Smartguage vs Solar

[Smelly]

I've noticed during days in, over the last 6 weeks I've been off the landline, that every day that I'm in; while it's sunny the SG never moves, the SOC never goes up or down, by one percent. The voltage does mind.

 

I've 2 cheapy PWM controllers on two different panels.

 

It strikes me as strange that it never budges.

 

I've been sat in with my radio on; domestic separates while the signal's so flaky so not exactly efficient. It's some coincidence that however sunny it's been i've used exactly amount of juice produced by the panels.

 

Wotcha reckon Gibbo?

[nicknorman]

I've noticed during days in, over the last 6 weeks I've been off the landline, that every day that I'm in; while it's sunny the SG never moves, the SOC never goes up or down, by one percent. The voltage does mind.

 

I've 2 cheapy PWM controllers on two different panels.

 

It strikes me as strange that it never budges.

 

I've been sat in with my radio on; domestic separates while the signal's so flaky so not exactly efficient. It's some coincidence that however sunny it's been i've used exactly amount of juice produced by the panels.

 

Wotcha reckon Gibbo?

Perhaps it's because the SoC is remaining constant! What voltage and current are you getting at the batteries when the panels are in the sun?

[Smelly]

No means of measuring current but betwen 12.7 and 13.4 today.

[nicknorman]

No means of measuring current but betwen 12.7 and 13.4 today.

Assuming the batteries are reasonably well charged, that voltage represents "barely charging". At roughly what indicated SoC was this, and what rating are the panels?

[Smelly]

250 watt at 80

 

250 watt at 80i half expect the pv to be effectively powering my usage with the batteries as a big resistor tbh but the fact that the SOC never varies, not one iota, has me puzzled aswith a pretty constant drain, against varying outputfrom the PV I'd expect at least some drift in the SOC.

[Paul C]

Can you disconnect the solar and if so, check to see the battery state of charge gradually drops as things are kept running. Then reconnect it and see if it goes up again?

[Smelly]

Can you disconnect the solar and if so, check to see the battery state of charge gradually drops as things are kept running. Then reconnect it and see if it goes up again?

 

I'd rather not... everynight the SOC drops as I'd expect.

[Paul C]

Remove the fuse?

[Smelly]

Remove the fuse?

 

Let it go dark?

[Paul C]

Without an ammeter you're limited in your diagnostics. By disabling the solar, at least you can have a day and a half without it, to see if the SOC goes down a bit, or a lot; then connect it and see it rise. I suspect the cheap PWM solar controllers aren't able to fully charge the batteries (hence not rising above 80% SOC) and that in normal use, solar power in, is exceeding usage (power consumed). But without measuring the current, its a guess. The suggestion was 33h of discharge, rather than 9h, could show this more clearly for you given your limited diagnostic ability (did I mention its guesswork without an ammeter?)

[nicknorman]

I suspect there is something up with the panels/charge controller because 250w panels should give a higher voltage than that at that SoC. By way of diagnosis, what happens if you turn the radio and all other power consumers off for an hour or so on a sunny day? The SoC should surely rise.

 

I suspect Gibbo may not contribute to this thread since he is not allowed to discuss how SG works since he sold the IP, so in his absence I suggest that the SG expects to be in either charging mode or discharging mode. With this very weak charging perhaps it is stuck in no-mans-land. Even so, if the actual state of charge is increasing I would expect the SG to show a rise eventually.

 

Most likely the panels are not charging as you would have hoped. For £25 you can buy a DC clamp meter from eBay that easily allows you to measure the current in a wire. Or you could borrow one! Probably only once you can measure what is going on, will you be able to fix it.

Edited August 25, 2012 by nicknorman

[Smelly]

Without an ammeter you're limited in your diagnostics. By disabling the solar, at least you can have a day and a half without it, to see if the SOC goes down a bit, or a lot; then connect it and see it rise. I suspect the cheap PWM solar controllers aren't able to fully charge the batteries (hence not rising above 80% SOC) and that in normal use, solar power in, is exceeding usage (power consumed). But without measuring the current, its a guess. The suggestion was 33h of discharge, rather than 9h, could show this more clearly for you given your limited diagnostic ability (did I mention its guesswork without an ammeter?)

 

I live aboard and have been watching this for 6 weeks.

 

The alternatives are to go to work and come home to replenished batteries to 70-90% SOC from 50 or 60, go away for a day or more and come back to100, stay in at night andsee an expected 20%discharge overnight ,or stay in during the day and see no change... ever.

 

Considering the variation I don't think I'm too far off the mark expecting to see at least a 1% shift in SOC over what, today, was nearly 9 hours.That 1% equates to 4 or maybe 5 amp hours over a day. As the trend has continued over weekends of varying insolation I reckon it's a fair question.it's a nominal 440 Ahr bank that's 2years old.

 

I've been on a landline for 3 months and 4 days during 22 months and 2 days of the bank's lifespan.

[PhilR]

In this electronic world I reckon we probably expect too much of monitoring devices.

 

You can't beat a decent voltmeter and hydrometer to confirm the state of charge etc

[Smelly]

I suspect there is something up with the panels/charge controller because 250w panels should give a higher voltage than that at that SoC. By way of diagnosis, what happens if you turn the radio and all other power consumers off for an hour or so on a sunny day? The SoC should surely rise.

 

I suspect Gibbo may not contribute to this thread since he is not allowed to discuss how SG works since he sold the IP, so in his absence I suggest that the SG expects to be in either charging mode or discharging mode. With this very weak chafing perhaps it is stuck in no-mans-land. Even so, if the actual state of charge is increasing I would expect the SG to show a rise eventually.

 

Most likely the panels are not charging as you would have hoped. For £25 you can buy a DC clamp meter from eBay that easily allows you to measure the current in a wire. Or you could borrow one! Probably only once you can measure what is going on, will you be able to fix it.

 

That's constructive... thank you.

 

I suspect a "no mans land" scenario as with 2 PWM controllers, fighting an inverter fueling an amplifier that's varying it's useage with every syllable transmitted, that the SG might be getting confused over a relatively small change in SOC. I'd borrow "resolution" to describe it.

 

I'm not so sure about the panels being throttled as I saw a significant increase in charging when i put the new 80 wt up and when I'm running my wee Pure radio I can watch the SOC increase. It's only with moderately higher use it seems to flatline; but it flatlines so much I suspect something adrift.

 

If I'm on 80% with, say, a 6amp drain would 13 be so bad?

 

In this electronic world I reckon we probably expect too much of monitoring devices.

 

You can't beat a decent voltmeter and hydrometer to confirm the state of charge etc

 

Testing my batteries every half hour with a hydrometer would be irksome. Pressing the button on the SG; less so!

[PhilR]

 

 

 

Testing my batteries every half hour with a hydrometer would be irksome. Pressing the button on the SG; less so!

 

Why would you need to test your batteries every half hour?

[Smelly]

Why would you need to test your batteries every half hour?

a

 

Because I can. And moreso when they (or maybe it) don't do what I expect them to; hence the thread.

 

Sorry, bad grammar. Editing on this tablet is a PITA.

[Justme]

I suspect the cheap controllers are cutting of the charge at the 13.4 v high you are seeing.

 

Things I would do:-

 

Check their specs, lots do stop the charge at stupidly low voltages.

Check the wiring.

Test voltages at all points in the wiring.

(back of panels, input to controller, output from controller, at all fuses & switches ect)

Connect the panels direct to the bats (but only while you are there to monitor / disconnect them) & see if the V & SOC go up.

Fit an amp meter to see what is actually happening.

[Gibbo]

The alternatives are to go to work and come home to replenished batteries to 70-90% SOC from 50 or 60, go away for a day or more and come back to100, stay in at night andsee an expected 20%discharge overnight ,or stay in during the day and see no change... ever.

 

I'm not so sure about the panels being throttled as I saw a significant increase in charging when i put the new 80 wt up and when I'm running my wee Pure radio I can watch the SOC increase. It's only with moderately higher use it seems to flatline; but it flatlines so much I suspect something adrift.

 

So if you're not in all day, and start from 50%, you come home to 70% to 90%.

 

If you do the same, but stay away for a few days, you come back to 100%.

 

If you stay in at night (thus using power) you see the SoC fall.

 

When you increased the total solar panel size you saw an increase in charge.

 

If you stay in but only have a small load on (your wee Pure radio) you see the SoC increase.

 

With slightly more load. You see no increase.

 

Put a bigger load on, you'll see the SoC go down.

 

Isn't all the above exactly what you should be expecting?

[Ally]

When you come this way again, we have a DC clamp meter you are welcome to borrow.

[Smelly]

So if you're not in all day, and start from 50%, you come home to 70% to 90%.

 

If you do the same, but stay away for a few days, you come back to 100%.

 

If you stay in at night (thus using power) you see the SoC fall.

 

When you increased the total solar panel size you saw an increase in charge.

 

If you stay in but only have a small load on (your wee Pure radio) you see the SoC increase.

 

With slightly more load. You see no increase.

 

Put a bigger load on, you'll see the SoC go down.

 

Isn't all the above exactly what you should be expecting?

 

Yes, but, well, errr...

 

It's weird that it doesn't move at all isn't it?

[Gibbo]

Yes, but, well, errr...

 

It's weird that it doesn't move at all isn't it?

 

Put a bigger load on, or reduce your load. Then it will move.

[Smelly]

One worry that's emerging is that sometimes the SOC seems to,drop quite precariously overnight; while I'm asleep. I've not ruled out an external actor; frinstance i thought leaving the radio on overnight was to blame but it dropped 15% last night without it,however I've wondered whether it might be hanging and catching up with itself overnight. I f I fancy running the engine I tend to do it 7 to 8pm.

 

Mr Occam tells me my batteries are probably getting tired.

 

 

Lots to check yet though...

 

As opposed to borrowing Ally's clamp meter (I'm probably starting the jaunt west next weekend, I fancy Redhill, then Sawley) I've got a 200mV 200A shunt in line. I know shunts should be matched to the meter but if I bought a similar 200mV 200A meter from a different supplier, the original having gone the way of small ebay vendors would it suffice?

 

Footnote... avid readers might remember I bought volts/ amps meter a few years back. The wiring harness came with a different colour sequence to the instruction manual. Gibbo volunteered to check it but the manufacturer advised to follow the sequence rather than the colours which I did. It then needed calibrating with a brass screw, I did that, started the engine and it went dark, never to work again and I gave up. The SG is now living in it's housing.

[bottle]

it dropped 15%

 

Your batteries may well be tired but another factor could be equipment running.

 

If you have two items and they both come on together they will hit the batteries harder than if they came on one at a time.

 

I get just such a happening and it does throw out the big drops in SOC.

[Smelly]

Dug my multimeter out and it's damp and showing 1.2v less than the SG... Curses.

 

Ah well, as SirNibs once said; it ain't broke til the lights go dim!

[smileypete]

Dug my multimeter out and it's damp and showing 1.2v less than the SG... Curses.

 

Ah well, as SirNibs once said; it ain't broke til the lights go dim!

Errr, what are you hoping to gain by fretting about the Smartgauge reading?

 

cheers, Pete.

~smpt~

Edited August 26, 2012 by smileypete