Dual batteries (for Dummies...)

[MY150 Lurker Find all posts View Profile Close MY150]

Hi All,


Yes i do realise there is a lot of threads on this topic, but Im still failing to understand each and every one of them!!!

Have decided that the next instalment into my newly acquired 150 is a dual battery setup. So off to my local 4wd accessory shop goes I and then the confusion starts... I would like someone to answer in VERY SIMPLE LAY MANS terms what the following do:

The Redarc Isolator (that everyone seems to love):
CTEK or DC - DC Charger (that was included in my quote)

Also if anybody else like me (that has not a single electrical wire in my body), has paid to have such a set up fitted? can you tell me an approx of how much it cost? and what was included?

Cheers.

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

The Redarc Isolator (that everyone seems to love):
CTEK or DC - DC Charger (that was included in my quote)

This seems to be a real can of worms and has been source of a lot of debate. The key seems to be to ensure that there is sufficient voltage to charge the batteries, I went for the $20 diode and my mate went for the $300 DC-DC. There doesn't seem to be any difference in the end result although like I said some people are quite passionate about this.

Price, when I was looking I was quoted $600-900. Did it myself following instructions on this site for about $350 (incl battery).

[MDS69 Advanced Member Find all posts View Profile Close MDS69]

Do you have a D4D or V6, hence the benifit of the diode to boost charging voltage as mentioned above. A cheap effective mod.
Ok I will explain my set-up in my V6 120 series.
We will start backwards as my aux battery is in the cargo area when being used.
From an anderson plug in the cargo area I ran a 16mm2 twin (electrical sizing) which is very close to 6B&S in size. This ran out through a grommet in the floor of the cargo area into the left chassis rail and exits the chassis rail near the fire wall of the engine bay. I mounted a Piranha DBE140S isolator like this

http://piranhaoffroad.com.au/index.p...s/dbe140s.html



The isolator is mounted on the firewall. The positive wire from the aux battery is lugged and bolted onto a stud on the isolator. On the other side of the isolator another positive wire is lugged and bolted on and is run to the positive terminal of your cranking battery. The negative wire from the anderson plug in the cargo area is run directly to the negative terminal on the cranking battery.

On my aux battery in the cargo area I have a short length (1m) of 16mm2 twin termintaed to the battery in the normal fashion and on the other end another anderson plug so the aux battery is plug and play. I only run my fridge from it via a smaller twin cable with a socket on it and bolted to the battery clamps.

[MDS69 Advanced Member Find all posts View Profile Close MDS69]

Do you have a D4D or V6, hence the benifit of the diode to boost charging voltage as mentioned above. A cheap effective mod for the D4D.
Ok I will explain my set-up in my V6 120 series.
We will start backwards as my aux battery is in the cargo area when being used.
From an anderson plug in the cargo area I ran a 16mm2 twin (electrical sizing) which is very close to 6B&S in size. This ran out through a grommet in the floor of the cargo area into the left chassis rail and exits the chassis rail near the fire wall of the engine bay. I mounted a Piranha DBE140S isolator like this

http://piranhaoffroad.com.au/index.p...s/dbe140s.html



The isolator is mounted on the firewall. The positive wire from the aux battery is lugged and bolted onto a stud on the isolator. On the other side of the isolator another positive wire is lugged and bolted on and is run to the positive terminal of your cranking battery. The negative wire from the anderson plug in the cargo area is run directly to the negative terminal on the cranking battery.

On my aux battery in the cargo area I have a short length (1m) of 16mm2 twin termintaed to the battery in the normal fashion and on the other end another anderson plug so the aux battery is plug and play. I only run my fridge from it via a smaller twin cable with a socket on it and bolted to the battery clamps.

[Whitey1 Advanced Member Find all posts View Profile Close Whitey1]

No ones really answered you question yet.
The redarc isolator does what its name suggests. When the car is running it connects the start battery to the aux battery. When the car is stopped it isolates the two so that when drawing off the aux battery the starter battery does not get drawn down too. Redarc is just one brand of dozens.
The dc to dc charger is supposed to up the charge to the aux battery. Only usually used for camper batteries which are a long way from the charging source(alternator) and therefore may suffer from voltage drop..
Some people swear by them. I haven't had anything to do with them.
I wouldn't have thought you'd need one if your aux battery is under the bonnet.

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

Simple answer is its a battery isolator
Most battery isolator systems seem very expensive for what they are and do.
I thought about just setting up with a manual switch, but decided to try out the hyperstart 140w simple system for $99 on special at supercheap, so far all good.

[MY150 Lurker Find all posts View Profile Close MY150]

Thanks all for your replies. Just for the record, I have a D4D.

[Matty80 Avid PP Poster! Find all posts View Profile Close Matty80]

Instead of the boost diode for the D4D, you could always just increase the size of the cable run from the alternator to the main battery. After all, the D4D cable is 3-4 times longer than the petrol and suffers from voltage drop due the the same cross section cable being used.

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

Instead of the boost diode for the D4D, you could always just increase the size of the cable run from the alternator to the main battery. After all, the D4D cable is 3-4 times longer than the petrol and suffers from voltage drop due the the same cross section cable being used.

What is the amp rating of that cable? If it is an 80amp alternator or similar one would think that Toyota would provide a cable to handle the current between the alternator and the battery?

My set-up cost as follows

1. D27F AGM battery $380 + $40 postage

2. Piranha battery tray $160

3. Redarc battery isolator SB12 (100amp) $90

4. Double insulated cable (black and red) 25mm2 or 3AWG plus 8mm crimp lugs, heat shrink, cable ties, battery terminal clamps and corrugated conduit is about $80 - $100

5. Voltage boost diode (made myself) $3

So a set-up could cost between $600 - $800 depending on battery selection etc.

I didn't bother getting the higher amperage isolator because if I need more current I can just join the two terminals with a linking plate.

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

The Redarc BCDC is a lot more than an isolator. Read the website or other threads here to get all the features. If you don't understand a feature, then ask away.

Since you have a D4D the voltage output of the alternator is not optimal for fully charging most batteries. Simply measure the voltage output of the alternator (mine is 13.7V). Next, read the recommended charging specs of the battery you chose. Now decide how important it is to keep that battery fully charged and well maintained. DePending on how you answer these questions will determine the solution that best meets your needs. Naturally, the pain felt in your hip pocket may also be a decider.

Loads of opinions, but in the end it's only yours that matters.

LFaR.

[davesomma Junior Member Find all posts View Profile Close davesomma]

Its funny you guys talk about the voltage out of the D4D not being high enough. For the most I agree if the voltage is low like im seeing on here at about 13.7 then this is bordering on the low side. However i use a scanguage to monitor my voltages ane mine sits at 14.1 to start with and then over the duration of 30 - 40 mins it drops to 13.8 which is the lowest i have ever seen.

Food for thought

[MY150 Lurker Find all posts View Profile Close MY150]

[QUOTE=LiveFreeAndRoam;360631]The Redarc BCDC is a lot more than an isolator. Read the website or other threads here to get all the features. If you don't understand a feature, then ask away.

Thanks LFaR,
That is the other thing i don't understand. What are the optional benefits of the DC-DC. I know the Ctek has an additional input (for solar etc) but what else? Please excuse my ignorance on the matter...

[roadblock Junior Member Find all posts View Profile Close roadblock]

Century MarinePro 720 (105Ah Deep Cycle) - $198
Projecta 150A isolator kit (includes all cables) - $179
Supercheap battery tray - $19

Approximately $400 all up... see the post here

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

Its funny you guys talk about the voltage out of the D4D not being high enough. For the most I agree if the voltage is low like im seeing on here at about 13.7 then this is bordering on the low side. However i use a scanguage to monitor my voltages ane mine sits at 14.1 to start with and then over the duration of 30 - 40 mins it drops to 13.8 which is the lowest i have ever seen.

Food for thought

Depends on your climate. In Darwin mine dropped to 13.2v.