Author Topic: Finding a 120v DC Power source for my MPPT Controller  (Read 11334 times)

0 Members and 1 Guest are viewing this topic.

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #27 on: November 24, 2016, 02:14:48 PM »
Your paraphrase appears to relate to the pwm version - which allows a x1.3 input overload, then ramps down - then disconnects as a fault condition.

The MPPT version appears to restart after 10 seconds post solar input overload (assuming the condition is clear) - but a rectifier fed from the mains isnt  current limited, leaving scope for a problem - if it could be simply current limited ......

Page 54 relates.

i dont understand what you are saying, i dont see where you are getting the different versions or this 10 second aspect from.

we are talking about a morninstar tristar TS-MPPT-60 here, the one i linked a manual to.  here is the same manual to the older 150v systems http://sunshineworks.com/downloads/morningstar/tristar-mppt-charge-controllers/tristar-mppt-installation-operations-manual.pdf

the manual clearly states in both 600v and 150v of the 60 amp tristar manual it will control its current input by throttling back and will only achieve 60 amps output by giving it over 150v and 110v input respectively.

sean_ork

  • Full Member
  • ***
  • Posts: 160
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #28 on: November 24, 2016, 02:28:30 PM »
I suppose it's easy to speculate with someone elses equipment - if the OP confirms that he was advised that input current doesn't need to be limited within the scope of its ratings I will happily concede the point (if only to avoid having to read yet another manual)

sean_ork

  • Full Member
  • ***
  • Posts: 160
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #29 on: November 24, 2016, 02:47:50 PM »
As everyday should be a learning day - how would your illustrated solution be seen by the ground fault protection ?

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #30 on: November 24, 2016, 03:29:58 PM »
As everyday should be a learning day - how would your illustrated solution be seen by the ground fault protection ?

Are you referring to the RCD/RCBO in the main consumer unit, how would it respond to a ground fault? Well neutral is grounded so that is safe anyway. A short between live and neutral would blow the fuse. A short between live and ground (via a person?) would be detected by there being a current difference between the netural and live at the RCB. There is no metal casing apart from the rectifier but that could be easily insulated from being touched so no need for ground.  If one of the diodes in the rectifier failed and caused a shorted state it would blow the fuse at worst burn out to an open state. Either way were dealing with 150v here i wouldn't touch that at dc let alone ac, so it's really a keep your fingers off that wire situation. The circuit is safe imo.
« Last Edit: November 24, 2016, 04:06:52 PM by welshman »

sean_ork

  • Full Member
  • ***
  • Posts: 160
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #31 on: November 24, 2016, 03:36:36 PM »
Thanks, but I meant the ground fault protection built into the charger

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #32 on: November 24, 2016, 03:40:11 PM »
Thanks, but I meant the ground fault protection built into the charger

The tristar does not have internal ground fault protection.

The circuit i illustrated can be improved no end. The thing is i'm having a hard time finding a 120v(output) dc 1500w off the shelf power supply to meet the minum voltage and wattage needed to get a tristar to put out 60 amps at 30v. They are probably going to need to make something in order to get what they need.

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #33 on: November 24, 2016, 03:48:52 PM »
Thanks, but I meant the ground fault protection built into the charger

The tristar does not have internal ground fault protection.

The circuit i illustrated can be improved no end. The thing is i'm having a hard time finding a 120v(output) dc 1500w off the shelf power supply to meet the minum voltage and wattage needed to get a tristar to put out 60 amps at 30v. They are probably going to need to make something in order to get what they need.

to give an example if the tristar was fed 50v dc input it would limit the output to 500 watts meaning at 30v that's only 16 amps at the batteries.

i dont think this is an off the shelf situation.

it might just be easier buying a 60amp 24v battery charger.
« Last Edit: November 24, 2016, 04:09:42 PM by welshman »

Mary B

  • Hero Member
  • *****
  • Posts: 796
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #34 on: November 24, 2016, 04:49:37 PM »
Mains with a full wave bridge rectifier and capacitor will provide about 160 volts...

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #35 on: November 24, 2016, 05:20:17 PM »
Mains with a full wave bridge rectifier and capacitor will provide about 160 volts...

which would be an ideal voltage for the 600v morning star (above 120) and about 20v too much for the older 150v versions.

BradKW

  • Newbie
  • *
  • Posts: 7
  • Country: us
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #36 on: November 24, 2016, 08:01:03 PM »
Thanks, but I meant the ground fault protection built into the charger

The tristar does not have internal ground fault protection.

The circuit i illustrated can be improved no end. The thing is i'm having a hard time finding a 120v(output) dc 1500w off the shelf power supply to meet the minum voltage and wattage needed to get a tristar to put out 60 amps at 30v. They are probably going to need to make something in order to get what they need.

Thanks...I've been following along, but the discussion went a bit beyond me. I think that given the choice between having to kludge something together from parts and theory I don't really understand, versus an off-the-shelf solution that might be less than optimal, I would go with less than optimal. Close would be fine if you've come across anything   :)

sean_ork

  • Full Member
  • ***
  • Posts: 160
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #37 on: November 25, 2016, 03:26:16 AM »
Thanks, but I meant the ground fault protection built into the charger

The tristar does not have internal ground fault protection.

The circuit i illustrated can be improved no end. The thing is i'm having a hard time finding a 120v(output) dc 1500w off the shelf power supply to meet the minum voltage and wattage needed to get a tristar to put out 60 amps at 30v. They are probably going to need to make something in order to get what they need.

Sorry, I worded my question badly - there's a version that does have ground fault protection - more of an add on device.

http://www.morningstarcorp.com/products/tristar-mppt-600v/

I use a large Variac through an ISO transformer to wake GTIs up for pre installation configuration, Ive never needed to fully drive them - but there'll be a safe means of doing so somewhere.

OperaHouse

  • Hero Member
  • *****
  • Posts: 1077
  • Country: us
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #38 on: November 25, 2016, 07:40:57 AM »
This is why you need a transformer, it will short on one polarity.  The picture of diode wiring is also wrong.

I build all my own equipment, so I don't have to argue about nebulous specifications.

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #39 on: November 25, 2016, 12:19:32 PM »
Thanks, but I meant the ground fault protection built into the charger

The tristar does not have internal ground fault protection.

The circuit i illustrated can be improved no end. The thing is i'm having a hard time finding a 120v(output) dc 1500w off the shelf power supply to meet the minum voltage and wattage needed to get a tristar to put out 60 amps at 30v. They are probably going to need to make something in order to get what they need.

Thanks...I've been following along, but the discussion went a bit beyond me. I think that given the choice between having to kludge something together from parts and theory I don't really understand, versus an off-the-shelf solution that might be less than optimal, I would go with less than optimal. Close would be fine if you've come across anything   :)

It's the voltage that matters here, you need to be above 110/120 volts dc or else the solar inverter limits the current it charges the batteries with anyway.

As i said before if you only feed it 50v dc input it will be limiting it's current output to the battery to a measly 500w or 16 amps at 30 volts. Which means if you're not going to give it the necessary 110/120v dc input to unlock it's current limiting you might well be better off with a 16amp battery charger on the batteries instead of building something and if you try to find a 120v ourput 1500w ac-dc power supply you might find you're cheaper and more efficient just buying a 60 amp 24v battery charger instead.

Can you clarify a few things, such as which model of tristar do you have, 150v or 600v input limit? and what voltage are your solar cells giving out?

The tristar really is a beast of a charge controller, it will take over 4.5kw of dc input to cause any damage to it and that is way over what you can get out of a mains outlet.

One note of caution for you as others may not realise. You must NEVER connect negative DC output of the tristar, the solar negative of the solar array or the battery bank negative to a common ground. You will end up with a fire - This is one thing that NEC standard get's wrong as it states to do the opposite.
« Last Edit: November 25, 2016, 12:26:23 PM by welshman »

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #40 on: November 25, 2016, 12:41:02 PM »
This is why you need a transformer, it will short on one polarity.  The picture of diode wiring is also wrong.

I build all my own equipment, so I don't have to argue about nebulous specifications.

I was thinking more of this kind of setup and with regards to a transformer. The mains is already coming from a transformer.. what would another one do?
« Last Edit: November 25, 2016, 12:45:46 PM by welshman »

OperaHouse

  • Hero Member
  • *****
  • Posts: 1077
  • Country: us
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #41 on: November 25, 2016, 01:07:43 PM »
Neutral is connected to ground.  That power line transformer is not isolated. so if the trailer is grounded there is a short.  If the trailer is not grounded, your dead.

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #42 on: November 25, 2016, 03:04:38 PM »
Neutral is connected to ground.  That power line transformer is not isolated. so if the trailer is grounded there is a short.  If the trailer is not grounded, your dead.

but dc negative of the solar array or the tristar output or the battery bank negative should never share the same earth that is also connected to a mains line neutral. the caravan should only connect dg negative to chassis, if at all and definitely should not be earthed with the mains earth. the mains supply inside the trailer should have its own earth seperate grounding rod and the tristar should also have its own earth and not share the same grounding rod. there should be no connection between the trailer ground, the tristar ground or the mains ground. doing this would destroy the tristar and create the situation where an electric shock would be possible. imo. regs are not always the best methods.

joestue

  • Hero Member
  • *****
  • Posts: 1424
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #43 on: November 25, 2016, 07:51:24 PM »
The DC side of things should not be floating., because a fault somewhere could raise the battery voltage to an unsafe voltage above ground.

BradKW

  • Newbie
  • *
  • Posts: 7
  • Country: us
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #44 on: November 25, 2016, 09:06:18 PM »

It's the voltage that matters here, you need to be above 110/120 volts dc or else the solar inverter limits the current it charges the batteries with anyway.

As i said before if you only feed it 50v dc input it will be limiting it's current output to the battery to a measly 500w or 16 amps at 30 volts. Which means if you're not going to give it the necessary 110/120v dc input to unlock it's current limiting you might well be better off with a 16amp battery charger on the batteries instead of building something and if you try to find a 120v ourput 1500w ac-dc power supply you might find you're cheaper and more efficient just buying a 60 amp 24v battery charger instead.

Can you clarify a few things, such as which model of tristar do you have, 150v or 600v input limit? and what voltage are your solar cells giving out?

The tristar really is a beast of a charge controller, it will take over 4.5kw of dc input to cause any damage to it and that is way over what you can get out of a mains outlet.

One note of caution for you as others may not realise. You must NEVER connect negative DC output of the tristar, the solar negative of the solar array or the battery bank negative to a common ground. You will end up with a fire - This is one thing that NEC standard get's wrong as it states to do the opposite.

According to Morningstar, my CC is max input of 150v. The total input watts on CC's is factored to what voltage your battery bank is...mine is 24v, so max of 1500 watts input. If I was doing a 12v bank, max would be something like 800 watts, and a 48v bank would be much higher...perhaps that's where your 4.5kw number comes from.

I'm not really understanding what you mean by "it's the voltage that matters". I'm guessing that you're looking at it from a perspective of the only amps coming in are straight from the 120v line, which would be 15-20? I think I need a power source that also boosts the amp output...like most chargers, converters, etc.

It's sounding like I should really work on this from the angle of trying to figure out how to use the Meanwell RSP-1500-48 I linked in OP...it puts out 1536 watts. But I've seen build threads where novices get stumped trying to make similar switching units perform to spec...making the magic blue smoke appear isn't something I'm real keen on with a $400 unit   ;)

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #45 on: November 26, 2016, 02:23:59 AM »

It's the voltage that matters here, you need to be above 110/120 volts dc or else the solar inverter limits the current it charges the batteries with anyway.

As i said before if you only feed it 50v dc input it will be limiting it's current output to the battery to a measly 500w or 16 amps at 30 volts. Which means if you're not going to give it the necessary 110/120v dc input to unlock it's current limiting you might well be better off with a 16amp battery charger on the batteries instead of building something and if you try to find a 120v ourput 1500w ac-dc power supply you might find you're cheaper and more efficient just buying a 60 amp 24v battery charger instead.

Can you clarify a few things, such as which model of tristar do you have, 150v or 600v input limit? and what voltage are your solar cells giving out?

The tristar really is a beast of a charge controller, it will take over 4.5kw of dc input to cause any damage to it and that is way over what you can get out of a mains outlet.

One note of caution for you as others may not realise. You must NEVER connect negative DC output of the tristar, the solar negative of the solar array or the battery bank negative to a common ground. You will end up with a fire - This is one thing that NEC standard get's wrong as it states to do the opposite.

According to Morningstar, my CC is max input of 150v. The total input watts on CC's is factored to what voltage your battery bank is...mine is 24v, so max of 1500 watts input. If I was doing a 12v bank, max would be something like 800 watts, and a 48v bank would be much higher...perhaps that's where your 4.5kw number comes from.

I'm not really understanding what you mean by "it's the voltage that matters". I'm guessing that you're looking at it from a perspective of the only amps coming in are straight from the 120v line, which would be 15-20? I think I need a power source that also boosts the amp output...like most chargers, converters, etc.

It's sounding like I should really work on this from the angle of trying to figure out how to use the Meanwell RSP-1500-48 I linked in OP...it puts out 1536 watts. But I've seen build threads where novices get stumped trying to make similar switching units perform to spec...making the magic blue smoke appear isn't something I'm real keen on with a $400 unit   ;)

What I'm saying is that if your 150v max input morningstar tristar doesn't get at least 110v dc input from a solar array then it limits the battery charging to only 500 watts. It needs at least 110v input to get it to charge over 500 watts and 500 watts on a 24 volt battery bank would equalise over 30v so that would only leave you with 16 amps charging your battery. To get between 16 and 60 amps at the battery you need to feed it with 110v DC. (read the manual)

The 4.5kw reference is to the maximum amount of surge that the tristar can withstand on the dc input, meaning it's tough. To put that it into perspective
a 110v ac mains plug can never deliver more than a measly 1760w with a 16 amp fuse/breaker.

You could use the Meanwell RSP-1500-48 charger, no problem. but since it's only giving 48v input to the tristar you will only get 16 amps at the battery or 500 watts, whichever is greater. Meaning the 1500 watt power ceiling of the Meanwell RSP-1500-48 never gets used, you only ever make use of 1/3 of it's potential and you would be cheaper buying a 16amp ($90) or greater 24v battery charger since the Meanwell RSP-1500-48 is around $200 at the cheapest price i could find it.

To get the full 60 amp output, the consensus is you're going to need a 120v to 120v transformer rated to 15 amps, to keep you safe from bad practice wiring, a bridge rectifier to turn it into dc and a few capacitors to keep the voltage steady. If you put together all of what we have said you should have a solution.

The only thing left to explore is, is it cheaper to buy a 60 amp 24v battery charger to connect straight to the battery bank, or is it cheaper and within your limits to build a 120v dc power source for your tristar to give it a 60 amp output, because i don't think anyone makes them.

« Last Edit: November 26, 2016, 03:18:50 AM by welshman »

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #46 on: November 26, 2016, 02:52:48 AM »
The DC side of things should not be floating., because a fault somewhere could raise the battery voltage to an unsafe voltage above ground.

However, battery DC negative and solar DC negative should never be earthed to each other or with the same wiring as the mains earth and in this case of the tristar it should also have it's own seperate earth to the casing.

There seems to be a mixup here where mains, solar and inverter technology collide and try to repeat the same job resulting in a hazard. Sure, you can earth everything, but you can't use the same earth.

OperaHouse

  • Hero Member
  • *****
  • Posts: 1077
  • Country: us
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #47 on: November 26, 2016, 05:11:34 AM »
I've deleted this because I do not want this thread to continue any further. You have saved my response for posterity.

First off, I would like to thank the monitors for the job they do on this board.  I've been slumming on some other boards and I"m uncomfortable with the tone they allow from members.  I've even seen real nastiness even from a moderator.  This whole concept of  direct power line hookup is disturbing from the concept of safety.  And now you think having grounds at different potentials is OK.  If I thought anyone would actually take this advice, I would be very concerned.  I've tried the gentle nudge approach to give you a way out.  But, you just continue.  It does remind me of this dog I knew.  It would grab onto something and not let go.  His teeth would be bleeding and I'm sure he felt pain.  To continue would just be sadistic.  And now we learn that anyone buying an expensive MPPT controller wasted their money if they have 500W of panels connected in series.  I just think you have a very limited technical understanding.  I've wasted enough good bandwidth already.  Goodby.
« Last Edit: November 26, 2016, 08:17:21 AM by OperaHouse »

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #48 on: November 26, 2016, 06:13:49 AM »
You're just a dog that won't let go of this.  I'm sure everyone else has figured it out.  Really, let this die.

Maybe it's just me but I would expect a higher quality answer if I was the OP than what others have brought to the table. This is the first time I have felt the need to reply off topic because I am just astounded that you would encourage someone to let it die simply because you have nothing to add.

Bruce S

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 4587
  • Country: us
  • USA
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #49 on: November 26, 2016, 11:48:57 AM »
---Begin GM MODE---
OKAY , now that this thread has taken not only a dangerous route, but there is now people getting snarky with a long trusted forum member.

ONE more outburst like that "welshman" and you'll be in read only.

Operahouse has been posting solid safe information, getting snarky will not endear you to this forum.
I'll remind you , we have a play NICE rule here.
---END GM MODE---
A kind word often goes unsaid BUT never goes unheard

joestue

  • Hero Member
  • *****
  • Posts: 1424
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #50 on: November 26, 2016, 12:13:13 PM »
The DC side of things should not be floating., because a fault somewhere could raise the battery voltage to an unsafe voltage above ground.

However, battery DC negative and solar DC negative should never be earthed to each other or with the same wiring as the mains earth and in this case of the tristar it should also have it's own seperate earth to the casing.

----
Sure, you can earth everything, but you can't use the same earth.

in the case of a non isolated converter such as buck, boost, or others, you could have a system where you can't connect the two negative terminals. you might have a system with the positive battery post "grounded" to the negative of the solar panel.

anyhow, few people do such things like that.

If you read the manual. http://www.morningstarcorp.com/products/tristar-mppt/ you will find the battery negative and solar negative terminals share a common terminal block.

now of course, if you just rectify mains ac and use it to supply a mppt converter, of course you can't ground the battery to anything. but this is dangerous for obvious reasons and an isolation transformer should be used.


and there's no such thing as a safe way to earth an electrical system that needs a different "earth"

you would have current flowing through your ground rods. which btw are often a far higher impedance than expected.

welshman

  • Newbie
  • *
  • Posts: 18
  • Country: gb
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #51 on: November 26, 2016, 03:00:44 PM »
---Begin GM MODE---
OKAY , now that this thread has taken not only a dangerous route, but there is now people getting snarky with a long trusted forum member.

ONE more outburst like that "welshman" and you'll be in read only.

Operahouse has been posting solid safe information, getting snarky will not endear you to this forum.
I'll remind you , we have a play NICE rule here.
---END GM MODE---

OUTBURST? I remained on topic with sound and safe information. I don't give a $#|+ about someones reputation. If you call me a dog and make out im not of any value adding what i know to the topic and tell me to shut up just because you think you can, I may have to address the accusation and go off topic once in a while.

If you look at the history of wha'ts been said i provided a solution and provided vital information of the working of the system. All others did was tell me how I'm wrong and provide nothing to clairfy to the benefit of the user asking the topic question and just rant on about how it could all be potentially dangerous if you stuck your dick in a live mains socket.

I see how the games are played, I see the capability of the people in question which is obvious by the quality of their answers. It seem as if im dealing with kids here.

And aint nobody got time for that.

So im out and its party because of your bias.


BradKW

  • Newbie
  • *
  • Posts: 7
  • Country: us
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #52 on: November 26, 2016, 03:07:47 PM »
Quote from: welshman

You [i
could [/i]use the Meanwell RSP-1500-48 charger, no problem. but since it's only giving 48v input to the tristar you will only get 16 amps at the battery or 500 watts, whichever is greater. Meaning the 1500 watt power ceiling of the Meanwell RSP-1500-48 never gets used, you only ever make use of 1/3 of it's potential and you would be cheaper buying a 16amp ($90) or greater 24v battery charger since the Meanwell RSP-1500-48 is around $200 at the cheapest price i could find it.

To get the full 60 amp output, the consensus is you're going to need a 120v to 120v transformer rated to 15 amps, to keep you safe from bad practice wiring, a bridge rectifier to turn it into dc and a few capacitors to keep the voltage steady. If you put together all of what we have said you should have a solution.

The only thing left to explore is, is it cheaper to buy a 60 amp 24v battery charger to connect straight to the battery bank, or is it cheaper and within your limits to build a 120v dc power source for your tristar to give it a 60 amp output, because i don't think anyone makes them.

There must be something basic that I am not understanding here. Let's use the RSP-1500-48 as the example so I can get my head around this: it has a rated output of 48v and 32 amps = 1536 watts. I look at that and say, ok, I will always get the 32 amps from the RSP into the TriStar 60, and then on to the battery...assuming the battery accepts it. Then I look at the 48v that gets changed by the MPPT into say 28v bulk rate, and think there's some voltage left over which will get changed to amps...because afaik that's one of the things a MPPT controller does. So I figure I get minimum of 32 amps, but really a bit more.

Please explain where I'm wrong with this in a way I can ask a follow-up, because I'm just not getting where the "500 watts/16 amp" comes from. TY

joestue

  • Hero Member
  • *****
  • Posts: 1424
Re: Finding a 120v DC Power source for my MPPT Controller
« Reply #53 on: November 26, 2016, 03:15:27 PM »

What I'm saying is that if your 150v max input morningstar tristar doesn't get at least 110v dc input from a solar array then it limits the battery charging to only 500 watts. It needs at least 110v input to get it to charge over 500 watts and 500 watts on a 24 volt battery bank would equalise over 30v so that would only leave you with 16 amps charging your battery. To get between 16 and 60 amps at the battery you need to feed it with 110v DC. (read the manual)

which manual and where did you read that?

http://support.morningstarcorp.com/wp-content/uploads/2014/07/TS-MPPT-150V-IOM_WEB_v5.7_10.26.16.pdf

page 67 clearly shows the efficiency curves. operation at 3000 watts is possible with just  52 volts going in, and 51.2 volts going out.

you may be miss reading figure 8-7.

i still think an Eltek is the way to go. maybe parallel two of them if you really need more than 1500 watts. some of them are good for 2000.