Question for the solar panelists.

[8ob]

As per title,, I would like to install some solar panels on my man cave roof that would run my 1000ltr electrolysis tank and also trickle charge the trucks. Can this be made simple or is it going to get overly complicated? I don’t need it to do any more than this, looking for ideas and a bucket list. Over to the collective, be gentle

Bob

Needing 24dc out of this.

 

[Blobber]

Sits back with a nice cup of tea to await the overcomplicated million pound installs along with the tube videos to support the facts!

 

[frank horton]

I'm planing the same but 7,5kw ish.....also need 3 phase.......dohhhhh.....
still trying to sort out what I need.....

 

[500e]

 

[voipio]

What are the power requirements of the electrolysis tank? Is there mains to the shed already? This may help to determine how many solar panels to buy.

Get a decent 24V lead acid battery, and make this the "centre" of the setup. Get a 24V MPPT charge controller, plus as many watts of solar panel as you can manage, and a mains powered variable power supply with current limit protection (ideally capable of constant current mode) able to deliver 24V or more. Make sure the solar panels are good for 24V systems. Set the mains power supply to deliver something like 27V output and connect to the battery. It should keep the battery reasonably close to being topped up. Connect the MPPT charge controller to the battery, and then the panels to the MPPT. The MPPT charge controller should be set to a default for charging the batteries up to something like 27.6V (possibly up to 28.4V). When there is enough sunlight, the solar panels will be the main source of power to the battery. Connect the various "drains" e.g. truck trickle charge, electrolysis tank and so on to the MPPT's battery out terminals. A setup such as this will give some protection from power interruptions (solar or mains). Get a feel for how this works for you. Panels and batteries can be added at any time, to add to the system capacity. You can then try lowering the output voltage setpoint of the mains power supply to allow the battery to drain somewhat in the absence of sunlight (the amount being dependent on the mains power supply setpoint voltage; e.g. 24.1V for 50% or 24.6V for 70% battery capacity). The charts here might be a useful guide: https://footprinthero.com/lead-acid-battery-voltage-charts

Don't forget to put appropriately rated fuses where necessary.

@500e's diagram is a good guide, except for the DC output, which should read 24V for this particular setup.

 

[sako243]

I know a bit about @8ob's intended use because we were talking about it - the main point of this is not to use any mains power doing the electrolysis.

What I'd proposed was verbally what @500e illustrated above with then a low voltage cut-out downstream of the batteries and a DCC supply (well only really a current limit) to regulate how much power is used by the tank. From my brief reading on this anywhere from 0 to 20A is a reasonable consumption for the tank at 24V. I may be completely wrong on this.

The beauty of that set up is that Bob only needs to dump stuff in and switch it on. If the batteries are charged up / solar is providing enough power then the tank is running. Once the sun disappears / batteries get discharged then it switches off and will then automatically restart when the sun charges up the batteries enough.

Obviously any trickle chargers etc., can be fed off after the cut-out meaning that they get charged whilst the sun is out.

 

[hotponyshoes]

For simple,
Battery changing is easy, 2 or 3 x12v panels in series, connect to a 24v charge controller. Ideally the controller wants to have one output for each truck.

Do you need to run the tank constantly?
I've never tried but what would happen if you put something in there for a week and only had it actually functioning for a few hours a day?

 

[minimutly]

For simple,
Battery changing is easy, 2 or 3 x12v panels in series, connect to a 24v charge controller. Ideally the controller wants to have one output for each truck.

Do you need to run the tank constantly?
I've never tried but what would happen if you put something in there for a week and only had it actually functioning for a few hours a day?

And this would happen overnight or during cloud cover especially in low sun. During misty weather you might be effectively offline for days, remember - in winter you will be down to 10% of peak summer output.

 

[pressbrake1]

Mppt charger, some batteries and a inverter
Done

 

[8ob]

A few more points, swmbo`s horsebox is permanently on charge/hookup, there are always other batteries on charge for things like the electric fencing and the odd van/truck battery, not sure what needs ordering in the way of panels that could run the hookup, battery chargers and the electrolysis tank simultaneously . not even sure what kind of supply the electrolysis tank needs. With all that in mind could do with some pointers at the best way to distribute the power and some kind of idea about panel output/numbers.

Bob

 

[Gareth J]

Only electrolysing when the sun shines - brilliant idea!

Assuming you have a grid connection at the shed, weigh up the pros (cheapness, simplicity, no need to get the DNO involved) of a DC only install, with the cons - you can't use solar to offset expensive electric at all other 240v AC points before the meter. Hence reduce your payback time more quickly.

A grid tied hybrid inverter will set you back between, very roughly, £200 and £400 per kW, depending on the size and quality.

 

[MattF]

Do you need to run the tank constantly?
I've never tried but what would happen if you put something in there for a week and only had it actually functioning for a few hours a day?

It'll come to no harm if not powered. It's an alkaline solution, so the piece(s) would be safe.

 

[julianf]

I assume there is mains electricity there currently?

If so, by far the cheapest, simplest way to do things is get a selection of second hand panels, and a grid tied inverter to match them.

They come up second hand all the time.

The grid tied inverter needs to be sized to the panels... So either but a complete setup, or get the panels and then find an inverter to match.

Batteries are expensive and, this way, the extra power generated is available to everything else on the system. Sure, you'll pay for the electrolysis during the night, but this cost will be more than offset by all those units you won't buy in during the day for other stuff.

As an indication of cost, I bought a system, used, a couple of years ago, 4kw, with inverter, mounting, the whole kit for just under £500 off Facebook, locally. Sure, that was a good deal, but it's not a million miles off stuff that's available if you keep your eyes open.

 

[8ob]

It'll come to no harm if not powered. It's an alkaline solution, so the piece(s) would be safe.

I realise none of this will work at night, its not that important. The tank will be outside and whatever is in it can stay there until its derusted. Looking at @500e `s diagram and wondering if I wouldn't be better off with four panels and two of those charge controllers, thats instead of a load of cleverness trying to run the chargers and power supply to the tank at the same time.

Bob

 

[Kayos]

What size area have you got?

Match the inverter size to the peak kw output of the panels, slight oversize is OK

I am happy to supply pics of my millions of pounds installs

 

[Popcorn]

https://www.amazon.co.uk/Jetcloud-Charging-Battery-Controller-Waterproof/dp/B0BBB2WGGW/ref=asc_df_B0BBB2WGGW/?tag=googshopuk-21&linkCode=df0&hvadid=622397534057&hvpos=&hvnetw=g&hvrand=5787961768682370834&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006816&hvtargid=pla-1873828638403&psc=1

 

[Barking Mat]

I honestly wouldn't bother @8ob , if you've got 220v just use that for your electrolysis and trickle chargers.

The outlay, maintenance and replacement costs long term would be financially counterproductive I'd imagine.

 

[knighty]

yes as above... get some used panels and a used grid tie inverter

when power/charge things with bog standard trickle chargers

ok you'll use a bit of mains power at night, but that will be offset by the lower electric bills because you'll generate too much during the sad and used it for other things (anything that's on your side of the meter, house, office, whatever)

julianf sounds right above, get 2nd hand stuff cheap​

 

[joebog1]

I did solar installations for more than 30 years.
If you dont wanna put the money in, you wont get nuthin out.
for knighty, second hand solar panels !! How many do you want ?.
They are one of the largest pollution problems we have in Australia right now.
They have a VERY finite life!!! Thats finite, not infinite. Somebody suggested MPPT controller !!! . YES perfect suggestion.
24 volts is peeing in your own pocket, minimum I will do is 48 volts as a minimum, and preferably 60 volts.

I have been roused on before for telling the truth!!. I hope this in ONE truth thats at least checked up on.

With respect

Joe

 

[henry Kadzielski]

I know a little about this also.
I have a truck 24v electrics, so I put 6 250w panels on the roof, fitted a MPPT 45amp max solar regulator, which charges the aux batteries in the truck(2 by 230amp/hr AGM's). This then powers the DCfridge freezer and the 2000w pure sine wave invertor with 50% overload capacity. When the truck engine is running the truck's alternator will charge the aux batteries through a continuous rated solenoid which is switched in the truck cab. So I have the DC system charged when I am stopped as well as 240v single phase to run the split system AC, boil the kettle, run the compressor etc workshop bits when there is no power out on site. The biggest advantage is when travelling from site to site, especially in summer when the outside temp is mid to high 30's and you are tired, the cab internally can be as low as 16c, so sleep is not a problem. I make my power fresh from the sun every day