The 150 series Dual Battery Guide

[MelbournePark Member Find all posts View Profile Close MelbournePark]

I also have the 39 litre Eutectic Autofridge, I don't think it uses any less power over the journey than my ARB fridge assuming we keep them at similar temps. Yes the Autofridge doesn't run all day, but when it does run the compressor runs constantly, where as cyclic fridges turn on and off so over a few days compressor running time would be similar. The efficiency comes from being able to decide when you use that power, I would turn it on an hour or so before I knew we would start the engine and that power draw would quickly be replaced and the fridge would effectively run off the alternator until we stopped. I generally only use it as a freezer now. We ran it for 6 years in 2 vehicles without any second battery.

Cheers Andrew

Its also the design. In yachts, they used to be standard ... but our yacht building industry went away.

The owner was my cousin, so, I know a fair bit about real efficiency. The nature of the heat exchange, the stored energy, the heat transfer methodology. But if you've had it a while, change the compressor - the newer tech Danforce ones were a lot more efficient.

[MelbournePark Member Find all posts View Profile Close MelbournePark]

I also have the 39 litre Eutectic Autofridge, I don't think it uses any less power over the journey than my ARB fridge assuming we keep them at similar temps. Yes the Autofridge doesn't run all day, but when it does run the compressor runs constantly, where as cyclic fridges turn on and off so over a few days compressor running time would be similar. The efficiency comes from being able to decide when you use that power, I would turn it on an hour or so before I knew we would start the engine and that power draw would quickly be replaced and the fridge would effectively run off the alternator until we stopped. I generally only use it as a freezer now. We ran it for 6 years in 2 vehicles without any second battery.

As for the guards, do you have the 2014 update model? I gather they have strengthened the inner guards.

Cheers Andrew

No, mine is early 2013, but not the upgrade.

As far as efficiency, I think it's how you manage it. With running it frozen, that burns a heap more power, but the Auto does it easy IMO. Also, yours has an older compressor. The later ones were quite a bit more efficient due to a better compressor. You can upgrade the compressor too, but I haven't. Unfortunately though, the business has been shut down, and the owner's retired. Shame the Chinese haven't copied them ...

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

The Autofridge is a very well made unit that has its place but its not a patch on my ARB fridge. It's not surprising they haven't been copied, they have a very narrow upside and a very large downside. As a freezer they work well though.

Cheers Andrew

[MelbournePark Member Find all posts View Profile Close MelbournePark]

The Autofridge is a very well made unit that has its place but its not a patch on my ARB fridge. It's not surprising they haven't been copied, they have a very narrow upside and a very large downside. As a freezer they work well though.

Cheers Andrew

My opinion is quite different. But its off topic IMO, and the Autofridge is not available anymore so i's good that you enjoy today's cheap low material cost mass produced stuff.

I'd like to know what maximum weight people here think is safe for the Prado. 22.5kg must be since that is the factory weight. I presume 25kg would be OK? That opens up lots of choices.

[MelbournePark Member Find all posts View Profile Close MelbournePark]

Weight and vibration crack the guards. You can find a lot of info if you search the forum.

I knew various bits of this before buying. Evidently the guard parts were changed in 2012, and those new parts carried over into the 150. The 150 also had another guard part. So there are three part numbers for front guards for the 150. The early ones are more suspect.

Evidently weight over the front axle is an issue, how the vehicle setup and driving setup and methods over corrugations, bull bar configuration also, and battery weight and fitment are issues, plus some bad luck with some guard metallurgy that resulted in cracking in some vehicles.

I think 25 kg would not be an issue for both batteries ie an extra 2 kg for each battery. IF 27kg was OK that would allow a lot of options. While a 31 kg unit can provide a lot of power, its a lot more weight and there are few statistics about battery weight.

I have a Toyota alloy bar and the increase in weight less what was removed results in a weight gain, but its not too bad.

Probably the best configuration is to have a light, compact purely starting battery in the engine bay, put a purely deep cycle ( they are longer life ) AGM battery in the middle of car (now that is not easy but then batteries cannot enjoy engine bay heat) and use the spare battery space in the engine compartment for a compressor and for other accessory placements. Rather than having such such accessories bolted up the back or sides of the engine bay where they are difficult to access.

What many do is put the battery in the front of the rear storage area and that is likely the most logical place.

From a handling point of view a battery in the centre of middle passenger area right behind the arm rest compartment would be good if batteries came in sizes that would fit there.

Not as sexy as one in the front though (which also minimizes cables).

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

Guard design changed late 2013, some early update models still had the old design.

[MelbournePark Member Find all posts View Profile Close MelbournePark]

Guard design changed late 2013, some early update models still had the old design.

Actually the part number changed I think in 2012. Then they changed with the update model. Some update models had the revised guard in them (the different part number to pre sometime in 2012).

The revised models mostly though look different, sort of a twin skin appearance. I presume the earlier revision was a more subtle change.

However I think by 2012 the issues were extremely rare. No evidence of that though of that expect peoples comments. Then again, some early guards were claimed to have cracked without a second battery, with the factory battery, and doing city driving.

Who knows ... but IMO if the car is legal and has two batteries within 10% of the factory battery weight, and the vehicle is recent, and the other issues previously mentioned are covered, it should not be an issue.

I wonder though with big batteries in the engine bay - its the hottest place in the vehicle. Turbines also give off a lot of heat. So if your hard driving with a fridge in the back on a hot day, then I think the batteries are not being done too many favors.

I haven't researched much on batteries, but I suspect another way for batteries is some thin ones put together in the back area,

For instance, these FullRiver AGM batteries are "DC" type, which have much superior to dual battery performance.

ie:
The difference between the FullRiver's "HGL" and "DC" deep cycle battery range:
600 cycles at 75% Depth of Discharge ("DC" range) vs. approx. 350 cycles at 75% Depth of Discharge ("HGL" range)
Extra Heavy Duty Grids
Higher Power Density
Deep Discharge Recovery
Nominal Voltage 12V
Rated Capacity (20 hour rate) 20AH
Dimension Total Height (with terminals) 167mm(6.57inches)
Height 167mm(6.57inches)
Length 181mm(7.13inches)
Width 77mm(3.03inches)
Weight Approx.6.44kg (14.20Ibs)

So, that battery weighs 6.5kg, and has 20 AH over and over ... they are quite thin (3" in the old measurement). You could put several alongside eachother in the bottom of the rear compartment perhaps. They are advertised for $80 each. So you get 60 AH deep cycle for $240, or for $320, 80 AH ... plus the cost of connecting them.

If I let the rear seats in place, and slid the right hand middle seats forward, there is a gap which would fit that thin battery. The distance from the side of the car to the normally positioned narrower rear seat, is a bit about 690mm. Another dimension of those batteries is 167mm. 167mm x 4 batteries = 668mm. So it might be quite easy to drop the leg room on the right hand central passenger seat, and pop in for trips a 4 battery setup with 80 very good AHs, in a good handling central place.

Put your fridge behind on its slider and on the left hand side somewhere. Draws might stop before the batteries ...

If you do city miles, do we need to have the fridge in the Prado, as well as 30kg of battery that we don't need for town work?

Just an idea, likely a crazy one ... these are Chinese made too so perhaps their performance is less than their specifications.

There are many Gel batteries that are very compact too, but for my use, I want quick recharge. Gel though is not that quick and also I think its delicate to recharge?

These batteries are typically golf buggy batteries, and can be bought well if you buy a few at a time ...



I think the average AGM needs around 14-3

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

MP not sure how many questions you are asking in your post anyway I will give some comments. Ever since we bought our first compressor 12V fridge it lives almost all the time in the car. We don't live in suburbia so it makes shopping easier, no need to rush home to get the cold stuff in the fridge. With the 120 I had the aux under the bonnet and the fridge took up one rear seat spot so we still left the other in. When we bought the 150 I decided to put the aux in the back because I couldn't comfortably fit what I consider a decent size (120Ah) under the bonnet, irrespective of any guard cracking concerns. So I pulled the third row out and fitted a replacement floor. I can throw the rear seats back in easily enough, it takes just over an hour. Pics of my install in my build.

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

The problem with multiple small batteries is the cell count goes up ie one 100 Ah battery
is 6 cells, five 20 Ah hour batteries 30 cells, potential failure rate has gone up not to mention of cell equalisation issues.

I believe for instance that Kimberly used several small batteries in their Karavan
and have had batteries issues. Most other manufactures with similar power
requirements have opted for two 100 Ah AGM's.

[MelbournePark Member Find all posts View Profile Close MelbournePark]

The problem with multiple small batteries is the cell count goes up ie one 100 Ah battery
is 6 cells, five 20 Ah hour batteries 30 cells, potential failure rate has gone up not to mention of cell equalisation issues.

I believe for instance that Kimberly used several small batteries in their Karavan
and have had batteries issues. Most other manufactures with similar power
requirements have opted for two 100 Ah AGM's.

Interesting point.

However in boats, banks of batteries are normal. They normally replace all the batteries at one time though.

But another point - in boats, they will use purely deep cycle batteries. For the motor start in most boats, the starting battery will be separate to the general power for the boat. I think that is because the starter battery is normally close to the motor, and since battery banks are heavy, they put them elsewhere (low and in the centre of the boat is preferred).

The interesting thing is that deep cycle batteries have thicker lead, hence they are more reliable and have longer life. When you want to have cranking power as well, then you have to have some plates which are thinner, because they will allow the reaction to be quicker hence are able to push out high cranking amps. But that technology is not as long life and thereby as reliable.

So I would argue that more cells of deep cycle are more reliable then less cells in a dual function battery (start and deep cycle). I have a couple of gold buggy batteries which are gel batteries. They are quite small and have lots of amps. The are made in Germany. I think they are very reliable. The problem with gel though - I think - is that they requires high voltage and also require careful switching of the power when they reach their charge.

On another aspect of charging and reliability etc, I do not know too about the actual build of an Optima ... it seems that their circular construction allows a lower charge voltage, and I am guessing that their cranking ability (dual function) is due to their thinner lead wound on the outer part of their circular wind of lead and fibreglass. That Optima doesn't make a purely deep cycle also points to me that their design has had them build starting and also dual function batteries (start and deep cycle) as suiting their circular wind characteristics. Incidentally I read in a boating battery review, that the Optimas were tolerant of lower voltages for charging, hence perhaps avoiding your voltage increasing fuse (although your fuse seems cheap enough to put one in anyway).

I think therefor that it makes more sense to have a purely deep cycle in the back if one is seeking reliability. The downsides of that though are getting the cable to it, and whether to go for complex electronic devices that may also handle trailer batteries, or just go for a solenoid switch.

The advantage for me of more than one auxiliary battery, is purely because it could be put into narrower places and better suit the room in the restricted space of a 4WD. Such as a few good quality thin deep cycle batteries from the golf buggy market.

The normal thing to do though is put a single battery in the back somewhere ... and because such batteries are so common, its much easier to work that out. I am still considering all the alternatives though. The more I puzzle, the easier buying a camper trailer seems!!

An interesting point too - is lead prices. Evidently the recent price is $Au2.3/kg for lead. So if a battery weighs 30kg and it has 26kg for lead, that means its raw material cost for the lead would be $60 alone - plus the lead used is an alloy which increases its cost. I give my batteries away too ... you'd think they'd be worth something with all that lead in them!!

Incidentally, does anyone know which type of electronic device can link both batteries together for crank starting, if the starting battery is running low on power?

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

Some of the redarc isolators have a linking ability.

Marine setups are a different kettle of fish they will generally be running higher voltages then cars, ie batteries in series rather than 5 or six in parallel, easier to equalise series cells.

Most professional RV power installation companies would tell yo to go for lower cell count, ie use 6V batteries with large amp hour capacities to keep the cell count down, of course if you have to have the room to house them, and most don't so a compromise solution is required.

Optimas will accept higher charge currents at lower voltages but still like higher voltages to fully charge them. Optima also state that you can discharge the battery to 0% SOC without damaging the battery, if that is not true deep cycle I don't know what is. PS that is what Optima state, as to the validity of their claim?

I've used Optimas, other AGM and flooded, still would recommend Century Marine pros above most others, fair deep cycle capacity, cheap, can take physical abuse, heat and can be topped up if required. Wouldn't mount inside a vehicle though unless it is in a battery box that is vented to the outside.

Generally I wouldn't mount any battery inside a vehicle, I have seen all types of batteries leak and cause considerable damage.

Generally if a car manufacturer mounts a battery in a car it will be in a battery box mounted in the floor of the vehicle with a sealed cover. If the battery leaks it drains through the bottom of the battery box.

[snapper49 Member Find all posts View Profile Close snapper49]

Generally I wouldn't mount any vehicle in a car

I wouldn't do that either

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

Having waded through all 14 pages of this epic I have a related question. I have a 120 V6 with an ABR battery box with a 105 amp inside the car for all of the reasons above ie no weight on the front guard, only use it once or twice a year on trips etc. As you are aware these have a built in isolator and suitable wiring. It works fine and only occasionally has the isolator fluttered due to low volts or whatever. The fix for this is to transfer the fridge to the car cigarette lighter to give the battery box a better chance to recharge. NOW the issue is that I have just got a camper trailer with a large deep cycle battery. 1] How do I charge it? A dedicated cable from the main battery with a nearby isolator to the Anderson plug? 2] A cable to the trailer Anderson plug from the Battery box which has an Anderson plug outlet. 3] I also just got an Aldi 120 amp solar panel for those times that I am sitting put. Which of the 3 batteries do I connect it to [ the one in the car runs the fridge so always goes down first] or does it not matter if all 3 are connected together? My brain hurts! neil

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

Anyone???

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

Your simple isolator and at least 13mm2 cable to the anderson plug will work,
you will also need a booster diode. The battery in the rear is separate
from the camper ie not normally connected to the camper, so to charge it
from solar you will need to connect solar to the battery in the box.

Trailercan be charged by plugging solar into the trailer anderson plug.

You could make a cable up to connect both batteries together and to the solar
panel if you wanted too.