Charge controller 12v panel, output 6V 1A

Mothernatura

Hi everybody,
Does anyone know some solar charge controller that can be powered by 12v panels to charge 6V batery. Battery charging current LIMIT on the specs says 1A.
I've spent hours googling but find nothing useful, most chargers are 110/220v, or come with their own solar panels, or charge 6V batteries at 3A. I'm terribly frustrated that I can't find a decent product for such a simple need.

I already have 2 12v 85w panels, a morningstar sunsaver mppt charge controller and a 12v battery, all work good. But the controller does not accept 6v batteries.

Now I have three 6v sealed batteries that will be used in series to reach 18v, but can't find an easy way to charge them in an intelligent way... I could charge 2 in series, but then the third one discharged would have to be charged in series with one of the already charged and I don't think that would be appropiate.

Any clues or brands to suggest?

Thanks. Paul.

BB.

Re: Charge controller 12v panel, output 6V 1A

There are random units out there like this one:

http://www.amazon.com/TruPower-6V-Solar-Charge-Controller/dp/B009B03SCC

And I found some on Ebay.

You could possibly make a 7.2 volt (or whatever) shunt controller by using an adjustable 3-T (three terminal) regulator and a heat sink.

Basically, the regulator would be off until 7.2 volts is reached. Then the regulator turns on and dumps any additional current to ground -- And heating the regulator by Amp-Input*7.2volts=Watts out heat sink.

You are correct that you do not want to put batteries in series that are charged to different levels. The ones that are fully charged will be damaged while the lower voltage ones charge.

One comment in the Amazon controller (not great reviews) said there was a guy on EBay that would make custom charge controllers based on your specs... ???

-Bill

icarus

Re: Charge controller 12v panel, output 6V 1A

Belieing my own ignorance, w by wouldn't an MPPT controller simply down convert to 6 volts? (assuming you could adjust the output to reflect the lower voltage battery. My guess is that the programming doesn't go that low)

Tony

BB.

Re: Charge controller 12v panel, output 6V 1A

That and most MPPT charge controllers appear to draw their power from the Battery Side of the controller... And a few I have seen have stated that they need something like 9 volts to "start" (and why they cannot charge a completely dead battery").

-Bill

icarus

Re: Charge controller 12v panel, output 6V 1A

Good point, yet once again Bill,

t

BB.

Re: Charge controller 12v panel, output 6V 1A

And, I just remembered/added to another thread--If you are into DIY electronics (do it yourself), there are solar chargers on chip that may work:

http://www.ti.com/product/BQ24650
http://www.ti.com/tool/bq24650evm-639

Thank again to "Sun Dog" for finding that part.

-Bill

CDN_VT

Re: Charge controller 12v panel, output 6V 1A

Three 6 Volt to make 18 volts , so your system is a 18 volt in series used.

I would use a buck converter from 12v to 20+ , that is adjustable , & with a timer.. One other way might be a 18 V black&decker charger , hacked open to/so modifiable. (Some assemble is required +++) they supply 21.6v DC to the system after the AC is converted to charge the 18 v Ni-cads ..

But I have seen smoke get away on my trials .

VT

PNjunction

Re: Charge controller 12v panel, output 6V 1A

How about this hack:

Hang a small psw AC inverter (like a Samlex or Morningstar) off your 12v battery. Then use a 6v maintainer, like a Noco Genius 1100 or perhaps a Deltran 6v Battery Tender, or maybe a BatteryMinder 6v/1A for 6v charging. These are typically .750 to about 1.1a output. I know the Noco is a high-frequency switcher, and not a linear transformer charger.

Ok, so not the most efficient thing in the world, going from dc > ac > dc, but I suppose that depends on your setup.

The main thing to watch for here is that while this 6v charging setup is attached to your 12v solar battery setup, the 12v CC may never get out of absorb while the 6v inverter/charger load is attached to it.

Not pretty, but might be smart enough.