Thread: D2 Dual Battery Setup

Hi Damo ... weighs a ton & a half! ... and the bigger D31A I replaced the starting battery is double that!

I'll try & take a few picks of my setup for you. It got it's first run over the 10th Anniversary gathering last weekend. Worked a treat.

I just modified the ARB heatsheild (flipped it around 180deg), slotted the holes so it could move closer to the turbo, cut out the other side to allow the battery to move closer to the guard, and wrapped the battery in a Thermo-Tec battery heat sheild.

I put up a post (in tutorials I think) on where I mounted the USI-160 controller.

One thing I have immediatley noticed, is that with my old calcium starting battery & wet lead acid aux' battery, the voltmeter on the nanocom always ran at around 14.2-14.7v .... does the same with the Optima's installed for a short time, then the voltage falls all the way down to 13.5-13.8v .... meaning the battery's are fully charged. Over the weekend I noted that 24hrs use seemed to get put back into the batteries in about 15-20min's worth of driving.

I'll see if I can get some pic's to-night.

Hi Kev and while your batteries are probably charging properly, you have fallen for one of the major drawbacks of trying to monitor battery State of Charge ( SoC ) using a volt meter.

With a continuos operating voltage of 14.2+v you will have no problems charging your batteries BUT, the 13.5-13.8v reading you got is no indication as to whether the battery is OK.

A battery’s fully charged voltage is 12.75.

This high voltage reading is actually the surface voltage not the battery’s SoC and this surface voltage can be found on good and bad batteries.

You could have a stuffed battery and after a drive of just a few minutes, you could get voltage readings like you have.

The best way to get a rough idea of whether your batteries are good or on their way out, before testing the batteries, turn your headlights on and measure the voltage at the battery terminals for a minute or two.

When you first turn the headlights on, the voltage at the batteries should drop but after a minute or two, the voltage should stabilise, around 12.5 or above for a fully charged battery.

If the voltage continues to fall and does not stabilise, your battery is either low and in need of a full charge or it’s stuffed.

This is still not a sure fired way to test batteries and there is NO simple way to test batteries but it can show up a battery thats in a bad way.

Hi Tim .... I should have said that those voltage readings are from the nanocom, whilst the engine is running, and we are driving. After 24hrs of use (fridge & lights, etc whilst camping), start the disco and head off, the voltage reads at 14.6-14.7 volts .... after around 15-20mins of driving the voltage has dropped to 13.5-13.8volts (it would have taken 5-6hrs to do that with the old calcium starting & lead acid deep cycle battery if we ever could drive for that length of time without a stop - have only done that a couple of times).... these are the voltages the alternator is applying to the batteries, not the static "battery" voltage ... when we stop, the voltage stabilzes at around 12.9-13.1 volts. Optima state that a fully charged D34/D31A has a static voltage of 13.1 volts. To me that seems to indicate that the Optimas are being recharged very quickly, as is stated that they are capable of doing. They are 2x brand new batteries only installed about a week and a half ago. It seems the closer the batteries get to fully charged, the more the alternator reduces the charging voltage.

It takes 6-8hrs after stopping (fridge still running) for the USI-160 to switch off the 2nd relay and start the LED glowing bright/dim (shared mode, 1 relay). For the 6-8 hrs after turning off the engine the LED just glows constantly (both batteries connected, with both relays engaed). After 24hrs of use (fridge, lights, radio, etc) the measured battery voltage (both batteries still in shared mode, was 12.58 volts .... with my old batteries, the USI-160 would have long disconnected the batteries from one another, with the starting battery at about 12.1v, and the aux battery at about 11.7-11.9v. The Optimas have more than doubled my available run time.

I guess what I was trying to say/show, was that with the old batteries, the more discharged they were, the higher the voltage the nanocom showed, and it took ages for the voltage to reduce as the battery state of charge increased, whereas with the Optimas it seems to happen very quickly ... which is why I choose to use the Optimas in the first place.

Damo ... pic's as promised.

I basically did what UP shows on his web site.

Flip the ARB heat sheild 180 degrees, and slot the bolt holes to allow the heat sheild to move all the way to the left. (The D34 is 16mm wider than the standard battery that fits).



The lip on the heat sheild for holding down the battery now fouls the battery tray edge ... took it off with a grinder, and the slot that's left is used for the new battery tie down rod to hook into (you can see in the pic' it's been bent a little so it runs parallel to the side of the battery)

.

The other side of the battery trays metal hold down lip has metal taken out to allow the battery to move to the right so it's not sitting on the heat sheild bolts. Took a carbide burr in a power drill and perserverance.



Drill a second hole for the rhs battery tie down rod. You might notice the tie down strip across the top of the battery has slotted holes for the tie down rods ... the rhs one needs to be hard up against the battery or the top of it fouls the rolled section of the underside of the bonnet and stops the bonnet from closing.



You can just see the heat sheild bolt head in the bottom of the tray in the picture above, and below.



Here's a shot from the drivers side of the engine bay ...



... and a shot showing the alarm horn ... it's mounting bracket needs to be flattened then rebolted back to the tray ... this takes a little bit of tricky manouvering.



The isolator is on the drivers side, on a steel bracket mounted to the two studs already existing in the inside guard skin. Earth is to the earth stud just next to that. See http://www.aulro.com/afvb/projects-t...overy-2-a.html



Hope all that helps a bit. It's a tight fit, like a finger in a bum so to speak, but it's a good fit if you take the time. I added the Thermo-Tec battery heat sheild as an extra insurance for heat. The battery is sitting on a sheet of the stuff, plus it's been wrapped with the overlapped part of the sheilding wrap at the turbo side of the battery tray. Was about $30 off Ebay for the kit.

You really have some great ideas, Kev (Fluids). I never thought of reversing the heat shield or mounting the fuse on the heat shield either.

An alternative to the the specialised battery insulation is to use 6mm closed cell foam which is metalised on one side, from Clark rubber. Very effective and cheap. I only used it on the 2 sides closest to the engine. Wanted to stop the heat from the engine getting in but also allow the heat in the battery to get out. Used the same stuff to make a cover for my fridge.

Mundy

Kev,

What can i say mate.. thanks so much for the info and those awesome pics!!

Now, as you can understand, i have a few questions id like to pick your brain about

I have also looked at UP's website and was looking at copying what he did too. Now i noticed that you seem to have gone to a lot more effort than he did, so i was wondering why that is?

He turned his clamp around 180 degrees too, but didnt grind the lip off. He also took a much smaller amount of the tray away from the opposite side. I was wondering why you needed to take off so much more to get the battery to fit? Is it because of the 'jacket' you have around the battery? I dont fancy my abilities with a grinder, so i would like to keep the modifications to a minimum, as you can understand (less chance of buggering something up!)

If you remember.. the clamp is not flat at the base. It has an angled section which i assume is to aid in holding the exide battery down. Did you bash this flat or remove it? Or did you leave it? If you arent sure what i mean then i can photograph it and show you.

How far away from the bolt heads is your battery? did you put something between the battery and the bolt heads to make sure there is no chance of damage to the battery?

Thanks again for the help. Love the neat install too!

Oh, and one more question.. where abouts did you run your earth wire to?

Kev,

What can i say mate.. thanks so much for the info and those awesome pics!!

You're welcome!


Now, as you can understand, i have a few questions id like to pick your brain about

I have also looked at UP's website and was looking at copying what he did too. Now i noticed that you seem to have gone to a lot more effort than he did, so i was wondering why that is?

I took another look at UP's writeup ... it's basically what I did, but I found that a fitters approach to my install was required due to the small amount of room I had for fitting, possibly because I have rear a/c and extra plumbing in that corner, or maybe there's a variance in the ARB trays ... mines a bit older than his ... and (below) maybe to get the battery off the lip. That's just how it ended up


He turned his clamp around 180 degrees too, but didnt grind the lip off. He also took a much smaller amount of the tray away from the opposite side. I was wondering why you needed to take off so much more to get the battery to fit? Is it because of the 'jacket' you have around the battery? I dont fancy my abilities with a grinder, so i would like to keep the modifications to a minimum, as you can understand (less chance of buggering something up!)


The "jacket" is just like a fibreglass backed foil lined sheet with a peel off adhesive, so it just deformed against the "peak" left in the rhs tray lip (all these lhs/rhs are as viewed from the front of the engine bay). There was also a black inner sheet of something like a scotch-brite pad/scourer that's wrapped around the battery (a battery acid absorbing/nuetralizing material) before the foil layer was applied. The battery is sitting on a sheet of that scotch-brite stuff as well (no foil). Was in the kit, and was recomended to be put there, so that's what I did ... not much chance of acid leaking with the Optima, but I used it more for insulation & vibration reasons.

A grinder ... not a hope of getting a grinder into the space available! I used a carbide burr in a drill (thousands of rpm's). Should really be used in a die grinder type tool, like a giant dremmel (10's x thousands of rpm's) but all I had was a power drill. I did the first 1/2 curve cut with drill bits drilling out holes vertically, then tried a grinding wheel in the power drill to cut out the remaining metal, then reverted to hand filing vertically .... then went out the next moring and bought a burr ... too bloody hard the way I started. It's a slow job, and you don't want to slip and take out the a/c lines in that area !

Looking at his clamp/heat sheild, I can see no lip ?? ... but I can see the slot left from the stamping the lip out ... either his tray didn't have one, or he just didn't document it. I notice his heat sheild doesn't sit hard to the left side of the tray. It is further inboard than mine. I cut the bolt holes into slots in my heat sheild, so that, when the battery is in the tray, the edge of the battery is not sitting on the bottom edge of the heat sheild bolt lip. It sits flat on the bottom of the tray. UP's battery might be sitting just on the edge of the heat sheild bottom lip ? From his photo's it doesn't look like he's slotted the heat sheild bolt holes. I had to cut the rhs lip out that far to get the battery off the lhs lip. I cut it out the same as UP's to start with, but found that battery was so close to the bolt heads that I couldn't get my socket onto it, and the battery was resting on the lip, so I cut the rhs lip out further to move the battery closer to the guard, and cut the lip bolt holes to move the botton lip on the lhs closer to the tray edge ... the battery now sits flat. I drilled a hole for the lhs battery tie down bolt like UP did, but my tie down was too long, so the threaded section was too high. Hooking it into the slot gave me just enough thread to make it all work.


If you remember.. the clamp is not flat at the base. It has an angled section which i assume is to aid in holding the exide battery down. Did you bash this flat or remove it? Or did you leave it? If you arent sure what i mean then i can photograph it and show you.

No, I just left it as it was ... It seems to act like a bit of a spring when your torque the bolts down against it. The rhs edge of that bottom lip sits level with the rhs edge of the bolt heads when all assembled, and the battery clears it all with just enough room for a socket to fit.


How far away from the bolt heads is your battery? did you put something between the battery and the bolt heads to make sure there is no chance of damage to the battery?

Because of the battery heat wrap it looks like there's less room than there actually is. Nothing other than the wrap between the battery case & the bolt heads.


Thanks again for the help. Love the neat install too!

Thanks.


Oh, and one more question.. where abouts did you run your earth wire to?

It runs down around the outside of the ABS unit and connects to the engine block. That was already there when I bought the disco ... the whole ARB dual battery setup was already installed using a Century 46T wet lead acid deep cycle battery ... I've just modified it to get the D34 to fit properly.

If I wasn't clear, or you need more pic's it's a quick job to pull the D34 out if you need more (clearer) pic's of how the heat sheild was modified & fitted.


If you think it's a bit beyond your ability, scribe the required curves into the rhs lip, then take it to a panel beater and ask them to use a high speed burr in an air grinder tool to cut the metal out for you ... the rest should be within your capabilities.


Cheers!

Well mine is DONE and I'm stoked. It's in the back bin and all went a treat. The final thing was getting the legendary father in law to help make up a bracket to stop it moving sideways if a collision occurred and also a typical bracket over the top. He also did some typical shuzzing as he does to make it all look a treat. I'll post pics soon. Thanks drivesafe for your kit and advice and help!

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