A good basic 12v for live in vehicle?

Hello,

I'm conscious that perhaps this should be in the newbie bit but then again seems to fit here so....

I'm currently converting a luton van to be my principle abode. I'm looking to fit it with a basic system with the best possible efficiency as I don't intend to move about a lot and so will be reliant on solar power.

I have 100W panel feeding 250ah battery bank with 5amps x 0.80 efficiency = 4 amps at best. Therefore I'd like the system to draw no more than 3/4 amps per hour. The idea being that on a sunny day it could run on purely the energy I would be dumping and that in general I deplete the batteries as little as possible and thus prolong their life.

I'm looking at a T-chip D class amp ( http://www.ebay.co.uk/itm/MUSE-M20-EX2-TA2020-power-Digital-Amplifier-T-Amp-2-20W-4-Silver-Power-Supply-/220956040788#vi- - http://www.ebay.co.uk/itm/MUSE-M20-EX2-TA2020-power-Digital-Amplifier-T-Amp-2-20W-4-Silver-Power-Supply-/220956040788#vi-content)

And then a couple of <6.5inch driver hifi speakers.

I won't be listening to anything extremely bassy.  Does the above seems suitable or is there any trick I'm missing?

Thanks


Edited by wildebeast - 17 August 2013 at 11:16pm

slightly tangential, but it would probably be worth getting a bit more PV than that - panels are so cheap now, a decent mppt and 200 watt panel can be had for a couple of hundred quid these days. A good rule of thumb is that you should aim for the system to fully recharge itself by midday on an average day, and have enough battery reserves to go for five or six days without sun...

Good PV potential estimator here:

http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#

Live on a solar powered barge, 1.7kWp array and 930 ah (c5) 48 volt battery...and keeping charged through winter not possible without genny/mains hookup...

Its more about keeping the battery optimally charged really, cheaper to buy more panels than replace batteries these days :)

Okay well I've got the wrong ones in this instance as they are monocrystalline silicon. On the other hand I did have a play with that calculator website linked to above.

I couldn't see any benefit to CIS over what I have BUT it was fairly clear about the advantages of getting an adjustable mount - twice the energy production in January.

Back to ebay.....

I've found with my panels, which are thin film, we do very well in diffuse light relative to a similar sized crystalline array - in winter here in London it's not unreasonable to get 0.5 kWh from an overcast midwinter day (though we still get the odd day with not enough to register), where crystalline arrays aren't producing anything. However crystalline arrays make up for it by producing much more on good days - so 1.7 kWp of thin film, or crystalline, will produce much the same amount of power for much of the year, and will average about the same over a year.

I do find that our panels overheat quite dramatically in summer (stuck to a steel roof in full sun!), which means our array is limited to about 800w peak. Best days are sunny with scattered cloud, peaks of 1.4 kW as a cloud passes.

Anyway, crystalline is so cheap now that unless you specifically need the characteristics of thin film (robust, always gives a bit of power, small modules, lower environmental footprint, etc.) framed conventional panels are the way to go, cheaper (and more reliable) to add a panel than go for a tracking array as well - at least going from 1 to 2 panels.

Though you do of course need direct sun for them to work, no good parked under a tree.

Oh, and the PV estimator is pretty good as a general guide, if you want to go crazy you can upload horizon profiles and so on...

Anyway, apologies for ramble...

Hrm......

Plus 1 panel with angle mount behind the flat mounted panel? Best of both worlds?

I'm pretty easy to convince to buy "the good stuff". Grade A+ magic beans you say? Sure thing they must be worth it...