One for the 12v Pro's

When you say remove the solar controller, do you mean the regulator. Why would i have to remove this?
Cheers
Eli

hi John,
The current system does work. What brought me around to thinking of change , was the fact that i have recently forked out a bit of$ for my 2 new AGMs. I want to nurture these little babies, and i have read they do not like to be over charged(like any battery i suppose) This isnt a problem when i am at home as i have a 25amp CTEK. But i was more thinking when travelling on trips. With the set up i have now, there is nothing to monitor the state of the batteries and reduce charge if needed, and for what i can see overcharging batteries and nuking them, doing damage. This is wheree i think this Ctek device comes into play.
Are there advantages of running solar panel into this CTEK device, over your normal panl/regulator set up.
cheers

My solar panel has one of these on it:
http://www.phocos.com/datasheet_cc_ciscu.html

Hi Eli,


The ctek DC250S comes in 2 flavours. I assumed (incorrectly ?) that you were referring to the DC250S Dual which includes a good solar controller (= regulator) as well as the dc-dc charging management. As you already have a good solar controller you don't need that capability in the ctek. The cheaper version without solar capability would be fine and you would continue using your existing solar controller. I mentioned the need to bypass the present controller because if you used two controllers with one feeding the next feeding the battery, they will interact and behave unpredictably.

Regarding overcharging batteries - At present your batteries are being charged from the vehicle alternator. It will not deliver excessive charging because it's voltage output is controlled to a suitable level. In fact your deep cycle batteries would benefit from a slightly higher voltage than that coming from the alternator. There is also voltage loss in the wiring, no matter how big the cables. (Voltage is the "pressure" that pushes charge into your batteries. Current (amps) is the flow of that charge.) The purpose of a dc-dc charger is to increase the available voltage so as to increase the current flowing into the battery. In addition, the ctek provides the battery management now needed to ensure that it doesn't overcharge the batteries. Your solar panels can deliver higher voltages themselves, so the solar controller (regulator) is there mainly to protect the batteries from overcharging. It is important to have one for this reason, though some of the better ones also convert the voltages so that conditions are optimum for both panels and batteries.

HTH

Cheers

John

Hi John

So basically if i was to change to Ctek (to replace car iscolator)i would only be tweaking the system to make it a little more productive and effective. Would i be right in saying the ctek system would better use the power it is fed, meaning better(faster) charge times.

On the Solar side:
Would the solar controller on CTEK be better than the one on panel now.? If so what are the advantages?

Sorry for all questions, i did read your blog and it does seem i have attracted the right person to give me advice so i will pick your brain whilei have your attention. LOL.

Hi Eli,

Happy to help if I can!

Why change to the ctek dc-dc charger? It will ensure that your batteries are fully charged, which both makes full use of that expensive storage cpacity and extends their life span. (Just how much extra charge you store is hard to judge - depends on the charging voltage from the alternator, which is optimised for the starting battery whose needs are different from those of the deep cycle batteries. That voltage is also determined by temperature, again, to suit the starting battery.) The ctek should deliver a full 20 amps whenever the engine is at fast idle speed or more - that's considerably more than you will get most of the time with your present setup. The ctek also includes a replacement for the isolator you already have so that's no advantage, other than saving the effort of removing it and refitting to your new vehicle.

I think one of the major advantages of using a dc-dc charger is the ability to put in a decent charge (20 amps from the ctek 250) at little more than idling speed. It doesn't seem very green to run the engine just to top up batteries, but if the other option is to carry and run a generator, I think using the generator that's already under the bonnet is a very cost effective way to go.

Would the ctek provide a better solar controller than you already have? From the specs I'm not sure whether your present one is an MPPT gadget. It looks a good unit, but MPPT (Maximum Power Point Tracking) allows the panels to operate at their optimum. I'll look further into it, or maybe someone here can comment. (We are talking about the Phocos CIS controller. It's referred to as pulse modulated and since they also offer an MPPT controller, I suspect that this one isn't MPPT, though still a seriously good bit of gear.) The ctek "dual" version does include an MPPT controller. This will deliver around an extra 25+% over a non-MPPT controller, but then, maybe you've already got one of those!

Cheers

John

just look at specs again (Phocos) and it says it has PWM regulation. I think you can only have PWM or MPPT> This article talks a bit about both:

http://www.morningstarcorp.com/en/support/library/MS.WP.MPPTvPWM.01.EN.pdf