must battery systems be expensive and difficult?

Submitted: Sunday, May 23, 2010 at 14:26
ThreadID: 78700 Views:4636 Replies:9 FollowUps:9
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A simple old caravan, is it really worth trying to fit a battery just to have 12volt interior lights? Seems like such a headache and expensive to get something hooked up to charge from the vehicle alternator while driving or solar.
Candles and a good ol' gas lantern seem like a good alternative to me. Those gas lanterns are like a little fire place too, giving a beautiful ambient light and warmth.!
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Reply By: oldtrack123 - Sunday, May 23, 2010 at 15:10

Sunday, May 23, 2010 at 15:10
Hi Eligar

Yes, been there done that 50yrs ago.
The heat of the gas lamp if placed too close to inflammable ,possibly being knocked over, the risk of burns , especially to the kids.
The constant replacement of broken mantles due to vibration on bad roads etc
All worried me until I fitted a battery & 12v lights to the van
Battery being charged @ that time with simple DIRECT HEAVY wiring from tug alternator via a DIODE isolator
With the old regs you could adjust them easily to get a higher voltage to overcome diode & wiring voltage drop.
Next step was a small 350watt 12v 4stroke Honda battery charging genny [still going strong]
Then a 40 watt solar panel
Finally motorhome with 200watts solar panels , VSR, with again DIRECT HEAVY cable from tug battery to van batts.
AnswerID: 417804

Reply By: Isuzumu - Sunday, May 23, 2010 at 16:41

Sunday, May 23, 2010 at 16:41
Cheapest way is to buy a couple of hand held led lights that you can recharge off 12 volt in car or 240 V when you have it.
AnswerID: 417817

Reply By: Member - Andrew (QLD) - Sunday, May 23, 2010 at 16:44

Sunday, May 23, 2010 at 16:44
It depends on what comforts you want when travelling. If you are happy with your current arrangements then why change? :)

Many people fit the battery not just for lights, rather for the object that keeps their beer and food cold when on the road.

Personally i would stay away from flame producing systems, as the choice for alternatives is great these days. Can't beat the flicker of the flame at night though ;)

AnswerID: 417819

Reply By: Gazal Champion - Sunday, May 23, 2010 at 17:02

Sunday, May 23, 2010 at 17:02
Hi Eligar,
Caravaning only has to be as complicated as you feel it needs to be for your comfort. Portagas lights as you say are brilliant in more than the litteral sense.

A good alternative is the LED camping lanterns which you can pick up from Bunnings for around 35 bucks which take four D cells and last a very long time. I bought two of them for emergency night lighting in the nursing home where I work. They look much like the old tilly lamps, pressurised kero lamps, of old but produce no heat. Therefore safe around kids.

A good shower setup which we used for about 20 odd years was a billy, a bucket
and a bilge pump for a boat which we used to drop into the bucket of warm water which was made up of 1 billy of boiling water and add cold to taste, so to speak. An old shower rose was fitted at the far end of the hose and the bilge pump at the other end of the hose. Connect to the car battery for power via a switch in the shower cubicle. Never lost a customer with that set up.

Four tent poles and some blue tarp made up the shower cubicle and later on we added another 2 poles which made a dressing room extension so that you could dress in the dry area.

When we went camping in locations where the facilities were non existant we would offer fellow campers a shower and without fail their wives and daughters would take up the offer instantly. The whole outfit fitted into the bucket.

Batteries and 12 volt lighting are great but the best advice is travel light if you can and make every thing do as many jobs as possible. I am 64 and have been camping since I was about 7 years of age but really got going when I was 18 or so. Plenty of experience there as you can imagine so that is the best advice I can give.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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AnswerID: 417825

Reply By: Robin Miller - Sunday, May 23, 2010 at 17:18

Sunday, May 23, 2010 at 17:18
Whats hard or tricky Eligar - you can make it so if you want high performance / capacity etc - but gee you can do it real easy to if you just want an interior light.

I mean you already have a trailer plug carrying power to the van - all you need is a 12v light of type that goes against a flat surface , preferrably cheap fluro or LED , and then if you want it to work without the car connected just wack one of those cheap little 7ah gel cells anywhere.
That'll do for a night at a time , and then you can build or not from their.
Robin Miller

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AnswerID: 417826

Reply By: paulnsw - Sunday, May 23, 2010 at 17:46

Sunday, May 23, 2010 at 17:46
Run 6B&S cable to your caravan and fit a Ctek D250S DC to DC charger and that will charge your battery to as close as 100% is possible.

Direct cable connection does not work and cannot charge a battery to more than 60% regardless of what the snake oil salesman like to promote.

If you want to add a solar panel later you use the Ctek D250S as a solar reg as well.

Yes, a simple old caravan is well worth while fitting a good deep cycle sealed battery and good DC to DC charger. Give the Mrs good light and a bit of TV and she will be happy and make you happy.
AnswerID: 417836

Follow Up By: Spade Newsom - Monday, May 24, 2010 at 17:16

Monday, May 24, 2010 at 17:16
paul, after reading your post I have had a look for this product to try to see exactly what it does. All I can get is nice glossy brochures saying you connect it and you beaty. Maybe if you have experience with it you wouldn't mind telling me how it does the job? Would it work on 240ah in the camper trailer?
FollowupID: 688010

Follow Up By: paulnsw - Monday, May 24, 2010 at 21:16

Monday, May 24, 2010 at 21:16
Spade the Ctek D250S is the only method to charge a battery in a caravan or camper trailer properly and as close to 100% capacity. Direct cable charging is useless and does not work regardless of the size cable you use. You need a device like the D250S to raise the voltage and operates like a 240V mains charger, but is powered from your vehicle alternator instead of 240V mains.
Direct cable charging at best may give you 60% capacity charge which is useless. The reason they make these DC to DC chargers is because they work and do the job properly. Half charged batteries from a direct cable system are useless and wreck your batteries

240Ah is excessive battery capacity for a camper trailer and excessive for a 20A battery charger to charge. 150A is max for a 20A battery charger.
FollowupID: 688050

Follow Up By: Maîneÿ . . .- Monday, May 24, 2010 at 21:33

Monday, May 24, 2010 at 21:33
where do you get your information:
"Direct cable charging at best may give you 60% capacity charge which is useless" ??

Maîneÿ . . .
FollowupID: 688054

Follow Up By: Spade Newsom - Monday, May 24, 2010 at 21:38

Monday, May 24, 2010 at 21:38
240 ah gives me four days in mild weather so suits me fine.
I am about to rig some cable for charging while driving hence my interest in the Ctek D250S. This will give me an extra day if I can charge on the way to ............ and a bit of a run from the alterator while camped could give a little top up if I wanted an extra day also.

The spec for the Ctek D250S in the brochure says 40 - 500 ah. I would have thought a 20 amp AC powered charger would be quite ample for 240ah so why would a DC powered one not do the job? (Even 15 amp surely would be sufficient to charge my set up)
FollowupID: 688057

Follow Up By: paulnsw - Monday, May 24, 2010 at 21:47

Monday, May 24, 2010 at 21:47
If you want to fully recharge your battery in an average days driving then 150Ah would be around the max to 100% recharge.
The great thing with the Ctek D250S if you want to add a solar panel you use the D250S as the solar regulator. The D250S is MPPT which is the best form of solar regulator you can get as it gives you up to 25% greater output from the solar panel.
Technically impossible to recharge a second battery and definitely not at a distance with direct cable. Your 240Ah of batteries would be constantly at half capacity even after 12hrs driving. Quickest way to ruin good batteries. The cost of a Ctek D250S will be saved in the life of your first set of batteries.
FollowupID: 688058

Follow Up By: Spade Newsom - Monday, May 24, 2010 at 22:02

Monday, May 24, 2010 at 22:02
paul, I don't expect or really need to get 100% from alternator whether via a charger system or otherwise. If the charger can get me to say 85% - 90% from 40% - 50% in a few hours (maybe a couple of hours) driving then getting the remaining 15% will either happen or not depending on the length of drive.

I certainly want the batteries to be sitting above 80% when I arrive on site but 100% is not really necessary.

I am prepared to spend that sort of money if it will do what I am looking for.
FollowupID: 688063

Follow Up By: Maîneÿ . . .- Tuesday, May 25, 2010 at 06:12

Tuesday, May 25, 2010 at 06:12
I think you should be advising all the companies, both big and small that have put out there in cyberland all the Voltage drop calculators that you are correct and they are all wrong :-(

With 7 meters of 2B&S cable (32mm²) you can realistically expect O.O5 volt drop at the auxiliary battery, so if alternator is putting out a realistic 14.20v the battery will be charged @ 14.15v which is more way than the 60% claimed, more like ~100%.

Forgetting all the voltage drop calculators, I've actually tested my dual battery system which is connected with 2B&S (32mm²) cable and have proven to various people on many occasions the larger capacity cables will give virtually NIL voltage drop.

When 14.4v is charging the cranking battery, ~14.4v is charging the AGM's.
This is definitely not possible with the skinny 6B&S cable you advocate using.

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What your not factoring into your equations is the battery system is not ‘flat’ anyway, it's just down that amount, a small percentage of total capacity, used by the accessories over night, which is not a lot at all comparative to being fully charged, then the vehicle is driven next day it will easily replace what was drawn from it overnight.

You say: "240Ah is excessive battery capacity for a camper trailer and excessive for a 20A battery charger to charge. 150A is max for a 20A battery charger"

What has "150A is max for a 20A battery charger" got to do with anything at all, it does not even make any sence as 20A is max for a 20A battery charger.

Just because his battery bank is beyond, as you claim, the capacity of a 20Amp battery charger does not make it excessive battery capacity.
It makes it very realistic battery capacity, and very suitable to charge by direct cable, of the correct thickness, and I assure you it will charge to 100% for a whole lot less money that what you are recommending.

As to your reference to “snake oil salesmen” I think it maybe a case of the pot calling the kettle a darker color.....

Maîneÿ . . .
FollowupID: 688070

Follow Up By: paulnsw - Tuesday, May 25, 2010 at 07:07

Tuesday, May 25, 2010 at 07:07
I will leave you children to play in the sand pit.
FollowupID: 688072

Follow Up By: Maîneÿ . . .- Tuesday, May 25, 2010 at 10:16

Tuesday, May 25, 2010 at 10:16

this IS your "sand pit"

You must remember it was you who created the "sand pit"

If the information gets too hard for you to answer then ok "leave"

Maîneÿ . . .
FollowupID: 688077

Reply By: Maîneÿ . . .- Sunday, May 23, 2010 at 19:00

Sunday, May 23, 2010 at 19:00
Buy a deep cycle battery, and some 6 sq mm (core) cable running from vehicle battery to the caravan battery via a battery isolator through an Anderson plug at the tow ball area.

It will charge the caravan battery

Maîneÿ . . .
AnswerID: 417858

Reply By: ChipPunk - Sunday, May 23, 2010 at 19:12

Sunday, May 23, 2010 at 19:12
I know what you mean by expense - but it does not have to be expensive.

A second battery, some cable whose size depends on the average load & average charge time etc, and generally a $5 relay is all that is needed.

I loved the old gas lamps, but since the advent of cheap 12V flouros - no way! Cannot use gas nor candles nor kero in certain areas etc (eg, fire-ban days).

The typical fluoro is only about 1A drain current - ie, 8-13W, ie, similar to a 10W dome lamp.... Less if using a dimmer.
The extra 1A "replacement" for an alternator is stuff all.
A typical car battery should last at least 2 days with one permanently on.

Add ~$20 for a low-voltage cutout to either protect your second battery from excessive discharge, or to leave you with enough cranking power if you only have one battery....

Whether you use solar or the vehicle is up to you...
Solar takes a long time to pay-back - say 5-20 years.
For a 13W flouro used 6 hours per day I'd use at least 20W of solar.
You can presently get 105W of solar as 3x35W panels for under $500. A regulator (kit - soldering & assembly required) adds $20.

Otherwise running an engine (alternator) for about 10 minutes should replace most of the power you used (till low-voltage cut-outs apply; depending somewhat on your alternator system - but usually it's only the single-wire "D+" alternator systems that are restricted in their "cheap modification" possibilities.
AnswerID: 417860

Reply By: Member - Brian R (WA) - Sunday, May 23, 2010 at 19:56

Sunday, May 23, 2010 at 19:56
Hi Eligar
Must say I am enjoying reading the response to your post. I think you have got a good choice, I had an 1970's York caravan when the kids were young which as well as 240 volt lights had 12 volts as well. If I had that van today...I would fit a 100 aph battery to run those 12 volts a simple battery charger for when I had 240 volt site and a small generator for alternative charging.
AnswerID: 417868

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