Backyard Aquaponics
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I want to test my new solar panel, and I understand I can connect it to my stinking great big, 12 volt deep cycle battery, but it seems strange to connect a 37 volt thinggy to a 12 volt thinggy.

Can someone confirm that I really can do this.

I'll be running an electric trolling motor (in a tub of water) from it and standing next to it to watch the charge of the battery and see what speed setting I can run it at to keep the battery near full all day, so I'll be keeping an eye on the charge state of the 12 volt battery.

Explosions are fun!

Seriously though, no. You will need to buy a controller for it.

http://www.ebay.com.au/itm/B02-Solar-Regulator-10A-12V-24V-Controller-Panel-Charger-Battery-LED-Indicator-/290683579500?pt=AU_Solar&hash=item43ae176c6c#ht_6861wt_907

That is assuming it is a car style battery. One that can be charged on a car battery charger. Not LiPo etc.

Lead acid 120amp hour deep cycle

Any advice on a charge controller?

Youl need a solar regulator. Pretty cheap check out ebay. Most camping solar panels come with regulators so you could try your luck at camping stores.
From memory lead acid dont take kindly to anything over 14.4v or so.



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At a quick glance, the one i posted to above should do the trick. Check ebay, they are as cheap as chips. Or if you are from my generation and have to have it now, a local camping/super cheap auto style store will most likely have them.

I was under the impression that the voltage would be drawn down by the battery, and that 14.4 volts was what the battery should not exceed, not the charger.

I thought it was all about amps, and my battery can cope with 8 amps.

I think a lot of stuff.

Perhaps today is a bad day for this...

I didn't even notice your link

Thanks

That charger rsevs3 linked to I am pretty sure won't work.
Its auto switch between 12 and 24v. You have a 24v panel and so far a 12v battery.
Most likely its going to try and charge your battery to 26v!

Normally you would use a panel with a Vmax of about 19v for a 12v system. You are going to have to look for a charger that can handle an input up to 37v but charge a 12v battery.
I'm not aware of any that do this.

Edit:
OK perhaps not a charger, but this will probably do you.
Most regulators like that put out 13.8v even tho its listed as 12v. So if it does it will float charge your battery without issues.

Yep Privatteer was right on the one i posted before. Like i said, quick glance.

A quick bit of google suggests that the type of magic black box you want is a Maximum Power Point Tracking controller (MPPT). As per this web site.

http://www.ebay.com.au/itm/MPPT-10A-Solar-charge-controller-100V-lcd-meter-12V-24V-auto-Tracer1210-/250955548812?pt=AU_Solar&hash=item3a6e1dc88c#ht_5048wt_1165

That one doesnt seem to clearly indicate that it has to be 12v panel for 12v battery. Maybe just message the seller

this one will do it.

http://www.ebay.com.au/itm/mppt-solar-c ... 682wt_1257

Regards - Colin

or.... you could build one

jk

I got some advice that some panels have a 2 x 12 volt option via some contacts in the back.

Mine has a small black project box on the back with 4 contacts so there is a chance that that's where the 12v to 24v bit is done.

If that's the case, I think I should be able to rearrange the contacts into twice the "somethings" at half the voltage.

Would half the voltage still be too high to connect directly to my battery?

14.8v is too high to leave it on permanently but fine for a quick charge. If the battery is flat it can be done short term if monitored but if left on it will basically start to slowly cook.
Float voltage is about 13.8v so I would still be using a charge controller. Batteries are not the cheapest thing to be replacing.

That said is the battery just standby, used 24/7 etc?

Even if you could connect it directly to the battery, what happens when the solar panel isnt producing full output and the voltage drops off?

Listen to what everyone is telling you and get a regulator