Powering your campsite over a few days

[JamesH]

Hi All

Early draft plans of next year's trek are taking place. Previously we have not stayed in one place for more than one da/ two nights and both vehicles have dual battery systems. I run and Engel 40ltr and my mate has his on freeze. We will be heading up to the NT so long drives.

This time we want to find a site a sit for a bit if we find it agreeable so we are discussing battery charge issues. Here are the options discussed

1) good quiet little gen - $1400 - ouch
2) solar panel and regulator - $1100 - ouch
3) third battery in one of those porta paks

The gen option is fine except in addition to the cost we are reluctant to carry petrol (both cars Defenders). Option 2 - I don't know it might work but $$$ to set it up properly. We sound pretty cheap don't we? It's just that our two battery set up suits us brilliantly for 95% of the time.

We are leaning to option 3

We have not completely discarded option 4 by the way. Which is hop in your car and go for a half hour drive. But you know, you set everything up and you don't want to move sometimes.

Opinion/comments/ideas?

[Bushie]

How long are you planning to be stopped?

We often stop for 3-5 days at one place just on dual batteries, so far it hasn't caused any problems. Given that the NT will no doubt be fairly warm I wouldn't envisage 3 days being a problem.

From my point of view the solar system would be the most desirable but certainly concede the dollars issue, 3rd battery also sounds a viable option provided you can hook it into the charging system.


Bushie

[Redback]

I have a friend that runs his 80lte Evacool with one of those 105AH thumper packs and he gets 4 days from it before he has to recharge.

He has it for his camper as he doesn't have dual batts or a battery in the camper, seems to work for him.

Baz.

[VladTepes]

:idea: maybe a camping place somewhere can rent you a gennie - that would same you some cash and you would learn whether buying one would be a good investment for you next time or not.

[JamesH]

Thanks for the advice

The renting or borrowing gennie is a possiblity. The thumper pack (that's what I meant) sounds promising.

I have only seen the thumper pack in the distance - don't know how they work or how you charge them etc but I can google that.

Frankly I can't see us sitting still for more than three days without at least going for a drive/scout around - it's just we want to feel secure out in the boonies without wondering what we are going to do with flat batteries.. As I said my mate's Engel will be on freeze and we would run a couple of versa lights for a bit at night.

[Redback]

They recharge with both 12 and 240 just like any other battery.

Baz.

[p38arover]

Go and buy one of the cheap GMC petrol gens from Bunnings or similar. Only about $100 - they'll charge your battery. Even KMart sell them.

There is a diesel version that is a fair bit more exxy.

Ron

[Disco300Tdi]

Originally posted by p38arover
Go and buy one of the cheap GMC petrol gens from Bunnings or similar. Only about $100 - they'll charge your battery. Even KMart sell them.

There is a diesel version that is a fair bit more exxy.

Ron

GMC come with a 30 day satisfaction warranty

Do the trip then take it back for a full refund

[DaveS3]

Never run the fridge directly off the generator, always connect to a 12v battery then run the fridge from this - just absorbs any voltage fluxuation.

Engel will not warrant running fridges off generators. I think that there are only 4 or so models that they reccomend all with voltage regulators and all very pricey.

Waeco make a batterpack that is 36 amp hours at around ~$300. Will run the fridge for a few days and is a good portable power source to run lights/compressors ect if need be.
I would go this route it is far more user firendly.

6 litres of 2 stroke will only run the generators for abour 5 - 6 hours.

Dave.

[p38arover]

Originally posted by DaveS3+--><div class='quotetop'>QUOTE(DaveS3)</div><div class='quotemain'>Waeco make a batterpack that is 36 amp hours at around ~$300.[/b]

Wow! That's pretty expensive. It would be easy to make one up that costs a lot less than than that and gives greater AH capacity.

<!--QuoteBegin-DaveS3
6 litres of 2 stroke will only run the generators for abour 5 - 6 hours.[/quote]

You shouldn't need to run the unit for anywhere near that long to recharge the battery.

Ron

[drivesafe]

Hi JamesH, the cheapest and simplest way to get more stored power for you camp site is get a third battery.

Your vehicles are quite capable of charging three batteries at a time ( cranking battery + 2 auxiliary batteries ) and it take not much longer to recharge three batteries as it does to do one.

Here is a trick a customer of mine has done for many years.

Every year he and a mate, along with their wives, go up to the Golf country to fish for barra.

They both carry two auxiliary batteries, one fixed in each vehicle and one they leave at the camp site to run the fridges.

They would go for a drive at some time or other and then on returning to the camp site they would hook up an inverter to the auxiliary battery in the vehicle and run a 240 volt extension cord in to the tent and power up a small battery charger which was connected to the battery powering the fridge and they would leave it running all night.

This topped the tent battery up and didn’t effect the cranking battery.

Just an idea and it works out HEAPS cheaper than the solar panels and is a lot quieter than a gen.

Cheers.

[Tusker]

Depends partly on whether you just want to safely start the car after 3 days, or run the fridges for 3 days - that obviously involves more trickery.

Just driving around for firewood doesn't always charge the second battery either. Some systems work off the main battery's needs - the second might only get a trickle charge, it can take hours to charge up.

I just run a smart solenoid type, and drive around when the 2nd battery is down. HF radios don't like low voltages, another reason to charge up the 2nd before logging into VKS 737.

regards
Max P

[abaddonxi]

I'm sure that Drivesafe's method works, but you'd lose a lot of energy along the way, each step is not 100% efficient in transferring the energy.

So, loss from battery to inverter, inverter to charger, charger to battery.

If you were going to go that way, why not have interchangeable second and third batteries? When the camp/fridge battery is getting flat switch it for the second truck battery. Then you can buy some of those fancy anderson plugs they keep advertising on ebay.

Cheers

Simon

[JamesH]

A lot of interesting stuff here to digest.

Thanks a lot for your input. There is an answer in here for sure.

Jamie

[drivesafe]

Hi abaddonxi, true about the inefficiencies, but there are some advantages.

It’s a lot lighter running an extension cord than changing batteries.

You could also simply make up 12 volt extension using heavy gauge cable but then you have the problem of battery equalisation and again this will be inefficient.

But buy using the inverter/charger, even if you drive for only an hour or so, you will still put a few whack of power back into the auxiliary battery and this power can be used to top up the camp battery and by using the inverter/charger method, even if the auxiliary battery in the vehicle is lower than the camp battery, you can still put more charge into the camp battery.

There are few situations where this is usable but it is a very simple way to keep your camp battery at a higher level of charge than can be done by simply swapping batteries.

Cheers

[p38arover]

And Aldi still have the 300 watt inverters at $59 which should power a trickle charger. I wonder how big a battery charger it would really power - forget theory, we need practical tests. I shall have to try it on my 4A charger.

The inverter could be useful for other things as well.

I bought an Aldi unit a while back and I think I should buy another - one for each Rover.

Re cheap portable generators, see this OL thread:
http://forums.overlander.com.au/viewtopic....1566&highlight= (http://forums.overlander.com.au/viewtopic.php't=31566&highlight=)

The GMC cheapies have got a thumbs-up.

Ron

[JamesH]

How do you guys feel about simply installing a third battery? Can a Tdi alternator handle it?

[VladTepes]

I beleive it can if you get the charging system right. However that doesn;t solve the problem of being able to leave the fridge on in camp whilst you drive out and about does it ?!

[p38arover]

Originally posted by VladTepes
I beleive it can if you get the charging system right. However that doesn;t solve the problem of being able to leave the fridge on in camp whilst you drive out and about does it ?!

Grateful if you&#96;d tell me where you&#96;ve left the fridgè whilst you&#96;re out and about. :twisted:

Ron

[drivesafe]

Hi JamesH, depending on size and type of battery, the TDi could easily handle 3 or even 4 batteries ( including the cranking battery ).

If you were using standard deep cycle batteries then you would be able to charge your cranking battery and two large deep cycle batteries or another two cranking batteries and depending on how you set it up, you could charge up an additional cranking or deep cycle battery.

This is the cheapest dollar pre A/H way to have enough power at a camp site.

Also the charging time for one, two or three batteries is about the same.

Adding a fourth battery will start to make the charging time longer.

What most people don’t realise is that these type of batteries only take high currents for the first few minutes, if they are low, after 30 minutes or so the batteries will only be pulling about 10 amps each, maximum.

So in a worst situation with three flat batteries ( 50% charged ), when you initially start off, you will need, at the absolute maximum, around 75 amps for the first few minutes then after about 5 to 10 minutes, your current needs would already have dropped to around 40 or 50 amps and again after 30 minutes you would only need 30 amps max. Remember these figures and they are very rough figures, would relate to 3 auxiliary batteries and one cranking battery.

In your case JamesH, you can take a third off the above amounts, so just workout what your alternator’s maximum rating is and take it from there.

One more point, when using these types of batteries ( standard wet cell ) if they are much lower than 50% they will actually take less current until they start charging up around the 50%.

Cheers.

[JamesH]

Hi Vlad: We had not intended moving the Engels out of the car they are fine to stay in there. Our only concern is being stationary for a 3/4 days and being able to get our cars started when time comes to do so.

Very interesting Drivesafe and thanks so much for your extensive input.

Would you recommend the use of deep cycle batteries in this case?

In my car the dual battery set up is very simple. A manual switch isolates the auxilary and everything - the various 12v plugs, starter motor etc runs off the main battery. When coming to start the car I then bring in the 2nd battery. I am aware of the downside to this system (equalising after switched) but it will do me for now. I was going to ensure my next main battery was a deep cycle given that it must have a fairly hard life under this set up.

My friend has all the periferals running off the aux and an automated system that joins both batteries when the ignition is on and isolates when off. Something horrendous happened on our last trip (2 days from end luckily) and both batteries got cooked by a rooted alternator. Now he has new deepc batteries and a new alternator that he has been told is more powerful than standard. He will be very interested in your notes re third batteries.

cheers

[drivesafe]

Hi JamesH, the choice of cranking battery or deep cycle battery is dependant on use.

In your case, if I understand your last post, you use both batteries to start the vehicle. In this case I would use two cranking batteries. Contrary to common belief, you CAN use a deep cycle battery to start your vehicle and it will have little effect on the battery but thats based on a once in a blue moon situation, but to use the battery to start the vehicle on a regular basis then you should be using a second cranking battery.

The advantages of using a deep cycle battery is that they tend to hold there charge longer and can be left out of use for longer periods than a cranking battery.

The main advantage of wet cell batteries, deep cycle or cranking is their cost per A/H ratio.

There are places where these types of batteries should NOT be used such as having to fit a battery inside the cab, as I have had to do with the Rangie, and in these situations you need to look at something like an AGM type battery.

One more point, I would try to keep all the accessories coming off the auxiliary battery(s) and leave the main battery for just the normal vehicle starting and operating requirements.

Cheers.

[bongo]

JamesH, I run a 75amp thumper pack in the back of the landy, and also have a eu20 honda genny.
Both excellent bits of gear, so it really just comes down to personal preference. I dont think it is a big hassle to carry a jerry can of petrol in the landy.
The battery packs are quite expensive, so another option is to make your own, using a battery box from the likes of supercheap .. etc..- More amps for less dollars.

[weeds]

I think first you need to work out your current draw per hour or total amps used each day if you are not starting your car to work out how much stored power you need. Remeber a fridge cycles on and off so you will need to time how many minutes the fridge runs each hour. Most good light are around .9-1.0 amp/h.

re: deep cycle battery - I was under the impression that the alternator will only ever charge a discharged battery back to about 80% and after each cycle ie discharge and recharge you lose capicity as well.

I did some tests on my older style 32L engle. it's max current draw is 3.5amps/h continuse. I orginally had a 80amp/h deep cyle battery fitted with a manual isolater. With the fridge already down to temp it cycled approx 50% of the time ie on for 8-9 min and off for 8-9 min therefore its consums approx 1.75amp/h. So best case out a an 80amp/h battery i would expect 45 hours however completely draining a deep cycle is not heathy. If my 80amp hour battery is only at 80% capicity ie 64amps I could expect 36 hours add a light for a few hours each night I should get two nights out of the battery.

In saying that my current setup is more than i need. I run two aux deep cycle batteries (1x 80amp/h and 1 x 120amp/h) off a manual isolator. I also have a 65W solar panel and on a good day it gives me at least an average of around 3amps over five hours, 15amps back into the battery. My isoalor is a marine switch which I can select where the charge from the alternator go to either main only, aux only or both. When I start the car after a day or two when camping I leave the isolator charging the AUX batteries until I'm an hour or so down the track than change to charging both.

There a lot of figures when you start talkikng power comsumption, in saying all this I have never let the setup run till the fridge stops working to see hour many hours I get, it has not failed me yet however the longest I have left it without starting the engine is about 45 hours.

A second aux might be a good starting point, I always through the battery charger on my aux the night before i leave to ensure they are topped up.

[drivesafe]

Hi weeds, that 80% charge capability off an alternator is an urban myth.

There is no reason why you can’t charge ANY automotive battery to at least 90 to 95% of charge without too much trouble and on a long trip, 100% is common place.

As long as your vehicle electrics and battery(s) are in good nick and you have decent size cable, both negative as well as positive, connecting everything together, then your good old alternator will easily FULLY charge the batteries.

Also there is there is no real advantage to isolate the batteries once you start the vehicle. Again your alternator is quite capable of charging everything at once. If you wanted to spread the initial charge load then it would be safer to charge your cranking battery first to make sure it is fully charged and ready to start the vehicle any time it is needed.

Back to the URBAN myth. We are not talking about a town car here, we are talking about driving for at least a number of hours at a time and unless your battery is flat ( 50% charged ) when you start, if you were to drive for around 3 hours and you started with a battery with only 70 to 80% charge, you will now have a battery charged in the 90% area and after 4 or 5 hours, it would be easily up to 95%.

If you read the different battery manufacturer’s web sites, they say that as long as the charging voltage is 13.8 or higher then the battery can be FULLY CHARGED and as most vehicles charge at around 14 to 14.2 volts then there is no reason, according to the manufactures themselves, why the batteries can’t be fully charged.

Having said this, don’t take my word, next time you do a trip, as soon as you get home, if your not going to need the auxiliary battery, disconnect the earth ( negative ) cable, this will make sure there is no charge or load applied to the battery. NOTE for safety reasons, leave the positive terminal connected.

No matter what type of battery it is, after 72 hours the battery will have settled and you can use a multi meter to measure the voltage at the battery terminals.

Check this reading with the manufacturers specs for that specific battery and you will have an idea within 95% of accuracy of what your battery’s charge state is. So if it shows that you battery is at 100% state of charge then even with the worst margin of error, your battery is going to be at least 95% charged.

Cheers and if anybody carries out this test, please post your results here so we can see how well your alternator works. :idea: