Power generation

[Robbo]

I have no idea if you are correct or not Paul - but I do "kinda" get what your saying, which is going some as I'm one of the "newbie's" who is struggling with understanding how the whole power system works. So well done you

 

I'm currently at the point of asking Dave if it's ok for me to hoover, or use the bread maker or can I do a load of wash today (and do I need to turn the fridge off when I do)......my goal is to understand it enough that I won't have to ask and I can just get on with my tasks in the understanding I'm not going to blow up an alternator, damage the batteries or any of the other multitude of things I can damage due to an incompetent understanding of how the power system works.

 

If water was electric, batteries are the equivalent of a sponge.

[bottle]

 

If water was electric, batteries are the equivalent of a sponge.

 

Only if they are AGM's, open wet lead acid are more like buckets.

[Paul's Nulife4-2]

Buckets with a Hole in !.

[Robbo]

 

Only if they are AGM's, open wet lead acid are more like buckets.

 

That's just the structure of the battery. AGM's are still "wet batteries"

 

I think more a sponge than bucket as (although you could say it's more like a sponge filled holey bucket).

 

They leak.

If you fill them quick, you only get the surface wet.

To get them filled, you have to go slow when nearly full.

The bigger the holes the more water it can take quicker and release.

The smaller the holes the more the sponge will last as it has more material (but takes longer to fill and release)

Edited May 6, 2014 by Robbo

[Paul's Nulife4-2]

If only you could buy 'Spongey Batteries' !

 

 

Aaah Squishy !

Edited May 6, 2014 by Paul's Nulife4-2

[Bettie Boo]

 

If water was electric, batteries are the equivalent of a sponge.

That's a brilliant analogy

[Keeping Up]

Also as you use them, the small holes in the sponge gradually get bunged up with dirt and so it holds less and less water as time goes by. In a battery they call it "sulphation"

[Phil Ambrose]

 

If you increase your storage capacity you will still need to produce more - not only to fill the 'old' capacity but to fill the 'additional' capacity as well

That is true but a bigger bank does give you more of a buffer for the PV array to fill up, otherwise we would all be using just one domestic.

Phil

[George94]

We would all be using one battery?

 

Hardly.

 

We use more than one battery to give us more electricity to play with.

[Robbo]

We would all be using one battery?

 

Hardly.

 

We use more than one battery to give us more electricity to play with.

 

Well some of the Rolls batteries are fairly big!

 

Basically more battery capacity extends the time between charges.

[George94]

 

Well some of the Rolls batteries are fairly big!

 

Basically more battery capacity extends the time between charges.

 

Indeed.

[Phil Ambrose]

 

Well some of the Rolls batteries are fairly big!

 

Basically more battery capacity extends the time between charges.

That's why I suggested the 3rd option of more batteries to provide a buffer.

Phil

[bottle]

and more batteries means, for the same usage, each battery does not get discharged as much. so extending their working life. Allegedly.

 

but whatever you use you have to put back more.

[Phil Ambrose]

and more batteries means, for the same usage, each battery does not get discharged as much. so extending their working life. Allegedly.

 

but whatever you use you have to put back more.

So proving there's no such thing as a free meal.

Phil

[Robbo]

and more batteries means, for the same usage, each battery does not get discharged as much. so extending their working life. Allegedly.

 

but whatever you use you have to put back more.

 

But if using a generator or alternator to charge your batteries, more battery ah's can mean lower fuel usage per watt if you can get the generator to work at around 75% (most efficient) for majority of the time.

 

So if you have a 1Kw genny, try to get 50amps (12v batteries and worked out at 75% of 1Kw and with 80% efficiency) into the batteries most of the time can only be done with more capacity.

[George94]

In an ideal world, we would plan to have enough batteries to supply our needs between charges, without going below say 75% SOC.

 

Then we would select generators, solar panels, chargers and alternators to "fit" the charging requirement in the most cost-effective way.

 

But of course, this is a world of compromise.

[bottle]

Got that, next problem.

[Ex- Member]

I've noticed that the flexible type solar panels are creeping lower in price. Found some on e-bay nearing £1.60p per watt.

 

http://www.ebay.co.uk/itm/141174400839

 

I'm now seriously considering using a couple of these through the winter November to End Feb when our current 740w of solar begins to struggle and BB requires alternative charging. Our charge controller is maxed out though with our current panels. So we'll need to cater for this additional 160 watt of solar.

 

I'm assuming I can simply fit another controller to the new panels and start charging. I plan to simply remove the panels to storage through summer, so would leave connections available to quickly and easily reconnect when required.

 

Is there anything we need to be aware of with regard to the electrics especially with regard to the existing Outback controller.

 

Also even with this level of solar at 900 watts getting batteries fully charged would still be pretty difficult. Would it be too risky to add the 160w to directly charge without a controller.

[Robbo]

I've noticed that the flexible type solar panels are creeping lower in price. Found some on e-bay nearing £1.60p per watt.

 

http://www.ebay.co.uk/itm/141174400839

 

 

I would stay clear or confirm where they would be posted from, as things don't add up in that "THE PRICE DOESN'T INCLUDE CUSTOMS/TAXED/DUTIES, THIS WILL BE CHARGED TO CUSTOMERS." and the working times are Beijing hours and the some negative comments say they posted from China.

 

These are similar priced (£30 difference), but from a UK company - http://www.titan-energy.co.uk/sale--80w----semi-flexible-mono-solar-panel-107-p.asp

[Ex- Member]

 

I would stay clear or confirm where they would be posted from, as things don't add up in that "THE PRICE DOESN'T INCLUDE CUSTOMS/TAXED/DUTIES, THIS WILL BE CHARGED TO CUSTOMERS." and the working times are Beijing hours and the some negative comments say they posted from China.

 

These are similar priced (£30 difference), but from a UK company - http://www.titan-energy.co.uk/sale--80w----semi-flexible-mono-solar-panel-107-p.asp

 

Hi Robbo

 

Yeah I had noticed not long after posting. Strange the listing says item location London. Believe it or not I found the exact same link you've posted after spotting this, so it's in my browser favourites.

 

Hopefully these will come down further don't need to buy until October.

Edited May 10, 2014 by Julynian

[Robbo]

 

Hi Robbo

 

Yeah I had noticed not long after posting. Strange the listing says item location London. Believe it or not I found the exact same link you've posted after spotting this, so it's in my browser favourites.

 

Hopefully these will come down further don't need to buy until October.

 

They were about £130 about a month ago - I notice the prices change quite often on Titan so it may be worth giving them a call for prices.

[Ex- Member]

 

They were about £130 about a month ago - I notice the prices change quite often on Titan so it may be worth giving them a call for prices.

 

I'll keep my eye open, Bimble solar also come up with some good deals too.

[Justme]

 

I'm now seriously considering using a couple of these through the winter November to End Feb when our current 740w of solar begins to struggle and BB requires alternative charging. Our charge controller is maxed out though with our current panels. So we'll need to cater for this additional 160 watt of solar.

 

 

 

I assume that you have the FM60 controller. I would be happy to put all of your intended 900watts through that controller.

 

There will only be an excess in summer. In winter the total array wont be hitting the peaks for very long. Also remember that the actual charging voltage will be higher than 12v nom. So 900watts / 14v is only 64amps. The main issue is max peak array voltage. The panels will also need to be closely matched in peak V or peak amps depending on how you wire them.

 

I have 1200watts going into a FM80 & a 12v nom battery bank. Yes it caps the peaks but even in summer thats not for very long.

[Ex- Member]

 

I assume that you have the FM60 controller. I would be happy to put all of your intended 900watts through that controller.

 

There will only be an excess in summer. In winter the total array wont be hitting the peaks for very long. Also remember that the actual charging voltage will be higher than 12v nom. So 900watts / 14v is only 64amps. The main issue is max peak array voltage. The panels will also need to be closely matched in peak V or peak amps depending on how you wire them.

 

I have 1200watts going into a FM80 & a 12v nom battery bank. Yes it caps the peaks but even in summer thats not for very long.

 

That's really interesting justme Cheers. I actually wondered if that was doable.

 

We currently have 2 x 250w panels polycrystalline and one 140w panel mono crystalline around 35v per panel.

 

I'm hoping I could use these

 

http://www.titan-energy.co.uk/sale--80w----semi-flexible-mono-solar-panel-107-p.asp

 

We're currently wired in series but happy to go parallel if need be. If I could incorporate in series though they could be added with no additional wiring which would be a big bonus.

[Justme]

If you let me know the peak amps & the peak volts of each panel I'll look at dif ways of setting them up so you keep within the safe voltage zone & max out the production.

 

It is also worth noting that high voltage DC is just as if not more deadly as mains AC.

 

 

Its also worth noting that you current set up if they are all wired in series & are 35v for each panel then the max input current is 4 amps (due to the 140 watt panel throttling the others back) so the array can only produce 420 watts max. What does the Outback say when its sunny?

 

 

edit to add,

 

If you added one of those panels in series to all yours in series you would be very close to the release of magic smoke voltages on a sunny but cold day.

 

What you need is to have two or three series strings in parallel.

Edited May 11, 2014 by Justme