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Author Topic: buggerit... psuedo solar doesn't work any suggestions?  (Read 4494 times)
sleepybubble
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« on: November 03, 2009, 01:30:09 PM »

Ok for reasons of my own, and for those that don't follow the trials and tribulations of my life...

I have a 48v battery bank (8x12v 90ah type 643 series and parrelell), which is to be charged by a 48v 1kw navitron windturbine.
I have a 24v APC1000 UPS which I am utilising as an off grid invertor.
I have a 24v ALCAD (18x1.2v Nominal) battery bank for the invertor.

I had hoped to charge the 24v bank from the 48v bank, by using a tristar TS45 solar charge controller. The tristar is wired correctly, and the dip settings are also correct. The wind turbine is not yet connected into the system. but the controller is.

When the tristar is connected to the 24v battery, all is great, it tracks the charge levels fine etc. When I hit the breaker to turn on the 48v bank (my pseudo solar array) the tristar displays an error. Overload solar/load.
Description of which is... " IF the solar input exceeds 100% of the controllers current rating, the controller will reduce the average current below the tristars rating. The controller is capable of managing up to 130% of the rated solar input.
When 130% is exceeded the solar will disconnect and the fault will be indicated...." etc etc

My questions are? Should I be looking for a way to throttle the current from the 48v battery to the solar controller? Should I be looking for a way to throttle the current coming out of the solar controller. Is there something I am missing which is obvious to anybody but a numpty like me.

If any more info is required then please ask....

ta,

Mark
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Justme
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« Reply #1 on: November 03, 2009, 02:06:01 PM »

Sounds like the 24v bank is drawing more amps than the controller can handle.

So either dont let the bank get so flat
or
control the charge current

Try testing it on a nearly full 24v bank

I also have "thoughts" about using a 180ah 48v bank to charge those huge alcads.

Why not fit the 48v turbine direct to the 24v bank? The power curve will lower so low wind performance should improve but top end power will be lost. But has got to be better than the double charging & conversion losses of doing it your way.
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
2 x Victron Multiplus II 48/5000/70
Cerbo GX & GX 50 touch
BMV 700
6kva genny
48v 1000ah
Grid Possibly coming soon
sleepybubble
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expect the unexpected, then its expected


« Reply #2 on: November 03, 2009, 02:45:57 PM »

Sounds like the 24v bank is drawing more amps than the controller can handle.

So either dont let the bank get so flat
or
control the charge current

Try testing it on a nearly full 24v bank

I also have "thoughts" about using a 180ah 48v bank to charge those huge alcads.

Why not fit the 48v turbine direct to the 24v bank? The power curve will lower so low wind performance should improve but top end power will be lost. But has got to be better than the double charging & conversion losses of doing it your way.


hmmm I'm not sure if the bank is 'flat' however the solar controller might think it is ( I havn't put in any custom voltage set points yet!). When I brought the Alcads back to life over the weekend I gave them a top up and a prolonged EQ charge, by charging strings of 9v with my 12v car battery charger. Then I bolted the whole bank back together and since then it has been on charge from the UPS charger. Today I ran a first load across it for a few hours to monitor voltage drops etc, which it seemed to handle quite well. It was at the end of this that I turned on the Solar controller to see if it could top the 24v bank up a bit whilst under load. hmmmm that might be the key, right of to try the same again with the invertor off see if that makes a difference!!!
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sleepybubble
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« Reply #3 on: November 03, 2009, 04:25:15 PM »

nope that didn't work still overloading, I'll wait till the kids are in bed and try it with the small 24v bank....
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RichardKB
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« Reply #4 on: November 03, 2009, 04:36:39 PM »

Not having the circuit diagram for your controller this is only an idea why it wont work.

The internal resistance of your 48V battery bank is very low and will allow loads more power than the 130% than the controller will accept.

I assume it is trying to find the maximum power point and because it is outside its range is fails with an error message.

Rich
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billi
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« Reply #5 on: November 03, 2009, 04:49:18 PM »

If you have two lakes on the same level  , with a dam in between , but one lake has 2 meter less water  and then the dam brakes  Tongue   the dam is your tristar i think, and cannot handle that !  If there would be a pipe in between then perhaps  Grin

There are a few thoughts in my head but perhaps nonsense  like DC-DC converters , get a cheap 48 volt inverter and a AC 24 volt battery-charger  ... there must be more

Hope i did understand all

Billi

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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
sleepybubble
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expect the unexpected, then its expected


« Reply #6 on: November 03, 2009, 05:27:22 PM »

If you have two lakes on the same level  , with a dam in between , but one lake has 2 meter less water  and then the dam brakes  Tongue   the dam is your tristar i think, and cannot handle that !  If there would be a pipe in between then perhaps  Grin

There are a few thoughts in my head but perhaps nonsense  like DC-DC converters , get a cheap 48 volt inverter and a AC 24 volt battery-charger  ... there must be more

Hope i did understand all

Billi



LOL, I started out thinking DC/DC converter and folk here suggested I could do it this way  fight

So anyways with the 24v bank up to charge I gave it another go.... result was the tristar tripped out once with the overload message ( I can tell by the sound of the buzzing) then it latched. Then I smelt smoke so ran around to see where the smoke was coming from, seemed to be general area of tristar so I have disconnected it again. Now I can't tell if it is an underated cable getting warm or whether something in the tristar has gone. Heinz going to have to take the damn thing out now to inspect it. Might be time for some inline fuses too  whistlie

Dontcha just hate smoke around expensive things.
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rogeriko
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« Reply #7 on: November 03, 2009, 06:18:20 PM »

Are you trying to recreate Chernobyl  A 48v battery bank when connected to a 24v battery bank will see it as a dead short 1000s of amps will flow and you will melt wires and burn the house down. you have blown up the tristar it is not a current limiting device. You can not do what you are trying to do.
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Billy
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« Reply #8 on: November 03, 2009, 06:26:56 PM »

Reckon 'es right,

Current is limited by the solar array into the Tristar.  Tristar fault or shut off within those parameters but will not cope with a massive overload from what I can see in the blurb.

On the boats we use dc/dc converters to charge remote batteries.

Hope its not too terminal Sad
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rogeriko
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« Reply #9 on: November 03, 2009, 06:31:49 PM »

DC to DC converters can be used but a discharged battery when connected to the output will be seen as a dead short and the converter will shut down or blow up probably the latter. Current limiting can be done with resistors but a lot of heat is produced =  wasted energy.
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Justme
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« Reply #10 on: November 03, 2009, 06:35:16 PM »

So home come my solar controller can have "cap" the charging amps at 80a when the array is producing more?
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
2 x Victron Multiplus II 48/5000/70
Cerbo GX & GX 50 touch
BMV 700
6kva genny
48v 1000ah
Grid Possibly coming soon
Billy
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« Reply #11 on: November 03, 2009, 06:49:18 PM »

Justme,

How much more, 130% or 1300%, how does it "cap"? to heat or switch on/off.  I have know real understanding of complex 'tronics, just about know how a transistor works!

Rogeriko,

yep the ones we use are hideously expensive, create lots of heat but they do work like a staged charger which means that the customer is happy with his winch battery fully charge even though it is 20 metres away from the engine start battery from whence it is fed.
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rogeriko
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« Reply #12 on: November 03, 2009, 07:05:17 PM »

Solar controllers control the voltage not the amps if you put too many amps in to the controller it will destroy the power transistors. When the battery voltage rises they stop conducting to a certain degree only allowing a portion of the voltage through to maintain a full charge thats why every controller on the market has an amperage rating if you exceed this it will blow. solar panels produce a fixed amperage which unlike any other generating device does not depend on the load. If you connect them to lamps, batteries or a dead short you still get the same output amps wise.
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StBarnabas
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« Reply #13 on: November 03, 2009, 07:15:17 PM »

Sleepy
sadly there is a big potential for disaster here hope things are not too fried. As others have hinted lead acid batteries are good voltage sources they can generate a LOT of current if loaded incorrectly. I also hate the smell of burning in expensive electronics. Do hope all is OK. I was going to say car battery chargers are often limited to about 8 amps  so you may need a lot of time to charge a battery bank
Sean
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Gestis Censere. 40x47mm DHW with TDC3. 3kW ASHP, 9kW GSHP, 3kW Navitron PV with Platinum 3100S GTI, 6.5kW WBS, 5 chickens. FMY 2009.
Justme
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« Reply #14 on: November 03, 2009, 08:08:26 PM »

Solar controllers control the voltage not the amps if you put too many amps in to the controller it will destroy the power transistors. When the battery voltage rises they stop conducting to a certain degree only allowing a portion of the voltage through to maintain a full charge thats why every controller on the market has an amperage rating if you exceed this it will blow. solar panels produce a fixed amperage which unlike any other generating device does not depend on the load. If you connect them to lamps, batteries or a dead short you still get the same output amps wise.

Well you best tell Outback then that the product they are selling does not work & that they should stop advising that the amps out will be caped at the max level (the input amps are much lower due to high input voltages). They do say that to high a V will blow it. They tell you that extra amps available from the array will not damage the unit.

I have a 1200w array. That could be 100amps if I let my bat get to 12v. The output amps are caped at 80amps. I have seen the full 80amps out on sunny days & have no doubt that its capping it at that 80amps (shortly before it was a 800w array & that often did the full 800watts & slightly more). I dont think its burning that extra power as it does not give off that much heat. I assume it manipulates the MPPT to bring the input amps & v to levels that reduce the outputs to the capped levels.
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
2 x Victron Multiplus II 48/5000/70
Cerbo GX & GX 50 touch
BMV 700
6kva genny
48v 1000ah
Grid Possibly coming soon
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