solenoid dual battery

Rotronics actually specify their isolator is suitable for systems with two 'different' types of batteries, eg; starter and a Deep Cycle battery.

Ask redarc that direct question and you will be advised that "they inform their customers to use identical batteries" yes, I have asked the question and still have the email from their CEO, stating the above.

There is far more to Dual battery systems than just the isolating method!

I run a Deep Cycle and Cranking type of a solinoid/relay with no problems. Have been for ages.

So do I. The Redarc works great and it's very reliable.

Guys, it's not my opinion
but the judgment of the Managing Director of Redarc…
when I asked about my system not being fully charged, and since 'learning' more you can look on the web and his judgement is backed up by various technical people.

(Quote)
Mainey in answer to your question:-
In our discussions with a large battery manufacturer it was commented that it is ideal to use two identical batteries in a dual battery system and therefore we pass that information on to our customers.
We are updating our website and we will remove the confusion. Thanks for letting me know.
Please let me know if you require further assistance.
Kind regards
Anthony Kittel
Managing Director
REDARC Electronics
(end quote)

You may believe your system is working 100%, and if it is then that is really good, as I once did when I obtained my first dual battery system, however it was proven to me by an auto electrician my battery was not being 100% charged, so I changed to a Piranha DBS150E isolator, and still with the same battery and in the same vehicle, and then to the Rotronics.

I’m not seeking to argue, just posting information sent to me when I complained.

Mainy, I have never said that my batteries charge to 100%. I doubt that anyones do off their vehicle, including people using RedArcs. That's why I use a 240v Charger to top the system up before and after trips away. I have proven, however that I am getting at least 90% out of my vehicle charging system and it's cheap and reliable.

Thats fair enough Mainey but what I'm concerned with is having a reliable system and enough power to satisfy demand without flattening the starter battery or stuffing the aux battery. So far the redarc meets the requirements...works for me!

Jeff,
You say you get a proven "at least 90%" with your system, I also got results similar to that and I was not happy with them, that is the sole reason why I changed isolators! as to cheap, I should have looked into things a little better years ago when I just trusted the local auto sparkie, I mean he was somehow 'qualified' but for a lousy extra $70 I could have got the Piranha system and saved money.

Ray,
Good to read the redarc meets your requirements...
would you be happy to know you get 90% capacity?

Jeff,
an interesting thought,

tomorrow I will disconnect the solar system and only run off the Rotronics isolator, and I will re-check the voltage of the two aux batteries after a few days and compare the numbers with the present voltage, keeping a note of start times to allow for no surface voltage to be accounted for at all....
would that be satisfactory to see a realistic comparison do you think?

Mainy, I would run the batteries down a little ie with a fridge or something then do a long drive. Once I've charged mine from 240v the voltages stay up for about a week (about 0.1v higher). Don't know the science to that, technically it shouldn't I don't think, but hey. It'll be interesting to see if there is a difference hey? At lest then people will have some hard evidence one way or the other and can decide to spend the extra if they want to with it all in mind.

Stan,
according to Exide, and yes, maybe they are wrong, but the Exide Extreme is a 4x4 and Light Truck battery...

their DEEP CYCLE battery is called the Exide ENDURANCE and can be seen at the link below

http://www.exide.com.au/products/deep-cycle.php

Exide EXTREME is a rugged 4x4 and Light Truck battery and are built to deliver the power that hard-driving vehicles demand - even when the going gets tough. Don't get caught short in today's fastest growing automotive market.
Delivering HIGH CRANKING POWER for quick starts first time, every time. It's durable case design resists impact and off-road vibration - the leading cause of failure in batteries whilst convenient carry handles ensure an easier and safer set up, rated as CCA.

Exide ENDURANCE; Built strong to withstand the pounding and vibration of marine, 4WD or heavy vehicle use, Exide Endurance DEEP CYCLE battery is developed for long-running power and LOW AMPERAGE DRAIN.
DESIGNED to outlast ordinary car batteries in Deep Cycle applications where there is prolonged power demand from accessories and other equipment. If you require an extended power supply for operating 4x4 accessories like a winch, CB radio, driving lights, refrigerator, extra camp lighting, auxiliary equipment or bilge pumps, a Deep Cycle Battery is the BEST SOLUTION, rated as Amp Hours.

The full specifications are available on their website, the Extreme is rated as CCA without Amp Hours quoted and the Endurance is rated as Amp Hours without CCA figures quoted.
Both are excellent batteries and are built for their respective purposes.

Mainey,

Thanks for bringing it up.

From the same web suite:
CODE BATTERY VOLTS CCA RC L W H WT Acid/l Terminal
N70EX Exide Extreme 12 620 150 300 174 220 25 5 SAE
N70ZZ Exide Endurance 12 600 130 300 174 220 23.3 5.5 SAE POST

Looks like it is the "same" battery just with little bit more. Also I did
a search on the forum and some members get 4-5 years out of
Excide Extreme using it as deep cycle battery. Nothing wrong with
Endurance one, I beleve this is just advertising staff and commercial
grade normally lasts longer than the consumer grade stuff...

Stan,
Posted direct from the Exide DEEP CYCLE website;

(Quote)
Are "Deep Cycle" batteries CONSTRUCTED differently?
YES!
Deep cycle batteries are specially designed with DENSER ACTIVE MATERIAL and THICKER plates to withstand deep discharge-recharge service.
Car batteries, on the other hand, use PORUS active material and THIN PLATES so that high-amp energy can be quickly delivered for maximum starting power. Repeated cycling WEAKENS the positive plates and makes the active material shed from the grids. Thus, in repeated deep discharge-recharge applications, the capacity of the car battery drops BELOW desired levels in about 50 cycles.
They are simply designed to do a DIFFERENT job.
(end quote)

Stan, Exide DEEP CYCLE batteries start with the battery prefix letters "ED".. not 'N'
the 'ED6' is the equivalent in physical size to the N70 in the Car/light truck battery range eg, 'N70' only weighs 25 kilograms and contains only 5 litres of acid.

However, the DEEP CYCLE range of batteries eg, ED6 weighs 28.5 kilograms and contains 6 litres of acid, which in fact is in excess of 10% more in the similar given area, simply because, as stated by the Exide website, the battery plates inside are in fact totally different in both design and materials and are specifically designed to do a DIFFERENT job. CCA ratings are not shown for Deep Cycle batteries, only A/H.

http://www.exide.com.au/faq/index.php?category=3&faq=32

Hoping this clarifies things for you, without confusion.

PS the solenoid I have fitted in Longreach cost $36 including labour.

Yep I had an elecronic type lasted about 12 months then shut off charge to the Aux never to return!!
I'm now using a $130 arrid smart relay and a home made voltage cut off switch together which gives me longer run times than the fancy pancy one did anyway!! ;-)