Bugger - Redarc SB112

[Bazza Senior Member Find all posts View Profile Close Bazza]

Last Monday was very cold at Mount Annan NSW. Went to start my 09 120 V6 at about 5.30am to leave for work, click, click, nothing ...bugger! The start battery did give me a warning about a week ago when it struggled slightly to start on another cold morning.
Anyway ........ no problem, I thought. New Redarc SB112 and a new MarinePro auxilary battery. I'll just just press the magic button and start it off the auxilary battery. Not so! I could hear the solenoid make, but no start. Not even a hint of starting. I will need to check the system on the weekend in the light of day. Strange though, I diid check that both batteries were being charged after I installed it, although I did'nt try the manual connection switch. Any ideas?

Bazza.

[winniliss Avid PP Poster! Find all posts View Profile Close winniliss]

The issue is if your starter battery is stuffed its sucking most of the 200amps (momentary current) or 100amps (continuous current) that your solenoid can provide before it even gets to your starter motor. Either way you won't be providing enough current to your starter motor. You have three options, hook both batteries up using jumper leads (as well as turning your solenoid on if you like, it won't hurt), swap batteries to get yourself going or place both positive cables on the same stud on the solenoid. This will bypass your solenoid and act like a jumper lead. Hence why I run 2AWG or 35mm2 cable.

Winston.

[Bear63 Senior Member Find all posts View Profile Close Bear63]

Also if your main battery has completely collapsed the aux battery wont start it either as the stuffed battery literally absorbs all the currant

[Bazza Senior Member Find all posts View Profile Close Bazza]

So guys, what your saying is ...... if my starting battery has a dead cell, ( which it did, 9.2volt ) the manual override on the Redarc SBI12 is vertualy useless. I would need to disconnect the leads from the starting battery and connect a set of jumper leads from the disconnected starting battery leads to the auxilary battery terminals? If this is the case, I guess we all still need to carry a set of jumper lead?

Bazza

[winniliss Avid PP Poster! Find all posts View Profile Close winniliss]

So guys, what your saying is ...... if my starting battery has a dead cell, ( which it did, 9.2volt ) the manual override on the Redarc SBI12 is vertualy useless. I would need to disconnect the leads from the starting battery and connect a set of jumper leads from the disconnected starting battery leads to the auxilary battery terminals? If this is the case, I guess we all still need to carry a set of jumper lead?

Bazza

Yes. I carry a set anyway to help other people who have starting issues. Also carry a small set of tools and inox (similar to WD-40). It came in handy the other day when a fella had really dirty battery terminals.

The end of the day I didn't buy the solenoid for the manual override feature but the ability to turn on and off automatically. If you want to harness most of the current your Aux battery can provide which is connected by a longer cable you would need a solenoid that could handle 700amps but the cable also. This is expensive and not practical. Hence why I have the starter and Aux batteries the same. If the starter fails I can just swap it around. It would take about 15mins and it probably would happen in the middle of the sticks where there is no help for a long time.

Winston.

[Bazza Senior Member Find all posts View Profile Close Bazza]

Thanks guys.
I now carry a set off heavy jumper cables should I ever need to connect both batteries again. On another issue, I've noticed that the Redarc takes hours to disconnect with two new batteries after the vehicle is switched off. This seems to me to defeat it's main purpose, isolating both batteries. I was thinking of wiring a momentary switch on the earth connection of the SB112. This would isolate both batteries immediately but would it do any damage to the Redarc?
Bazza

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

The Redarc will disconnect when it sees the main battery at 12.7V. That's fine, leave it alone. The one I have in the Rodeo can take 30 minutes to disconnect if there is no load on the outtake (auxiliary fully charged for example) this is perfectly normal. You can test this with a multi meter (I did!).

[Bazza Senior Member Find all posts View Profile Close Bazza]

The Redarc will disconnect when it sees the main battery at 12.7V. That's fine, leave it alone. The one I have in the Rodeo can take 30 minutes to disconnect if there is no load on the outtake (auxiliary fully charged for example) this is perfectly normal. You can test this with a multi meter (I did!).

I'd have no concern if mine disconnected in 30 minutes or so, but mine can take 12 hours or more. My understanding is that the Redarc should disconnect when the starting battery drops voltage. Shouldn't it have nothing to do with the voltage in the auxiliary battery? If I put my high beams on for about 3 -5 minutes the Redarc will disconnect. I would like it to disconnect faster.

Bazza

[D4D Addicted PP Member Find all posts View Profile Close D4D]

I would like it to disconnect faster.

Why? If you can still start your car from the cranking battery it is working as designed.

[Bazza Senior Member Find all posts View Profile Close Bazza]

Why? If you can still start your car from the cranking battery it is working as designed.

I could still start my car from a good cranking battery even if I didn't have a Redarc connected. I would just prefer that the "isolator" disconnects both batteries faster than 8 hours. Am I being pedantic or is that an unreasonable expectation from a dual battery isolator.

Bazza

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Am I being pedantic or is that an unreasonable expectation from a dual battery isolator.

Probably, my Surepower (ARB) will disengage with a quick flick of the high beams. Check the V with a multimeter when it disengages, this will enable you to determine if it is working to spec.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

A load on the auxiliary (or main) will drop the main battery voltage until the Redarc drops off. The mates Challenger I did does the same as yours because he has no load on the Anderson plug unless his van is connected so he trips the manual breaker. As I said it isn't a problem so forget about it.

[Bazza Senior Member Find all posts View Profile Close Bazza]

Thanks D4D.

I have checked the voltages and I'm confident that it's working as designed. I think that it has something to do with the combination of a booster diode, two band new big amp batteries, and a good charging system...... but anyway. My original question was, if I install a momentary switch on the Redarc's earth lead to quickly disconnect both batteries, would it do any damage to the SB112?

Bazza

[Scratcingman Lurker Find all posts View Profile Close Scratcingman]

Not sure if anyone else has mentioned this already (didn't see it on my quick read) talk to the guys at Redarc. I read on here how good their support is and after sending them an email a while back about an issue with an SB112 I had I got fast responses and follow ups until I had figured out the issue whihc turned out to be nothing to do with the isolator anyway. Didn't cost me a cent and helped this novice out so much.
Aaron.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Your missing the point mate... the Redarc will disconnect the moment it sees it neccessary to do so, I have seen them (and other brands) take over 12 hours to disconnect. It just means you have no load on the batteries and they are in great shape! After 12 months you will notice that time takes less and less. As one battery will discharge (no load) faster than the other.

By installing that switch, it won't harm the redarc but you just totally defeated the purpose of an automatic system. You could've saved a lot of money and just whacked in a big honking solenoid and be done with it.