Using high output panels on a 12v system, is it possible?

[acid_clown]

Hi,
I have access to a few trade price solar panels from a friend. The panels vary from 235-250watt with voltages from 36.5 to 52 depending on manufacturer. I want to use some of these panels to charge a 12v battery+inverter off grid system that I already run in my truck. What would I need to do to charge a bank of 3 12v batteries? I assume I would need some sort of gadget that turns the high voltage into 19v or so and have that gadget inline before the charge controller?
I currently run lights, pc, music studio, and occasionally a 0.7kw soundsystem, so I could do with panels to top up my batteries instead of running my engine for an hour every couple of days!
Any help would be well appreciated

[Sunking]

Running the engine will be a lot cheaper.

[Mike90250]

Welcome.

The "gadget" you need, is called a MPPT charge controller.
Morningstar, Blue Sky and Rogue make small and medium size ones. Xantrex, Midnight and Outback make larger ones.

You may be better off exchangeing the high voltage panels, for 20V panels, which are more often used to charge 12v systems. The wider the gap between the panel voltage and the battery voltage, the more power is lost.

[Sunking]

The "gadget" you need, is called a MPPT charge controller.

You may be better off exchangeing the high voltage panels, for 20V panels, which are more often used to charge 12v systems. The wider the gap between the panel voltage and the battery voltage, the more power is lost.

Not true with MPPT

[acid_clown]

So would something like this be what i want if i have 2x 250w @ 50v panels :

Electrical Data
Efficiency 97,5%
Nominal Voltage of Battery 12 or 24V
Maximum Charging Current 20A
Battery Voltage Range 7-36V
Max. PV Off-Load Voltage 75V
Typical Generator Output 12V 300W
24V 600W
Digital Output 100mA
Consumption of Auxiliaries 27mA

The thing thats throwing me is the "typical generator output" WTF is that?

Considering I can get these panels at a third of the market value, Im happy to spend an extra

[acid_clown]

Although this looks more like it would do the job better, but I'm no elec whizz!!

Technical Data
MPP voltage > 17 V > 34 V
Open circuit voltage module < 100 V < 100 V
DC output data
Charge current 20 A
Load current 10 A
End of charge voltage 13.9 V 27.8 V
Boost charge voltage 14.4 V 28.8 V
Equalisation charge 14.9 V 29.8 V
Reset voltage (SOC/LVR) > 50 % / 12.5 V (25.0 V)
Deep discharge protection
(SOC/LVD)
< 30 % / 11.5 V (23.0 V)

I'm not sure what this board's stance on posting links and naming brands etc is, so im trying to keep it bare bones as possible! I honestly want to find out some strong advice, but dont want to be accused of spamming, its such a hard life isn't it!!
Thanks

[Mike90250]

[QUOTE=acid_clown;33397]So would something like this be what i want if i have 2x 250w @ 50v panels :

Electrical Data
Efficiency 97,5%
Nominal Voltage of Battery 12 or 24V
Maximum Charging Current 20A
Battery Voltage Range 7-36V
Max. PV Off-Load Voltage 75V
Typical Generator Output 12V 300W
24V 600W
Digital Output 100mA
Consumption of Auxiliaries 27mA

The thing thats throwing me is the "typical generator output" WTF is that?

Considering I can get these panels at a third of the market value, Im happy to spend an extra

[acid_clown]

That is a Soltronic MPPT 7520 controller. basically, I have gone round, found a few controllers that I think would work, but if anyone out there is running a system using high voltage panels to charge a 12v battery bank then I would love to know what is the best way to do it. cheers

EDIT: people that are bad at engrish usually have small fingers for doing fiddly electronics with! haha

[Mike90250]

i don't know anything about Soltronic controllers.

I do know there are a lot of "box of crap" controllers that have a MPPT sticker over the PWM tag, and are a total rip.

Morningstar, Blue Sky and Rogue make small and medium size ones. Xantrex, Midnight and Outback make larger ones.

I've also heard Steca is OK too. Anything else - you are on your own. Maybe look at the reviews in amazon ?

[acid_clown]

ok, thanks for the help Mike, I'll do some digging around

[Wy_White_Wolf]

[QUOTE=acid_clown;33397]So would something like this be what i want if i have 2x 250w @ 50v panels :

Electrical Data
Efficiency 97,5%
Nominal Voltage of Battery 12 or 24V
Maximum Charging Current 20A
Battery Voltage Range 7-36V
Max. PV Off-Load Voltage 75V
Typical Generator Output 12V 300W
24V 600W
Digital Output 100mA
Consumption of Auxiliaries 27mA

The thing thats throwing me is the "typical generator output" WTF is that?

Considering I can get these panels at a third of the market value, Im happy to spend an extra