battery regulator help please!

jimbo198966 · Jun 9, 2009

hi guys, i've made a musical suitcases (12v battery, car stereo amp, 6x9 speakers in a retro suitcase

), but i'm trying to 'adapt' solar power into it...
i brought one of these from maplins:
DC 12 V Battery Charging Regulator > Maplin
"Starts charging automatically, whenever there is a drop of voltage "
Great, but it doesn't let the charger charge the battery when the unit (the musical suitcase) is turned off. the charger only charges the battery when the units turned on and the amp is taking power from the battery....
How i've wired it up (how it was described to):

[ElectriciansForums.net] battery regulator help please!

(the charger/solar panel connects onto the 'power input terminals')
Obvisouly the car stereo amp is wired up off the battery, off negative and positive...
The reason why i brought the 'battery regulator' is so the solar panel won't over charge the battery...
If you get me?

Anyone got any ideas as to what i can do?? maybe a different/better regulator someone can reccomend?
Thank you! jimmy
ps be easy on me

boatnik1 · Jun 10, 2009

If the regulator is set to cut in around 12v or less, it will only work when there is a current draw as the usual battery is 13.8v fully charged.
Likewise if the charger cuts out at less than 13.8v.
Acid type batteries are usually down to less than half charge at 12v.

jimbo198966 · Jun 12, 2009

cheers man, what would you suggest i buy? for my 'requirements'?
thanks

boatnik1 · Jun 12, 2009

It all depends on the capacity of the battery and the ACTUAL output of the solar panel. Providing the panel output is 13.8-18v or thereabouts and low current I would be inclined to dump the regulator and just mount a diode on a heatsink (alloy plate) for the Pos line to go through to the battery with the neg line going direct to the battery. Generally most of these solar panels only put out less than 1A so would take days to charge a battery of any decent capacity capable of running a car type amp. Any excess supply would just be lost as heat through the heatsink.
Some panels also don't supply anything like their rated voltage output until they are in bright sunlight so are virtually useless for your purpose. Lets's know the numbers on the components, i.e. Battery capacity/Panel V & A./ Amp current and watts output.

jimbo198966 · Jun 20, 2009

cheers for your help mate
i'm just toying with the idea at the moment. i haven't actually got the solar panel yet, but i'm looking at the 5/6W ones on ebay, copied this from one i've got my eye on "Nominal current: 400mA @ 15V in full sun", "Maximum power 6Wp. "(so it would take around 30 hours to charge my battery?!)
The battery i've currently got is 15Ah (but i'm also looking around for better ones...)
The Amp info:

(thought it'd be easier than explaining it all!). Maybe i could get a lower ampage Amp?
And you'll have to explain to me about the diode on a heat sink bit (like specifically what bits to get and from where (i'm guessing maplins?))... i'm totally new to that kind of electrics!
Cheers dude, jimmy

boatnik1 · Jun 20, 2009

You need to establish the purpose and viability of this kit, it just doesn't sound worth the effort. To work the amp you need a voltage of 13.8 and a current of 15A so given that the efficiency of the amp will rapidly fall as the battery discharges you would be lucky to get half an hours running out of the battery. The panel output is in strong sunlight so unless you are at the equator you are unlikely to get more than an hour or two max daily on average and none at all for most of the year, so the charge time is probably a couple or three weeks rather than a straight 30hours. For that sort of output ordinary radio type diodes would be OK. You'll find them in any scrap piece of radio/video or similar kit, they are typically from about 10 to 20mm long and black with a silver line around one end to signify the direction of flow. A heat sink would not be needed for these types. Maplins can give you the correct ones if you want to buy them, they are only a few pence each. Better just to think about a car type charger and charge the thing up over a couple of hours. If you are useing a gel type battery you'll find a lot of them get dumped by date rather than condition at your local recycling depot.