Dual battery controllers

In the past 24 years I've only owned 2 isolators - both were made by Rotronics.
The first one was still going after 13 years on my 40series and 61 series landcruisers then the second one is still going after being used in 2 Prados and now my 79series.

I've got the Rotronics MH10 - I'm pretty sure they are electronic - use FETs instead of the old solenoids.

And they isolate as soon as you turn the ignition off, and only consume 8mA when not in use. They cost the best part of $300 - bought mine at Opposite Lock.

Four years into my Redarc SBI, no problems with it.

Draws nothing when not in use.

Cheers

Frank

A search of the forum might have prevented the can of worms Rossco lol. It's a popular topic alright and one that is a needed consideration given that just about everyone 4x4ing and travelling this country with vans, trailers etc relies to some extent on power. I'm a big fan of the Redarc products because they have robust products built in Australia to meet our needs and a great service network Australia wide.

I've reviewed the units I've purchased and usedHERE - Redarc review

Why I chose what I did and the research I undertook is also outlined HERE - Ute build

Just be aware that a simple solenoid may not adequately charge a modern day battery in the manner in which the manufacturer intended possibly resulting in reduced capacity and life. There are a lot of good products on the market so do your research and identify something that suits your needs.

Cheers

Mick

I just use a 180 amp circuit breaker. No problems.

What exactly is the reason for failure.

There are a whole pile of design factors that lots of people don't seem to want to talk about, or persistantly claim aren't an issue.

issues such as surge current on connection of the two batteries, and how that is to be managed.

In my view there are lots of dual battery controllers out there that have insufficient current rating for the way they are installed.

cheers

I have made a few of these kits, all work well. Site Link

I also use a Rotronics unit and have found it to be extremely well made and reliable. The Rotronics units are also made in Australia.

Cheers
LeighW

I have the dual battery isolator and battery monitor from Sidewinder 4x4 accessories - he is a business member on this forum.

http://www.sidewinder.com.au/page79.html

Great product- I have had it for 3 years now. Once I left the ignition on overnight to have a flat primary battery - with the battery monitor there is a switch to start off my second battery - so easy. Whole unit was easy to fit and very small and compact.

No affiliation just a happy customer.

Cheers

Serendipity

G'day Rosssssss,
I've had 3 different solenoid set-ups & have had no trouble with any of them.
They were all fitted by the same auto sparkey.
The first one had a very heavy duty solenoid that would isolate the axillary battery when the ignition was off & while cranking the starter.
The second one I had worked the same way, but had a light duty solenoid. It looked more like a relay that you would use for accessories. I can't remember the load capacity, but it was no where near the first one.
The advantage of the first one that was that I could disconnect the earth off the start battery & drive around using the axillary battery as the main battery. This produced a faster charge, if needed. I couldn't risk doing that with the light duty solenoid in case the draw from the battery exceeded it's capacity. I still never had any trouble with that one though.
The third one is a redarc solenoid type.
It's OK so far & works no better than the other 2 I have had.
There may be some technical things someone is going to come forward with about these 3.
If it came to the crunch I would say the first one, with the heavy duty solenoid, was the most practical. This is simply for the reason that you could start the car & then isolate the start battery putting all the charge straight into your axillary battery.
Right from the start I have avoided those computerised jobs & gone for simple systems. This was also the advice of the auto sparky I use. He told me that it wouldn't take long to figure out how your batteries were going & that with the heavy duty solenoid I could easily modify the system to suit my demands for charging.
These days my demands on the batteries are not as great as we move more often & the redarc seams to work fine.
Fatso

Another with two Rotronics over the years. Not a problem with either.
Dave

Solenoids & Voltage sensitive Relays (VSR's) like Redarc's SBI 'Smartstarts & similar have given good service for years & continue to do so BUT there are now newer & better products that will allow your batteries to be charged more fully & faster than the alternator can via a VSR. I am referring to DC to DC smart chargers. These will charge house batteries to 100% compared to the alternator's best of 70% -80%, giving greater capacity when you stop. They also allow proper charging of differing types of batteries.
I am building a camper (ex telstra Patrol with canopy) & just bought a Redarc BCDC1240 - Combined Solar Regulator & DC to Dc charger (40 amp).

Cost is a lot more than $20, but it depends what you want/need.

Thanks everybody for your info, at this point in time I think I will go with the Redarc, should have bought this in the first place 2 years ago, I won't name the ones I have had the trouble with but they are mentioned in replies.

Cheers Ross.