Thread: 12 volt camping

Originally Posted by Gullible

Well I'm starting to get adventurous.

First the engine saver, then the up-graded wiring loom and now the solar charger for the car battery. All this has got me thinking.

Could I take the solar battery charger with me camping and charge up a 12v battery for lights, shower, etc?

What would be the best type of battery for the constant drain of a 12v fluro light (physical size does not matter as it will be going in the trailer)?

Also, can anyone recommend a make/supplier of solar panels? There seems to be a big variation in price. I was thinking around a 40 - 60 watt panel.

I'm only doing this because I enjoy crimping wires.

if its only for lighting, charging a mobile phone or 2, a shower pump and maybe a dvd player, almost any car battery will do you if you have a 60W panel to top it up.

I suggest you get one the same as whats in the tow vehicle so if the car battery dies you can swap them over.

Are there any safety issues with using a lead acid battery? Would a different type be better/safer?

Lead acid batteries are safe enough if properly secured and fitted to a tray that catches any spillage. They are often available second hand, removed from emergency power supplies. Example:

12 VOLT 110AH DEEP CYCLE/START BATTERY | eBay

You can purchase lithium ion batteries now but they are many times the price of lead acid. They are less than half the weight for the same capacity.

Basically you purchase a solar panel from a shop, with a warranty, or trust your luck on the internet. Jaycar is one source of panels, a 12 volt shop is another. Chinese el cheapo panels will work well enough if you don't have the panel outside permanently.

I havent had any hassles and I pretty much exclusively use stock flooded cell batteries.


ball parking....
you need to know 3 things.

1. how many amps your going to draw for how long

The small fluros I use draw about 1.1A, I have 2 of them and they both wind up being on for about 4 hours thats 8.8Amp hours (2*1.1A*4hrs) I also use my phone charger for about 30 minutes a day and it burns up about another amp. lets just call it 10Ah worth of Draw a day (always round draw numbers up)

2. the Reserve capacity of your selected battery


I use n70's they generally have a RC of 95minutes This works out as (25*95/60)=39AH (I'll explainr RC later always round storage capacity down)

3. the effective Ah of your panel

for a 60w panel thats a 5amp supply at 12v (amps is watts/Volts) and you multiply that out by a bunch of other numbers that basically translate how effective your panel is at producing power from the sun... drawing a line across the map of australia my ready reckoner is

Melb - 4 hours
sydney 5 hours
Townsville 6 hours

so in melb you'll get maybe 20Ah out of the panel... (always round this number down)


If you were looking at running a fridge and more accessories for a longer period Id have probably suggested a deep cycle battery but pretty much multiply you expected draw at 12v in amps by the number of hours you expect to draw it and if the reserve capacity (which is how long the battery can pump 25 amps for before dropping below about the 50% charge state) is 50% over that your apples.

Yeah, Lead Acid batteries are safe enough unless your an idiot like me.

Lead Acid battery on charge makes hydrogen gas (an explosive when mixed with Oxygen)

So there I was in the shed with the Oxy Accetelyne torch, & being the lazy sod that I am could not be bothered getting a new flint for my lighter so next best thing I made a bad habit of sparking the battery charger leads together to light the torch.

You know what happened next - KaaAABooOOM

The only thing left of the battery was the bottom casing and the lead plates, I was totally covered in Sulphuric Acid, no eyebrows or fringe and was deaf for the rest of the day, (the front of my overalls totally disolved over the next two days) I still cant hear properly, at least I think my Defender is quiet.

Originally Posted by goingbush

Yeah, Lead Acid batteries are safe enough unless your an idiot like me.

Lead Acid battery on charge makes hydrogen gas (an explosive when mixed with Oxygen)

So there I was in the shed with the Oxy Accetelyne torch, & being the lazy sod that I am could not be bothered getting a new flint for my lighter so next best thing I made a bad habit of sparking the battery charger leads together to light the torch.

You know what happened next - KaaAABooOOM

The only thing left of the battery was the bottom casing and the lead plates, I was totally covered in Sulphuric Acid, no eyebrows or fringe and was deaf for the rest of the day, (the front of my overalls totally disolved over the next two days) I still cant hear properly, at least I think my Defender is quiet.

Sorry to laugh, but I unwittingly did something similar.
I started my angle grinder, KABOOM and made a quick dive for the pool once I realized WTF had happened. Likewise, overalls U/S and battery in pieces, luckily no major skin or other body damage. Battery was an almost new N200? - one of a pair of HD truck batteries. Ironically the other battery didn't blow.

This is so much fun.

I've made the solar charger with regulator and it works a treat.


Now I have ordered 2x 110Ah deep cycle gel batteries with the intention of connecting them to some 12v led lights (and may be a water pump if funds allow).

How should I connect them together?
Do I need to put anything other than a wire between them? I've heard talk about diodes and they puzzle me?
How can I stop them running completely down when in use? (I've heard that it is not good to run a battery completely flat)
When charging them with a car battery charger do I need to disconnect them or can I charge the two together at the same time?