Deep cycle battery

Lizz · Member

Deep cycle battery

hako · Guru

My opinion only, but I'd say a 20 watt panel will be sufficient to keep the battery fully charged especially seeing as you only have minimal drain on it. I presume the panel has a regulator and if not may I suggest the one bvelow which I've recently bought. You also should never allow a battery to get fully discharged - this kills them big time. You can spend a lot of money on panels and regulators but I reckon keep it simple.
http://www.ebay.com.au/itm/SOLAR-PANEL-BATTERY-REGULATOR-12V-10AMP-/111540293881?pt=AU_Solar&hash=item19f851d0f9

Good Luck.

Jaahn · Guru

Lizz wrote:
Hi there,
I have recently bought a deep cycle battery for my little camper trailer. I have no fridge, only use the power for charging phone and tablet, fan and LED light. I do have a little solar panel (only 20 Watt), and am going away just for a week soon.
Do you reckon that would be enough? and do I just always have it hooked up? Or do I wait until the battery is flat to charge? Should I have a regulator on it?
Do I bite the bullet and get a 120 Watt solar panel ? ( I am planning to grey nomad it in the future)
Thanks
Lizz

Hi Lizz,

Not sure what the size the deep cycle battery is but here are some thoughts.

Always use a regulator on the panel. A small one is very cheap and easy to wire up. Keeps the battery from being overcharged. Put it close to the battery.

Do not use the battery till it is flat. As Hako said also it is very bad for them. If you wire your usage from the regulator output terminals it can also protect the battery from being discharged too low.

The 20W panel will probably do what you want in sunny weather. If you put longish wires on it then you can put it out easily in the sun when you stop. I have found a 120w panel is hard to handle. Two smaller ones eg 2x 60w are much easier to handle if you want to have loose panels. Long wires too and a long small cable and lock through a hole in the frames for peace of mind smile To make it better put a plug and socket on the panel wire so you can seperate it for storage and it makes life a bit easier.

jaahn confuse

PS now might be the time to buy a regulator which can handle the bigger panels. It will be OK with the small one now and leaves some room for more panels when the budget allows biggrin

-- Edited by Jaahn on Sunday 7th of December 2014 11:06:37 AM

Stratman77 · Senior Member

I agree with the comments above, but not knowing the capacity of your 'house' battery and the need to protect it from over discharging you might consider fitting a battery discharge protector similar to this one if you don't have a suitable solar regulator:

www.ebay.com.au/itm/Battery-Discharge-Protector-12v-20amp-/321272973886

moblet · Senior Member

Jaahn wrote:
now might be the time to buy a regulator which can handle the bigger panels. It will be OK with the small one now and leaves some room for more panels when the budget allows

If you get a controller with sufficient capacity then scaling up will be very simple when the time comes. You could also continue using your 20W panel in conjunction with any additional ones you buy. For an ultimate solar capacity of 120-150W you'll need a controller rated to 10A or above.

As others have advised the best way to manage lead-acid batteries is to keep them as fully charged as possible for as much of the time as possible, so ideally you'd have the panel hooked up full time, including when the battery is not in use.

oldtrack123 · Guru

HI

A 20W panel will at it's best ,when located in bright sun, put out ONE amp

That equates to not much more than 6 Amphrs per day

In fact a 20W panel will do little more than maintain a battery fully charged . provided it has no load on it

I would suggest at least a 40W panel make sure it is suitable for battery charging[ spec with a Mpp around 17V @ 2.3A]

Yes, you must have a regulator & leave the battery connected at all times

If a portable panel, you wil get substantially more charge into the battery ,if you regularly reposition the panel so it faces directly into the sun.

Do not over discharge your battery ,that will shorten it life

You have not given battery, flooded wet cell? AGM? type or size, but generaly for long life ,with those sorts of loads they should not be taken much lower than 12V

A low battery cut out is ideal ,a simple volt meter can be used to check battery voltage, which is best done first thing in the morning

Y

PeterQ

Lizz · Member

Thanks everyone! Who needs Google, eh?