Dual Battery Wiring

[Quinny]

... to everyone, thanks for the replies. I bought the ctek today, and found a pretty cheap 105 A/H as well. For the price I may get two of them

Sure does quinny if U want too check out mine and how it works your quite welcome.

I didn't realise you're just up the road ... wouldn't mind a look if that's ok ...

I thought the ctek was capable of running as an isolator on its own, so running it with the vsr might be doubling up on the same function?

I believe you are correct ... reading the spec sheet, it does not require a VSR ... Thanks CD.

Just putting the batteries in series. Not sure if the first isolator could act as some barrier on the ctek charging the third battery but it shouldn't I think.

Thanks BB1st. I've been wondering about this myself and I'm trying figure the pros & cons. So with the VSR the crank battery will be charged first and then will flip over to the second battery. In this situation the ctek will never get any power until the first battery is fully charged. I don't know if this is a good thing or not. It does provide an extra point of failure, which is the case I am trying to avoid. Without the VSR, I guess this problem goes away but I'm not sure if this also leaves me vulnerable to other issues, like a fault that could possibly drain both "starting" batteries. Dunno ... for now I think I will leave the VSR in ...

I have a voltmeter on the dash which switches between main & aux batt.
the ctek keeps the aux battery at up to 14v with no real load on it eg no fridge.
usually sits in the high 13v range.

This made me think of something ... if the batteries are wired in series, can you monitor them individually ?

So quinny U want to have a start battery charge first then the vsr charge the second battery and the ctek charge the third battery. So the ctek won't charge unless the vsr is on And second battery is up to the cut in voltage of the ctek.
The first battery and second battery would have too be of the same type but the third could be whatever U
Want as the ctek will automatically detect type and charge is accordingly.
Chuck up a wiring diagram too show what your thinking if this is wrong.

Geeze... I ask questions, to which the answers, lead to more questions ...

That's pretty much the plan hvac ...

I didn't think about a minimum input voltage for the ctek, and couldn't find that info on the web ... What's your view on this ? - reliability being the goal ...

I'm getting a diagram together now ... I may need to ask some recommendations on circuit breaker sizes and where they need to go ...



Thanks everyone

[Cowboy Dave]

I might be after a battery Quinny so if you found one online let me know yeah? Although I am after a sealed AGM item so you might be talking something different.

[Quinny]

^ PM sent Dave ...

Q

[hvac guy]

hey q the cut in is 13.1v and cut out at 12.8v

[hvac guy]

i just a a quick look in your shed for a winch is it in? if so i would use the vsr too charge the second battery
under the bonnet and the run the ctek off that, so the ctek wont charge unless the vsr is on and that the second battery is charged. i would then connect the winch too the second battery so the start battery all ways stays charged when u use the winch. Then once that battery has recharged, the ctek will sense that and will resume charging your aux battery/s in the tub. thoughts ?

ps my gramma is shit sorry.

[big_bob_thefirst]

Hvac opinion sounds good. The cut in shouldn't only impact the ctek as discussed. Once the second battery is over the 13.1v, the ctek will work normally. No difference between running off of the first or second battery. Might just b a slightly longer charge time on the 3rd battery but that's to b expected.

[Snooozy]

I have a voltmeter on the dash which switches between main & aux batt.
the ctek keeps the aux battery at up to 14v with no real load on it eg no fridge.
usually sits in the high 13v range.

This made me think of something ... if the batteries are wired in series, can you monitor them individually ?

yep, that would be easy enough to set up, pretty much the same as I have mine now, just wire the gauge via a double pole changeover switch

[Thommo3337]

If I have a ctek 250s duel and I hook up a 240v car charger to charge the secondary battery would I have to disconnect the ctek unit from the battery?

[Thommo3337]

Sorry guys to be a pain am trying to find out the amp rating of 3b&s cable I have just under 6m to the tray and was wanting to install the right cb to protect the cable etc.

[Snooozy]

Sorry guys to be a pain am trying to find out the amp rating of 3b&s cable I have just under 6m to the tray and was wanting to install the right cb to protect the cable etc.

scroll down to Single Core Battery/Starter, 125A
http://www.12volt.com.au/redirect.html? ... ewire.html

[Quinny]

ps my gramma is shit sorry.

I understood what you meant ...




Yes - the winch is in the bar, but not wired up yet - but that idea has sold me on the idea of leaving the VSR in and running it from the second battery ...

As everyone with a Triton knows, V6 or otherwise, there isn't a hell of a lot of space under the bonnet for another battery.

With the current AUX battery I have - the biggest cranking battery I can fit in the battery tray is L: 231mm, W: 173mm.

I chose a Delkor 55D23L sealed - maintenance free, calcium. CCA 550.

(Now this is a bit embarrassing After googling for the dimensions, I find that the aux battery I am using is a calcium battery, not an AGM which I though I bought ...) Dimensions are: L: 305mm, Width: 174mm. (MRV70 allrounder) ... Maybe the three years of punishment I have given it, isn't that bad after all ...

The first battery and second battery would have too be of the same type but the third could be whatever U Want

So Hvac ... a question - from your quote above, I recon I could get another MRV70... Quick search, for around $200 delivered. (probably could find better if I look a bit harder.) CCA rating for this is 760. Is that what you meant about the same type of battery (sealed calcium ?) What sort of CCA rating is good for a winch battery ?

As usual ... thank you for your assistance gentlemen ...


Q

[Thommo3337]

Thanks Snooozy! Have spent ages pulling the draw system out moving things around changing my mind etc and finally bit the bullet and started doing it just need to find a place to put the CB under the bonnet at this stage thinking of the plastic cover around the battery (bit dodgy but nowhere else suitable) a trip to middeys in the morning and start crimping and shrinking. Then pack for my land based fishing/kayak trip to Green Cape. Million things to do....

[Quinny]

Look what I just got

[Quinny]

This is the circuit breaker I'm thinking of using at the battery in the front ...

[big_bob_thefirst]

Quincy, just a heads up as the instructions r a bit misleading. U need to run a negative from the negative terminal to both the "starter" battery (ur second battery in this case) and the "aux" battery (in the tray). So run a dual core cable from the front to the back so u only have to pull 1 wire.

[big_bob_thefirst]

And u may need a circuit breaker at the the back? Not sure if u can get flow thru the ctek the wrong way from the "aux" battery..???

[Quinny]

And u may need a circuit breaker at the the back? Not sure if u can get flow thru the ctek the wrong way from the "aux" battery..???

Mate - thanks for that ...

This is what I am thinking of running from front to back. I scored 10 metres of double insulated 16 mm^2 for about $50




I intend to put another 40 amp circuit breaker in the back as well, but I need a different design. The one in the pic above ... the orange "reset button" will not be much chop with all the gear packed in the canopy - worried about it tripping. I'm looking for one with a cover or some other sort of functionality ...

[big_bob_thefirst]

I'd get a simpler cheaper thermo automatic reset in the back. If the cable goes, the front manual reset circuit breaker will go, so u'll have a good idea what the problem is, so an automatic reset is a cheaper option.

[Quinny]

Is 40 amp around the right number ?

[big_bob_thefirst]

Depends completely on the wire. Should b enough. I have two 50amps and works fine...

[viking shippy]

If I have a ctek 250s duel and I hook up a 240v car charger to charge the secondary battery would I have to disconnect the ctek unit from the battery?

No just connect the charger straight to the battery as I have done .if you connect the charger to the Ctech terminates it won't charge...

[Thommo3337]

If I have a ctek 250s duel and I hook up a 240v car charger to charge the secondary battery would I have to disconnect the ctek unit from the battery?

No just connect the charger straight to the battery as I have done .if you connect the charger to the Ctech terminates it won't charge...

Thanks mate in all my wisdome I was worried about the 240v through the unit but on the charger the output is 12v dc (idiot I am)
The other question I have with the ctek is if it is 20a unit(pretty sure it is) does hat mean it will restrict the charge off the alternator to no more than 20a?
Going away and am thinking if this is the case I may be better off by passing the unit and charging the battery straight off the alternator to maximise charge half way through the trip instead of driving for 2.5 hours I may only have to drive for an hour to top it up.

[big_bob_thefirst]

Hmm, defeats the whole purpose of having it... I drive for around 15 minutes in the morning and 15 minutes in the evening and run a fridge the whole time. Ctek charges fast enough...

[Cowboy Dave]

If you don't use it how do you know how many amps you'd be getting out of your alternator?

[Thommo3337]

I understand bob but say if u had to charge 100ah half way through a stay do you drive around for 5 hours or charge at say 80 amps and drive around for 1.2hours?