D-4D Dual Battery Install - Completed

[Fungi2003 Senior Member Find all posts View Profile Close Fungi2003]

Hi Fungi2003,
Great install and great photos.
Just one question is the cable between the two batteries fused at both ends.

No it isn't, the reason being is that I will be using the Redarc manual override (jump start) in the event that the cranking battery fails.

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

My concern here is if for some unknown reason the cable shorts to earth or overloads it heat up, and eventually the battery will explode. The fact that there is two batteries in the circuit means the odd chance of double the explosion. Big picture - someone is walking. ops:
You can get oversized fuses from auto electrical wholesalers that are rated up to 100 amps but 60 amps is more common in most other auto shops.
Couldn't tell you of the top of my head what size you would need, but someone else here would probably know.
By the way fuses are there to protect the cable and nothing else, so if you do somehow manage to overload the cable between the 2 batteries, the wire will definately heat up to red hot and melt everything. At this stage you lovely wiring job will turn to burning plastic and all the wiring loom will also start to melt. Warranty/insurance might be a hard issue to contend with.

[Fungi2003 Senior Member Find all posts View Profile Close Fungi2003]

My concern here is if for some unknown reason the cable shorts to earth or overloads it heat up, and eventually the battery will explode. The fact that there is two batteries in the circuit means the odd chance of double the explosion. Big picture - someone is walking. ops:
You can get oversized fuses from auto electrical wholesalers that are rated up to 100 amps but 60 amps is more common in most other auto shops.
Couldn't tell you of the top of my head what size you would need, but someone else here would probably know.
By the way fuses are there to protect the cable and nothing else, so if you do somehow manage to overload the cable between the 2 batteries, the wire will definately heat up to red hot and melt everything. At this stage you lovely wiring job will turn to burning plastic and all the wiring loom will also start to melt. Warranty/insurance might be a hard issue to contend with.

Thanks for the feedback!

I based my design on the ARB dual battery installation (documented in various threads within the forum) that many people have installed in their vehicles; this kit doesn't have a fuse installed at either positive terminals. My initial design did include two ANL type fuses rated at 100Amps at both batteries.

The question I have is whether the fuses will blow if the vehicle is started with the override switch engaged? My understanding is that when a car is started with this engaged there is a huge rush of current going through the batteries which (could) potentially blow a fuse in the circuit.

What do you think?

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

As far as I've seen NO car manufacturer use fuse on any of the large cables used for starting, due to the extreme currents used in starting. As fungi2003 is intending to use these cables as emergency start cables, I don't see he has any option.

We have numerous vehicles at work that have dual Batteries, if the controller doesn't have a aux start, we jusat simply fit a soleniod between the batteries to enable this, but unfortunately there is no way that we have found to protect the batteries or cable.

It is just something you need to be aware of when running the cable. Keep it away from items that may damage it, and keep it well tied to stop movement. Also keep a regular eye on it to make sure no damage is occuring.

Matt

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

Hi Guys,

If you look on some O/S Toyota websites you will note that all cold climate D4D Prado's/Lexus come standard with a second battery, the main wiring runs (battery inter-connectors) are mounted on plastic brackets fitted above the radiator fan cowling the wiring runs are over the coolant expansion tank to the Aux battery, that is why there is a relief at the back of the expansion tank to allow for the conduit.

You will see the two spare plastic stand-offs available in this position. My dual battery interconnects will run this route in conduit with no fuses.

If a meltdown occurs due to a battery internal short/ high resis. etc. then its only going to melt the stand-offs and maybe the top off the radiator fan cowling and expansion tank top, not burn the guts out of the important looms at the rear of the engine bay or short to the firewall $$$$$. But I doubt I will have a problem as heavy cranking is not a big deal up in the warmer climes unless some glow plugs have died, crook fuel or poor maintenance.

So location of the Redarck will be important! closer to the starting battery I expect.

Hope this helps a little

[Fungi2003 Senior Member Find all posts View Profile Close Fungi2003]

I wonder how the new 200 series dual battery system is wired up?

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

I wonder how the new 200 series dual battery system is wired up?

I have not had a close look but it does have more room but are we not dealing with Landcruiser 120 series :?

[Fungi2003 Senior Member Find all posts View Profile Close Fungi2003]

I wonder how the new 200 series dual battery system is wired up?

I have not had a close look but it does have more room but are we not dealing with Landcruiser 120 series :?

It would be nice to know what Toyota does with their dual battery setups, hence the reason why I mentioned it.

[Fungi2003 Senior Member Find all posts View Profile Close Fungi2003]

I'm heading off to the snowies this weekend for a camping/4wd-in/fishing trip. The cars packed and the fridge is purring away keeping the food and drinks cold. I'm stoked the system is working well; this weekend will be a test to see how well it performs.

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

Im fairly sure the now superseded Turbo Diesel 100 series have twin batteries standard here in Aus ? and im almost positive they are 2 batteries in Paralell so really only usefull for giving you current and capacity for starting, so not disconected from each other while the motor is stopped.

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

Hi Speedcom,
I think you are spot on, I checked out a setup O/S and the batteries are in parallel for cold weather starting.
The maintenance manual/cd also shows this somewhere if I remember.

Glad to hear the fridge is a goer Fungi2003 hope you have a great weekend.

[Fungi2003 Senior Member Find all posts View Profile Close Fungi2003]

She lasted the whole trip! Only when I got back home I noticed the error light on the fridge flashing (temp of the fridge was 1 degree below set temp of 5) - I suspect that the battery voltage might be low. I'm going to buy a hydrometer and see how much charge the Trojan has at the moment.

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

She lasted the whole trip! Only when I got back home I noticed the error light on the fridge flashing (temp of the fridge was 1 degree below set temp of 5) - I suspect that the battery voltage might be low. I'm going to buy a hydrometer and see how much charge the Trojan has at the moment.

Hey Fungi well done.

Sounds a little strange that you're getting the error light coming on when you got home. your battery should've been charging on your trip home. What position do you have the battery protection switch set to?

Oh and you should be able to get a fairly good indication of charge by testing with your multimeter. Go to the trojan home page and they have a table there that will give you battery volt vs state of charge.

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

Re: D-4D Dual Battery Install - Completed

I'm about to start my install and want to get the tray and battery this weekend. I've been considering getting the Piranha BTPRAD03 Battery Tray and Trojan 115Ah 27TMH.

I was checking the sizes of everything and found that the tray will only support a standard 12" battery which is normally around 300x175mm. I rang the local TJM and the fella there measured the internal tray size and he confirmed that this is 300mm long.

The Trojan 27TMH has dimmesions of 324x171 so this is too long (apparently)
http://www.batteriesplus.com.au/pd/5.../trojan-27tmh/

But Fungi posted the following pictures:
This looks very much Piranhaish to me


Trojan 27TMH battery in above tray


While this will appear to be a stupid question but can somebody confirm that the Trojan 27TMH will fit the Piranha BTPRAD03 battery tray?

If it turns out to be a no go on the Trojan and tray then I'm considering an Exide DC12V105.

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

Re: D-4D Dual Battery Install - Completed

The Trojan 27TMH has dimmesions of 324x171 so this is too long (apparently)

I think you will find the battery dimension is the max length. If you look at the picture of the battery, there are "overhangs" on both ends. You might need to ring around and get someone to measure up the bottom of the battery :wink: