Further to Dave's remarks about the charger I'd strongly recommend as a start point using a "smart charger" if you don't already do so. I would also recommend not fully discharging the battery even though it's a deep cycle unit as this will in most cases considerably reduce the life of the battery. While some types of batteries are more tolerant than others I still consider this to be good overall advice.

I use a 7 amp Cetec charger but there are many similar units on the market now and a higher capacity charger may be a better option for 100 amp-hour or 150 amp-hour battery. Check out http://www.bainbridgetechnologies.com/chargers

I also have a low voltage cut-out installed to shut off the supply when the battery is getting low, check out http://www.bainbridgetechnologies.com/12v/baintech-low-voltage-cut-out-40amp

Both these products are sold by Battery World but there are many other suppliers as well.

Other members of this forum will probably suggest solar panels and I'll leave it to them as my knowledge of solar is more theoretical than hands on.

John - I see that you only have a small van and a larger battery may go towards overloading it.

Do you wish to sit for more than 3 weeks in the one spot? If not then you are better off charging it as you travel. Install a battery booster, RanOx or similar. You connect this through to your alternator with heavy cable. There is no need to fit a battery management system to your tug as it is built into the RanOx.

The RanOx is programmable. You can set the absorption and float voltages in 0.1 V steps and the maximum bulk current in steps from 5 to 25 A. It will thus suit any battery. Its output is the same as a three stage charger so you will be able to fully charge your battery on the move. I use one and I can disconnect my solar and 240 V battery charger and run the van with very little discharge of the battery provided every 5 or so days (and we are fairly heavy users of 12 V power.)

Roamin I just reread your post and to answer your original question I think it would last 4 - 6 weeks with only light usage, I have two batterys on board little blue, 1 cranking and 1 100amp standard battery for powering up the "home"

neither of these is deep cycle, I find that my batterys last about 2-3 years without needing replacement and have yet to find a good reason to expend the extra dollars on gel or deep cycle,

I just replace the normal batterys at about $120 each, this set of Batterys has lasted me for 4.5 years, and touch wood they will continue a while longer, but if they ceese operation tomorrow I have well and truly got my moneys worth

I use only a 100watt "briefcase" solar panel to recharge the second battery when standing and thats running a 40 litre engel fridge and lights

I can stay out indefinately or at least until the tucker runs out, never had a battery problem!

I have an 240 volt auto charger on board for when I'm hooked up and a battery isolator for when I'm travelling

Daryl is oatley electronics online, i wouldnt mind getting one of those panels, thats a pretty good price, my briefcase solar was just under a thousand! with mates rates

thanks Daryl, I'll look into that!

yep thats right, dont mix the two!

I cant see the setup Dave as my computer has blocked all piccys again for reasons better known to itself

the battery solution issue tends to get a bit over complex and look thats fine provided simple and easy solutions are placed out there as well, we could quite literally go on and on for weeks describing varying setups from small and simple, (a battery from a car), to huge and expensive involving many solar panels and huge ammounts of batteries that would power small cities

I like to push the barrow of a "common affordable" ground, simply a battery capable of powering a small campsite and a means of recharging it, in this case a simple off the shelf solar panel and a solenoid isolating system

I like the input from fellow travellers as to what they use as it is a means of getting "real life" power solutions out to the masses after all most folks can afford a reasonable size battery and a 100 watt solar panel

and you are right the battery posts are one of the most popular but look thats fine, everybody wants a little bit of power at their campsite whether it be for just lighting or to run a fridge, stereo, and lights, gone are the days of the tent and a torch with a bag of ice in an esky thank god

we will continue (I hope) to just keep giving out info that will benefit the majority and at the same time cater to the larger power users with descriptions that I can only drool over and hope one day to understand, at the moment it's all gobbldy gook to me, i know the basics but thats it!

Your right there davo6, the simple things in life are the best.

some seem to go way over board with complicated systems that they dont understand how they work or even what it should be doing .if you are going to have one of these you need to study & learn the system & be able to deal with it & thats good .

I too believe in the KIS principle but unfortunately some of the issues around operating multiple battery systems in conjunction with multiple charging sources can be a bit more complex than we'd like them to be. On the issue of mixing battery types this should not be a problem provided that the batteries are isolated by using a proper dual battery system and that the batteries chosen are suitable for the installation, this can be an issue with calcium and some gel batteries. It would seem to me that using a box such as the Ranox would one way to simplify this as one can connect all the thingies to the box and the smarts inside the box will sort it all out.

Re mixing batteries, I personally never advocate just wiring batteries in parallel, even identical types. Many years ago I did this in a standby generator system and I observed first hand the reduced battery life as a consequence. I replaced the two parallel wired 12v batteries with two series wired 6v units and there were no more problems.

Using "wet" (or "flooded") batteries does have some "downsides"....some of these are...

The need to more strictly limit the discharge depth to avoid reducing the battery life. This significantly reduces the usable battery capacity.

The need to more regularly recharge and/or float charge the batteries when in storage.

The need to remember to regularly check the fluid level in the battery cells.

They cannot be installed inside the caravan or vehicle cabin.

I'm not suggesting Do or Don't use wet batteries, just take into account these factors.




-- Edited by jimricho on Friday 8th of January 2010 08:06:37 AM

I too use a wet battery for my auxiliary in the car to power my fridge (Bushman). It sits beside the starting battery and is wired through a "Rotronics" isolator. As the car is used almost every day it is kept charged. I also have a small "smart" charger installed and from time to time I plug this in to "top up" the battery, especially when in a caravan park where it also serves to power the fridge.

The battery in the van is an Optima Red Top that is now almost 8 years old and still performing satisfactorily. I only charge this off the mains via the Cetec as to date I haven't needed to charge it while travelling......Yes, it's a Red Top starting battery but it works fine as a deep cycle unit.

Several years ago before many of the newer sealed batteries became readily available a former 4wd tag-along guide I know found that Yuasa Overlander 4wd drive batteries were a better option for auxiliary battery use than a dedicated deep cycle battery. The main advantage he found was that they recharged much quicker. Note that I haven't tried this myself so I can't give this a first hand endorsement.

no worries roamin, I like to keep it simple as i possibly can, i hope you got the info you were after as well as little bit of knowledge about deep cycle at the same time, it's all good!

Hi Justcruisin, The arrangement you describe is quite common in boats, in fact I bet your changeover switch is one built for marine use. You obviously have a good "handle" on how to use this arrangement and it works for you. There is no better test.

I wouldn't recommend this arrangement for those who are not so "au fait" with auxiliary battery issues and here I'm referring to the more usual set up of a main for starting and auxiliary for a fridge. Also I don't think it's very practical for "on the road" charging of a caravan battery.

ROAMIN wrote:

---

Hi Guy`s
The reason i asked about the battery was the battery i have is 5 year`s old and came with caravan new at that time and do not know life of battery.
But i like to keep it simple i have sat for 3 weeks just using lights and when i have gone to c/park charged with 240.

Cheer`s Roamin.

---

Hi Roamin,

Sorry, should have posted this earlier before we drifted too far into the technicalities (guilty as charged ). If the battery is a "common or garden variety" wet battery, after 5 years it is quite possible you are getting nothing like its full rated amp-hour capacity. A larger amp-hour capacity unit should give you some extra "endurance" if this is all you require, subject to there being no physical limitations such as size and weight. If your requirements change then many of the other previous comments may apply.

That said, I would still strongly advise installing the low voltage cut out mentioned earlier as totally discharging a 'wet' battery (and others too) will not only reduce its life span but its amp-hour capacity as well. Other requirements previously mentioned such as using a "smart" charger (you may already have one of these), regularly checking the electrolyte (fluid) levels and topping up only with demineralised (or distilled) water, and regular re-charging or float charging the battery still apply. If the LVC saves just one battery from an early grave it has more than paid for itself.

Techie note: the Baintech LVC has a residual current < 10ma in both on and off states, less than the self discharge of many batteries so this is not an issue. It also has a time delay to prevent false triggering due to in-rush currents of fridges, fluoro lamps etc.

 

-- Edited by jimricho on Sunday 10th of January 2010 06:55:00 AM

That problem hapens quite often Dave had to rescue vehicles like that quite often, if you chek witha hydrometer they are still charged but develop a faulty conection betwean cells. Ocasionaly when this happens & you goto crank the engine it will arc betwean cells & the battery explodes very messy. Never had a prob claiming warranty. Daryl