navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address - following recent spam/hack attempts on the forum, all security is set to "high", and "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1] 2 3 4   Go Down
  Print  
Author Topic: Diversion Load Control Question  (Read 19707 times)
Eleanor
Hero Member
*****
Offline Offline

Posts: 2574



« on: January 08, 2011, 12:08:02 PM »

I've looked everywhere : here, the Morningstar site, the manual, under the bed but haven't managed to find the answer to this  surrender

Is it possible to use more than one Morningstar Tristar Charge Controller TS45 or TS60 together in diversion load control mode to increase the current to a dump load? We've occasionally seen 70A at around 30V from our 24V wind turbine rated at 1.6 kW and presumably one unit on it's own won't be sufficient.

Thanks  faint
Logged

I'm doing this for free, please be nice to me surrender
"Very few batteries die a natural death ... most are murdered" stir
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 8943



WWW
« Reply #1 on: January 08, 2011, 12:40:49 PM »

Hi Eleanor

Have no right answer for you in relation to the Morningstar  ( but assume it would work )

But you can use your Victron  to Dump  AC into a heater as well  ( say at 29.5 Volt  600 watt heater (or so ) on until down to 27 volt again = heater of )

Billi
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Eleanor
Hero Member
*****
Offline Offline

Posts: 2574



« Reply #2 on: January 08, 2011, 01:13:37 PM »

Hi Billi

Thanks for the reply. Considering how long I've been hanging around here it still amazes me how little I seem to know! Is this the virtual switch? I've known about it but should really have looked at it more as it would be a really simple thing to do. At the moment it's the wind turbine that switches itself on and off at set voltages!  wackoold

I think we are trying to avoid cycling the batteries so a PWM controller with DC dump load is better? Have I got that right? My thoughts are to use the diversion load controller set at around 28.8V and send the excess to one or more immersion heaters. The DC elements I've seen seem to require a "dedicated" 24V supply which we can't supply so I've asked emacandco if they can make a 30V unit. Does this make sense or am I being  ralph
Logged

I'm doing this for free, please be nice to me surrender
"Very few batteries die a natural death ... most are murdered" stir
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 8943



WWW
« Reply #3 on: January 08, 2011, 01:38:54 PM »

Yes  thats the Virtual switch , but you need an adaptor for  your laptop to operate it

Quote
I think we are trying to avoid cycling the batteries so a PWM controller with DC dump load is better? Have I got that right?

I would say on the long run the controller is the better idea , but do not know ,if one can call it cycling of a battery , when Voltage  is kept above or around float Voltage

I thought you have one Morningstar already , than  on rare occasions the Victron could dump, in addition

By the way your Battery monitor has an  "Programmable alarm or generator start relay"  as well to start a heater via a second relay

Billi
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Eleanor
Hero Member
*****
Offline Offline

Posts: 2574



« Reply #4 on: January 08, 2011, 02:08:59 PM »

Hi Billi

Thanks again. We don't have any diversion load control at all at the moment. For various reasons the turbine has had little use and my New Year's Resolution is to get it all sorted out and running with a proper sytem. I think that using the inverter to switch a small AC heater on and off will be a good start while we organise the DC side unless anyone has a better suggestion. The turbine controller (Crouzet Millenium 3) also has some spare relay outputs but we need to get hold of the software to configure it. We've got the Victron cable already.

So, when just using one Morningstar TS60 if the current goes over 60A will this just result in the battery voltage rising and the additional heater switched on by the Victron absorbing the excess? If this is the case then it would probably be best for the turbine to switch off as it's probably too windy for it anyway! The condition where 70A is produced is a rare event but the TS60 manual says several times not to install where the current can exceed the rating when in diversion load control mode.

I'm feeling better now, this has been bugging me for a while ....  extrahappy
Logged

I'm doing this for free, please be nice to me surrender
"Very few batteries die a natural death ... most are murdered" stir
EccentricAnomaly
Guest
« Reply #5 on: January 08, 2011, 03:23:33 PM »

Would it be possible to use the dump load output of the Tristar to activate a relay to switch in another dump load?

Perhaps a bus/truck starter solenoid might be suitable if they're OK for continuous operation (coil doesn't overheat) otherwise a bunch of FETs might be better.
Logged
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 8943



WWW
« Reply #6 on: January 08, 2011, 09:39:03 PM »

I do not know the Tristar in real action, Eleanor and surely will not advice  to connect higher AMPS than the manufacturer recommends

So double check that with your windturbine supplier

But in my  (former ) setup the  dump load controller just passed surplus Amps to the heating element  , still a good part  went into my battery

So i am just guessing here , that normally  only a Percentage of AMPS will flow through the Tristar to be transferred to the dump element  , the rest still flows into your battery  until that battery is  full , fuller , the fullest

But i do not know the tristar and its just a guess

When you configure the Victron   you can make sure that there is always  some "space " even battery is officially full  and the Tristar will never have to dump 60-70 AMPS

How much PV have you now and what controller ?  It can happen that the Tristar will dump PV as well in addition to the Windturbine  , so fine Tuning will be essential

Programming the Victron in any case for Dumping in case some other device  fails , calms my brain

Hope others know more

Billi
« Last Edit: January 08, 2011, 09:47:25 PM by billi » Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Eleanor
Hero Member
*****
Offline Offline

Posts: 2574



« Reply #7 on: January 08, 2011, 11:20:51 PM »

Billi/EA

Thanks. Billi, in my total thicketry I misunderstood your first post and thought you were suggesting an AC solution instead of DC when in fact you were suggesting using the two together. I caught up half way through my last post so it probably all seems a bit confused  help

I understand that the dump load controller will only send some of the current to the dump load depending on how much is needed to get to and maintain the set battery voltage. Hovever, we've got used to using so little electricity that our bank is never very discharged and until we learn to consume more we will always be sending most of the current to the dump load. I'm all for belt and braces and it seems that we have two simple safety options available to us :

1. Your suggestion of using the virtual switch to activate a small AC load if the battery voltage rises
2. We can set the turbine controller to switch the turbine off at a set voltage. This possibility already exists.

And there is also EA's suggestion of using the dump load output from the Tristar which will need a bit more investigation.

There seems to be no reason not to use both, or all three, options together as long as we set the voltages correctly.

I'm quite happy to take responsibility for deciding that it is too windy to run the turbine (I have previous here  Roll Eyes) and I tend to get a bit twitchy if the wind is around 15 m/s or more. I think it's gusts that will be the problem but I know that the turbine controller is very fast acting in shutting the turbine down at a set voltage.

I think that if the Tristar isn't likely to be fried by a few extra amps then I'm making a mountain out of a molehill  stir

Billi, at the moment only 160W of PV but this is soon to grow significantly (but not as big as yours  genuflect). Probably 1kW or maybe even 2kW  faint

Once I'd got my head around this bit I was going to start being a nuisance on the complete system. I'd already realised that we'll have to add the PV to the total so if there's a raging gale and blazing sunshine together we'll be  sh*tfan Cool or at best all switched off. I suppose we'll be wanting an MPPT controller as well. Is that the distant sound of Ivan rubbing his mitts together and planning his retirement  ralph

I guess I'll just have to pull my finger out and contact Morningstar so that I can satisfy my curiosity as to whether it's possible to use more than one Tristar. Or is there a better way which charges the batteries more effectively  Huh

That's enough for one day  wackoold
Logged

I'm doing this for free, please be nice to me surrender
"Very few batteries die a natural death ... most are murdered" stir
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 8943



WWW
« Reply #8 on: January 09, 2011, 12:38:22 AM »

Hi Eleanor

 
Quote
We can set the turbine controller to switch the turbine off at a set voltage. This possibility already exists.


I have no Idea how that works ?    and where the excess power from the turbine goes !  I thought all turbines need a dump  

If you go for  more PV  than ( or only )   an outback FM 80 chargecontroller is needed to   regulate your PV and your Turbine , perhaps

But   again , i am not into all the details (anymore )   cause  found out my 3 years sons brain is more complicated than my chargecontroller(s)  Grin,  but in my manual  of my FM 80 ( outback ) i read this  

Quote
When external DC sources (wind, hydro) are
directly connected to a battery bank, any excess
power should be sent to a diversion load, such as
a heating element, via a mechanical or solid state
relay. In Diversion, which features Relay and Solid
State screens, the user programs set points—from
-5.0 volts to 5.0 volts relative to the Absorb, Float and
EQ voltages—to activate the AUX MODE. With wind
or hydro generator applications, keep the Charge
Controller’s diversion voltage slightly above its
Absorb and Float voltages for effi cient functioning.

Outback MPPT PV controllers are used as Dump load controllers as well

Thats just another Idea ( and another plan how to confuse  you   Tongue   Kiss)


But do not know in detail ,  if it is possible to have a Max  80 AMPS of PV and a Max 80 Amps of Wind on the same controller


It should work cause the Amps of the PV are  regulated down or ignored



Billi




« Last Edit: January 09, 2011, 12:46:10 AM by billi » Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Eleanor
Hero Member
*****
Offline Offline

Posts: 2574



« Reply #9 on: January 09, 2011, 01:31:16 AM »

Billi, you are naughty trying to confuse me even more. Just when I thought I might be starting to understand you throw in something else  facepalm

I'll deal first with the little bit that I do know - the turbine literally switches off ie stops! No need for anyone to have a dump unless it doesn't work  Grin

I have some homework now, to read about the Outback system  tumble

Thanks for your help, it will eventually percolate through  Tongue
Logged

I'm doing this for free, please be nice to me surrender
"Very few batteries die a natural death ... most are murdered" stir
Outtasight
Hero Member
*****
Offline Offline

Posts: 886



WWW
« Reply #10 on: January 09, 2011, 01:48:55 AM »

You can run Tristars in parallel for diversion load control but not into the same dump load.  Connect the Tristars to the same battery but to independent dump loads.  That way, they can absorb as much power as you need, but will not have their MOSFET switches stressed by driving too low a resistance dump load.  If the dump load can draw only 60A when connected directly across the fully charged battery, then that's right for the Tristar, as it can switch up to 60A.  

If you use a dump load of double the power, then when the Tristar closes its switches, they'll see pulse surges of 120A before the protection starts to throttle the current to an average of 60A.  Not good for the long term health of the controller or the battery (the Tristar will limit its current to save itself at the expense of the battery cooking!).  Running two 60A controllers into a 120A load won't work reliably, as you can't guarantee that the load will be shared equally by the controllers.  One will run hot and go pop, followed shortly by the other.

But running each Tristar into an independent 60A dump load is safe because each controller is only being asked to switch a maximum of 60A.

You could use the output of a Tristar to trigger a slave switch of a much higher rating but you'd have to use a FET bank, as the switching frequency is a few kHz in normal operation;  much too fast for a mechanical relay.  Even if the speed were a few Hz, it would kill the relay in a short time from the arcing burning out the contacts.  You'd have to use a solid state switch at these power levels.

Reliability-wise it would be better to have independent controllers and dump loads anyway.  If one goes pop, gets unplugged, or a fuse blows, you'll still retain partial battery control, provided the source wasn't consistently delivering more than 60A of current that would swamp the surviving controller & dump load.  
« Last Edit: January 09, 2011, 01:50:37 AM by Outtasight » Logged

http://solarbodge.blogspot.com/
3.58kWp & 800Ah LiFeYPO4 off-grid(ish). See 'Cobbled together PV in W.Sussex' (in "Show Us Yours")
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11957


An unpaid Navitron volunteer who lives off-grid.


« Reply #11 on: January 09, 2011, 09:15:29 AM »

hi outtasight,
              this is a really good thread and the info coming through is exellent, better still,it is in laymans terms and not to difficult to grasp. it is a pity there is no quick solution like dumploads you could connect direct to the battery and which you could set to trigger independently at different voltages, rather using the diversion mode of a very expensive controller.
                         biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
EccentricAnomaly
Guest
« Reply #12 on: January 09, 2011, 10:54:01 AM »

You could use the output of a Tristar to trigger a slave switch of a much higher rating but you'd have to use a FET bank, as the switching frequency is a few kHz in normal operation;  much too fast for a mechanical relay.

Excellent point, thanks.  I'd just assumed that it either dumped or it didn't which is a bit silly of me really.
Logged
EccentricAnomaly
Guest
« Reply #13 on: January 09, 2011, 11:23:54 AM »

I'll deal first with the little bit that I do know - the turbine literally switches off ie stops! No need for anyone to have a dump unless it doesn't work  Grin

As I understand it from the Miniwind brochure (2200-24, page 9) you have two switches to stop the turbine.  The first shorts it out and can only be used in low winds or where the turbine is already stationary.  The other connects a dump load resistor which can stop the turbine in any wind (or, at least, up to the maximum operating wind speed).  The idea is that you stop it with the dump load before the wind gets too strong then operate the short-circuit switch to keep it stopped in any wind, I suppose.

A couple of things confuse me.  The PMGs they sell standalone have six wires out to allow star or delta connection.  I'm not clear if the wind turbines also have six wires out or have integral  rectifiers and only two wires out or even three wires out.  (I speculate that the difference between the 2200-24 and 2200-48 is just the choice of star or delta in the turbine head).  The brochure seems to imply two wires out in that it doesn't talk about a separate rectifier pack.  In which case, why do they need 4-pole switches for the short circuit and dump load?  Is it to do with one pole being used for breaking with a suppression capacitor and the other for isolation or something?  The fact that they only talk about a single dump load resistor also indicates a two wire system.

I have to admit that I'd rather the braking switches were upstream of the rectifiers.  If enough rectifiers fail open circuit then you're left with an uncontrollable turbine.  Two O/C diodes could leave you with just one winding trying to stop the turbine.  It seems to me that the time the diodes are likely to fry is when you're trying to stop the turbine.
Logged
Eleanor
Hero Member
*****
Offline Offline

Posts: 2574



« Reply #14 on: January 09, 2011, 01:13:52 PM »

You can run Tristars in parallel for diversion load control but not into the same dump load.  Connect the Tristars to the same battery but to independent dump loads.  That way, they can absorb as much power as you need, but will not have their MOSFET switches stressed by driving too low a resistance dump load.  If the dump load can draw only 60A when connected directly across the fully charged battery, then that's right for the Tristar, as it can switch up to 60A.  

If you use a dump load of double the power, then when the Tristar closes its switches, they'll see pulse surges of 120A before the protection starts to throttle the current to an average of 60A.  Not good for the long term health of the controller or the battery (the Tristar will limit its current to save itself at the expense of the battery cooking!).  Running two 60A controllers into a 120A load won't work reliably, as you can't guarantee that the load will be shared equally by the controllers.  One will run hot and go pop, followed shortly by the other.

But running each Tristar into an independent 60A dump load is safe because each controller is only being asked to switch a maximum of 60A.

You could use the output of a Tristar to trigger a slave switch of a much higher rating but you'd have to use a FET bank, as the switching frequency is a few kHz in normal operation;  much too fast for a mechanical relay.  Even if the speed were a few Hz, it would kill the relay in a short time from the arcing burning out the contacts.  You'd have to use a solid state switch at these power levels.

Reliability-wise it would be better to have independent controllers and dump loads anyway.  If one goes pop, gets unplugged, or a fuse blows, you'll still retain partial battery control, provided the source wasn't consistently delivering more than 60A of current that would swamp the surviving controller & dump load.  


Outtasight, thanks for all this very useful information. I did wonder if the way to do it was independent controllers and dump loads but would never have known why.  Certainly the idea of some sort of redundancy in the system is appealing. So, am I right in thinking that a combined wind/PV system of say 4kW would need (4000W/28.8V) 138.8 amps worth of diversion load control? This would be just outside the range of 3 x TS45s (135A) so to give a good margin (>25%) 3 x TS60 would be much better? I suppose that immersion elements will require thermostatic control and presumably another dump load to take over when we are hoarding a tank of hot water in the same way we cosset our electrons. Perhaps just one immersion element (28.8V x 60A = 1728W so around 1.8 kW) and two other DC air heaters plus the one to take over from the immersion. I think I'm starting to see a problem here in that they will all be sharing the load when we want to send everything to the immersion. Or am I creating an imaginary problem?

Time to look at the Outback. Outtasight does the Morningstar MPPT charge controller have any diversion load capability or does it just disconnect the PV? Huh

I think it's probably become a subject for a new thread
Logged

I'm doing this for free, please be nice to me surrender
"Very few batteries die a natural death ... most are murdered" stir
Pages: [1] 2 3 4   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!