Deep Cycle Battery charging

There are heaps of issues with putting the battery in the van, did you get some advice before doing it.

Do you have a 12 volt power supply in the van. Other than the battery that is?

You will need a "Smart Charger" They will cost anywhere from 200 to 300 dollars for a half decent brand, but I suggest some professional help with the set up.

Barry, Have a look at the ctek from sweden. All fully auto to keep the battery in good fully charged condition.
go to www.ctek.com

Hi Barry

There are many automatic chargers that will charge your battery effectively , like the Ctek already mentioned and the key thing is that they monitor the battery voltage and reduce the charge
to a floating or long term charge voltage when the battery requires it.
This is what your woolies one doesn't do!


You have probably read about those with 3 or 4 or more stages and these work well usually but what you pay for is a faster charging time and not in your words "max efficency".
Fast charging usually means more control electronics and protection circuits.

Many such chargers also have more settings for the finer differences between battery types and can even monitor the batteries temperature as it charges and compenstate for it further
quickening the charge time.

But I'll assume you want something pretty basic - just connect it up and forget and at a reasonable price.

Hence I suggest a Jaycar MB3612 retail $99 as a good workhorse, which is sized well for your battery.

If you want something fancier with more features then go for there MB1620 at $169

Have alook here:
http://www.sidewinder.com.au/product5.html

I have one of those blue coloured (the 15 amp version) ones in my camper trailer and another one in the back of my Patrol.

You may also want to consider fitting one of these:
http://www.arrid.net.au/twin.html
These are great for supplying a 20 amp charge from the tow vehicle, without having to use really heavy cable.

Roachie

Barry,
you say: ""We have *NO* means of charging the battery *UNLESS* we are on a 240v powered sight""


Do I understand you can ONLY recharge from 240v
.... and NOT from the Alternator while driving ??

Mainey . . .

Barry,

As advised above, get a 3 stage. Or to do it on the cheap, Projecta Charge Controller BM 140, is a device that you fit (easily) between your old charger and the battery. It is a two stage device that swings into float mode to stop overcharging occurring. I've had one for ages, works well. About $50.

Trickle chargers are bloody dangerous. They continue to put charge in when it is not needed. Think of it like a dripping tap into a bucket. Eventually the bucket fills and then overflows. Problem is with a battery, it can't overflow effectively.

Result is with conventional wet cell batts they boill dry, and AGM's simply expand and swell, rooting them. Chris at Battery World, Wantirna, has told me stories of having to smash cupboards in Winnebago's to get swollen AGM's out that have been "trickle" charged.

Jim.

Hi Barry,

I have been looking at all the issues of dual batteries in the tow vehicle, and batteries in the caravan for quite some time now. I am about to pick up my new caravan and like you we are looking at a mixture of free camping and caravan parks.
I think I am now at the stage of knowing what I don't know, which I think is healthy.
If the van does not already have it, my recommendation would be to install a CTEK or equivalent "smart" charger either a 7 A or 25 A version depending on your budget. I happily got away with a 7A version in my last van but we did very little camping where there was no power.
Bainbridge Technologies are the Australian agents:-

http://www.bainbridgetechnologies.com/index.php?page=catalogue&cid=63&local=yes

The CTEK charges also have a "supply" mode but can be left on "float" indefinately.

Now charging the van battery when you don't have access to 240 V ac is a whole different matter.
Three normal methods (or combination of all)
Solar with quality regulator
Generator
Tow vehicle alternator
The first two have the capability to fully charge your battery. The third, under most circumstances can't.
At the moment I am researching the best way to maximise charging the battery in the caravan from the vehicle's alterantor and looking at battery to battery bosters/smart chargers such as made by RANOX and Sterling.
So far, by actual practical testing, I have found that my vehicle's alternator puts out about 14.2 V DC when first started and the engine is cold. After about 20 minutes or so of driving the output drops to 13.69 V DC. This I a believe is due to temperature compensation in the alternator to prevent overcharging/damaging the cranking battery.
There has been much debate about this, but I can only report as to what ACTUALLY happens with MY car.
My conclusion is that at 13.69 V DC at the alternator you will never adequately charge the caravan battery even if you have zero resistance in the cables that runs from the car to the caravan battery.
If you use a simple batterry to battery booster that does not incorporate a smart charger you run the risk of damaging the caravan battery from over charging.

As far as I can tell the same is true of any auxiliary battery installed under the bonnet.

These are my thoughts/findings only. I am by no means an expert and these comments may be challenged by others but that is the beauty of forums such as this

Regards,

Rosscoe

Barry

You said your van was wired for a battery system. What is your van? Is it a Jayco? If so it has a power supply to power the 12 V lights. Some people in the dealer organisation claim this power supply is also a battery charger. Some also call it a "transformer" which it is certainly not, that shows up the poor level of electrical knowledge in the caravan industry. If you have a Jayco it is good to see that you are prepared to swap the Setec for a proper battery charger.

PeterD

Barry posted, "" what I realy need to know is :-> what sort of 240 volt plug in charger should I have to charge such a battery to *max efficiency* ? ""

He's not asking for the correct charging terminology of various types of battery chargers, he just wants to plug in a battery charger and forget it for a few days while it does it's thing when (and while) he's camped and has access to 240 Volt power.

Yes, the 12v battery will be in use, so it has to remain on charge and will continue to be charged (as required) simply because it's being used by the electrical appliances attached to it.

(the battery won't discharge because the 2 (or 3) stage charger will "maintain" it fully charged, or is that supposed to be 'trickle' charged or maybe I should simply use the terminology 'just getting a lick' of current, yes political correctness gone totally haywire, grrr)

Said very simply, in an automatic 2 (or 3 or even 6) stage battery charger the 12v battery *initially* gets charged (@ 14 PLUS Volts) then when this is achieved the voltage is *finally* reduced to 12.6v - 12.8v or thereabouts, and the current is reduced to just a 'trickle' (as in very very very small) just to maintain the battery in a fully charged state, if the battery is damaged when being charged in this way, it's because the battery charger is faulty - not the battery
(unless it's a battery with an inherent fault to start with)

Mainey . . .

gentlemen,

when we talk 100% battery charge, we are asking something that most battery chargers will not give. most chargers are set to very safe default voltages that will suit a range of batteries and not damage them (or fully charge them). eg a boost voltage of 14.2 will suit some batteries but 14.5 may suit your particular style. Now, try and find a charger that will allow you to select voltages for a variety of batteries. if you can then be ready to take out a second mortgage.
Another huge overlooked area that is never found in "average or cheap" chargers is battery temperature compensation. how many people have commented to you at the campsite that you can never fully charge acold battery. This is because a cold battery requires a higher charge voltage (as a warm one needs a lower voltage). As you can imagine, the charge voltage required in Tasmania in winter is completely different to that in summer at Cairns, so the default is set to the LOWER voltage.
How many chargers have temperature compensation?. Certainly none from the cheaper outlets.
Under cold conditions and without the optimum charge voltage you may not reach 80% from a "average" 3 stage charger
What I am getting at is if you are chasing that 100% (or close to it) you need a charger that will suit your battery (AGM, SLA, flooded etc) or be adjustable, and including battery temperature compensation. If the salesman says NOT needed, then you will be settling for less than your batteries capacity. Unfortunately chargers of "integrity" will cost, but so do those batteries you carry and rely on.