Ideal electrical set up???

[ghost123uk]

im doing all this from a bardge off the coast, arn't Andriods Great! Lol.

I got ragged for doing this once before as the guy took it in the wrong spirit, but I never learn, here goes =

Yes andriods are great, and even better with a spell checker app installed

The fridge is not bought yet - I sappose the first Q is what amps range is siutable, the fridge doesnt have to be great all its gotta hold is milk and meat or hold a 6 pack for exsample.

OK, any fridge will hammer a battery, simple equation of energy required to cool stuff equals too much for a battery to supply for very long at all. My "average" fridge uses about the same as having both headlights on so will run down a 85AH battery in no time.

You really need to be looking at a gas powered fridge (usually found as a "2 way" = 12 Volt and Gas or "3 way" = 12 Volt, 240 Volt (mains) and Gas). On a 4.5 Kg Calor gas bottle the fridge will run for many weeks. The only way to go imho. Try and avoid the "907" size gas bottles as they work out a lot dearer to use.

As for lights, get LED types (cheap on Ebay) they use so little power they can be pretty much ignored. They come in a wide variety of colours = Ice White, Warm White (best imho) and all other colours

[v-lux]

OK, any fridge will hammer a battery, simple equation of energy required to cool stuff equals too much for a battery to supply for very long at all

That very much depends on what sort of fridge you have....

Long thread about just that here: https://club8090.co.uk/forum/viewtopic.p ... sor+fridge

[ghost123uk]

Fair enough but unless you come across a bargain you are looking at 300 to 500 £'s new

[v-lux]

Its true, they ain't cheap...

However, never have to buy anything to keep them running. Gas will always run out. Not much of a saving i know, but ever little helps.

My fridge is actually so efficient i barely ever turn it off these days.

[trentjim]

Yep.. all the decisions start with the fridge - chose a model & work out how many watts that will gobble... then whether you drive enough miles to top up flat batteries via the alternator becomes the next pinch point - the panels will help out a lot in summer but be near useless in winter - were you going to have a heater? . you may need to consider whether you can get access to a hook up point or run a generator if you are planning full time use through the winter without doing many miles.
if you find you dont have a sufficient recharging capacity for winter use you might need to swallow the cost of running a gas fridge

[GoosemanG40]

[quote="trentjim"]
Yep.. all the decisions start with the fridge - chose a model & work out how many watts that will gobble...

Thats my next perchase so im looking into it very carefully, im torn betwen the http://goo.gl/6QHbX or the http://goo.gl/k2DqL
but only because the once choosen fridge will be built into the cupboards, so astheticts.

[quote="nesty"]
Additionally I have 2 X T105 Trojans. These batteries are ace! They really give you decent power for small space. I have mine connected up in serial circuit making 6v to 12v

Im I've looked into this Nesty and that set up looks great but i cant help thinking it might not be enough for me as i shant have any windows in the back, so no natueral light... 1 I thought 3 Trojans might be the way forward at 6v 240ah each, but then that makes it 18v, should that matter 2 I couldnt find any 12v equivalent with the same ah out put, can you point my in the right direction please. I do big distances on Fri's and Mon's so as long as it can last for 5 working days im not fust, I can alway get a quick hookup at work if last resort and two I always charge over weekends.
Goose

[kevtherev]

Your wrong to assume it's 18 volts batteries connected in parallel share the same voltage only when connected in series you add the voltage of the batteries together

so with 6 v batts.. two in series and two in parallel would work

[GoosemanG40]

ok so i could run two in series and the therd parallel does that make sence a forth i cant afford...

as an additional feature to charging I'm considering this. its got great reviews and will really help with the charge management.
http://www.sterling-power.com/products-altbatt.htm" onclick="window.open(this.href);return false;

[ghost123uk]

I thought 3 Trojans might be the way forward at 6v 240ah each, but then that makes it 18v, should that matter 2

Yes.

As Kev points out you can either get 1 huge 620 ah (3 x 240 ah) 6 Volt battery (parallel wired) or 1 x 240ah 18 Volt battery, (series wired) neither of which is any use

You mention worries about having no widows but remember LED lighting uses so little power, even a very average leisure battery would run them for many days, or even weeks (depending on how bright you want it in there !)

The fridge is the only thing that is a drain worth taking into account.
Both those you link to use 35 Watts, assuming that is only when actually running, the built in stat will probably have it actually "on" for maybe 10 to 20 % of the time to maintain temperature) This = 3 Amps by the way.

Lights (LED) ain't a problem.

[ghost123uk]

ok so i could run two in series and the therd parallel does that make sence a forth i cant afford...

No = you certainly cannot do that, end of

as an additional feature to charging I'm considering this. its got great reviews and will really help with the charge management.
http://www.sterling-power.com/products-altbatt.htm" onclick="window.open(this.href);return false;

Whilst not having personal experience of these, many on here and elsewhere rate them very highly.

[GoosemanG40]

ghost123uk wrote No = you certainly cannot do that, end of

right oh Ghost thanks for clearing that up ill look closely at the battery situ and work out what i can afford.

[trentjim]

goose... just noticed you are ok to plug in for the weekend.. You are therefore looking for power to last from monday morning to friday afternoon correct? - 4 nights?
is the 15 miles you estimated a daily movement or a total for the monday - friday if its daily then with the right charging setup you might see an input of 25Ah per day (maybe more if you are hanging around in traffic), which would be a pretty helpful contribution to offset consumption... if its only 15miles a week then you will need to rely more heavily on storage from the home hookup.
I think that as your peak energy usage is going to be in winter, and as you are going to hook up at weekends, that the solar panels are surplus to your requirements, though they may help to avoid deep cycling the batteries in summer - you can't size the system based upon their contribution

with my (theoretical) reckoning on 46Ah per day for an electric fridge
then how much are you going to use the heating? how many amps for how many hours? pluck a figure out of thin air for now and say 40Ah per day
allow a bit for laptop, phone,lights and waterpump gets us to a ballpark 100Ah per day total in winter
you want to last from monday to friday so thats 400Ah ish total (then subtract the input from driving... 25 or 100 ah)
How hard do you want to work your batteries? how long do you want them to last?
as you are doing this every week...if you want to try and keep to 50% discharge for longevity on leisure batteries then you want about 600 - 800 Ah of storage -Ouch!
Since the Trojans allegedly handle deep discharge better you could perhaps drop this to a Trojan reservoir of 300 - 500Ah...

you need to reseach the consumption values more tightly so you can size the system more precisely than this as there are substantial costs, both in terms of finacial and weight/space, if you oversize it. If you undersize it you will need to do a bit more driving, idle the engine or top up with a generator

[GoosemanG40]

Since the Trojans allegedly handle deep discharge better you could perhaps drop this to a Trojan reservoir of 300 - 500Ah...

Wow that really brought home actually how much i need.

Ok so on a WAECO CDF-25 Fridge its between
0.44 Ah/h at +20°C ambient temperature,
0.67 Ah/h at +32°C ambient temperature,
both at +5°C interior temperature

at +20c that'll be just over 10amps per hr so i Might get the J250p x2 which make 500AH
http://batterymegastore.co.uk/product/J250P/" onclick="window.open(this.href);return false;

with charging over the weekend and turning on only when i really need it it should do.

[AdrianC]

Trying to figure the cost of charging with an alternator... this is what i've got

Idling consumption of a merc sprinter van
2.2 4 cyl AC on: 0.86 Litres per hour
2.2 4 cyl AC off: 0.49 Litres per hour

i'snt an aircon fuse usually 10A, so lets guess the aircon load at 8A.

<goes back several pages, in new-to-him thread>
Small problem with this - you're assuming all the load on the engine from the aircon is electrical - it isn't. Most is going to be mechanical, since the pump is belt driven.

[trentjim]

I figured on the way in this morning that I might have the sprinters figures completely wrong, as I dont know for sure if the Air Con compressor is electrical or belt driven (IIRC the Air con on my old MGF was belt driven off the alternator pulley).

quite right... quote above was my next post on the thread... I twigged that once i'd slept on it
still havn't been able to find anything reliable to calculate the "fuel consumption" of an idle engine loaded with an alternator pushing 50A or so