HELP needed; Wire size for minimum voltage drop, etc.; full house 12v lighting off-grid

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  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    While we are considering top quality here, what about the Xantrex XW MPPT 60 Amp?
    I thought Xantrex was the 'flagship' of solar in terms of quality? $480 at NAWS + $204 shipping

    Does anyone have input on the MPPT vs PWM argument? MPPT maximises PV input, PWM maximises battery life; battery cost vs extra wattage!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Sascha wrote: »
    While we are considering top quality here, what about the Xantrex XW MPPT 60 Amp?
    I thought Xantrex was the 'flagship' of solar in terms of quality? $480 at NAWS + $204 shipping

    No comment. Count the number of times I've recommended Xantrex equipment. You'll have fingers left over. And it isn't the actual equipment that is the problem. Whoops! That was a comment. :p
    Does anyone have input on the MPPT vs PWM argument? MPPT maximises PV input, PWM maximises battery life; battery cost vs extra wattage!

    I don't know where you got the idea that PWM "maximizes battery life" - possibly from the notion that the pulsing helps desulphate batteries? There's not as much to that as some might have you think. Many batteries charged from MPPT have outlasted those on PWM controllers; it is mainly due to having the right system set-up more than the controller type.
    On the whole, the larger the array the more it will benefit from MPPT function. Then there is the added bonus of more configuration flexibility with MPPT. Being able to run a high Voltage array can solve a lot of problems with V-drop and wire sizing.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    No comment. Count the number of times I've recommended Xantrex equipment. You'll have fingers left over. And it isn't the actual equipment that is the problem. Whoops! That was a comment. :p

    Thanks Mark (it is Mark, isn't it?), I'll cross Xantrex off the list without further ado. :D
    I don't know where you got the idea that PWM "maximizes battery life" - possibly from the notion that the pulsing helps desulphate batteries?

    Yes, that's what I came across googling the two. I personally lean far more towards MPPT. It's similar to boosting a cars performance with computers by maximising revs between gears and other things. Some people don't understand how one can exceed standard capabilities of equipment, some even think it's impossible.

    Hey, have you just recently been promoted to super moderator? I don't think it was there a few days ago. If so; congratulations, well deserved. 8);)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Sascha wrote: »
    Thanks Mark (it is Mark, isn't it?), I'll cross Xantrex off the list without further ado. :D

    Actually it's 'Marc', which isn't surprising for Canada but would be terribly confusing if you knew I was born in Warsaw. :D
    Yes, that's what I came across googling the two. I personally lean far more towards MPPT. It's similar to boosting a cars performance with computers by maximising revs between gears and other things. Some people don't understand how one can exceed standard capabilities of equipment, some even think it's impossible.

    No trickery here; it's just physics. The power is the same coming in and going out (minus a bit for the controller op), just re-arranged in terms of Volts and Amps.
    Hey, have you just recently been promoted to super moderator? I don't think it was there a few days ago. If so; congratulations, well deserved. 8);)

    That label turned up some time ago. Nobody knows why. :confused: Probably a software glitch.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Actually it's 'Marc', which isn't surprising for Canada but would be terribly confusing if you knew I was born in Warsaw. :D

    Hey Marc, 'my neck of the woods' (not quite but close). I used to be a Slovenian national (former Yugoslavia) but born in Germany. :D
    That label turned up some time ago. Nobody knows why. :confused: Probably a software glitch.

    I thing it may have something to do with your number of posts. Mine changed from new guy to something else and now to not so new guy. :cool:
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    Sascha, Sometimes nws not using usps loses a sale from me. Don,t understand why they don,t use the PRIORITY SHIPPING BOXS FOR SMALL ITEMS. The way that works is whatever fits in the box ships for the same price regardless of weight. I shipped a mx-60 controler in a box for $8.00. Probably if I used ups it would have cost $20. :Dsolarvic:D
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    solarvic wrote: »
    Sascha, Sometimes nws not using usps loses a sale from me. Don,t understand why they don,t use the PRIORITY SHIPPING BOXS FOR SMALL ITEMS. The way that works is whatever fits in the box ships for the same price regardless of weight. I shipped a mx-60 controler in a box for $8.00. Probably if I used ups it would have cost $20. :Dsolarvic:D

    Hi Vic,
    It's a shame really, their prices are very good! I'll email them to see if they are flexible on the shipping, unless some of the moderators here can contact them and arrange shipping. PLEASE!;)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Sascha wrote: »
    Hi Vic,
    It's a shame really, their prices are very good! I'll email them to see if they are flexible on the shipping, unless some of the moderators here can contact them and arrange shipping. PLEASE!;)

    Nope. No can do. Sorry.
    We moderators are volunteers here and have nothing whatsoever to do with NAWS and how it runs. Your best bet is to contact them yourself and get a firm quote on purchase with shipping.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Nope. No can do. Sorry.
    We moderators are volunteers here and have nothing whatsoever to do with NAWS and how it runs. Your best bet is to contact them yourself and get a firm quote on purchase with shipping.

    No worries Marc, sorry if I crossed a line there. I didn't know what your connection is with NAWS.:blush:
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    Not a problem.
    There's quite the "arms length" association between NAWS and the forum, which is unusual for such an endeavour.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    I've emailed NAWS to quote USPS shipping if possible, included the eBay quote for comparison. I got a prompt reply confirming they can ship via USPS for approximately $100 which sounds great! I need to contact them at the shop to get that shipping price.
    So Marc, are you happy with your OB MX60? So the FM60 is the next generation of the MX60, have looked at one of your previous posts on this.
  • mike95490mike95490 Solar Expert Posts: 8,429 ✭✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Does anyone have input on the MPPT vs PWM argument? MPPT maximises PV input, PWM maximises battery life; battery cost vs extra wattage!

    meh ! MPPT controllers, as soon as they are done with bulk, revert back to PWM, so you get some of both ! And the DC-DC conversion internally, for the amps boost, is likely screaming along at 30 - 50 KHz so ther are "pulses" too.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    mike90045 wrote: »
    meh ! MPPT controllers, as soon as they are done with bulk, revert back to PWM, so you get some of both ! And the DC-DC conversion internally, for the amps boost, is likely screaming along at 30 - 50 KHz so ther are "pulses" too.

    Thanks Mike, it was just curiousity to see others opinions on that. I'd prefer mppt.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Can you charge the battery from an AC source and add panels later? You certainly can! I don't know how many times I've helped people set up systems like this - dozens at least. All based on "can't afford the panels now". Usually they're remote cabins and charge from a generator power something like an Iota charger or a good inverter with built-in charger. But the process is the same. The only trick is that you have to know when to turn the charger on. Some, like the Iota, can be left to handle the task on their own. Others require monitoring. Or you could rig up a simple timer to come on once a day and see through the charging cycle and then turn off so the charger isn't eating up electric unnecessarily. These chargers are not quite as good at recharging deep cycles as solar panels & controllers, even though they're made for it.

    I see no reason why you couldn't maximize your PV output by selling all its power to the grid and then buying back whatever is need to recharge the "emergency power batteries". Just remember that if the grid goes down, so does the battery recharging (without additional rewiring and fuss).

    Hi Marc,
    EUREKA!!! I found a way to integrate the solar PV & OB FM60 into the Victron 24/3000/70 UPS/inverter charger. :DThe Victron can be programmed via a 'virtual switch' in such a way that the inverter function of the Multi is switched on when the battery voltage has increased to a certain value (indicating the batteries are charged). Simultaneously the back feed protection relay in the Multi is opened, this to prevent power to be fed back into the mains. The Multi can be programmed to switch back to mains supply when the battery voltage has decreased to a preset voltage. The Multi remains off until the solar panels have recharged the batteries. I will have to purchase an interface to connect the UPS to a laptop and adjust the settings but I think it's worth the $100. The interface will also be used for detailed monitoring through the BMV600 battery monitor.
    So it is possible to use the UPS in reverse; use battery power as the main source andonly supplemet the mains charge or throughput when solar activity is low and/or bateries are discharged to a pre-set level. This way the batteries won't get discharged to a damaging low.
    I've attached a file if you'd like to dig into the manual to confirm this. :-)
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    Hi Marc,
    Long-time-no-chat!:cry:
    Before I start cutting the 0 AWG cable, would it be possible to split the 24v/440Ah bank into two 12v/440Ah banks?
    Well, I know it's possible but what are the pro'a & con's of doing this?
    I'm thinking about running some 10mm2 cable directly from the battery bank to power the 4 x LCD TV points, since all our small LCD TV sets have an additional auto lighter socket power supply cable and they are OK to run directly from 12v car batteries, regardless of the voltage fluctuation one would experience through a direct connection. Rather than power these points through the inverter i'd like to connect them directly so I don't lose amps converting the battery bank's 24 volt to 240v and then back to 12v. THe batteries I have are 6v/220Ah.
    If I had two banks, each having 4 batteries in parallel to produce 6v/880Ah then in series to produce 12v/440Ah. The 2 x 12v/440Ah banks derived from this would then be wired in series to produce 24v/440Ah to power the UPS-inverter/charge controller.
    Is it possible to use one of the two 12v/440Ah banks to output 12v directly to load and then daily or weekly switch from one 12v bank to the other to somewhat equalise the extra load/discharge, perhaps start off with using 'jump starter lead clamps?
    Man, I really want to get this right from the start rather than wasting batteries and learn the hard way. Would I need some kind of separation between the two 12v banks before they are joined together into one 24v bank to avoid the other bank crossing over and increasing the voltage to 24v+, if I want to use them at 12v?
    I have received most of the components; 25 ft of 0 AWG, terminal connectors, 2 x fuse holders with 200A fuses (each 12v string before joined to 24v) and 12 ton crimping pliers so I'm ready do 'cut & paste' the parallel & serial connectors. ;)
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Sascha wrote: »
    would it be possible to split the 24v/440Ah bank into two 12v/440Ah banks?
    Well, I know it's possible but what are the pro'a & con's of doing this?
    , perhaps start off with using 'jump starter lead clamps?

    No on both counts. Tapping 12 volts off a 24 volt bank will cause the state of charge between the two halves of the 24 volt bank to drift apart, ruining the batteries. One half will end up undercharged, while the other may get properly charged, or even overcharged. Bouncing back and forth between the two halves won't do the trick either. It's a no go.
    The other point, the jumper cable clamps is also a no go. There is just no comparison between a properly bolted, solid, positive connection, and the comparatively terrible connection of a jumper cable clamp. These two points will be the weakest points of your system, and the whole system, no matter how high quality, or how expensive, can never be any better than these two bad points.
  • Rick1Rick1 Registered Users Posts: 24
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    Why not use two 12v banks hooked in parallel from the battery terminals. You can have another set of wires from the batteries wired as a 24 volt system.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Rick1 wrote: »
    Why not use two 12v banks hooked in parallel from the battery terminals. You can have another set of wires from the batteries wired as a 24 volt system.

    Nope.
    Two 12 Volt batteries in parallel is 12 Volts, not 24. Once you make that parallel connection on (+) and (-) 24 Volts isn't available.

    The only way to get 24 Volts from 12 is to use a DC to DC converter, and they are not capable of handling the current load of an inverter.

    But if the 12 Volt loads are light enough you can use the converter to reduce the 24 Volts. DC to DC converter example: http://www.solar-electric.com/12to24or24to.html
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    It occurs to me that Rick1 may have been referring to wiring the battery bank as 24 Volts but using two separate 12 Volt charging systems to keep each "half" charged as per its needs. If you then balance the 12 Volt loads over the two halves as best you can this would appear to work. But it won't work for long.

    It should be explained here that the whole point in trying to charge and discharge multiple batteries in the same bank as equally as possible is one of battery lifespan. If they're unbalanced no catastrophic failure will occur - unless you count that fateful day when one of them that has been doing all the work gives up and there's a sudden drop in Voltage or current.

    It's hard enough to keep batteries equal when they are being used as one bank with the same current flow throughout. Sometimes batteries go bad without any abuse, even if of the same batch.

    So if you set the system up as described above (24 Volts, two 12 Volt charging systems [careful: need for negative isolation here], 24 Volt load on both, 12 Volt load divided between the two) it will work for a while. Especially if your unbalanced loading occurs during daylight hours and the panels will handle most of the power need. But the panels don't supply power at night, so inevitably (even with EQ cycles) the batteries will "age" unevenly. You might get 6 years instead of 8 or 3 years instead of 10 depending on the many factors involved.

    Many people will read the above and just say "HUH?" and I don't blame them. That's why we take the simple (and simplistic) short response of "don't do this" because as you can see it's more trouble than it's worth.

    I suppose you could say it's really a question of how often do you want to have to replace the batteries? Some of the industrial equipment I used to repair used split 24 Volt systems: 24 for starting & charging and a 12 Volt "tap" from the center to (+) to run lights and other accessories. Want to guess which battery gave up first every time?
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    No on both counts. Tapping 12 volts off a 24 volt bank will cause the state of charge between the two halves of the 24 volt bank to drift apart, ruining the batteries. One half will end up undercharged, while the other may get properly charged, or even overcharged. Bouncing back and forth between the two halves won't do the trick either. It's a no go.
    The other point, the jumper cable clamps is also a no go. There is just no comparison between a properly bolted, solid, positive connection, and the comparatively terrible connection of a jumper cable clamp. These two points will be the weakest points of your system, and the whole system, no matter how high quality, or how expensive, can never be any better than these two bad points.

    Thanks Wayne,
    'No' was not the answer I was hoping for but it answers my questions and confirms the most important thing I've learned from this forum; keep it simple. No good splitting the 24v bank (before it becomes 24v). Can't split a mule in two and try to whip the two halfs to work harder because there would be two of them instead of one, lol.
    I want the bank to last for as many years as possible since they are the one part of the system likely to be an ongoing cost anyway, if treated as consumables. Even though they are consumables, with mantenance and used sparingly they should last longer than if abused in different ways.
    The clamps were an afterthought to simplify the switchover so thank you for explaining the obvious. I don't want to jeopardise the rest of the system with dodgy connections after spending $$ on proper cables, terminals & crimpers.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    But if the 12 Volt loads are light enough you can use the converter to reduce the 24 Volts. DC to DC converter example: http://www.solar-electric.com/12to24or24to.html

    Hi Marc,
    I was trying to find a way to avoid having to convert LV power to 240v through the inverter and then back to LV to feed 30w LCD TV sets through their own transformers. Just seemed a waste because each link; inverter & transformer consume some power to convert.
    Again, I'll have to keep it simple and live with the few amps lost through the step-up and step-back-down components.
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    So if you set the system up as described above (24 Volts, two 12 Volt charging systems [careful: need for negative isolation here], 24 Volt load on both, 12 Volt load divided between the two) it will work for a while. Especially if your unbalanced loading occurs during daylight hours and the panels will handle most of the power need. But the panels don't supply power at night, so inevitably (even with EQ cycles) the batteries will "age" unevenly. You might get 6 years instead of 8 or 3 years instead of 10 depending on the many factors involved.

    Many people will read the above and just say "HUH?" and I don't blame them. That's why we take the simple (and simplistic) short response of "don't do this" because as you can see it's more trouble than it's worth.

    Thanks Marc,
    I realise it would be possible to do the above but it's not worth the 'can of worms' I'd be opening by doing so. It's complicated enough working out all the components' connections, fuses/breakers in a 'as simple as possible' system..., it would be good to have one huge battery without all the parallel & series connections but a huge battery would in effect be the same as multiple small batteries. I guess it would still have the same number of cells ond wiring 'inisde the box' but one would need a crane to move it. :roll: At least this way it's all in front of you and cells can be maintained individually.

    I suppose you could say it's really a question of how often do you want to have to replace the batteries? Some of the industrial equipment I used to repair used split 24 Volt systems: 24 for starting & charging and a 12 Volt "tap" from the center to (+) to run lights and other accessories. Want to guess which battery gave up first every time?

    My guess is the middle one gave up first!?:cool:
    The bottom line is, I want to keep the batteries alive for as long as possible and they don't take lightly to one having to work harder than the others, even for a short time. Keep them happy in a theoretical communist way but don't whip them! :cry: The latter would have been communism in practice!
  • westbranchwestbranch Solar Expert Posts: 5,153 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    re the TV, it is not clearly self evident but with the new hi efficiency appliances, there is little to be gained by attempting to avoid one or 2 power conversions... I tired that route and it requires so much fiddling about and in the end you cross your fingers and hope for the best. The biggest issue with PV is the high and low voltages we deal with daily and most electronics can not deal with that full range, so KISS (inverter based) in the end is the most stable, reliable and economic power system we can get.

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Then there's the battery to inverter wiring. This is going to be the heaviest gauge as it will carry the most current and also needs to minimize V-drop so the inverter doesn't read "incorrect" Voltage and shut down because it thinks it's too low. Again it needs circuit protection and a disconnect. If there are two or more battery strings each should have its own fuse in addition to the inverter fuse/breaker.

    You've probably answered this one before but I can't find the answer;
    If I wire the batteries in parallel first to give me 4 x 6v/880Ah, then in series to give me two strings of 12v/440Ah and then connect these two strings in series again to total 24v/440Ah and connect to the inverter, the final two strings would have 200A rated fuses fitted..., is this the correct way to wire them and is 200A too high?
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    westbranch wrote: »
    re the TV, it is not clearly self evident but with the new hi efficiency appliances, there is little to be gained by attempting to avoid one or 2 power conversions... I tired that route and it requires so much fiddling about and in the end you cross your fingers and hope for the best. The biggest issue with PV is the high and low voltages we deal with daily and most electronics can not deal with that full range, so KISS (inverter based) in the end is the most stable, reliable and economic power system we can get.

    hth

    Thanks for clarifying this. I was hoping the conversions don't use too much power..., the big self-consumer is probably the inverter? The TV's own transformer shouldn't use too much and whatever it does consume should already be included in it's rating figure on the compliance sticker. Is this correct?
    PS; trying to avoid having to cross fingers, that's why I'm seeking advice here.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Sascha wrote: »
    You've probably answered this one before but I can't find the answer;
    If I wire the batteries in parallel first to give me 4 x 6v/880Ah, then in series to give me two strings of 12v/440Ah and then connect these two strings in series again to total 24v/440Ah and connect to the inverter, the final two strings would have 200A rated fuses fitted..., is this the correct way to wire them and is 200A too high?

    "Give us this day our daily 'eek!'" :p

    Wire the batteries in series first, to create the strings of the proper Voltage. Each one of these strings would have its own fuse according to the expected current draw. In theory this value would be the total expected current divided by the number of strings, but in practice you can go higher all the way up to the maximum value for the wire.
    Then make the parallel connections for (+) and (-) at each end.
  • westbranchwestbranch Solar Expert Posts: 5,153 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr

    foe example we have a 26" lcd tv that uses (by K-A-Watt) 13 watts running, there may be a start-up spike but it doesn't measure (show ) it. I think it would be tough to beat that low consumption.
    To try and bypass the transformer, could be done, but the risk of failure is still there, read 'warranty'. A clunker is a different story. Plus the MTBF on new tv's is quite low, design life of ?? ~ 5 years??... (personal experience so far) the CRTs just keep chuggiin' along.

    Whenever I have asked the manufacturer about inverters the answer comes back TSW, not MSW, is acceptable. So if you 'build' your own DC-DC converter what happens when it fails due to ?? = headache and frustration...

    It is relatively easy to have lower idle draw from the inverter by using 2 inverters, or more if you want. Small ~ 300W for lights and a 1500-2000W for big appliances ( fridge etc.) Small one runs all day and big one sleeps till needed.

    hope this clarifies what you are asking ...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    westbranch wrote: »
    foe example we have a 26" lcd tv that uses (by K-A-Watt) 13 watts running, there may be a start-up spike but it doesn't measure (show ) it. I think it would be tough to beat that low consumption.
    To try and bypass the transformer, could be done, but the risk of failure is still there, read 'warranty'. A clunker is a different story. Plus the MTBF on new tv's is quite low, design life of ?? ~ 5 years??... (personal experience so far) the CRTs just keep chuggiin' along.

    Whenever I have asked the manufacturer about inverters the answer comes back TSW, not MSW, is acceptable. So if you 'build' your own DC-DC converter what happens when it fails due to ?? = headache and frustration...

    It is relatively easy to have lower idle draw from the inverter by using 2 inverters, or more if you want. Small ~ 300W for lights and a 1500-2000W for big appliances ( fridge etc.) Small one runs all day and big one sleeps till needed.

    hope this clarifies what you are asking ...

    Sounds like a good TV only using 13w, I guess ours are rated at 30w because of the built in DVD player so running the TV alone would consume less. The TV sets come with a auto lighter plug included for RV use but taking into account the voltage spikes from a solar PV array would probably be too high for that.
    Two inverters is the way to go!
  • SaschaSascha Solar Expert Posts: 121 ✭✭✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    "Give us this day our daily 'eek!'" :p

    Wire the batteries in series first, to create the strings of the proper Voltage. Each one of these strings would have its own fuse according to the expected current draw. In theory this value would be the total expected current divided by the number of strings, but in practice you can go higher all the way up to the maximum value for the wire.
    Then make the parallel connections for (+) and (-) at each end.

    I just read somewhere else I should wire them in parallel first as it is supposed to be more stable, equal for charging purpose but your advice looks straight forward simpler, which is good.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: HELP needed; Wire sze for minimum voltage drop, etc.; full house 12v lighting off-gr
    Sascha wrote: »
    I just read somewhere else I should wire them in parallel first as it is supposed to be more stable, equal for charging purpose but your advice looks straight forward simpler, which is good.

    It's series strings for keeping the batteries equal, parallel if needed. The parallel pathways are what play havoc with keeping current flow consistent through all the batteries.
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