sjc

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About sjc

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    Bridie
  1. Just did a quick test on my panels : 3 x 100W in series. Blanking out a single cell, then multiple cells on the same panel had a very different effect to that in the video. As I would expect you only lose half a panel for a single cell, or a complete panel for multiple cells. But we don't have the benefit of a clear blue sky so the clamp meter was forever changing. It looked like the MPPT took a few seconds to re-adjust then things continued as normal. So I have no idea what went wrong on the video, they had the perfect opportunity to carry out a scientific test but left unanswered questions instead !
  2. Your description is correct which is why they have bypass diodes, to prevent this happening. Maybe their panels did not have bypass diodes ?
  3. If I have remembered correctly, the series connection dropped from about 15A to about 1A when just s single cell was in shade. I am struggling to understand how this can be true, anyone care to explain ?
  4. This is where the CE markings come into their own. The standard would state the current and duration before a relay could claim to be rated at that value. BUT, how the general public knows which CE numbers to look for is a mystery, apart from Google of course ! Not wishing to get political, but the British Standard kite mark may be making a come back and replacing the CE mark !
  5. I would suggest he following :- 1) Protect it from direct sunlight as this may affect the outer casing. 2) I agree with Tony about the wicking, it is usual to seal the ends with pvc tape or similar to prevent moisture ingress.
  6. I am assuming the Adverc replaces the alternator regulator ? In which case it certainly looks like an Adverc fault. Sadly I am not familiar with the cable colours on your chart, could you add signal names so we can see what each one is doing ( eg : main output, regulator feed, ignition lamp etc etc ). The values you say are varying, are they at the 0.5Hz frequency as well ?
  7. We have the same inverter, and the same problem. It runs for months without the fan coming on, then it will run constantly for days on end. I also wondered if it was more frequent at night, but I don't think it is. At one time I turned the inverter off for a few minutes then back on again and it seemed to "reset" the problem. It had absolutely NOTHING to do with ambient temperature or current drain. I exchanged many emails with the Victron technical contact but they were of no help, eventually telling me to return it for them to examine. I never did as this isn't convenient, at the moment things are quiet ! I wondered if it was a software fault switching the fan on accidentally, but the previous post about connectors is a thought.
  8. Fair enough Dave, each to their own. The shunt method is more common and what people would think of first and foremost. But any solution will involve a compromise, whether people realize or not. I haven't re-checked the specs recently but seem to remember linearity <1%, and the electrical isolation appeals to me. Also, with a shunt ( say 200A == 50mV ) you will need to use an op-amp that will run off a single supply ( 0 -12v ) AND operate right up to its' voltage rail ( not all, especially the cheaper ones do this ). Otherwise a dual rail device ( +/- 12v ) could be used. As for accuracy, to detect 50mV on a noisy electrical system is quite an achievement, as for your 1A error, that involves a 0.25mV drop across your shunt, you do not have a hope in hell's chance. People think because the display shows 3 or 4 decimal places it is accurate, often those digits are a work of fiction ! ( unless you spend a fortune on expensive circuitry ). Even 10A requires detection of 2.5mV, if you put a scope on the signal and checked out the voltage spikes you would appreciate the challenge. You will always have a value, and a figure on display, but it is not much more than a guess ! There are clever filtering techniques but you would need a Paul Daniels filter for that ! Good luck and please post back the outcome !
  9. This subject has come up before so if you search the forum you might find it. I would dis-regard the shunt method altogether and get a hall effect current sensor ( see link below for examples from Farnell ). I doubt they are more expensive than the shunt ( with extra electronics required ), are more accurate, more linear, provide electrical isolation, and give a simple analogue voltage output proportional to the current. ( probably 0 - 5v or similar which could be reduced with a simple divider ). http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000005923&st=current%20tansducer&beginIndex=1&showResults=true&aa=true&pf=110151160
  10. Yep, I completely missed the 24v point, in which case should be fine ! Never the less something for the 12 volters to consider !
  11. At 300W you are already beyond the max ( 20A ) output of the Tracer, 400W exceeds both options ! I suggest it is better to have spare capacity in the MPPT ( ie : get a 50A ) as it would allow for system expansion should you decide to do so, more importantly it will mean the MPPT runs cooler on a hot sunny day when the ambient temp in the electrical cupboard is high.
  12. If the motor was completely locked I would have expected a fuse / circuit breaker to activate - hmmm
  13. Alan is spot on, I would add the following :- 1) Do a sanity check on the wiring to ensure the diagrams are correct. 2) Check for a Galvanic Isolator or Isolation transformer 3) Carry out a power audit. 4) Check for leakage currents etc to catch any problems early. 5) Check fuses / mcb's operate as they should. 6) Try to assess the condition of the batteries. 7) Do you have a dedicated alternator for the starter battery or a split charge system ? All the above have been covered elsewhere on this forum. Otherwise, you seem to have the basis for a good system.
  14. From the age and description it could be the motor not starting because the brushes are worn. This happened to us and we swapped out the motor ( luckily a warranty issue for us ! ). You may be able to tap or wiggle it ( gently ) into life intermittently, which would confirm the diagnosis. This assumes you have done nothing to it, or near it recently, that may have affected the wiring, first thing would be to check fuses, wiring, and a voltage on the motor terminals when it should be flushing.
  15. This is somewhat misleading, the current at 12v is 20 times that at 240v. Example to estimate average continuous drain :- Rating : 365KWh per year ( often given for white good etc ) Where : 24 * 364 = 8760 hours per year And : 365Kw = 365000W Divide rating in Watts by Nbr hours per year :- Power : 365000W / 8760hours = 41.7W Now divide by appropriate voltage to get current drain :- @12v : 41.7 / 12v = 3.5A @240v : 41.7 / 240v = 0.174A Notice the current at 12v is 20 times that at 240v.