Davianni wrote:

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[deletia]

I have a 130w solar panel, 2x 100w house batteries so if I stayed off the grid, how long would these last running the basics?

Cheers, and see you on the road, Davianni

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 Hmmm. That all depends on the "basics". Questions about solar and battery capacity are always a bit like "how long is a piece of string ?".

We have 200Ah of battery and manage to keep them pretty well charged with 350W of solar panels given good power harvest conditions. Our usage is a few LED lights, a 40l Engel fridge/freezer, charging phones and laptops and sometimes a small TV.

We need to have a couple of good harvest days if we've had a few days of overcast conditions though.

If push comes to shove we can always connect the car and fire it up to get about 30A charging. Another thing to keep in mind is that conventional wisdom says that you really shouldn't discharge to below 50% state of charge although we've been guilty of going down to a lot less than that.

There's a bit more about our system here.

Whenarewethere wrote:

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markf wrote:

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Another thing to keep in mind is that conventional wisdom says that you really shouldn't discharge to below 50% state of charge although we've been guilty of going down to a lot less than that.

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 There are swings & roundabouts. I been guilty as well. If it happens every so often you will make up for it as probably you are only discharging 20% most of the time.

 A piece of string is twice as long as half a piece of string!

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 Hi Davianni  

Welcome here and a good question. You have more battery than we do, but really need more solar. You could get a portable panel or two, or make your own for a better outcome cheaper. What is your regulator/controller.

How long you can stop depends on the details, what area you are in, summer or winter, what fridge you have, (compressor type or gas/electric), whether you do turn off the lights and TV , if you charge up your phones etc during the day when the sun is shining, and where you park(in a good sunny spot) or under a tree. But ultimately you do need a meter that tells you battery voltage and learn how it reads under your use style. Then you can know if you can sit up for a while and watch TV/listen to the radio/read or say bed time now, turn it all off  

Keep asking the questions. But try it out in the back yard and see what happens to the power. Tell us what you might use and what you have. Led light are good to have too.

Jaahn

 

-- Edited by Jaahn on Monday 8th of June 2020 09:27:51 AM

We are going to try our first run next week to Torquay site. Have tried to brush up on basic electrics but it keeps doing my brain in. The fridge is gas/electric 175l and wed only be running that, the tv, my laptop and internet wifi. Am probably just a bit paranoid this being our first outing and not having a record of a days power usage. 

Gas fridges when running off 12 volts use about 12 - 15ah per hour. If you want to run a fridge off 12 volts get a compressor fridge.

In the meantime run it off the car while driving & as soon as you get to your camp switch it to gas.

markf wrote:

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 Hmmm. ---------

If push comes to shove we can always connect the car and fire it up to get about 30A charging. Another thing to keep in mind is that conventional wisdom says that you really shouldn't discharge to below 50% state of charge although we've been guilty of going down to a lot less than that.

There's a bit more about our system here.

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 Hi  Davianni 

Great information coming in for you. Use the gas for the fridge. The rest will be OK. But still run it at home if you can before you go to check things.

But note the 'free backup charger' markf has mentioned and whenarewethere also.  You already have one and look to the future to 'hook it up'.  

But what sort on meter do you have to monitor your useage and the battery condition. Important IMHO as it enables you to be confident of  knowing what is going on. Not rocket science either but you need to learn what it does and what it is 'telling you'. Good luck. I have one of these

 

Mine is a dual one, does the MH battery too. But so easy to see the voltage my wife knows exactly whether it is charging or discharging or getting low etc. Not cheap but the second one I have bought now. You do need to learn what the voltage means though but you learn that as you go.

Jaahn

PS for the technical people those lights are not spaced equal voltage but matched to the capacity better, not like the cheap ebay indicators. 

-- Edited by Jaahn on Monday 8th of June 2020 11:18:13 AM

-- Edited by Jaahn on Monday 8th of June 2020 11:19:54 AM

Davianni wrote:

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We are going to try our first run next week to Torquay site. Have tried to brush up on basic electrics but it keeps doing my brain in. The fridge is gas/electric 175l and wed only be running that, the tv, my laptop and internet wifi. Am probably just a bit paranoid this being our first outing and not having a record of a days power usage. 

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Hi Davianni
As I pointed out in your previous post, I am not a techie, but in this post, I will assume that the techies can not answer your question, without knowing all the technical details of your system

I hope that if my calculations are wrong, then a techy will come along and correct them

• Assuming that (being a new RV) all your lights are LED

• Assuming you will (like most people) be running your three way fridge on GAS, when parked up

• Assuming, (like my wife, when we got the Motorhome) the basic for the TV, is that it will be on, most of the time

 Then here are my (pure guesswork) calculations, using the details you have given

1. Lights (only using those you require) 1 AH X 5 hours = 5 AH per day
2. 12 volt TV 3 AH X 16 hours = 48 AH
3. Laptop (assuming you only charge it when required) 2 AH X 4 hours = 8 AH
   Internet WiFi (no idea how many AH) as I use a USB WiFi dongle plugged into my laptop
4. Water pump uses 7 amps each hour of running,  but is in use for less than 25 minutes each day = 3 AH

Total AH each day = (approximately) 64 AH each day

Solar input @ 130 watts would be (theoretically 7.3 AH X 8 hours) (practically 5 AH X 6 hours) = 30 AH each day

If your 2 X 100 AH batteries are (Lead Acid) such as AGM or GEL then you have 50% or 100 AH to safely use
As you will (in my theory) be using 34 AH, more than your solar is replacing each day, then on the fourth day, you may be shortening the life of your batteries

Therefore being economical with your 12 volt usage, with full batteries at the start of your road trip, you may be able to spend four days at a time, parked up, and off grid

If you let us all know how long the batteries did last for, then it may help others in the future

Don't run your fridge on gas whilst driving things tend to burn down, including service stations when you try to refuel; Just run it for at least 24 hours to get it to the desired temp, in freezer and fridge. I use freezer blocks or frozen water bottles in the freezer section as well as in the fridge, to get it to cool down quicker. Make sure you are on as level a ground as possible, they either wont run, or will be inefficient on non level ground.

-- Edited by Bicyclecamper on Monday 8th of June 2020 02:41:25 PM

Davianni wrote:

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Thanks Jaahn, I do have control panel......instructions all in German! Looks pretty self explanatory though. As I cant hook up to 240 at home, looks like I must use gas and turn on the day before leaving. Think I better pick a site away from everyone then I dont look like too much of an idiot!

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 Hi 

Just a comment ! We all started somewhere even if a while back. Mistakes, did I make any, not telling you , but the fact you ask questions is good, and makes you not a moron for sure. So go with the flow and try to enjoy the trip. You are not at school, and that bully of a teacher is not asking questions when you finish  Park where it suits you and ask anyone there questions too if you need to. Walk around and chat to any friendly 'natives' and you might get some ideas anyway. That's the great caravan lifestyle.

have a great time. Jaahn  

PS as said do level the van for the fridge. It should have a bubble or get a small cheap level or even a saucer of water on the floor or bench top. Do not drive with the gas on but you can drive there with it off after it is cold and then light it again.   

-- Edited by Jaahn on Monday 8th of June 2020 06:06:17 PM

HI
Davianni

Agm batterries last longest if not discharged below 50%
100Ah agm 50% = 50ah . In your van you have 100ah usable battery !!!

The issue
U can only use what u can recharge
Your consumption around 50Ah per day
Your production is less from 130w

160watt solar recharges 38ah per day
200watt solar recharges 48ah per day

2x 100Ah batteries = minimum 320w ----400watt
Installed 1 x roof mounted and 1x portable

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Calculation is based 100% sun hrs at 5.5 per day common on mainland Ozzy summer spring autumn
Sun occurs out side these hrs but is unreliable to measure
Calculation allows 20% loss due to wiring, panel position , controller etc

Hi David, congrats on the motor home, as others have said make sure you get the whole thing as level as you can when parked up else the fridge wont function well , you can buy plastic levelling ramps from most places and yes get yourself a small level from Bunnings etc

As others have said 12v while your on the road , 240v when available and gas when not

The next important thing is familiarise yourself with your water system , the onboard water tank and pump and the mains connection section and how it all works

For ease of use you could get the solar upgraded on the roof by going with a couple of 200w panels or else get a large sized portable , what ever suits ..... even doubling up the 130w on the roof and run a portable will work too ...... no rush

Good luck and enjoy mate

Going off on a tangent! It's worthwhile getting TPMS (tyre pressure monitoring system), it's better to catch a flat tyre before destroying it. It saved us 3 tyres in 2018.

& having a tyre repair kit & compressor (good quality) gives you more options & greater peace of mind, more so if remote.

Mine is only for 4 wheels as I don't tow.

 

Hi Davianni,
Excuse me coming in after all the good advice has been given, but a good reference book (that I got for Christmas) is "Caravan & Motorhome Electrics - the complete guide" by Collyn Rivers. Road Track Marine sell them, also available on line.

Collyn has been considered an expert for many years on RV electrics & has written several books - the one I mentioned is his latest with several combined into this one.

And never be shy in asking questions - you don't learn anything by not asking & knowing something about your system could become more than useful when something breaks down & you're some distance away from an auto-electrician. And you never know if the question you have asked might have been one that someone else was thinking about.

One important & hard lesson I & guess many others have learned is when you're on the road, stop (the govt says every two hours) & stretch the legs, walk around your rig - checking hub temperatures (bearing, seal, brake problems), tyres & anything out of the ordinary.

I ignored the suggestion to stop once at a good bakery for lunch in SE NSW - I had other opportunities before that too but it ended up costing me $1500 & nearly a total loss of our camper had I gone on an extra five minutes!
Another couple we met at Alice Springs a few years ago had travelled the Plenty Highway. I wondered why they didn't have any lights in their camper. They threw a stone that smashed a vital connector on their power system. It blew an auto-resetting circuit breaker but it kept resetting. In the dust, they couldn't see the smoke coming from their power bank - $8,000 worth of power equipment was destroyed (two batteries & all the associated automatic equipment) - they were "lucky" not to lose the lot!

oldbloke wrote:

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This is a great thread. I'll add my 2 jobs worth.

On a cloudy day you get zilch from solar.

So, how do you get around that?

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No, not zilch, just a lot less.

Then you have to option to not bake that loaf of bread and to go for an evening walk instead of watching telly until the wee hours :)

Then you will be grateful that you installed more solar than you thought you needed. You can not have too much solar.

After that you will be looking for some back up generating capacity. Ours is to go for a drive and the 85A alternator will slam up to 70A into the batteries to bring them up quite a lot.

Cheers,

Peter

I also look at its a 12v power supply source . Being most things are 12v . Why I fitted 50amp unit . Ok most the time its no higher than 25-30 amp on led gauge . Much like alternator in vehicle. There are no 5 or 7 amp ( under 50amp) alternators on vehicles ! Most are up around 80 to 150 amps regulated .