3rd battery?

[lars04]

Hey everyone! Wanting to see if anyone has set up a 3rd battery using a ctek charger or similar?

[the evil twin]

More info on what you are trying to achieve maybe?

Otherwise, buy battery, buy Ctek, buy Cable, connect to Alternator as it is no different to setting up a second battery

[lars04]

More for future travels being able to stay out bush for a hell of a long time

[the evil twin]

More for future travels being able to stay out bush for a hell of a long time

Fair enough.

You will be much, much better off witha reliable method of recharging existing dual capacity IMHO.
A 'balanced' system will run a fridge, lights etc for days.
By that I mean that if you increase battery capacity you also need to increase the amount of recharging capacity by the same amount.

So your very rough power budget would look like this...
Add up all the power drain in AH of your gear = 'X'
Battery capacity required = 'X' times 3 times # of days reserve if there is no recharging available
Charging capacity required = 'X' times 2

[threedogs]

As above if you have a 100 amp alternator for a triple battery set up.
If your aim is to remain in one place for long periods , you may want to look at solar
Panels to charge your batteries [free].
What are you using [12v] that requires 3 batteries??

[blocko05]

If you are just running a fridge , lights and a stereo then adding a solar panel to the equation would be a better idea. If you add a third battery and stay out longer and not charge the batteries while camping you also run the risk of over discharge of the batteries and end up needing to replace them. Most people hook up solar panels and this solves their problem. I have a duel battery set up and with my solar panel have stayed in one spot for over a week and not run out of power at all.

[tuckertrucker]

Do the patrol have dual batteries? I know my safari has dual batteries as it is 24volt. I'm getting a dual bank setup so that the primary bank starts the motor, and the secondary bank powers lights, stereo, dash, fridge etc etc. The charger unit I'm using charges the primary back to capacity and then switches to charging the secondary as thats what everything is using.
Not sure if it helps but thats my 2 cents worth. Cheers

[the evil twin]

snip... The charger unit I'm using charges the primary back to capacity and then switches to charging the secondary as thats what everything is using.
Not sure if it helps but thats my 2 cents worth. Cheers

What Charger is that?

I don't know of very many that are smart enough for that scenario.

[threedogs]

Is he saying his dual battery system charges the main first to capacity
then concentrates on the Aux, as most of his accessories come off the AUX

[the evil twin]

Is he saying his dual battery system charges the main first to capacity
then concentrates on the Aux, as most of his accessories come off the AUX

Yeah... just curious as I don't know of an 'off the shelf' Charger Unit that will do that.

Certainly Redarc/Projecta/Ctek/Pirhana et al don't make one AFAIK.

[DX grunt]

I've got a dual battery set up in mine with 2 x 120 solar panels on the roof.

Last summer I tested it out and had my HF radio on scan, uhf cb on, my 95lt Evakool fridge/freezer and my hot/cold water in the pod, on. In the middle of the day, my solar regulator never moved off 100%.

I've got lots of 'toys' I'll be using this summer, but I won't be using all at once. I was considering getting a 3rd battery, but I'm actually happy with what I've got.

Rossco

[dom14]

As above if you have a 100 amp alternator for a triple battery set up.
If your aim is to remain in one place for long periods , you may want to look at solar
Panels to charge your batteries [free].
What are you using [12v] that requires 3 batteries??

Yeah, solar panels are lot cheaper nowadays, and combined with LED lights, there's less demand on the batteries than old days as fas as light concerns. But, it may be still a good idea to have a third deep cycle battery as a backup, depending on the length of the time. Some batteries can die suddenly in outback conditions(constant vibration, heat, etc).

[dom14]

Yeah... just curious as I don't know of an 'off the shelf' Charger Unit that will do that.

Certainly Redarc/Projecta/Ctek/Pirhana et al don't make one AFAIK.

Apparently, there are 40amp smart charge units that will charge main battery first with a similar output to the alternator, but I'm not sure how reliable they are. Ctek and projecta sells 20amp dc to dc smart charge units. Smart charge process can extend battery life as well as fully charging the batteries to full capacity, but Ctek units, etc outputs maximum of around 20amp, which can be even far less in practical terms and can take a while to fully charge a battery, so it makes sense in longer non stop treks. Newer Ctek Smartpass unit allows the main battery to be charged directly via the alternator, at least according what they say in specs and what I've heard.

I personally prefer the simpler idea of using a mains smart charger and charge the batteries once a month or so. I also use a pulse charger as well. I'm using a secondhand 4WD starting battery which is still putting out the same CCAs as it was three years ago. I've been charging it once a month off the car with a smart charger and then occasionally with a pulse charger as well. Both chargers are not the high end Ctek stuff, but cheaper ones apparently does the same thing.

[the evil twin]

Apparently, there are 40amp smart charge units that will charge main battery first with a similar output to the alternator, but I'm not sure how reliable they are. Ctek and projecta sells 20amp dc to dc smart charge units. Smart charge process can extend battery life as well as fully charging the batteries to full capacity, but Ctek units, etc outputs maximum of around 20amp, which can be even far less in practical terms and can take a while to fully charge a battery, so it makes sense in longer non stop treks. Newer Ctek Smartpass unit allows the main battery to be charged directly via the alternator, at least according what they say in specs and what I've heard.

I personally prefer the simper idea of using a main smart charger and charge the batteries once a month or so. I also use a pulse charger as well. I'm using a secondhand 4WD starting battery which is still putting out the same CCAs as it was three years ago. I've been charging it once a month off the car with a smart charger and then occasionally with a pulse charger as well. Both chargers are not the high end Ctek stuff, but cheaper ones apparently does the same thing.


Totally agree with your comments about the Mains charging.

No way I would fit a DC/DC device between my Alternator and Main.
The issues that could occur in regulating the Alternator Output and Sense Voltage would give me sleepless nights.
You would need to connect the Alternator sense line to the DC/DC input and that would mean you now have a 40 Amp Charging source no matter the load on the vehicle

Smartpass is the Ctek 'fix' to the DC/DC low current charging taking so long that you need to charge a depeleted Aux battery directly from the Alternator for a period of time.
Fit that to your Main and you would get all sorts of weird effects as load changed IE spotties on/off etc

I still don't know of any 'Smart Chargers' that will allow charging the Cranker/Main to capacity and then do the Aux.
Perhaps I have missed the intent of the OP

[dom14]

Totally agree with your comments about the Mains charging.

No way I would fit a DC/DC device between my Alternator and Main.
The issues that could occur in regulating the Alternator Output and Sense Voltage would give me sleepless nights.
You would need to connect the Alternator sense line to the DC/DC input and that would mean you now have a 40 Amp Charging source no matter the load on the vehicle

Smartpass is the Ctek 'fix' to the DC/DC low current charging taking so long that you need to charge a depeleted Aux battery directly from the Alternator for a period of time.
Fit that to your Main and you would get all sorts of weird effects as load changed IE spotties on/off etc

I still don't know of any 'Smart Chargers' that will allow charging the Cranker/Main to capacity and then do the Aux.
Perhaps I have missed the intent of the OP

Yeah, I think you're right about that.
I'll check around to see if there's a DC-DC smart charge unit that charges the cranking battery first via the smart charge process.
Electronically, I don't see why it's not possible to make a one by Ctek and similar guys.

Many new cars come equipped with smart charging alternators, according to what I've heard.

First stage of the smart charging process is the Boost stage, which is basically giving all the amps the battery could handle and keeping the voltage
steady. This basically can be done directly via the alternator. I think the Ctec smart pass thing was invented for that, realizing alternator is better during
the boost stage, 'cos it can provide more amps directly than via the DC-DC smart charger.

Another thing pops into my mind is that whether the high amp(20 amp and above, etc) DC-DC smart chargers are any use at all.
As I understand, the high amp alternators(100 amp and above) exists, so it can keep up with the electrical demands of the extra accessories,
but not necessarily charge a battery in a flash. Lead acid batteries take time to charge, whether cranking or deep cycle.
So, I'm thinking, the high amp alternator is not there to instantly charge a lead acid battery like a Boost Pack(Super capacitor car battery boost packs).
So, even though the alternator can put out 120 amp, the battery can't use all that instantly and charge the battery in a flash, 'cos the
chemical process takes time.

[tuckertrucker]

My charging system uses a marine VSR switch. Its a high amp capacity switch that connects in the main power line from the alt to the main battery bank. When the main battery bank reaches a certain voltage (ie 13.8v) it switches to the secondary system. As soon as the main battery drops below a set point (ie 11.8v) it automatically starts charging that battery again.

It's a marine grade system and in the environments our boats are in we have a fark load more dependance on our battery power than most 4WD applications - so I doubt they'll ever be any trouble. And if they are - just take VSR out and connect the alt to the battery directly. Problem solved.

[dom14]

My charging system uses a marine VSR switch. Its a high amp capacity switch that connects in the main power line from the alt to the main battery bank. When the main battery bank reaches a certain voltage (ie 13.8v) it switches to the secondary system. As soon as the main battery drops below a set point (ie 11.8v) it automatically starts charging that battery again.

It's a marine grade system and in the environments our boats are in we have a fark load more dependance on our battery power than most 4WD applications - so I doubt they'll ever be any trouble. And if they are - just take VSR out and connect the alt to the battery directly. Problem solved.

I'm not sure what VSR stands for(Voltage Sensing Relay?!). But, it sure sounds like the battery isolation system we use in 4WDs. Perhaps a more expensive and robust version of the 4WD battery isolation systems.
Generally, considering the big money we spend on deep cycle batteries, it's worth smart charging them, either via DC-DC charging unit or Mains smart charger.

[the evil twin]

I'm not sure what VSR stands for(Voltage Sensing Relay?!). But, it sure sounds like the battery isolation system we use in 4WDs. Perhaps a more expensive and robust version of the 4WD battery isolation systems.
Generally, considering the big money we spend on deep cycle batteries, it's worth smart charging them, either via DC-DC charging unit or Mains smart charger.

Hiya Dom,
Yes, VSR is shorthand for Voltage Sensitive Relay

I have a feeling that what TT is talking about is an Alternator Splitter.
I could be wrong (lost count of the number of times today so far) but maybe TT will pop up a link or Manuf/Part# for us?

Quite prevalent in the marine world and I have driven several vessels with them fitted.
http://www.victronenergy.com/battery-isolators-and-combiners/argo-diode-battery-isolators

The main advantage of an Alternator Splitter device is it allows the Alternator to 'see' the voltages at batteries.
The main advantage of an Isolator configuration is it allows ease of parallelling and is usually much cheaper by the time you add the extra parts IF that is needed.

There are other advantages and disadvantages to both depending on particular useage and preferences and both will stop a load on one Battery depleting another.

[dom14]

Hiya Dom,

The main advantage of an Alternator Splitter device is it allows the Alternator to 'see' the voltages at batteries.


Hi Evil,
Aren't they both essentially the same thing?
I mean, they both allow isolating the main and aux batteries and prioritize the main battery?
Cheers
Dom

[the evil twin]

Hi Evil,
Aren't they both essentially the same thing?
I mean, they both allow isolating the main and aux batteries and prioritize the main battery?
Cheers
Dom

No, not really.
Generally a VSR on its own will not prioritise the 'main' battery (no matter what the sales blurb says)
A VSR will only stop the Aux depleting the Main

A dual battery Isolator only controls the Isolation IE disconnects the parallel circuit if the low voltage cut is reached.
The Alternator Sense + is still connected to the Cranker and any losses due to the long cable runs are not picked up in the regulator.
That is why DC/DC converters are so popular (altho not always necessary)

Using a splitter means the Alternator Regulator can sense each battery and the Output is reglated accordingly and distribution is controlled by the Splitter.

Remember tho that Vessels are not wired the same as Vehicles.
Vehicles have 1 battery bank as standard that does everything IE Starting, Lighting, Accessories etc
Vessels have multiple banks and, simplistically speaking, 1 bank is dedicated to Starting the Engine and assoc duty and then rests until next req'd for a start while the other/s is dedicated to all house loads IE lighting, navigation systems, fridges, winches etc

[dom14]

No, not really.
Generally a VSR on its own will not prioritise the 'main' battery (no matter what the sales blurb says)
A VSR will only stop the Aux depleting the Main

A dual battery Isolator only controls the Isolation IE disconnects the parallel circuit if the low voltage cut is reached.
The Alternator Sense + is still connected to the Cranker and any losses due to the long cable runs are not picked up in the regulator.
That is why DC/DC converters are so popular (altho not always necessary)

Using a splitter means the Alternator Regulator can sense each battery and the Output is reglated accordingly and distribution is controlled by the Splitter.

Remember tho that Vessels are not wired the same as Vehicles.
Vehicles have 1 battery bank as standard that does everything IE Starting, Lighting, Accessories etc
Vessels have multiple banks and, simplistically speaking, 1 bank is dedicated to Starting the Engine and assoc duty and then rests until next req'd for a start while the other/s is dedicated to all house loads IE lighting, navigation systems, fridges, winches etc

Ok, cool.
How long is too long for battery to alternator cable runs?
Do you think two or three meters of cable can drop a significant level of voltage?
I'm guessing we can use a voltage regulation circuit to manage any voltage drops along the cable runs?

So, the popularity of the DC-DC converters are mostly for the voltage regulation that it brings for long cable runs?
Not for smart charging of the aux batteries?

BTW, I'm waiting for some company to introduce a fulltime high amp output DC-DC smart charging unit for the cranker.
4WD cranking batteries aren't that cheap either. Good quality ones are as expensive as deep cycles.
I've been running a second hand el cheapo cranker for three years now, thanks to regular smart charging off the car.
But, I would love to have a DC-DC smart charging unit that works properly for the cranker as well.
It can't be rocket science to use the direct alternator amps for the boost stage of the smart charging and then use the DC-DC circuitry for the
adsorption stage and float. Ctek smart pass thing basically does that for aux batteries.

I do understand that the float stage for a running cranker may not make sense as much since it's constantly getting used,
but the alternator is constantly running and can take care of that.
I do believe 5+ years is doable for crankers with constant smart charging.

I have a secondhand crapper cranker that's been going good for three years. I believe, it must be due to frequent smart charging.

[BigRAWesty]

Ok, cool.
How long is too long for battery to alternator cable runs?
Do you think two or three meters of cable can drop a significant level of voltage?
I'm guessing we can use a voltage regulation circuit to manage any voltage drops along the cable runs?

So, the popularity of the DC-DC converters are mostly for the voltage regulation that it brings for long cable runs?
Not for smart charging of the aux batteries?

BTW, I'm waiting for some company to introduce a fulltime high amp output DC-DC smart charging unit for the cranker.
4WD cranking batteries aren't that cheap either. Good quality ones are as expensive as deep cycles.
I've been running a second hand el cheapo cranker for three years now, thanks to regular smart charging off the car.
But, I would love to have a DC-DC smart charging unit that works properly for the cranker as well.
It can't be rocket science to use the direct alternator amps for the boost stage of the smart charging and then use the DC-DC circuitry for the
adsorption stage and float. Ctek smart pass thing basically does that for aux batteries.

I do understand that the float stage for a running cranker may not make sense as much since it's constantly getting used,
but the alternator is constantly running and can take care of that.
I do believe 5+ years is doable for crankers with constant smart charging.

I have a secondhand crapper cranker that's been going good for three years. I believe, it must be due to frequent smart charging.

Voltage drop depends on load being draw to cable size over a set distance. Also quality of cable..
So if your pushing a cables capacity you'll have more voltage drop over a set distance than if you went oversize cable..

Dc-dc chargers not only make the most of the power coming in they maintain the battery and charge up to 100% capacity (or as close as possible) where an alternater will only get the battery to 90% or around that..

For your cranking option simply put a high current solinode on a seperate line to the dc-dc charger and operate it via a switch.
Need crank power flick the switch and have them joined.
They are cheap, and simple, you'll just need desent cable if your planning on running it over a few meters.
I went 30mm2 for my crank cable.