Experienced Electrician! Here to Answer Any and All Growroom Electrical Questions

Discussion in 'Grow Room Design & Setup' started by bricktown73, Apr 7, 2009.


    Closetgardner Well-Known Member

    As far as I know the only panel is on the ground floor next to the electricity meter.
    I only want to run 300/400w of cfl for veg. And a 600w hps for flower, and the necessary fans for each tent.
    Im no electrician so I don't know if thats a lot. My main concern really is, if someone saw a cord coming from the roof into say,a bedroom socket. Well it goes without saying that it would arouse suspicion

    ScoobyDoobyDoo Well-Known Member

    chances are you already have electricity somewhere in the attic. usually there are lights in your attic and if you have high hats (recessed lighting) then it's run through your attic. what you want to run can all be don e with 12/2 romex and a 20amp breaker.

    is there anyway for you to snake a wire down the side of the wall to the breaker panel?

    Closetgardner Well-Known Member

    There's no lights in the attic at all man.
    I've had a look and I can take a wire from the attic into the boiler cupboard, then through the floor into the cupboard (directly underneath?) where the electricity breaker/meter is located.
    If you can tell me what things to buy I'll get into my nearest city over the weekend and buy the stuff.
    Thanks again man

    ScoobyDoobyDoo Well-Known Member

    depending on how long the total run is you should get a 25-50' roll of 10/2 romex. 2 single gang electrical boxes. 2 Lutron commercial grade 20amp duplex receptacle & faceplates. total cost should be around $50-$100 max. you will also need a 20 amp breaker. it has to be the same make and model as your existing breakers. take a picture of your electrical panel door and then a closeup of the breakers with your phone and when you go to the store just find the exact same ones.

    Stevie51 Member

    I notice your location is Scotland. I hope the readers of your post realize this when responding.

    Closetgardner Well-Known Member

    Yh I hope so. I never thought about that

    Sparkz125 New Member

    Hi there

    I have a question about running a full grow off batteries...

    basically as my situation stands I'm going to be moving onto a canal boat where we have power on board threw the batteries which are charged from the engine, my plan is to buy a couple (hopefully no more than 2) deep cycle batteries which are dedicated to run a set of led grow lights plus fans, I want to have the batteries to charge up as normal through the engine, which I hope means I won't have to run the engine more than the normal twice a day to top them up..

    how possible does this sound and what advice can you give me as this is a must have thing if I'm living on a boat haha :)

    hope to hear from sombody

    ExileOnMainStreet Active Member

    The first thing you'll need to do is a load analysis to figure out how many watts your proposed system will draw. Then you'll need to figure out how many amp*hours of battery you'll need to know if it's going to be feasible. Keep in mind that you don't want to draw a deep cycle battery below 50-60% of its capacity or you'll shorten its lifespan considerably. What that means is that you'll need to install almost twice as many batteries as you calculate you'll need.
    This is the single most common mistake people make in planning off-grid installations.

    For reference sake, 2 deep cycle Group 31 batteries will give you an honest 100A*h when new: about the same as a pair of Trojan T6 6V batteries wired in series.

    Sparkz125 New Member

    So I've think I have found out a rough guide on wattage with the appliances I wish to get

    budmaster 450; consumption is apparently 300w
    a couple fans one for extraction and one for circulation both small low power so hopefully no more than an extra 40w I think

    from this how would i work out how many amp*hours of battery I will need?

    Also I gather from what you was saying that Trojan t605 6v batterys wired in series would be a better option??

    ExileOnMainStreet Active Member

    Sorry, that should have been Trojan T105 not T6. It all comes down to costs and availability: many people go with T105s wired in series because the batteries are widely available, inexpensive and are often available as surplus from equipment where they're changed out as part of a preventative maintenance regime regardless of whether or not they're showing diminished capacity. The drawback is that a two-battery bank won't run with one battery down and the one dead (shorted, sulfated, etc) battery will quickly draw the other down as well. If you're buying new, I'd go with 2 12V batteries through an isolator and a battery switch because your system will still function, albeit at reduced capacity, on one battery.

    The next thing you need to figure out is what light cycle you're going to use for veg. Because of the consumption, you may not want to go 24/0...or you may want to build your system so you can...that's up to you.
    Let's assume 500W for everything. If you're running off batteries, I'd suggest PC fans exclusively for circulation: they are made for use where power supplies are limited and meant to run on 12V, so they can be powered directly off the batteries without the inverter losses that come from running an inductor (motor) off of a MSW (less expensive) inverter.

    That's 500W/220V= 2.27 Amps. We now multiply that by the hours of runtime to get Amp*hours (A*h), which is why you need to decide on your light cycle. The 50 A*h of usable capacity in a 100A*h battery will give you 22 hours of run time if there are no other draws or losses. You will have a bit of loss from the inverter used to convert the DC back into AC, but even the most inexpensive Xantrex units are well over 90% (stated) efficiency.

    In itself, that's not so bad: you are looking at about one group 31 battery per day of runtime before you need to recharge. It's recharging that presents a bit more of a the problem: if your charge rate is 10A @ 12V, it will take 5 hrs per day to replace the energy you use. You'll need to find out what your alternator's charging capacity is, derate that (usually by ~20%) and subtract what the rest of your electrical system uses. What's left is what you have available to charge your grow batteries...which will probably mean installing a larger (or an additional) alternator.

    Some food for thought: I did a refit on an old ocean tug that was used to pull a spud barge to a job and then as crew quarters. Since the engine was being used to charge the batteries more often than for propulsion, it worked out cheaper for them to install a separate AC generator to run all the time than it was to run the engine every day to recharge batteries.

    Sparkz125 New Member

    Wow thanks for all the info, that has helped me a great deal to understand some of the measures to take into consideration...

    I understand what you mean about the Trojans now, I probably will go with your advice and get 2 12v as your logic behind it makes more practical sense.. As for veg lighting I was thinking possibly 18/6 maybe 20/4 if it all works as good as I hope..

    i was looking at alternator upgrades and after a quick research it sounds like a 70amp 12v upgrade is easily possible but I don't know what the spec of the one I have already fitted is, I might be able to use what I have but otherwise if I was to have two 150ah Trojan t1275s that would give me a total of 300ah, of which 150ah is usable without causing damage to batteries, so going by your 500w/220v for example should give me 60hrs runtime before charge is needed... By using a 70amp 12v alternator taking into mind a few things would mean it will take around 3hrs to get back to a full charge? Surely I've gone wrong somewhere it sounds a bit too efficient, not that I'll complain if it's right... Lol... And what sort of price figure comes to mind when u think of the kit needed to make a grow possible? Any ideas of an estimate?

    As it stands I'm still quite new to this and all this info is going to help me prepare for this project when I move in the near future, haven't got dates yet but looking around April, so in the mean time I may have a quite a few questions to ask on here,

    if anyone has any advice that comes to mind than please let me know.. Everything is helpful


    ExileOnMainStreet Active Member

    I couldn't begin you estimate what it would cost in the UK. Here in Canada, you'd probably be looking at $600-800 to buy the batteries, isolator, inverter, switch and cables. A basic 100A Balmar marine alternator with internal regulator will run you around $1000, plus 10-15% for an installation kit for your engine.
    That's just for the boat upgrade, grow equipment is on top of that.

    If you have the space, 4D and 8D batteries (~$350-500) might be a better way to go in terms of capacity, though you'll definitely need the extra alternator in that case. 8Ds typically kick out around 200-225 A*h each. They are commonly used as forklift batteries and, like T105s, may be found less expensively at auctions or disposal sales than buying new.

    Good luck with your build - I'll be interested to hear how it works when you get it up and running. This is an area where manufacturers are notorious for overselling their products, so real-world experiences and results are always good to hear about. I don't get on here too often so feel free to pm me if you wish and I'll get an email.

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