Heading up to central Aussie for a couple of weeks. Will be staying in Motels half the time and in the van the other half. Will be bringing along a laptop and a couple of phones. Planning on staying on a powered site when staying in the van.

I was looking at buying a car battery charger to hook up to the van battery on the days/nights we are staying in the van - just to watch tv listen to the radio, power lights charge laptop etc. Not doing anything hard core. Just don't want to have issues starting the van when it's time to move on. Prices range from $40 - $400

What do I need to get - do I need a "smart charger" WTF is that anyway. If I get a cheapo ebay thing is it going to wreck stuff? So bloody confusing.

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oliver said..

If you get a charger for a standard car battery, you should be right. If you want to get technical, you could download the datasheets of the charger and battery and check that the charging regime of the charger does not exceed the specs of the battery.

I've been researching a second battery for powering equipment in the back of the work van. Jaycar has an isolator kit that hooks the secondary battery up to the alternator for charging while driving but doesn't let the primary battery get too low to start the engine. $150 + $150 or so for the second battery.

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jn1 said..

oliver said..

If you get a charger for a standard car battery, you should be right. If you want to get technical, you could download the datasheets of the charger and battery and check that the charging regime of the charger does not exceed the specs of the battery.

Yeah, looked at that option too. Probably the way to go if I'm planning on doing this sort of thing often. But that means getting a second battery, an isolator and then wiring my accessories in my van to the second battery.

oliver, did you look at this product ? they are on amazon, but not shipped to Australia, someone told me Costco in docklands sells them for$100

Staying on a powered site you say ? just take an extension lead and run it from the site power box and plug in your van.

^ What, run my car stereo and interior lights of 240 Volts instead of the battery?

Btw, Dimitri, that Jump starter looks amazing. How do I charge that.

^^^wouldn't have a clue TBH. mate of mine was doing shopping at costco few days ago and sent me this pic

Hi Oliver,

A volt meter might be a good investment too...

A cheaper car battery charger should be fine... Some of the cheaper ones should have 4 lights, representing 25% 50% 75% and 100% charge...
What you really want is a nice long Power Lead/cable, and nice long "black and red" leads on the alligator clips... You'll probably get 6V and 12V charging options, and Trickle and Fast Charge... I use mine every 2-3 months... Give the cars and motorbikes a trickle charge. Especially over winter... Keeps the batteries boosted.

A smart charger is useful when you have a lead acid battery permanently attached to a charger. The most important thing that a smart charger does for you is that once the battery is fully charged, it switches to 'float' charge mode that maintains the lead acid battery in a fully charged state without over charging it. If you have a vehicle you do not use often, then you might attach a standard charger every couple of months to keep it charged, but with a smart charger you can leave it attached permanently and maintain your battery in a perfect state of charge.

Some smart chargers also have an 'equalisation' setting. This charges the battery very hard for a short period of time to cause bubbles to be produced that stir up the acid. This is useful for batteries that are sitting stationary because the acid becomes stratified, so that it is very concentrated at the bottom of the cells, and weaker at the top, which can damage the battery. The bubbling stirs up the acid. It's like stirring a glass of Milo that has been sitting still and all the cocoa has settled on the bottom of the glass.

One thing you may not know is that standard car batteries are not designed to be heavily discharged, and doing so repeatedly will damage them bit by bit each time, so it's a very good idea to keep it topped up with a charger when you are camping. For your two week trip, just connecting your vehicles battery for the odd day here and there, a standard charger will be fine.

If you had a camper trailer with a dedicated deep-cycle lead acid battery that sat in the garage for months at times, you'd want a smart charger connected to it to maintain it in perfect condition. They are getting very cheap now, and might not cost much more than a standard charger if you think you might make use of the features some time.

If you do buy a dedicated battery some time in the future, make sure you get a deep cycle battery. This is the one I have in my camper, and it lets me run lights and a fridge for 4 days. It's a bloody good battery. www.trojanbattery.com/product/scs225/

Excellent description above. Get a smart charger. Your draw won't be that big so a 7 amp smart charger will be absolutely adequate and much cheaper than more high powered options. I would have it hooked up before I started drawing. They do do an awesome job of keeping batteries in tip top condition.

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thedrip said..
Your draw won't be that big so a 7 amp smart charger will be absolutely adequate and much cheaper than more high powered options. I would have it hooked up before I started drawing. They do do an awesome job of keeping batteries in tip top condition.

thedrip is spot on. A 1 amp charger is not enough, they are designed to charge small sealed gel cells. You could only just get away with a 4 amp, but around 6 to 8 amp is ideal for what you want to do. Anything above 10 amps would be overkill, although useful if you want to quickly charge a discharged battery.

I have a 12 amp charger, which is good for touring, as I may spend a few days without mains power and drain my battery low, and then pull in somewhere with power late at night. The 12 amp charger makes sure my large deep-cycle battery is fully charged by the next morning before I leave.

Something like this would be ideal. www.batteriesdirect.com.au/shop/product/23374/ctek-mxs7.0.html

I recently got the mxs5 as a kit with some other leads and a case etc from Battery world.
It was $10 cheaper to get the kit than the charger on its own? $178 from memory.

Get a couple of clip on lamps from Bunnings for ten bucks each and just use shore power.

What about if I just got a dual purpose battery. Something like this:

www.batteriesdirect.com.au/shop/product/4357/optima-d34.html

Just by the 7a smart charger from Jaycar. Use the van battery even if conventional lead acid. It will still do it. If it dies you can replace for 100 bucks. Not worth upgrading for what u want. Or u could ask bono and get a kilowatt charger

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myusernam said...
Just by the 7a smart charger from Jaycar. Use the van battery even if conventional lead acid. It will still do it. If it dies you can replace for 100 bucks. Not worth upgrading for what u want. Or u could ask bono and get a kilowatt charger

No buy the CTEK as others above suggest. I bought the Jaycar cause it was cheap, but subsequently needed another charger and got the CTEK. It cost more but is clearly way smarter and does a much better job. Worth the extra dollars

A Ctek or a Projecta is they way to go.

I run a 25amp projecta that costs about $250.

The better chargers will have a power mode that supplies 13.8 volts so you can be running your 12v system and it will supply the charge through the battery. The average "dumb" charger does not charge very well if your running stuff from the battery.

Your charger should be about 10% or more of your battery capacity.

With regards to dual battery systems that's a whole other ball game that has a lot of variables that you probably don't want to consider if your only worried about it for this one trip. Newer cars have variable alternators that reduce power supply and don't necessarily charge batteries very well unless you have a DCDC charger or alternator booster. Then you have to stuff around and wire both the car and caravan for it, which can be time consuming to do properly.

Have a great trip.

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oliver said..
What about if I just got a dual purpose battery. Something like this:

www.batteriesdirect.com.au/shop/product/4357/optima-d34.html

I've got a d34 that I had in a commodore, and now in a Falcon.

It must be about 7 years old now, but stories vary about whether they are as good now as they used to be, so I am not sure how many years I will get out of it.

They are meant to be able to handle a deep discharge without too much damage, but please note, they still don't have much reserve capacity. If you run your lights and TV off of it, it will still be flat when you go to start your van. The same as any car battery.

I flattened mine while running the stereo for an hour or two! I also had the cars ignition on, so there might have been more drain than just the radio.

The Optima batteries are meant to be able to be used in a passenger compartment, but other than surviving deep discharges a little better than a regular battery, are no better.

They do recharge very quickly as well. If it was me I would probably just go for a bog standard 100ah AGM.

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oliver said..
What about if I just got a dual purpose battery. Something like this:

www.batteriesdirect.com.au/shop/product/4357/optima-d34.html

If you're always staying somewhere with power, then you don't need a special battery - just make sure you connect an ample sized charger wherever you stop, and there will be no demands on your battery at all.

If you are staying somewhere without mains power you could get away with your car battery for a single night if you use it sparingly for a couple of low lights only, and then make sure that you do some driving the next day to charge your battery. Otherwise, you want a decent battery. The one you link to is only 55ah. You'd want a dedicated large capacity deep cycle battery in excess of 100ah to be of any use.

Battery chargers charge in "Stages", so after a period of time they simply switch off to settle the battery contents before starting again!

Just got back from a week up north...

For lights I bought a LED 10w Rechargeable worklight ($50 from Masters) lasts 3 hours on a charge and comes with a cig charger cable as well as a 240v charger.
It got left on one night and ran for longer than 3 hours


Had an old 12v home alarm battery (Sealed type) that I hooked up to a 1m strip of LEDs. Just used this in the tent at night so not on for long.
When I got home, just for a laugh I left it hooked up, so far... its run for a week! (24hrs a day)

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Harrow said.. lots of smart stuff

Harrow, you know your electrickery. I have to ask, after two decades of DINIS and a few year of PSS Adept my organisation is moving to Digsilent. Will my load flows ever converge again?

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knot board said..

Harrow said.. lots of smart stuff

Harrow, you know your electrickery. I have to ask, after two decades of DINIS and a few year of PSS Adept my organisation is moving to Digsilent. Will my load flows ever converge again?

Ah, now we're facing the important issues, but you are asking the wrong question! What you really have to ask yourself is this.... how long until your mouse finger is crippled due to RSI!!

So what should I go for to maintain the deep cycle battery from the caravan and the small ride on mower battery?

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gh said..
So what should I go for to maintain the deep cycle battery from the caravan and the small ride on mower battery?

Pretty much any multistage (ie:smart) charger will do the job.

Something like this would be fine: www.roadtechmarine.com.au/12v-5-stage-car-motorbike-maintenance-charger-0-8a-3-8a-ip65-rated/p/TEA525

Thanks Knot Board

I got myself one of these: www.batteriesdirect.com.au/shop/product/23374/ctek-mxs7.0.html

My existing battery is an 55AH Ultima AGM. Just charging it up now.

Noticed the charger has a special AGM mode and a supply function - I think this is exactly what I needed.

Thanks brains trust.