty of posts, on many many forums, about how much trouble it is to get the warranty honoured when the fail.

You have a nice day Phillip.