Dual Battery TD 150 GXL

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

I think this is what Roo means...

This is my AC charger

http://www.projecta.com.au/site/Defa...ons_Issue4.pdf

If you read the destructions you can see it varies current and voltage for some nefarious purpose. Guess the DC-DC does this too? Haven't researched it yet.

Andrew the difference I think is I had an issue and you haven't. All the DC charger does is totally isolate the auxiliary (ies) and lets you decide what input voltage it charges the auxiliary at. The diode upgrade goes some way towards that but the DC charger gives you options. It might also make a damn fine cup of tea but I doubt it.

[steve167 Lurker Find all posts View Profile Close steve167]

Awesome thanks mate. How about the section from the back door to the actual outlet shown in your pics. Do the back side panels come off? Locating the wire through the small hole made for the 12V socket looks very difficult.
Cheers for your detailed post on the dual battery system btw. I found an awesome tray from ARB thanks to your post.

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

All the DC charger does is totally isolate the auxiliary (ies) and lets you decide what input voltage it charges the auxiliary at. The diode upgrade goes some way towards that but the DC charger gives you options.

Hi mjrandom and actually it is the reverse.

Using a DC/DC device removes a number of options.

Fitting the fuse adds a number of options.

Folks, these DC/DC devices can fully charge batteries, but you need to have all the facts presented to you before you set up with these device.

First, the biggest advantage of using the fuse set up is that ALL your batteries are charged at a higher ( faster ) rate, not just a single the battery connected to a DC/DC device.

Next, these devices can condition a battery while you are driving around town with a fully charged battery to start off with.

The problem with this claim is that if you are on a trip, and if you use lots or power while camped and then expect your DC/DC device to fully charge your battery while driving, again yes they can but how many of you drive for much more than 5 hours between camping spots and this type of driving will still see you battery only reaching around 90+% charged, not fully charged and your alternator can do the same thing, in the same time.

As I have pointed out numerous times, the biggest single draw back with a DC/DC devices is the very time you need to recharge low batteries, unless you drive long enough, these device give you no advantage over your alternator and in many cases don’t do as good a job as your alternator.

Have a look at the advertising for all the different makes of DC/DC devices and see it you can find one single time based graph that shows the specific time it takes a given DC/DC device the recharge a given size battery.

Such information is the single most important factor needed to see if one of these devices is actually able to do a better job than an alternator and not one of the wonder device sellers has such a graph, because you would instantly see the glaring draw back of these devices.

Do your math before you spend the big bucks and just to give you an idea of reality. An AC battery charger has not fully charged a battery when the charge goes into float mode. It can take another 8 to 10 hours of being in float mode before the battery is fully charge and DC/DC devices work in exactly the same way.

BTW neither can an alternator for the same reason and this is why NOTHING will fully charge low batteries while you drive but an alternator ( with a fuse set up if you have a low voltage Toyota ) will replace far more of the bulk capacity of the batteries before a DC/DC device can.

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

Not sure how it is the reverse? The DC - DC charger runs from the main battery as per below (Borrowed unashamedly from Derek...) through the DC - DC charger to the auxiliary. No reverse flow, no back feed, no trickle effect. Please explain what you mean. And when you say fuse I assume you mean diode?



As for charging a low battery there is NO substitute for a good AC charger. Just my opinion refer signature below...

ta

[downunder Find all posts View Profile Close downunder]

Redrarc has a newer dc-dc the BCDC 1240. It can will bulk charge the battery at 40a per hr. Which is more than fast enough to recharge your battery
Therefore the dcdc chargers are slow comment is no longer an issue.
I have this charger and is works great.

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

Interesting observation about the charge rate.

My experience, as opposed to theory, when I go camping with a mate who has a DC-DC is that he spends a lot of time idling his car to charge the auxiliary battery while I, using a diode, go for short drives and never worry about it.

We both run our fridges ok but he spends more time getting his battery charged. And we both run the same size fridges at similar temp settings, although I tend to run mine a bit colder (more current draw).

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

As for charging a low battery there is NO substitute for a good AC charger.

Hi mjrandom, and I could not agree with you more and this is the point, as I posted, nothing will fully charge your battery while on the road, so giving your batteries, all of them, a once a month boost charge is the only way to get your batteries to a fully charged state.

As for a 20 amp verses a 40 amp DC/DC devices, you still have the problem that they WILL NOT fully charge low battery under 5+ hours of continuous charging and even longer for many batteries.

The battery governs the charging time not the device charging it.

I have 60 amp charging systems for caravans, that charge the battery and runs a 3 way fridge at the same time.

Even with a 60 amp set up, you will still need more time to fully charge low batteries than most people drive for.

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

I thought this was interesting reading re the optima batteries , as I heard people saying an optima can recharge in an hour. I got the below info from this site http://jci_media.s3.amazonaws.com/47...pecs_Sheet.pdf
Whats happens if the temp is over 52 degress on the rapid recharge below, does that harm the battery or does it just take longer to charge?
Also what is the leftover for charging Amps on avergae from the Prado d4d alternator. I presume you dont get 90 amps etc as the car, headlights, aitr con etc all take some ?


Alternator: 13.65 to 15.0 volts
Battery Charger (Constant Voltage): 13.8 to 15.0 volts; 10 amps maximum; 6-12 hours approximate
Float Charge: 13.2 to 13.8 volts; 1 amp maximum; (indefinite time at lower voltages)
Rapid Recharge: Maximum voltage 15.6 volts. No current limit as long as battery
(Constant voltage charger) temperature remains below 125°F (51.7°C). Charge until
current drops below 1 amp.
Cyclic or Series String Applications: 14.7 volts. No current limit as long as battery temperature remains below 125°F (51.7°C). When current falls below 1 amp, finish with 3 amp constant current for 1 hour.
All limits must be strictly adhered to.
Recharge Time: (example assuming 100% discharge – 10.5 volts)
Current Approximate time to 90% charge
100 amps - 52 minutes
50 amps - 112 minutes
25 amps- 210 minutes

Verses a Fullriver battery
http://www.springers.com.au/images/c...cs/dc85-12.pdf
I read somewhere else that said the fullriver should be charged with no more than 44 Amps. But i cant find the reference. Is there any hard figures?

Basically I am tossing up between an Optima D34M Blue top and an Fullriver DC85 85AH AGM as my new aux battery. (Limited by size) Fullriver has a lot more AH for the same size.

Cheers
Robert

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

After years of following this same debate over and over in various threads I'm at the point of thinking it's a lot of time wasted for not much benefit. Just do what you think is best and get out on the tracks.

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

After years of following this same debate over and over in various threads I'm at the point of thinking it's a lot of time wasted for not much benefit. Just do what you think is best and get out on the tracks.

Soooooo true

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

I am about to start my dual battery set-up this weekend...
I am going to do very similar to BRAINS set-up. Funny hey a full circle for this thread....
I will go with the allrounder mvs50 battery for AUX as I have the ARB tray install previously.
I will also change the main crank battery to the allrounder mvs70 only because I like the fact that it has the extra threaded terminals as the mvs 50, I can run my spotties, uhf & they maintence free.
Will also fit the abr diode fuse to up voltage output.
I will use red arc isolator.
I am only going to use the AUX battery for the fridge when its in the back during trips and added batt capacity.
I will also have a battery in my camper trailer that will charge off the system via cables from AUX battery to anderson plug at rear of kaka.
I will be running an earth from aux batt to eng block and chassis.
I will fit the abr sidewinder battery monitor as per their photo on web site in centre console.
I like the idea that I can see what the batteries read at all times and at the flick of a switch link the batteries in emergency situation.
I will also fit a DC-DC charger in camper trailer to charge the battery for the camper and AUX batt via anderson plug when driving.
The dc-dc charger would also do two things for me:
1. aid the alternator output and charge batteries to full capacity
2. I can also charge via sollar when camping so its going to be out of redarc, traxide,or ctec. for the dc-dc yet I not decided on this yet.

When i am driving the car every day, the diode/fuse will keep the voltage up to the AUX batt and thus not need the dc-dc as less amp draw on system due to as only two batt's in system. when three are in syst. then the dc-dc will aid.
What are your thoughts on this set-up guys??

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

I am about to start my dual battery set-up this weekend...
I am going to do very similar to BRAINS set-up. Funny hey a full circle for this thread....
I will go with the allrounder mvs50 battery for AUX as I have the ARB tray install previously.
I will also change the main crank battery to the allrounder mvs70 only because I like the fact that it has the extra threaded terminals as the mvs 50, I can run my spotties, uhf & they maintence free.
Will also fit the abr diode fuse to up voltage output.
I will use red arc isolator.
I am only going to use the AUX battery for the fridge when its in the back during trips and added batt capacity.
I will also have a battery in my camper trailer that will charge off the system via cables from AUX battery to anderson plug at rear of kaka.
I will be running an earth from aux batt to eng block and chassis.
I will fit the abr sidewinder battery monitor as per their photo on web site in centre console.
I like the idea that I can see what the batteries read at all times and at the flick of a switch link the batteries in emergency situation.
I will also fit a DC-DC charger in camper trailer to charge the battery for the camper and AUX batt via anderson plug when driving.
The dc-dc charger would also do two things for me:
1. aid the alternator output and charge batteries to full capacity
2. I can also charge via sollar when camping so its going to be out of redarc, traxide,or ctec. for the dc-dc yet I not decided on this yet.

When i am driving the car every day, the diode/fuse will keep the voltage up to the AUX batt and thus not need the dc-dc as less amp draw on system due to as only two batt's in system. when three are in syst. then the dc-dc will aid.
What are your thoughts on this set-up guys??

Almost exactly what I am doing...almost exactly, incl the ABR diode etc. Except that I will charge the camper trailer battery (AGM sealed battery) directly from the anderson plug we installed at the rear of the car, it will charge quickly whilst driving etc, and then we will top up with solar when camped. When not using the camper trailer, we use a CTECK electronic charger to trickle charge the AGM (and also occasionally top up and recondition the car batteries as well).

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

So brogers, you are not going to use DC-DC charger??
only Solar for camper batt when camping.
What charger are you using for solar??
The only reason I am thinking to use one is that I have a feeling that our little Alternators have got a big job to charge the crank batt, the second Aux batt, & supply voltage to a battery in a trailer 2mt away and getting it to it with some heavy cables. I think we might be changing our alternators sooner than expected in this situation as they will be working O/T and getting very hot if the campr batt are very low from a long stay but I suppose thats what the solar is for( if it can charge batt to 100% state).
I just think the charger (DC-DC) would help to keep a higher system voltage across the three batts and lower amp draw on our ALT. what you think, im i wrong or write??

[sbclover Member Find all posts View Profile Close sbclover]

Almost exactly what I am doing...almost exactly, incl the ABR diode etc. Except that I will charge the camper trailer battery (AGM sealed battery) directly from the anderson plug we installed at the rear of the car, it will charge quickly whilst driving etc, and then we will top up with solar when camped. When not using the camper trailer, we use a CTECK electronic charger to trickle charge the AGM (and also occasionally top up and recondition the car batteries as well).

That what I have done for 12 months and no failed batteries for me.

Sean

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

So brogers, you are not going to use DC-DC charger??
only Solar for camper batt when camping.
What charger are you using for solar??
The only reason I am thinking to use one is that I have a feeling that our little Alternators have got a big job to charge the crank batt, the second Aux batt, & supply voltage to a battery in a trailer 2mt away and getting it to it with some heavy cables. I think we might be changing our alternators sooner than expected in this situation as they will be working O/T and getting very hot if the campr batt are very low from a long stay but I suppose thats what the solar is for( if it can charge batt to 100% state).
I just think the charger (DC-DC) would help to keep a higher system voltage across the three batts and lower amp draw on our ALT. what you think, im i wrong or write??

Don't forget that depending on what you are doiing when camping, but we often do trips during the day, often up and down the beach etc etc, so the car gets a run most days, and we take the frige with us then, and the camper battery charges off the solar panels without any load, so its just not a problem in reality for us. I guess if you were staying in one place for more than 4 or 5 days and it was cloudy, but you can always run the car for a bit. A dc-DC charger, from what I understand, can just take a long time to charge batteries. We have a 100ahr battery as the second battery in the car, and another 100ahr battery in the camper, and we did run quite thick cables to the rear anderson plugs (I can't recall the thickness, but certainly twin cable and quite thick so as to avoid significant voltage drop to the camper so the battery charges quickly. Anyway, it seems to work for us quite ok, and so far no alternator problems. But its good to discuss and see what peopel are doing and what others think. The voltage booster diode seems to have been a good option, anyway, I'm interested in what you decide and how it works out for you, there are more than one way to skin a cat and it alll depends on what you are wanting to do, where you are travelling and what you are running off your batteries when camped. take care and keep seeking advice and suggestions