Newbie upgrading inverter--Sparks flew

Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
ok i have 2 85 watt panels 2 12v batteries a 400 watt cobra inverter which runs good just way to small. I have ordered a 1500 watt inverter roadpro when i hooked up the road pro i hooked the ground up then when i touched the + sparks flew and burned a spot on my battery post. I sent it back and amazon is sending me another one. Im wondering if i did something wrong i never even turned the power on to the inverter and made sure i had the + and - wires right. The inverter says for 12v its frustrating me cause i payed for next day shipping and now i have to wait 4 days to get a replacement.
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Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,716 admin
    Re: Newbie upgrading inverter--Sparks flew

    Earnest,

    I moved this to your own thread--That way we can discuss your system without confusing the stuff that happened with other people's discussions.

    With MSW (modified square wave) inverters, there can be an issue with AC grounding...

    For North American Homes, the NEC requires the AC Neutral (White Wire) to be grounded to earth (ground rod, cold water pipes, etc.).

    With MSW inverters, in general, if you ground the AC "white wire" and ground the battery bank to the earth ground rod--It can create a dead short through the inverter and let out the magic smoke.

    The other thing that may have happened is the inverter was connected backwards to the battery bank--That can also cause damage too (positive inverter lead to negative battery bus terminal).

    Do you have a fuse/circuit breaker between the inverter and the battery bank (typically) in the positive lead?

    http://www.solar-electric.com/infubr.html

    wind-sun_2206_16187133

    wind-sun_2209_53312511


    http://bluesea.com/products/2151
    Attachment not found.
    Any other ideas of what may have happened while connecting the new inverter?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Welcome to the forum.

    You did not necessarily do anything wrong nor was the inverter defective. That have electrolytic capacitors in them that need to charge up; when connected they can immediately draw a big jolt of current. Then they'll behave and come on when you flip the switch. This is why you really want some form of spring-loaded disconnect for the inverter; to make the connection (or disconnection) instantaneous and safe (spark, if any, contained in switch body). There's choice for these from the Blue Sea battery switches http://www.solar-electric.com/blseabaswon3.html to the Bussmann breakers http://www.solar-electric.com/mr60ampdccib.html

    Your smaller inverter probably did not do this, or at least not noticeably so, because it is a smaller inverter: smaller caps, smaller current draw, smaller spark.

    So there might have been a problem, or then again there might not. In either case it would be a good idea to use one of the above mentioned devices to at least keep from scaring the living daylights out of you when you power up.
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    I do have a ground running from one of the - terminals to the house grounding rod. I do have a 30amp fuse connected to my charge controller to the cobra 400watt inverter but i did not have one connected to the other 1500 watt inverter which i connected directly to the battery and not the charge controller.

    i put an some pics as attachments i dont know if i did it right
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Okay that's some scary looking wiring with joints wrapped in electrical tape. But it's probably not the problem.
    which i connected directly to the battery and not the charge controller.

    Never should an inverter be connected to the charge controller. Always through fuse or breaker directly to the batteries.

    What Bill was referring to is that if the negative battery terminal is connected to Earth ground and you have a neutral-ground bond on the AC out of a MSW inverter (which yours probably is) the inverter will fry. This usually does not happen with the inverter turned off, however.

    I still think it was the caps charging that made the spark.

    I also think your wiring could stand a bit of improvement just on general principals. :roll:
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Wow thanks that helps alot i will disconnect the ground running to the grounding rod and yes i know my wires are a mess im using some old wire i had laying around the house that is #12 wire. I connected 3 of the #12 wire together to and ran it to the charge controller which i will also disconnect and run directly to the battery. I do have some more of that welding ground wire left ill use that to connect the inverter to the battery. The welding wire is about an inch wide is that ok to use to hook up the inverter with? i do have another 30 amp car fuse will that be ok to run between the battery and the inverter?
  • BB.BB. Super Moderators, Administrators Posts: 29,716 admin
    Re: Newbie upgrading inverter--Sparks flew

    Assuming this is a 12 volt battery bank, the wiring should be around:
    • 1,500 watts * 1/10.5 volt bat cutoff * 1/0.85 inverter eff * 1.25 NEC safety derating = 210 amp circuit

    That is some pretty hefty wiring. Around 1/O wiring if free air--Near 4/O in conduit. Keep wiring short too (reduce voltage drop).

    In general, large inverters just do not work well (long term) with small battery banks (large inverters with small AGM/GEL batteries are typical for UPS type functions where you need to run the computer for 15-30 minutes to let you shutdown the computer and not lose data).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    I do have a house fuse panel and a lockable disconnect box ordered which will be here Tuesday should i wire it from the battery and put a big house fuse on it and run that to the inverter. Ive seen a lot of people on YouTube have fuse boxes but don't understand how they actually have them wired. I'm sorry im asking so many questions but im really passionate about this and love it. Im actually adding batteries as i go im buying one a week until i have at least 6. This is a 12v system. i will have to order another charge controller soon its only 10 amp that will do 150 watt which my panels are 4.7 amp and 85 watt each which is almost 10 amps and 170 watt.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew
    I do have a house fuse panel and a lockable disconnect box ordered which will be here Tuesday should i wire it from the battery and put a big house fuse on it and run that to the inverter.
    Make sure your house fuse panel and the fuses are rated for DC current. Many/most house fuses, breakers, panels are for AC only.
    Im actually adding batteries as i go im buying one a week until i have at least 6. This is a 12v system.
    Are your batteries 12 volt batteries? If so, then 6 batteries in parallel is a big mistake. If you are using 6 volt batteries, then you have 3 strings of batteries in parallel and that is also a mistake, but not as big a mistake as having 6 parallel strings.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • BB.BB. Super Moderators, Administrators Posts: 29,716 admin
    Re: Newbie upgrading inverter--Sparks flew

    It is very difficult to, cost effectively, expand solar power systems...

    I would suggest you stop buying hardware and write down what you want the system to do (what your loads are, Watt*Hours per day, AC or DC, surge current needed, backup genset needed?, etc.).

    For the most part:
    1. Conservation. Pick appliances/tools/etc. that use energy efficiently and are not consuming more power than you need (i.e., a 9 cuft chest freezer conversion vs 32 cuft refer). It is almost always easier to conserve a watt than to generate a watt.
    2. Measure your loads. Off grid Solar power is expensive (around 10x the cost of utility power)--Designing to meet your known needs rather than guessing will help you contain costs and build a system that you are happy with.
    3. Do paper designs and costings of your proposals. There are many different paths towards building out your system. In some ways, large battery banks scare me more than storing 20 gallons of gasoline... Yes the gasoline can fuel a huge fire--But battery banks can start fires all by themselves (wiring, fusing/breakers, switches, designed for loads, etc.).
    4. Now go out and locate the optimum system components at the optimum price (include shipping and handling--Solar panels and batteries can be very expensive to ship to your front door).

    You may find that you have two needs... For example a small 300 watt true sine wave inverter to power a few LED/CFL lights, laptop+cell charging, a small radio/TV, etc. A large inverter to run power tools, pump to cistern, etc... Large inverters can suck 20-40 watts just being "on"... It can take over a 230-460 watt solar array just to run a good sized idling inverter 24x7--before you connect the first load.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Just two 85 watt panels to charge all those batteries you plan on adding? Slow down and do a whole bunch of studying and learning before you spend any more money on anything more for your system. That, or prepare yourself for some major disappointments. Just being honest with you.
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    The system im building is going to only be for emergency use only. The power here only goes out maby 1 or 2 days a year and the only thing that i will be running on it will be lights and maby a tv so im not board and in the dark ;) I want a large battery bank and ive heard this not good to add new batteries to old I am planning after i get the batteries where i want them 6 12v rv deep cycle batteries to add 24 more 85 watt panels at one time all the same make and model. I have done a test with the 85 watt panels i ran a 100watt light bulb for 8 hours ( at night ) which droped my battery voltage down to 11.7v and by 12:00 the next day they where fully charged floating at 13v. Im lucky i have no trees in my yard and 2 large fields next to me so i get ALOT of sun 14+ hrs a day. this is realy just a hobby right now im doing it for fun not to cut my light bill or do away with my power company. My light bill is usualy under $120 a month. Its more of a joke that im doing it cause i build coal burning power plants for a living ( welder tig,mig,and stick )
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Working back up the last post here ...

    You may get 14 hours of sun a day (we get 16 in Summer here) but unless you are moving those panels all day they won't get 14 hours of direct sun on them. They need direct sun to produce any significant amount of power. You probably get as much as 6, but the arc of the sun will really detract from direct exposure.

    You should not discharge a 12 Volt system below 12 Volts, really. That's about 50% DOD and repeatedly taking it below that will shorten battery life. Also, float Voltage will be better if it's a bit higher than 13 Volts, particularly on RV/Marine batteries. If your charge controller is adjustable, try 13.8 for Float (and 14.4 for Absorb). The RV/Marine batteries are not the best choice for RE, but they'll certainly work for emergency purposes (and might be cheaper or more readily available for you than the good old golf cart 6 Volt units).

    Do not add batteries and/or panels randomly. Determine how many Watt hours of back up power you actually want to have and plan from there. Then you can figure out how big the battery bank should be and how much panel you need to properly recharge it. Why spend more money than you have to, right? And don't fall for the old trap that a small amount of panel can recharge a large amount of battery given enough time.

    It never ceases to amaze me the number of people who, when faced with a utility outage, immediate put "TV" on the top of the list of things they "need" to run. :p Silly ol' me always thinks "refrigerator". :D
  • Joe_BJoe_B Solar Expert Posts: 318 ✭✭✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew
    Welcome to the forum.

    You did not necessarily do anything wrong nor was the inverter defective. That have electrolytic capacitors in them that need to charge up; when connected they can immediately draw a big jolt of current. Then they'll behave and come on when you flip the switch. This is why you really want some form of spring-loaded disconnect for the inverter; to make the connection (or disconnection) instantaneous and safe (spark, if any, contained in switch body). There's choice for these from the Blue Sea battery switches http://www.solar-electric.com/blseabaswon3.html to the Bussmann breakers http://www.solar-electric.com/mr60ampdccib.html

    Your smaller inverter probably did not do this, or at least not noticeably so, because it is a smaller inverter: smaller caps, smaller current draw, smaller spark.

    So there might have been a problem, or then again there might not. In either case it would be a good idea to use one of the above mentioned devices to at least keep from scaring the living daylights out of you when you power up.

    Coot is right on, I have a XW4024 and it does exactly what you described when you hook it up with just the cables. Big electrolytics charging up can draw hundreds of amps instantaneously. Use a BIG DC rated breaker to make the final connection.
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    lol i did not even think of the refrigerator ;) im sure glad you told me about that low voltage on the batteries. i got a cheep pos charge controller just to get started and quickly realized that it would have to be replaced im going with a 60amp controller. I had originally gave myself a budget of $200 a week to buy the equipment and im going to stick to it untill i get the charge controller and batteries then i will throw a little bit of money into the panels (ie the 24 panels at once). I did see some 6v golf cart batteries when i got the RV ones but was fooled by the sticker that said for home and rv use. I thought it would be a better battery. But like i said its just a hobby if it will power a light bulb, tv, AND a REFRIGERATOR ;) ill be a happy camper ( pun intended ). I would still like to know what i should hook the breaker box to its a house fuse box with 6 breaker spots i will have to get those later they have 15 - 60 amp fuses at the store i ordered the box from, there AC breakers im sure. I also ordered a lockable disconnect box ( just for giggles ) should i connect that between the batteries and the inverter or run my ac current into it to break that connection?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew

    If it were me, I'd stick the $200 per week in the bank 'til I had enough to buy a nice, homogeneous system that would meet the needs all in one go. Piecemeal assembly has some built-in trouble spots as manufacturers change specifications even while we speak!

    And so we return to the old familiar litany: buy a Kill-A-Watt meter and get some real world numbers on how much power your 'essentials' will use in normal use. Then you'll have a target of how many Watt hours you need to supply and what kind of peak current & Watts you have to come up with. Refrigerators, for instance, draw a lot on start-up and then settle down to usually <200 Watts, but tend to use 1kW hour or more per day. A lot depends on the particular 'frige, the climate it's in, and how it gets used.

    So then you have your power needs which will be supplied by a battery bank of 'X' Amp hours @ 'V' Volts through an inverter of 'W' Watts. The batteries will be recharged by panels enough to supply 10% of 'X' Amps @ 'V' Volts, with a controller capable of handling that current. All the wires have to be sized properly to both handle the expected current and keep the Voltage drop to a minimum, and of course each circuit needs an appropriate fuse/breaker.

    How you arrange the mechanical aspect of the layout is largely up to you. You can have the inverter feed stand-alone outlets and plug in when needed or you can get fancy with transfer switches on the household circuits for essential loads. There are a lot of variables.
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    ok i have ordered a kill a watt meter it will be here Monday ill see how much electricity im actually using buy all my stuff at once i didn't want to take a chunk out of my savings but i will if that's what it takes ;) any suggestions for a do it yourself er like i said its a hobby not a job.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew
    ok i have ordered a kill a watt meter it will be here Monday ill see how much electricity im actually using buy all my stuff at once i didn't want to take a chunk out of my savings but i will if that's what it takes ;) any suggestions for a do it yourself er like i said its a hobby not a job.

    I started out small, as a hobby, but became addicted and am now living without using any grid power except to run the heat pump when the weather is not cold enough for the wood stove. Gotta tell you, if I had known years ago what I know now, I could have saved thousands of dollars on controllers and inverters that had to be upgraded. Starting out small, then growing as I could afford it, wasted a LOT of money in the long term. So if you can truly determine what you need before hand, and purchase only what you're max needs will require, you'll be far better off. Also if I had known then what I know now, I would have gone with a 24 volt system. To change now would be very expensive, as I've painted myself into a 12 volt corner. :cry:
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    all good advice for you. if you find that you have too many batteries currently to keep them charged up with the solar (unlikely) then hit them with a good charge from a battery charger, but watch that this only is for the initial bulk charge as many cheap chargers will overcharge your batteries. you need to find out what the proper voltages are for your batteries for absorb and float.

    you do need to figure out what is important for you to maintain during an outage and for how long you will need to maintain things. this will help to determine the approximate size of everything else you will need.

    coot,
    i must be an oddball as i thought lights first, refrig 2nd, and security cams 3rd and never thought tv. tv usually does not help or inform much during times of an outage and may only serve to poorly pass some time.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew
    niel wrote: »
    coot,
    i must be an oddball as i thought lights first, refrig 2nd, and security cams 3rd and never thought tv. tv usually does not help or inform much during times of an outage and may only serve to poorly pass some time.

    Niel, we're both odd. :p
    I hardly ever watch TV even when there is power. I can light candles if the power goes out, so keeping the 'frige going (food is expensive) is #1 on my list. As for security, my dog-system never runs out of energy! Ever! :D
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    well, i do confess to watching tv, but only certain things. i was really referring to when the power goes out that i do not hold tv to be very important. btw, my cams don't need the monitor on as i record.;)
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    https://partimages.genpt.com/partimages/686462.pdf
    this is the batteries i have i have 2 connected + to + and - to - the 2 85 watt panels i have connected to them are though a 10 amp 150 watt controller and i have checked my voltage on the batteries each day and 13v even is what i get when the charge controller goes into float mode. Im ordering a 60 amp controller this week and want to make sure its not my batteries not allowing my charge controller to go to 14.4 or if its the charge controller itself. The system is purely for backup right now the only draw i have on the system is a 12v fan about 3" x 3" pulling air out of the box i have the batteries in, which says 12v .5 watt.
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Ok i have a ghost in my solar panels or my batteries one i just received my replacement for the 1500 watt inverter plugged it up hooked a 26 watt light bulb up and it works great went and checked my voltage on my batteries and it jumped up to 13.5v i turn the inverter off and it dropped down to 13v am i crazy or is the volt suppose to go down and not up?
  • BB.BB. Super Moderators, Administrators Posts: 29,716 admin
    Re: Newbie upgrading inverter--Sparks flew

    That is strange... Assuming the meter is working OK (and has a good battery--meter set to DC volts, not AC, etc.), I would look at grounding and make sure that everything it what you think it should be.

    Also, are you measuring the voltage directly on the battery posts or somewhere else?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Yes sir i have a multi meter i borrowed from an maintenance man at work i checked the voltage on each battery separately then + on one battery and - on the other they all read the same. He had it set to 20vdc and i double checked it on my car battery its reading 14.2v which is real close to the meter on the dash says.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    are you sure your meter is giving good readings as i'm at a loss in figuring that one out?
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Im going to check it again ill let you know maby it was a fluke with the meter or something. ok im an idiot i see now whats going on when i turn the inverter on the charge controller comes out of float and starts charging the batteries but why is it jumping up that high that quick on each battery?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew

    Don't know what charge controller you've got, but it's possible the load of the inverter is causing it to shift from Float to Bulk pulling more current from the panels and pushing the Voltage up as it tries to achieve Absorb level again. This could indicate too much resistance in the wiring. Measure the Voltage at the battery, inverter input, and controller output under different circumstances and see how much variation you get between these three points.
  • BB.BB. Super Moderators, Administrators Posts: 29,716 admin
    Re: Newbie upgrading inverter--Sparks flew

    You are probably correct, the charge controller is going to Bulk/Absorb with the addition of your inverter load...

    Still, 13.5 volts bulk and 13.0 volt float is pretty darn low for most batteries. With a small array and large battery bank (or one partially discharged), that 13.5 volts may be as high as the array can pull the battery bank under those conditions.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Earnest TilleyEarnest Tilley Solar Expert Posts: 56 ✭✭✭✭
    Re: Newbie upgrading inverter--Sparks flew

    I got another charge controller coming going to get 4k out of the bank and buy more 85 watt panels i also have a ac fuse box coming which im going to rip out the buss bars out of and use to hook my panels together with. I have the 2 panels just stripped and wired + to + and - to - right now i got to fix that with the buss bars.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Newbie upgrading inverter--Sparks flew
    I got another charge controller coming going to get 4k out of the bank and buy more 85 watt panels i also have a ac fuse box coming which im going to rip out the buss bars out of and use to hook my panels together with. I have the 2 panels just stripped and wired + to + and - to - right now i got to fix that with the buss bars.

    85 Watt panels are not the best bargain in the world. If you're spending $4,000 on equipment, go for something with a better value per Watt. Have a look at what big (over 100 Watt) panels go for here: http://www.solar-electric.com/hiposopa.html

    You're spending serious money; it's time to get serious equipment, right? :D
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