powering an inverter

happy campers

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really need some advice please!

we're in the process of totally renovating our camper....on a budget!

its 27ft long, so space isnt a problem.we're wanting to put in a household table top fridge and a household under counter freezer, and we basically know that they can be powered from a big inverter with a solar panel and leisure batteries.....

now, we've bought a 5000W inverter, but does anyone have any advice on what size leisure batteries we need and what size solar panel? we were looking at 120ah batteries but someone said they're too small and would need at least 230ah....is that right? and how big a solar panel would we need? we were looking at a 40watt one

we're going to be living in the camper when its done, thats why we want domestic appliances cos theres more room in them.the oven's sorted, its just a fridge and a freezer we need to fit now

has anyone done this already and can offer some advice please? thanks xx
 
The general advice is to get as much battery power as possible and the biggest solar panel you can get/afford. If you are living in this country then solar wont provide much power except in summer??, what is this?, or so they tell me!!!
 
Hi Happy Campers, The advice I am giving you is what I have on my MH. I have 120w x 2 Solar panels on my roof. Inside I have 110AH x 4 + my starter battery. The 4 inside are all coupled up with the 2000 watt inverter less than 18 inches from the batteries. All this was done professionally. I have never gone on hook up ever. It is enough for all the electrics I have, including 240w power. I check my Instrument daily and my batteries are always full. From what I have been told, keep your batteries together, including your Inverter. Use the heavy duty black & red cables for hooking up the Batts: like the ones on jump leads. If there is any more to add I am certain there are a few folks on here who can and will advice you further. Good luck with the connections.
 
hi david and ann

thanks for your reply.....but can you manage to run a 240v small fridge and a full size freezer on your set up? as thats what we're wanting to do...thanks
 
Hi

Agree with above posts - buy the biggest solar panel(s) you can afford/fit and similar with batteries.

You will need to find out the power ratings of you intended appliances and calculate what you will need to run these and other electrical items in your van.

Have found this on a canalboat forum - interesting reading if you read further down JustCanals.com ::: A Narrowboaters heaven - View topic - Fridge /freezer conversions to 12v

One point made, I thought was quite useful - if you running fridge &/or freezer through an inverter, the inverter will be on all the time and, as we all know, inverters are quite noisy - esp at night!

Hope this is of help - Bev
 
Have a look at this site Caravans, Motorhomes and Solar Panels It explains things pretty simply. Basically you need to know how many Amp hours you are going to use then work out what solar panel you need from there.

I would NEVER connect the car battery to the leisure batteries for two reasons. Firstly they are different types of battery so designed for different rates of charging. More importantly, if the batteries run down, you always want the car battery full to start the engine. You can easily make up a separate circuit to manually switch on the 12V charging from the battery when the engine is running and isolate it by turning it off using a headlamp relay (or hhave it do it automatically wiring it through the alternator) - both scenarios keep the car 12v separate from the "caravan" 12v system.

To a large extent it's impossible to advise beyond this because only you know what you're going to use and how long you're going to use it for - it is this that dictates what you need.

Have a read of the site and if you have any questions, come back again. Hope this helps!
 
hi. i run similar to the above 3x80wt panels 2x200amp bat. 2-3 x100ampbat. this runs my 240v 110wat fridge with a smallfreezer comp. i,m about to fit a further 3x80wt panels as in dark of winter in portugal we have to turn the inverter off at night. i also run things through a 2kw ring inverter. firget a 40wt . that powers almost nothing. really you need much bigger panels. i also charge on the move with a 24v to 12v durite charger. this gives priority to the engine24v system then chargers the 12v i keep a 12vbat permenantly on this because i drive my unit with out the trailer as well and have a 12v system on hand. for stereo etc (telephone). but honestly forget a 40 go for something bigger . a 40wt will not even give you 3amp on the best day of the year at midday even if its sloped towards the sun. and very little the rest of the day. cheers alan.
 
vwalan said:
hi. i run similar to the above 3x80wt panels 2x200amp bat. 2-3 x100ampbat. this runs my 240v 110wat fridge with a smallfreezer comp. i,m about to fit a further 3x80wt panels as in dark of winter in portugal we have to turn the inverter off at night. i also run things through a 2kw ring inverter. firget a 40wt . that powers almost nothing. really you need much bigger panels. i also charge on the move with a 24v to 12v durite charger. this gives priority to the engine24v system then chargers the 12v i keep a 12vbat permenantly on this because i drive my unit with out the trailer as well and have a 12v system on hand. for stereo etc (telephone). but honestly forget a 40 go for something bigger . a 40wt will not even give you 3amp on the best day of the year at midday even if its sloped towards the sun. and very little the rest of the day. cheers alan.
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Sounds brilliant Alan. In a motorhome my preference is still to be able to manually isolate the two 12v systems - I doubt he'll be running a 24v system. Also in motorhome normal advice is to have leisure batteries of the same size, and if possible same type bought at the same time.
 
hi, yes you can as i did with my previous truck just use a link cable from engine to leisure bats . better though to use a 12v to 12v bat charger. in practice i have foud it makes no difference to size or age of batteries . but if one is down it will bring the bank down. a regular check i all thats reqwuired . i use the 100amp as they can in a real emergency be a direct swap for the truck bats .never know battery,s have been stolen from trucks or even had nails knocked into the cases. . better be safe than sorry. so the third is also 100amp under the rear seat in truck. the rest inside the trailer. i hoped you would realise i dont run a standard camper .the main thing is get loads of panels if you want to have good leccy available. i use gas lights as well light ,heat ,help get rid of midges. i did use a gas fridge but at hot climates they dont work . after 32c they soon start to give in. the price of panels as dropped alot lately making it quite viable to get a system started.
 
happy campers said:
hi david and ann

thanks for your reply.....but can you manage to run a 240v small fridge and a full size freezer on your set up? as thats what we're wanting to do...thanks
Click to expand...

The answer to your ? is Yes you can. Except, for how long before you drain your batteries, I am unable to answer. A lot of folks on here may be able to advise you further
 
happy campers said:
really need some advice please!

we're in the process of totally renovating our camper....on a budget!

its 27ft long, so space isnt a problem.we're wanting to put in a household table top fridge and a household under counter freezer, and we basically know that they can be powered from a big inverter with a solar panel and leisure batteries.....

now, we've bought a 5000W inverter, but does anyone have any advice on what size leisure batteries we need and what size solar panel? we were looking at 120ah batteries but someone said they're too small and would need at least 230ah....is that right? and how big a solar panel would we need? we were looking at a 40watt one

we're going to be living in the camper when its done, thats why we want domestic appliances cos theres more room in them.the oven's sorted, its just a fridge and a freezer we need to fit now

has anyone done this already and can offer some advice please? thanks xx
Click to expand...

Please remember that a 5000W inverter will consume an substantial amount of your charging current from the solar array even if it is not being used. A 40w panel will not get you anywhere and if you have the space you need to be 10 times that if you are thinking of using in the region of 3kW with your domestic appliances. In fact unless you are talking of a small microwave, a domestic oven will drain your batteries in no time.

The other thing you need to consider is the alternator capacity. I have been advised professionally that I need to upgrade my alternator to 150w from the existing 90W to keep my 200ah batteries in good nick. This is because I am having an air conditioner installed which will draw 800W,using a 1kW inverter. I have 210W of solar panels installed.
 
just googled this, and it says that the freezer will use 1KWh per day, whatever that means! gonna stick to the 3way fridge, but still really really want a freezer...so if it uses 1KWh a day how big a solar panel would we need, and if we got 2 big leisure batteries for the solar panel to charge, how big should they be?

i appreciate all your answers, but i'm more confused than ever!!
 
If you are doing a complete rebuild have a think about using built in chest type fridge/freezers. I've seen a couple of nice installations using the benchtops as the top of the fridge/freezer. Advantage is that when you open the top the cold air stays put inside the chest - whereas opening a door all the cold air drops out.

Waeco/Dometic make chest freezers - set of sliders and mounted inside a cupborad?

3 way fridges need to be T for tropical rated if you want reliable cooling in hot climates.

Welcome to Our Website are in Oz but I'm sure there are similar in the UK, but it gives you an idea of whats possible.
 
can we ask why so much you need a big freezer . i live in my truck half the year and have never really found the need to go too big on the freezer. i would like a fridge with half freezer hopefully get it soon . but thats really extavigant i think. you really are asking alot to power so much by solar and battery. if you get in a few weeks darkness you will be in trouble . the winter is a bit of a bugger even in spain or portugal. in the day isnt so bad but in winter its short days long nights. . where are you planning to go with it. sorry to ask so many questions but you are asking alot . maybe you will have to get a big gennie. you may have to have a rethink. the battery bank alone will be quite a size to cover your needs.
 
we're in the process of totally renovating our camper....on a budget!
Click to expand...

The last three words are the deal-killer


Seems as if there are a few optimists here. Perhaps they live in a parallel universe with entirely different laws of physics to those I know about.

Running 240V fridges from an inverter is not a particularly efficient way to keep food cool so to ensure you have enough power to cover say a week of very overcast weather, you will need a LOT of battery capacity.
Trouble is a LOT of battery capacity requires a LOT of charging capacity to charge the batteries up within a reasonable time and there are several ways to achieve this.

One is to keep moving on every couple of days and fit a high-capacity alternator-to-battery charging system.
Another is to use campgrounds with EHU and recharge the batteries from a decent mains charger big enough to fully recharge the batteries overnight. A generator can be carried to provide power for the fridges and charging in emergencies.
Then there is solar. Seriously misunderstood by many and rarely sized big enough to cover the sort of demand that you want to place on the system. Panels flat on the roof in high latitudes in the middle of winter will give you 2/3 of 3/4 of close to zero and even in high summer in spain will deliver about half of what you expect. A properly-sized solar system is magic, but don't expect it to do the job if you have a limited budget


Other alternatives include buying a 12V compressor fridge and spending a few thousand on a decent solar system or stick with the tried and tested (and sometimes found wanting) three way absorption fridge. Make sure it is installed strictly to the manufacturers specifications and they will usually do the job. Source a genuine "T" rated unit and they will work in areas close to the tropics as well.

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like i say at the moment i,m running a 65wat larder fridge in my house from an extension lead from the trailer. itas 3x80wt panels 2x200amp batteries and a ring 2kw inverter. other than a couple of week ago its been running it since early may. for a while i ran the deepfreeze as well but it was too much. in winter it struggles to keep the trailer 110wt fridge with small freezer comp running night and day. does work ok in maroc but not europe. so a further 3x80wt panels are going on the roof. all laying flat .not the best way but simple and easy. i do add batteries in winter and can charge on the move. as a rule of thumb through an inverter 11watt = 10amps near as dam it. so with about 6 hours of good light as the fridge cycles i have timed it to be on about 30mins in 1 hour so 5amps required to run my trailer fridge .so roughly i can keep the fridge on for 12-14 hrs aday. turn it off at night and it seems ok. but to run a big freezer seems far too many panels and batteries. hope this makes sense. with the extra panels i hope to be able to leave it on all night.
 
right...having a re-think!!! settling for the 3 way fridge, and possibly a table top freezer...getting another big battery, a 270ah, and theres already a 200watt solar panel on the roof, so gonna get another 80watt one......then those 2 will power the 270ah battery when we're not on the move. we're gonna be driving for about 4 hours every day anyway, so hopefully the solar panels will just be a back up

the other 2 leisure batteries are on a trickle charge solar panel, and they'll be enough to power a tv or little bits one at a time, cos we've already tried them out

why is everything so flippin complicated, or are we just making it that way!!
 
hi, it does take a bit of working out. like i say you could fit some caravan gas lights that saves abit of power. and gives a bit of heat in cool evenings . (get a box of mantles though as spares.)think simple . you stil havent told us where you are going. it may give us chance to direct you to things you may need on the journey. quite a few of us spend months at a time living in our campers so we have either made the mistakes or witnessed others and learnt from them. mistakes are costly. let us know . its different needs for different countries . what to buy where etc. you can loose or gain a few shilling by being a bit wiser. have a good trip where ever you go . cheers alan.
 
thanks alan.....we're planning on spending a year going round france, germany, spain and portugal then see what happens the following year

we've already got a solar panel installed....do you know if we bought another big one, do we link it to the panel we already have, or does it have to connected seperately to the batteries? what did you do? have all the solar panels linked, then cables connecting them all to the leisure batteries? or does one solar panel have to go to one battery? thanks xx
 
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