Dual Battery TD 150 GXL

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

Re: Dual Battery TD 150 GXL

So basically, this problem won't be a problem since the choice of cabling is 8B&S?

[Brains Find all posts View Profile Close Brains]

Re: Dual Battery TD 150 GXL

William,

I used 25mm2 battery cable to connect my start batter to redarc and redarc to auxiliary battery. The cable from the start battery to redarc is from memory 1100mm (110cm) not really that long and I have not experienced any voltage drop. I guess some people may just go to a automotive shop and get some very thin guage wire which could result in voltage drop although I'd be more worried about the wire being too thin for the amperage.

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

Re: Dual Battery TD 150 GXL

Hi again William, 8B&S ( 7.9mm2 ) would be the absolute minimum cable size and 6B&S ( 13.5mm2 ) would be the better and more suited.

Over distances greater than 2m, you can start to get some decent voltage drop with 8B&S if the auxiliary battery is very low, but 6B&S, while there is still going to be a potential for voltage drop, the voltage drop will be with in tolerable levels to avoid causing an isolator to oscillate.

Hi Brains, you would be surprised at how many auto electricians still use 6mm AUTO ( 4.5mm2 ) cable so Redarc's recommendation is probably based on problems created by people who should know better.

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

Re: Dual Battery TD 150 GXL

Paul, only 110mm?? If the aux tray (ARB tray) is housing the aux battery (Allrounder), and the isolator (Redarc) is mounted right next to the aux battery - right? In that case, how can the length of the cable of the isolator to the main battery (located on the far side of the engine bay) be 11cms?

Thank you drivesafe, it was my mistake, what I meant was 6B&S. I plan to use this as a guide: http://www.fridge-and-solar.net/dual_bat.htm

Actually I think I'll grab one of Dereks wiring kits too!

[Brains Find all posts View Profile Close Brains]

Re: Dual Battery TD 150 GXL

William,

I have edited my post with the correct measurement. I was typing it on the iPhone and obviously had some issues with my finger typing. The 1100mm also includes the length if the 100A online fuse that I used. I have measured voltage with the multimeter at both start and auxiliary batteries and both read the same when charging. As a test I ran my fridge off the 75AH Thumper pack and had it running for 3 days before I had to put it back in the car to go to work. With our camping we are usually driving every day so topping the battery up wouldn't be an issue for us.

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

Re: Dual Battery TD 150 GXL

Hi again William and Paul, one more point I forgot to mention, because of the way the SC80 works, it allows the alternator, even when running at 13.2v, a common voltage for a number of newer makes of vehicle, not just Toyotas, but again even with low operating voltages, the SC80 will replace used battery capacity QUICKER than any other dual battery set up, including DC-DC devices.

This means you fully charge your batteries in a shorter drive time and this means a heap of advantages for your batteries.

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

Re: Dual Battery TD 150 GXL

Because of the way the SC80 works, this problem will not occur and the SC80 is so stable in this kind of situation that it can be and is fitted in caravans or camper trailers instead of the tow vehicle, and SC80 will still operate as designed.

Hi Drivesafe,

Do you have a link to how your SC80 works ? I have looked on your website but can only find a lot of interesting circuit diagrams.
Without some sort of description, most people would be wondering how

the SC80 will replace used battery capacity QUICKER than any other dual battery set up

Unless it has some real fancy smarts I cannot see how it would charge an Aux battery an faster then me flicking a switch and switching the battery in via a heavy duty solenoid at its simplest, or using something automated like a Redarc, Piranha or a Sidewinder one.

I have looked at quite a few of your posts in other forums and have not found one yet that mentions how the SC80 works in its entirety. You mention "snake oil merchants" in reference to DC-DC chargers quite often, but at least they generally have specs and informative data on hand to allow knowledgeable people to compare units to make their own choice.

WIlliam,

I too am looking at a few of the kits form Sidewinder for very similar reasons to yours - yes could get the parts cheaper from elsewhere, but time is precious these days and if the cabling is pre-terminated to the correct length and there is instructions and pictures, then the extra cash can be sort of justified with a shorter installation time.
About the only thing I will probably do different is look at a longer negative cable for the aux battery so that you don't rely on a chassis earth return which I think Drivesafe highlighted in another post.

cheers

Damien

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

Re: Dual Battery TD 150 GXL

About the only thing I will probably do different is look at a longer negative cable for the aux battery so that you don't rely on a chassis earth return which I think Drivesafe highlighted in another post.

cheers

Damien

Damien, if you have a look at this post http://www.pradopoint.com/viewtopic....st=0&sk=t&sd=a there is a photo of how I connected the aux battery to the engine block with the sidewinder 60cm negative cable.

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

Re: Dual Battery TD 150 GXL

Damien&Wendy: I'll more than likely be getting all my wiring and terminals from ABR Sidewinder. Before I decide, I'm going to measure up all the lengths and see what I need, then I'll see if its cheaper to terminate my own cables or buy the premade ones. As in the fridge&solar link I posted, I will be following their wiring diagram in that I'll be running a direct cable to the negatives of each battery rather than through the chassis.



I picked up the ARB battery tray today. It came in a HUGE box... when the part inside is a tiny piece of steel. Anyway, it looks shmick! I'd expect it to be, after all it's $142 of laser cut goodness :roll: The fitting was too easy with 4 bolts attaching to the chassis.

It was then a matter of getting a battery. I had a good source quote me $140 for a 65Ah Century battery but I wanted to see how cheap I could find an Allrounder MRV50 for.... I sent a few emails around last week and most online stores sell them for $220. So thinking how Zerosecta (someone who lives locally) got his on special at Autobarn, I decided to go there first.... and what do you know it's on special at $179! What luck, I snapped one up immediately :lol:

So I came home and tried to install the battery to the tray.... :| That's when I encountered a problem! The battery is slightly too long. By slightly, I mean 5-10mm too long! I understand why Paul bent the mounting bracket a little and I will be doing the same. I'd better get some advice from him before doing so though. It would fit perfectly fine if it weren't for that plastic cap with the "L" letter on it sticking out at the wrong angle. I managed to get the battery in, but that damn cap was resting on the side of the battery. I took a photo of it with my phone but I'm unable to transfer it at the moment so I'll upload it tonight.

All that's left to do is buy a redarc, some cabling and some fittings.

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

Re: Dual Battery TD 150 GXL

Without some sort of description, most people would be wondering how

the SC80 will replace used battery capacity QUICKER than any other dual battery set up

Damien

Hi Damian, the basics of how an SC80 is able to replace more used capacity in a shorter drive time is because of the way the SC80 shares the accessories load over both the auxiliary battery and the cranking battery.

If you have a standard isolator set up or a DC-DC type set up, you are getting all your accessories power from one battery.

If you’re a light power user then there is no real difference between any of the set ups, including the SC80, but if your a medium to heavy power user then there is a major difference in charging times and the more power you use, the great the advantage is when using an SC80 set up.

Say you have a 70 Ah cranking battery and a 100 Ah auxiliary battery. In a single battery set up, you have a maximum of 80 amperes available if you take the battery down to 20% SoC.

But with the SC80, you have a total usable capacity of 115 amperes.

In the shared set up that the SC80 offers, you can still just use 80 amperes of power but because it’s spread over two batteries, you are now only using about 47% of each battery’s capacity or the two battery’s are discharged down to 53% SoC.

This equates to 32.9 amperes from the cranking battery and 47 amperes from the auxiliary battery.

The SC80 exploits the fact that an alternator, if large enough and any alternator of 80 amps or more will work, will charge two batteries in the same time it take to charge one from the same depth of discharge.

So even with an alternator voltage of 13.2v, it will take about 4 hours driving to fully charge the two batteries.

With a single battery and a standard isolator it will take about 6+ hours.

With a 20 amp DC-DC converter it will take a little over three hours to raise the single battery from 20% to around 80% SoC and then the Converter will taper off and it will need around another two hours to fully charge the battery. So you need 5 hours driving time.

With a 25 amp DC-DC converter you could reduce the recharge time by roughly 45 minutes but even if it was a saving of 1 hour, the advantage is still with the SC80.

This is because the SC80’s initial set up costs are a fraction of what any of these DC-DC devices cost and because the SC80 spreads both the discharge and charge over two batteries, your batteries are not worked anywhere near as hard as a single battery set has to be to give the same amount of power, so the SC80 helps to extend the life span of your batteries and again this lowers the over all cost of an SC80 set up.

Now I have used a worse case scenario for the SC80’s set up. If you had a 100 Ah cranking battery instead of the 70 Ah battery and the alternator voltage was 14.0v, you would easily fully charge the two batteries in around 3 or less.

last but not least, by using an SC80 instead of any other set up, you automatically give your set up an minimum of a 50% increase in useable accessories power with out spending 1 cent on additional battery capacity.

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

Re: Dual Battery TD 150 GXL

Damien&Wendy: I'll more than likely be getting all my wiring and terminals from ABR Sidewinder. Before I decide, I'm going to measure up all the lengths and see what I need, then I'll see if its cheaper to terminate my own cables or buy the premade ones. As in the fridge&solar link I posted, I will be following their wiring diagram in that I'll be running a direct cable to the negatives of each battery rather than through the chassis.

I always thought it was best to earth to the engine block as this is what the alternator connects directly to and hence earths to. The Toyota dual battery system in Europe does not seem to run an lead between the negative of the 2 batteries.

I'd be interested in any comments

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

Re: Dual Battery TD 150 GXL

Krypto, there are a few reasons I decided to do it this way:
1. The majority of dual battery setups link the batteries together rather than running a lead to the chassis. A dedicated line that I can easily troubleshoot if something breaks.
2. I reckon it'll be easier to put a wire between the batteries than one from aux to the chassis and another from main to chassis. The reason for this is due to the lack of space to get to the chassis terminal after the battery is installed. It's already cramp there with various cables running along the side..
3. I don't believe it to be any different in charge rate or operation if I were to run the lead to the chassis or directly to the battery. The circuit more or less remains the same - except for the medium in which the charge is travelling.

I too would be interested in any comments as I haven't yet bought the wiring! :lol:

Oh and perhaps the reason the European models haven't run a neg lead between the batteries is for cost savings?

Cheers

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

Re: Dual Battery TD 150 GXL

William, I think you missed my point. There is a difference between connecting to the chassis or the engine block.

The engine is the "earth" reference point for the vehicle and the chassis is connected to this. The alternator mounts directly to the engine block and the chassis is generally earthed to the engine block by direct contact and a wire connection.

That is my understanding, but I'd happily be corrected

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

Re: Dual Battery TD 150 GXL

William, I think you missed my point. There is a difference between connecting to the chassis or the engine block.

The engine is the "earth" reference point for the vehicle and the chassis is connected to this. The alternator mounts directly to the engine block and the chassis is generally earthed to the engine block by direct contact and a wire connection.

That is my understanding, but I'd happily be corrected

Oh I get what you mean now... My guess is that there still wouldn't be much of a difference, if any at all. I've read on the overlander forum that there can be a slight difference in voltage compared with chassis and direct battery hookup (but it is negated with the use of proper guage wiring), I can only imagine it would be the same case with a direct hookup to the engine block... It's an interesting question you raise.

Cheers

[ABR-SIDEWINDER Member Find all posts View Profile Close ABR-SIDEWINDER]

Re: Dual Battery TD 150 GXL

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