gunning1987
Member
Hmm that's true...
Dual battery setup
- Thread starter Laith
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Hmm that's true...
thats about right nathan
it will work but with expensive batteries(mine are $400 each x2)the dc/dc is a lot better at "looking after your agm"
when the unit sees no voltage at ign it will switch off
the main and the aux are never "linked" with a dc/dc charger
the unit draws power from main battery and charges the aux when it sees the right conditions
Oh not at all. That relay stops the system from drawing power from your cranker battery when the ignition is off. Ignition on usually means engine running so you're safe.
The relay is essential. It's how mine works, too - no charging for the auxiliary (or trailer) unless the vehicle ignition is on.
AGMs can be charged differently to crankers although the same method won't kill an AGM. Conversely, it is possible to kill a cranker using an AGM charger because the charge rates of an AGM can be much much higher and although crankers can deliver high current rates, they don't really like being charged at high rates. We don't really have a lot of chargers (eg 50A) that are in small recreational vehicle use, so your 15A CTek is perfect for both cranker (SLI) or AGMs.
The real difference is in gel batteries. These are the ones to be very careful with. Gels not only need a gentle charge, they need their charge voltage capped at 14.1V (so charging a gel via the alternator is asking for trouble0.
Charging at high rates causes fizzing of the electrolyte. In a typical older style battery this means you need to refill it with distilled water more often. In sealed (VRLA) batteries - AGMs are almost always these - you still get the fizzing, but the internal pressure assists in "recombination" of the gases and so there's not a lot of fluid lost. AGMs also are fluid in glass matt (like a wet cotton ball), whereas Gel batteries have their fluid held like a jelly and once a bubble forms it's toast.
With the voltage and the agm battery I under stand that they need a high rate of charge not that the lower rate will harm them as I have a yellow top as my starter in my Statesman once every 3 months or so I hook the car up to my ctek msx7 and do a full charge. Once winter is over I'll do a full recon to clean the batter up.
bgorm6
Member
ive got a 120amp going into the tub, with a 150amp isolator in the engine bay, do i need one or two circuit breakers inbetween ? cheers
gunning1987
Member
How big is you charger? If its a 20amp youll need a 30amp breaker if 40am= 50amp breaker. 150amp would be from the battery to a fuse panel. As for the number id go one before the charger and one after close as possible to the source in and then charger straight out.
Circuit breakers/fuses are there to protect from short circuits. The isolator can deliver 150A but should overload or better still recognise a short and switch the output off, leaving the only place the breaker/fuse is needed is right next to the aux battery in the rear, assuming:
starterbatt---isolator-------------------------------------------------------------------------fuse---aux
You CAN add another fuse/breaker in before the isolator if it makes you feel comfortable, but have a read of the documentation for the isolator - it might already detect and handle short circuit conditions (cable faults).
starterbatt---isolator-------------------------------------------------------------------------fuse---aux
You CAN add another fuse/breaker in before the isolator if it makes you feel comfortable, but have a read of the documentation for the isolator - it might already detect and handle short circuit conditions (cable faults).
Batteries like to remain fully charged. On a shelf, they'll slowly lose power (it's a thing with 12V lead acid batteries) so if you DO take it out, you have to remember to give it a charge every few months, or leave it on a trickle (float) charger.
I leave mine in - but I also leave the Engel in at all times too, because we're constantly moving food from shops or from house to house.
I leave mine in - but I also leave the Engel in at all times too, because we're constantly moving food from shops or from house to house.
motojunkie86
Member
tony i have been watching the forum closely lately, you seem to have lots of experience with the electronic/ dual battery type setups.
75 GRC
Member
He most certainly does!!!!!!
Hats off to you Old Tony
You certainly have a wealth of knowledge about anything 12v.
And it's good to see people appreciated it and recognise it.
YOU'RE THE MEN OF 12 volt KNOWLEDGE!!!!
Cheers
Geoff
"GO THE NAV V6's"
Sundowner2
Member
Not a good solution to connect two batteries of differing chemistry, age or capacity....it will almost certainly result in shortening the lives of both...and in 2011 Nissan started installing ECU Variable Voltage Alternators as part of the CANBUS on D40's....I suggest you do a bit of research on the consequences of this with your set-up in mind.
^ Normally that is the correct approach especially (and particularly) in a bank of batteries, but in a starter-deepcycle scenario like many of us run, that's impractical and the reason why I prefer to either invert the incoming power and run a mains charger (no real connection between the two batteries, and the way that I do it at the moment) or use an isolating charger system like the C-Tek D250S.
The reason for not connecting batteries of different chemistry is simple. Starter batteries, designed for very brief periods of super-high current, don't enjoy being drained below 50% and are often not charged up over 75% of their actual capacity (long drives and bench charging of course change this).
Deep cycle applications generally don't see anything near the rush of current, typical draws usually are below 10A (fridge from 4-5-7.5A, lights of 2A tops with LED these days). Even gel batteries (which I will never, ever buy again unless it's unavoidable) can manage this without any difficulty and they can continue doing so for longer periods - most deep cycle batteries these days can be drained to around 20% capacity unless it's a LiFePO4 which you can apparently use 100% of (I haven't tested this because I'm not wealthy enough to own one or experiment on it if I did).
Charge rates on deep cycles vary. Ordinary lead acid at about 20% of rated capacity, so a 100Ah can be charged at 20A per hour. Gels should be limited to 10% (amps) and <14.1V so that bubbles aren't formed on the surface of the plates. AGMs are much more tolerant allowing charge rates typically of C/3 (40A for a 120Ah battery) and up to C/2 for spiral wound ("military") batteries - 37.5A for my Optima D31A. This tolerance comes from the battery acid being held in a glass matt rather than as a gelatine-like substance between the plates.
Word of warning for experimenters: you can still cook an AGM. Grab a 50Ah AGM and throw 100A at it. The electrolyte will boil quickly, over-pressuring the battery causing it to vent. Most AGM batteries are "VRLA" - valve regulated lead acid - meaning they have pressure valves in their cases preventing any gas from escaping under a certain limit, which forces it to recombine thus retaining the original electrolyte for the life of the battery. Oh, if you DO experiment, don't smoke or have any naked flames or sparks near the battery. It vents hydrogen. And oxygen. A spark means major flames. Add a burning fireball to spraying battery acid and chunks of lead and you've not only got an expensive cleanup bill, but you could be badly hurt.
The reason for not connecting batteries of different chemistry is simple. Starter batteries, designed for very brief periods of super-high current, don't enjoy being drained below 50% and are often not charged up over 75% of their actual capacity (long drives and bench charging of course change this).
Deep cycle applications generally don't see anything near the rush of current, typical draws usually are below 10A (fridge from 4-5-7.5A, lights of 2A tops with LED these days). Even gel batteries (which I will never, ever buy again unless it's unavoidable) can manage this without any difficulty and they can continue doing so for longer periods - most deep cycle batteries these days can be drained to around 20% capacity unless it's a LiFePO4 which you can apparently use 100% of (I haven't tested this because I'm not wealthy enough to own one or experiment on it if I did).
Charge rates on deep cycles vary. Ordinary lead acid at about 20% of rated capacity, so a 100Ah can be charged at 20A per hour. Gels should be limited to 10% (amps) and <14.1V so that bubbles aren't formed on the surface of the plates. AGMs are much more tolerant allowing charge rates typically of C/3 (40A for a 120Ah battery) and up to C/2 for spiral wound ("military") batteries - 37.5A for my Optima D31A. This tolerance comes from the battery acid being held in a glass matt rather than as a gelatine-like substance between the plates.
Word of warning for experimenters: you can still cook an AGM. Grab a 50Ah AGM and throw 100A at it. The electrolyte will boil quickly, over-pressuring the battery causing it to vent. Most AGM batteries are "VRLA" - valve regulated lead acid - meaning they have pressure valves in their cases preventing any gas from escaping under a certain limit, which forces it to recombine thus retaining the original electrolyte for the life of the battery. Oh, if you DO experiment, don't smoke or have any naked flames or sparks near the battery. It vents hydrogen. And oxygen. A spark means major flames. Add a burning fireball to spraying battery acid and chunks of lead and you've not only got an expensive cleanup bill, but you could be badly hurt.
bloffy13
Member
Hi guys. One of my first posts here.
I just installed a dual battery system in my 08 D40 extra cab.
Followed the instructions with the BatteryLink pro series DC to DC charger, took my time and double checked everything as I went. Pretty chuffed with the outcome. The allrounder battery went in today and everything lit up as it should. All the joints were fully swaged and heat shrunk, 2 x 20amp circuit breakers went in between the batteries and the charger and everything was properly secured in with cable ties.
About the only extra thing I needs do now is add an extra earth to enhance its grounding, but not a war loser.
I put another system in my former 4WD, a Mitsubishi Delica, and that was much more problematic due to there being very little space to work with. Had that vehicle for 10 years and only had the battery go flat once when I went away for a week and left the internal lights on. Ooops. And replaced one battery at the end of its life.
My next step will be to add to Anderson plug set ups off my Aux battery.
One into the rear of the cab so that I can run a car fridge (When I get one. Will be looking around the forum to see what others have).
The other will lead to the front of my tray back.
I have a removable tradesman back which will become my camper.
I intend to install the aforementioned plug to a short extension lead to the inlet on the trady (Anderson to Anderson) and then straight into either a circuit breaker or resettable fuse box (pretty much the same thing, the way I see it. )
From there, I plan on installing dimmable LEDs both inside and to the gull wings, an external light or two, a small bank of USB chargers for phones, tablets, GoPro etc. and maybe a small fan or two to keep me and she cool if temperature warms up.
Anything else I should consider?
I think I will run all the lights and the fans through individual switches.
At this stage, I don't think I will need an inverter but I might leave provision for it for the future.
Sounds elaborate but pretty simple and low draw if I have my way. Trying to get the best bang for my buck, so will have to do it all myself.
Would welcome your feedback.
Cheers
Bloffy
I just installed a dual battery system in my 08 D40 extra cab.
Followed the instructions with the BatteryLink pro series DC to DC charger, took my time and double checked everything as I went. Pretty chuffed with the outcome. The allrounder battery went in today and everything lit up as it should. All the joints were fully swaged and heat shrunk, 2 x 20amp circuit breakers went in between the batteries and the charger and everything was properly secured in with cable ties.
About the only extra thing I needs do now is add an extra earth to enhance its grounding, but not a war loser.
I put another system in my former 4WD, a Mitsubishi Delica, and that was much more problematic due to there being very little space to work with. Had that vehicle for 10 years and only had the battery go flat once when I went away for a week and left the internal lights on. Ooops. And replaced one battery at the end of its life.
My next step will be to add to Anderson plug set ups off my Aux battery.
One into the rear of the cab so that I can run a car fridge (When I get one. Will be looking around the forum to see what others have).
The other will lead to the front of my tray back.
I have a removable tradesman back which will become my camper.
I intend to install the aforementioned plug to a short extension lead to the inlet on the trady (Anderson to Anderson) and then straight into either a circuit breaker or resettable fuse box (pretty much the same thing, the way I see it. )
From there, I plan on installing dimmable LEDs both inside and to the gull wings, an external light or two, a small bank of USB chargers for phones, tablets, GoPro etc. and maybe a small fan or two to keep me and she cool if temperature warms up.
Anything else I should consider?
I think I will run all the lights and the fans through individual switches.
At this stage, I don't think I will need an inverter but I might leave provision for it for the future.
Sounds elaborate but pretty simple and low draw if I have my way. Trying to get the best bang for my buck, so will have to do it all myself.
Would welcome your feedback.
Cheers
Bloffy
Last edited:
happy john
Member
Seperate into paragraphs mate!.
bloffy13
Member
Better?
The setup sounds alright to me. A reminder that USB chargers are step-down circuits and they will consume power whether charging a device or not, so adding a switch for those would also help for longevity.
Is there any solar in the plans? Even a portable folding panel (now, here's an idea: buy two 200W panels and stick a hinge between 'em) would massively improve your ability to stay off-grid and not have to start the car to get things topped up. Of course, you do want to kick the engine over every 3-4 days anyway unless you do what I've done - I've put a 40W panel in the roof tray and connected it (via a PWM charger and a ignition-on relay that disconnects it) to the starter battery. Means my starter gets topped up all the time, so the car can sit idle for a month and it'll crank over without pause.
Anyway, sounds like a good setup. I did run dual cables (positive and negative) because I didn't want to change a bad earth ruining my holiday and it looks like you're considering covering that base too.
Let us know how it goes!
Is there any solar in the plans? Even a portable folding panel (now, here's an idea: buy two 200W panels and stick a hinge between 'em) would massively improve your ability to stay off-grid and not have to start the car to get things topped up. Of course, you do want to kick the engine over every 3-4 days anyway unless you do what I've done - I've put a 40W panel in the roof tray and connected it (via a PWM charger and a ignition-on relay that disconnects it) to the starter battery. Means my starter gets topped up all the time, so the car can sit idle for a month and it'll crank over without pause.
Anyway, sounds like a good setup. I did run dual cables (positive and negative) because I didn't want to change a bad earth ruining my holiday and it looks like you're considering covering that base too.
Let us know how it goes!
