Breaker Switch- Low/High Amps Unpredictable

StevenB · July 2009

I'm observing a weird affect. (2) 60w Kaneka panels in parallel, connected to a BZ 500 controller, then to 48volt battery bank, and a Xantrex 6048.
I know from previous postings the BZ's rep is not great....but it's what I have, and the owner has been available, and replaced a unit no problem.

The controller was not producing anywhere close to the amps expected.... -zero to point 4, and scrolling back and forth between those points. We tested by jumping the Battery+ lead into the controller over to the controller's PV+ and got 1.9amps. Measured 80 (or 90 I forget) volts inside the unit which was a correct level. And we advanced the float adjuster to keep it from prematurely cutting out the charge to the battery.

Still scrolled between zero and point4 amps. The BZ owner told me from our tests our connections to the controller was fine, and he was going to send a new unit and he would preset the float adjustment.

When we first swapped them, sure enough....it produced 1.8 amps and 85 watts, and held all day never dipping below 1.5 amps.
The next day, clear sunrise, kept waiting for the higher sun to produce amps but all it did was scroll between zero and point 4 amps.

Here's the weird part.........for no real reason, I turned the PV breaker off for about 30 seconds and flicked it pretty hard on again. It went right up to 1.7 amps and held for about 4 hours......some very light clouds came and it went back to low amp scrolling even after the sun came out again....and would not respond to my unscientific switch flipping. That was yesterday....I went out there today and tried flipping the breaker again and sure enough up the amps jumped. Same thing....little cloudy ...held at the low scrolling amps and would not respond to switch flipping.

The Breaker is: Midnite Solar Circuit Breaker, DIN Mount, 20A, 150VDC

Is this just a case of a bad switch? My supplier told me it may be that there is just too little amps to get the switch to operate properly....does that sound possible?
I plan to take the breaker switch out temporarily and see if it continues to do the same thing.....is that ok to do temporarily?

I'll include the Kaneka specs below. If anyone can help...I'm still an idiot on the math, so those who write out the way they calculate conditions is a terrific help to my education in all this.

KANEKA GSA-typeSpecifications
Model
GSA-type
Nominal Power
60W
Open Circuit Voltage
92V
Short Circuit Current
1.19A
Voltage at Pmax
67V
Current at Pmax
0.90A

icarus · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

What can I say,

Regardless of what BZ is telling you, if you are not getting near expected output from you panels (and you know the panels are putting out) I suggest throwing the BZ in the trash, and buy a simple Pwm controller if that is all you can afford, or a Morningstar MPPT or a Bluesky MPPT, but it sounds like the BZ is doing exactly what it does,, NOT WORKING PROPERLY!

I would connect the Pv panels together one at a time with a ammeter to determine that they are indeed putting out proper current.

Good luck,

Tony

PS Unless I am missing something,, your 120 watts of Pv if they are only yielding ~1.7 amps you are only getting ~90 watts out of your Pv depending on battery voltage.

Cariboocoot · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

BZ - named for the sound they make just before they quit working. Never heard any good reports of them, and it wouldn't surprise me to see someone get one bad one after another.

"My supplier told me it may be that there is just too little amps to get the switch to operate properly....does that sound possible?"

I don't understand what he's on about. A breaker is either connected and flowing current, or it isn't. There can be too low a current to trip it, but it does not require a minimum current to operate. It could be that you have a bad breaker which is connecting imperfectly or intermittently, and that the charge controller is not connected up to the battery. If the battery is 'disconnected' the controller will read no amps and probably will search up and down trying to find 'a charge rate for thin air' as it were.

Check all your wiring connections, and then by-pass the breaker - preferably with a fuse - and see if the controller behaves.

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Thanks Tony....I already have an email to another supplier, and I appreciate the starting place to look. I pretty much had come to that conclusion.

But I was thrown off by the idea that I could flick a breaker switch on and off to affect something. And as bad as BZ may be, I don't want it to camouflage another problem, that I still will have with a new controller.

And I think 1.7 amps is too little, even though I am still pretty stupid about all this.

Can you or someone tell me though if the volt size (12,24,48 ) of the battery bank affects the expected PV amps.....when you are dealing with such a small load as 2- 60 w panels?

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Marc,
Thanks. I couldn't follow what he was saying on the phone call about too little amps...and I am just too new to challenge him. But it sounded funky. He's given me good info to date....but now I'm guessing he's sold a bunch of BZ controllers, and he's getting pretty warped.

Cariboocoot · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Basically, 120 Watts/48 Volts = 2.5 Amps (not including efficiency losses). The same 120 Watts charging a 12 Volt battery would be 4X that: 10 Amps.

My question would be: how big is your battery bank? Based on the maximum possible charge rate, you're probably not running enough current to keep your batteries from sulphating. If you're powering a Xantrex 6048, wouldn't you have several hundred Amp/hrs of battery? 2.5 Amps would only work for about 50 Amp/hrs, long term (unless I'm doing the math wrong or completely crazy today - it's very, very hot here!

)

But that wouldn't effect the controller's ability to function. Shouldn't, anyway. Better check and charge those batteries anyway - they've probably been suffering from lack of proper charging just from the trouble you've been having.

Personally, if I was powering a 6000 Watt inverter I'd have about 3000 Watts of panels and 800 Amp/hrs of battery - maybe more. But that's just me.

BB. · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Try measuring voltages at at various points... And measure voltage drops (across connectors, and wires)... It is possible that you have a poor connection or corrosion somewhere.

A 120 watts of panels is not very much energy for an MPPT controller.

Trying to understand 120 watts of solar panels and 6,000 watts of inverter--and how much in batteries?

If you are going to pull near 6kW out of the Xantrex Inverter--you probably need 400 amp*hours of 48 volt battery bank.

The minimum recommend panels/charger current would be at least 20 amps for that size battery bank (5%-13% of AH rated battery capacity rule of thumb). Less than 2 amps is not even trickle charging.

-Bill

icarus · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

The equation is pretty simple Volts*Amps=Watts

Watts are THE measure of power used,, over time it is expressed as watt/hours. A 100 watt bulb burned for 10 hours will use 1000 watt/hours or 1 kilowat hour (KWH)

So in your case your panels are rated (sold) in watt units,, say 60. That rating is a combination of their rated voltage and rated current (amperage)

So in your case, 120W/48V=2.5A
Or 120W/12V=10A

Understanding that Pv panels/mppt controllers don't just put out 12 or 48 volts, but more like 17 or 72V, so that there is enough "head" room to "push" power into the battery. If you just had a 12 volt panel plugged into a 12 volt battery it would never charge.

So in the case of your 1.7 amps,, it is probably at ~52v maybe higher depending on the state of charge of your battery, so 1.7A*52V=88.4 watts. A good mppt controller should be able to do a bit better I think.

So,, wattages remaining equal, if you double the voltage, you halve the amperage. If you double the amperage you halve the voltage.

Another part of the problem might be,, I don't know what the open circuit voltage of the Kanaka panels are, are they 48V (nominal) panels in parallel or 2 24V in series, or 2 48V in series. If they are 48V in series it is possible that they have more voltage than the BZ controller can handle, or if they are 48V panels perhaps they have too LITTLE voltage for the controller to handle. I haven't bothered to look at the BZ specs. since it has been demonstrated that they probably couldn't handle their design power in any case.

Good luck,, see if you can get a refund on the BZ bs.

Tony

Cariboocoot · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Forgot to ask: has this set-up ever worked?

It occurs to me that if the batteries have been habitually undercharged and are now toast, the CC might see it as a big pile of 'AAA' cells: there's 48 Volts there but they can only take a few milliwatts now (because the plates are caked in sulphur). A 'flick of the switch' could show good current initially, which would rapidly settle down to almost nothing.

And would somebody please turn down the thermostat here?

mike95490 · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

StevenB wrote: »

I plan to take the breaker switch out temporarily and see if it continues to do the same thing.....is that ok to do temporarily?

For a temporary test, while you are present, sure, not a problem. They might be thinking the contacts are "dirty" and need a little more current to "arc" into good contact. I say BS, you are not running that much/little power where I'd expect that sort of problem to happen.

If the battery is charged up, no matter the PV, you won't pull any amps, that's why you should check each panel with ampmeter.

You have enough voltage from the PV's (Open Circuit Voltage 92V) to give yourself a nasty shock, so be careful, or throw a blanket over the panels as you work with the wires.

niel · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

for your own arguments sake, do bypass the breaker and watch that bz junk do the same thing again. i could imagine how mad people would be with circuit breakers if all they had running was their clock and when the frig needed to run that it wouldn't allow the current to pass through the breaker. we'd all be using fuses in that case.:roll:
it also isn't that there's too little power to run it either. again, if that were the case we'd all stick to straight pwm controllers. they operate, but it's a matter of internal power usage overall as opposed to the current gained while it operated. it would still pass the current and would not do what that junk was doing.
it also isn't that the batteries are full or when the cb was flipped it wouldn't be passing such higher amps. you need another controller plain and simply.

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Oh my frigging gosh...I've got a day's reading and study here!Thanks everyone.
I've got an email into NAWS to look at another controller.

To answer a few questions:
1) The 6000 watt inverter was what I wanted to start with to add on eventually an independent bank of more powerful panels and a xantrex controller.
2) The BZ never performed satisfactorily...I just recently had time to turn my attention back to it. My wind turbine during winter and spring rocked, not so much summer so I finally started focusing on the panels.
3) Battery state (16 - 85 amp 12v AGMs - I don't think they are "chronically undercharged'. The Xantrex will kick in and charge at 50v if it needs it. The batteries only supplies the inverter's power and a sub-panel when there is a power outage (only happened once for an hour) Batteries seem to stay pretty much between 50.3 and 51.3.

This arrangement with the 2 panels and the BZ were a way for me to screw up before I ground mount the 16 220watt panels. I'd say I'm at least accomplishing that!?
I better get to studying this info and advice. Thanks!

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Niel-
Thanks. Plain and simple thanks.

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

BB-
Here's where I'll get really ignorant. My hope for the panels was that they would be essentially a trickle charge for my backup batteries, for when the wind didn't blow, and until I could add a bigger system.
I did not have a belief that they would do more than compensate for the load the Inverter used up....and keep the veggie freezers (energy stars) in the barn (the sub-panel)going if there was a power outage if we were out of town for a few days.
During the periods over these last few days when I'd click the breaker and the Pentametrix would show 1.7amp/80 something watts.......the battery would slowly raise from 50.5v to 51.5v.

halfcrazy · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

maybe it is to close to its 100 volt limit and it is shutting down? resetting it may allow it to load the panels and bring the voltage down? either way trash it and get something more reliable.

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

As suggested I am replacing the BZ 500. I've been told that the Xantrex C40 40A,12-48V CHARGE CONTROLLER will work with my 2 Kaneka 60's that are in parallel.

Any comments on compatibility, and expected performance?

Below are the specs for the Controller and Kanekas...Thanks!

Voltage Configurations 12 VDC 24 VDC 12 VDC 24 VDC 48 VDC 12 VDC 24 VDC
Maximum PV Array Open Circuit 55 VDC 55 VDC 125 VDC 125 VDC 125 VDC 55 VDC 55 VDC
Charging/Load Current @ 25 �C 35 amps DC continuous 40 amps DC continuous 60 amps DC Continuous
Recommended Breaker Size With Recommended Wire Size in Conduit 60 amps DC, #6 AWG 60 amps DC, #6 AWG 60 amps DC
(100% continuous duty cycle),
#6 AWG (90 �C rated)
General specifications
Maximum Peak Current
Maximum Voltage Drop
Total Current Consumption
Charge Regulation Method 85 amps intermittently-electronically protected
0.30 volts -charge control mode
While operating - 15 ma (typical), at idle - 3 ma (tare)
Solid state, 3-stage (Bulk, Absorption and Float) Pulse Width Modulation (PWM).
Regulation Adjustment Settings Charge Control Mode Setup for:
Lead Acid Battery 12 Volt Configuration:
Float 12.5 - 14.5 VDC
Bulk 13.0 - 15.0 VDC
EQ +1 VDC above Bulk 24 Volt Configuration:
Float 25.0 - 29.0 VDC
Bulk 26.0 - 30.0 VDC
EQ +2 VDC above Bulk 48 Volt Configuration:
Float 50.0 - 58.0 VDC
Bulk 52.0 - 60.0 VDC
EQ +4 VDC above Bulk

Model
GSA-type
Nominal Power
60W
Open Circuit Voltage
92V
Short Circuit Current
1.19A
Voltage at Pmax
67V
Current at Pmax
0.90A

BB. · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

I don't see any issues (as always, read the manuals/data sheets closely).

The only drawback is that you are 1/3 the way to getting a true MPPT type charge controller ($150 vs $500 for an Outback FM 60)... If you had 400 watts or more of solar panels (and/or planning on adding more panels)--then I would avoid the C40...

But you don't have many panels right now--and it is questionable that the "better" controller may even generate less power for you than the simple C40 controller (internal electronics consume more power in the large/more complex controllers--so with low wattage panels, they may use more power than the MPPT function can gain you).

-Bill

icarus · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Morningstar makes a nice MPPT controller: http://forum.solar-electric.com/forumdisplay.php?f=9

Bluesky also makes one, I have one and like it, but others have different opinions:http://store.solar-electric.com/blskyenmpsoc.html

Tony

halfcrazy · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

I second the Morning star Just make sure whatever you get will handle the tempature corrected VOC of those panels.

Solar Guppy · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

The C40 just shorts the input to output for Bulk mode ... so any PWM controller is a poor choice for your Asi panels as your vmp is about 20-25 volts higher than the battery voltage , so that's about a 30 watt lost on your two panels... since the panels could NEVER overcharge the XW-6048's battery's, why not just use a 2 dollar diode from Radio Shack? , you have no need for regulation. You can always put the XW-6048 to grid-tie to protect the battery's , just use a sell voltage of ~54V to be safe

The MorningStar Mppt is a maximum of 75V, so that's not an option

StevenB · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

Can you explain "The C40 just shorts the input to output for Bulk mode" ....I think I understand just fair what follows in the rest of what you said...........but I'd like to get a grip on this statement first.

Cariboocoot · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

StevenB wrote: »

Can you explain "The C40 just shorts the input to output for Bulk mode" ....I think I understand just fair what follows in the rest of what you said...........but I'd like to get a grip on this statement first.

In bulk mode the solar panels are connected directly to the battery with no regulatory circuitry involved - like hooking them together without the C40 being there.

Solar Guppy · July 2009

Re: Breaker Switch- Low/High Amps Unpredictable

There are 3 common types of charge controllers

On/Off

PWM

Mppt

On/Off and PWM are similar, typically on/off uses a relay to connect the input to output, when it needs to regulate ( absorb or float ) the relay toggles at a slow interval ( think 10's of seconds )

Pwm uses FETS or Transistors, same as above except the regulation modes, it toggles typically at 400 hz, bulk mode is solid on, meaning the input and output are a very low resistance path.

Mppt is an actual down converter power supply, its allows a differential between input and output and as the voltage difference increase, so do the output current, losing only a few percent of the true power. Further, the supply can be controlled via software to find the best differential that harvests the most energy from the solar, that's the Mppt part.

Your Asi panels have a high vmp ( voltage maximum power ) point, that is 20-30 volts above the battery voltage ... now one can connect the solar directly to the battery, but the difference is lost between the vmp and battery voltage times the active current. So say 1.5 * 20 or 30 watts for your panels using a diode, pwm or on/off controller.

Its not worth spending 150 dollars on a charge controller that does pretty much what a diode does, the diode can't regulate, but you have other options to deal with over charging, which frankly, the tar load of the XW-6048 will consume all the little Asi panels could put into the battery's

The BZ is actually the worst choice, at least a diode will always harvest power, the BZ with its flaky performance typically just shutdown .. its a totally worthless piece of junk

If your going to spend any money, get either the XW-Mppt, Outback Mppt or the new MorningStar Mppt controller if you can wait a few months

Breaker Switch- Low/High Amps Unpredictable

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