Advice on solar controllers needed

AntarcticPilot said:
Knowing the actual amps going in is handy - it tells you if the output from the panels is what you expect, and whether your panels are oriented optimally. I do have an alternate way to monitor battery voltage, though being ancient moving coil analogue meters I suspect they don't have a high enough impedance to read correctly when the battery is full.

I don't understand your statement re volt meter impedance. Volt meter impedance (resistance might be a better word) does not affect reading when measuring a battery voltage. An analogue meter will have a lower resistance so draw some current from the battery compared to typical electronic digital high impedance volt meters. But the current for a analogue moving coil meter will typically be less than half a miliamp so can be disregarded. However an analogue meter will not give the accuracy or ease of reading small changes that a digital meter will give. Small digital volt meters are crazy cheap from China.
What you might consider doing is converting your analogue moving coil volt meter to an amp meter. It will have the advantage of not needing a supply voltage and being OK in the positive or negative line.
firstly open up the meter and inside you should find a series dropping resistor. Find this and bypass or remove it. Now you have a typical 1 ma full scale meter. You now need a shunt to change it to read perhaps 20 amps full scale.
A shunt is just a peice of metal which has resistance. A piece of stainless steel can be ideal. Try 20 g plate about 2cms wide and 5 cms long. Drill 2 holes in each end.Into one hole each end you bolt in lugs with your main power passing through from one end of the ss to the other. Into the other 2 holes you bolt lugs with light wires which go to your meter. NB you use separate connections to the meter because any resistance over time of the main power lugs can change meter reading accuracy. Nb also you must fit small fuses in both wires to the meter if you have the shunt in the positive side of supply. This because these light wires will have pos volts on them compared to negative ground.
Once this is set up you start passing current through the system and shunt and see what the meter does. Now you really need to know how much current is passing through the shunt. Add a temporary amp meter (digital multimeter) or even use an incandescent lamp of known wattage so you can guess current. You can then choose the max current you want the meter to cope with and remark the dial as needed. You can make the meter read more by making the shunt more narrow or longer and make it read less by shortening the shunt. Alternatively you can buy a ready made shunt makes mounting easier and fit a resistor between the meter and shunt to reduce the meter reading. Or even fit a variable resistor so you cna easily adjust it.
Your amp meter does not have to be very accurate. Just to get an indication of normality can be very useful. Just a thought if you have a moving coil volt meter. ol'will
https://www.ebay.com/itm/DC-Panel-4...hash=item3ac6fd1a50:m:mETuYmjPyaTCfHU4nEBr1TQ This one gives 4 digits.
However this one with 3 digits are tiny and really cheap and good.https://www.ebay.com/itm/Mini-DC-0-...+Vj6nta7CKEs3N0qWiEHAttM3Ig+9GHw51kkXinNe87Sw
PS the cobined amp meter volt meter may suit you however the shunt or current circuit usually must be in the negative side of the load which can cause difficulties.
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You can buy from China moving coil ammeter very cheaply might be easier than messing about modifying a voltmeter.
 
peteK said:
You can buy from China moving coil ammeter very cheaply might be easier than messing about modifying a voltmeter.
Click to expand...
And lots panel ammeters on ebay. IMHO a large voltmeter direct to the battery terminals visible from lots of places around the boat is one of the biggest bang for buck additions you can put in a boat.
 
William_H said:
AntarcticPilot said:
Knowing the actual amps going in is handy - it tells you if the output from the panels is what you expect, and whether your panels are oriented optimally. I do have an alternate way to monitor battery voltage, though being ancient moving coil analogue meters I suspect they don't have a high enough impedance to read correctly when the battery is full.

I don't understand your statement re volt meter impedance. Volt meter impedance (resistance might be a better word) does not affect reading when measuring a battery voltage. An analogue meter will have a lower resistance so draw some current from the battery compared to typical electronic digital high impedance volt meters. But the current for a analogue moving coil meter will typically be less than half a miliamp so can be disregarded. However an analogue meter will not give the accuracy or ease of reading small changes that a digital meter will give. Small digital volt meters are crazy cheap from China.
What you might consider doing is converting your analogue moving coil volt meter to an amp meter. It will have the advantage of not needing a supply voltage and being OK in the positive or negative line.
firstly open up the meter and inside you should find a series dropping resistor. Find this and bypass or remove it. Now you have a typical 1 ma full scale meter. You now need a shunt to change it to read perhaps 20 amps full scale.
A shunt is just a peice of metal which has resistance. A piece of stainless steel can be ideal. Try 20 g plate about 2cms wide and 5 cms long. Drill 2 holes in each end.Into one hole each end you bolt in lugs with your main power passing through from one end of the ss to the other. Into the other 2 holes you bolt lugs with light wires which go to your meter. NB you use separate connections to the meter because any resistance over time of the main power lugs can change meter reading accuracy. Nb also you must fit small fuses in both wires to the meter if you have the shunt in the positive side of supply. This because these light wires will have pos volts on them compared to negative ground.
Once this is set up you start passing current through the system and shunt and see what the meter does. Now you really need to know how much current is passing through the shunt. Add a temporary amp meter (digital multimeter) or even use an incandescent lamp of known wattage so you can guess current. You can then choose the max current you want the meter to cope with and remark the dial as needed. You can make the meter read more by making the shunt more narrow or longer and make it read less by shortening the shunt. Alternatively you can buy a ready made shunt makes mounting easier and fit a resistor between the meter and shunt to reduce the meter reading. Or even fit a variable resistor so you cna easily adjust it.
Your amp meter does not have to be very accurate. Just to get an indication of normality can be very useful. Just a thought if you have a moving coil volt meter. ol'will
https://www.ebay.com/itm/DC-Panel-4...hash=item3ac6fd1a50:m:mETuYmjPyaTCfHU4nEBr1TQ This one gives 4 digits.
However this one with 3 digits are tiny and really cheap and good.https://www.ebay.com/itm/Mini-DC-0-...+Vj6nta7CKEs3N0qWiEHAttM3Ig+9GHw51kkXinNe87Sw
PS the cobined amp meter volt meter may suit you however the shunt or current circuit usually must be in the negative side of the load which can cause difficulties.
Click to expand...

peteK said:
You can buy from China moving coil ammeter very cheaply might be easier than messing about modifying a voltmeter.
Click to expand...

GHA said:
And lots panel ammeters on ebay. IMHO a large voltmeter direct to the battery terminals visible from lots of places around the boat is one of the biggest bang for buck additions you can put in a boat.
Click to expand...
First of all, I already have an analogue voltmeter that can be switched to read from either battery. This gives a reading slightly different from that of the HRDi when the battery is fully charged; not at other states of charge. Whatever the reason, this is observed fact, and I can only account for it by the HRDi have a much higher internal resistance than the analogue voltmeter.

In any case, while this gives interesting readings, it is NOT useful for what I want the monitoring for, which is to check the amperage going INTO the controller from the solar panels. As I noted above, this is useful to (for example) check that the solar panels are oriented as efficiently as can be managed, and to check that the panels are operating correctly. My panels are on a wandering lead, and I can easily relocate them to accommodate different mooring locations.The monitoring box is doing a different job from the panel voltmeter, though it may duplicate the function of the panel voltmeter.

I am pleased to see the descriptions of electrical theory, which confirm that I still remember my A-level physics, which covered most aspects of setting up and using electrical meters. Not relevant here, but I could still set up a Wheatstone bridge if I needed to, and I can still remember Ohm's and Kirchoff's Laws.
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AntarcticPilot said:
In any case, while this gives interesting readings, it is NOT useful for what I want the monitoring for, which is to check the amperage going INTO the controller from the solar panels.
Click to expand...

For that I commend to you the MT-1 remote meter for the Photonics Universe (and elsewhere) dual battery thingy. It estimate of battery condition isn't great, because assumes no load and so just one LED light on is enough to convince it that the battery is only half charged, but the current monitoring is very good and I have twice caught failed panels that way. You get both instantaneous and maximum current readings for what's coming in.
 
JumbleDuck said:
For that I commend to you the MT-1 remote meter for the Photonics Universe (and elsewhere) dual battery thingy. It estimate of battery condition isn't great, because assumes no load and so just one LED light on is enough to convince it that the battery is only half charged, but the current monitoring is very good and I have twice caught failed panels that way. You get both instantaneous and maximum current readings for what's coming in.
Click to expand...

Thanks. I was leaning in that direction already; the only question is whether I want the 10A or 20A version of the controller (which looks very similar to other controllers at similar prices; I suspect there's a lot of rebadging going on!). 10A will cope with what I have but with little expansion capacity; 20A will give expansion capacity but is a lot dearer!
 
GHA said:
And lots panel ammeters on ebay. IMHO a large voltmeter direct to the battery terminals visible from lots of places around the boat is one of the biggest bang for buck additions you can put in a boat.
Click to expand...

Agreed.
As well as permanently mounted meters, I've got a couple of LED voltmeter/ammeter combos installed in little plastic boxes with 4mm binding posts in and out.
 
AntarcticPilot said:
Thanks. I was leaning in that direction already; the only question is whether I want the 10A or 20A version of the controller (which looks very similar to other controllers at similar prices; I suspect there's a lot of rebadging going on!). 10A will cope with what I have but with little expansion capacity; 20A will give expansion capacity but is a lot dearer!
Click to expand...

If it helps, the most I have ever had (according to the MT-1) out of 2x50W panels is 5.1A. I'd therefore have thought that 10A would be fine for less than 200W installed and 20A for 200W up. It's only another twenty quid ...
 
JumbleDuck said:
If it helps, the most I have ever had (according to the MT-1) out of 2x50W panels is 5.1A. I'd therefore have thought that 10A would be fine for less than 200W installed and 20A for 200W up. It's only another twenty quid ...
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You're further north than I (at the moment) so the maximum insolation is less than I get "darn scarf". Not sure how big an effect that is, but I'm pretty sure I've seen higher currents from my 100W panel. However, you're probably right in principle.
 
AntarcticPilot said:
You're further north than I (at the moment) so the maximum insolation is less than I get "darn scarf". Not sure how big an effect that is, but I'm pretty sure I've seen higher currents from my 100W panel. However, you're probably right in principle.
Click to expand...

I have 260w of solar connected to a Victron 15a controller Andy. I have, on odd occasions, seen close to the 15a, but not very often, if that's any help.
 
For the extra money go for the expensive one, the cheapies may sound and get good reports but for peace of mind pay the extra.
 
You assume ASS U ME and in doing so you make an ASS of U and ME.
My advice is based on the principle that you usually get what you pay for and with controllers in particular. Like you I sought advice concerning a controller, in my case for a bank of 400w of panels.
I went for a Chinese under £20.00 despite experienced advice to the contrary, it failed in 2 months, it actually melted luckily I was aboard at the time and averted a possible fire. This was in Greece where the panels were producing high amps and 28v.
I replaced it with one made in Germany, which had the ability to sense not only my 750amp/h domestic bank but also my 120amp/h starter.
It cost I recall about £68.00 that was 10 years ago, it monitored both, indicators told me what was going on, which was confirmed by my battery shunt monitor.
Quite contrary to the silly remarks I have a budget to keep to, and never been accused of profligacy, but where my safety is concerned I buy the best I can, there is no premium on safety.
A word to the, I hope, the wise.
 
Freedom35 said:
You assume ASS U ME and in doing so you make an ASS of U and ME.
My advice is based on the principle that you usually get what you pay for and with controllers in particular. Like you I sought advice concerning a controller, in my case for a bank of 400w of panels.
I went for a Chinese under £20.00 despite experienced advice to the contrary, it failed in 2 months, it actually melted luckily I was aboard at the time and averted a possible fire. This was in Greece where the panels were producing high amps and 28v.
I replaced it with one made in Germany, which had the ability to sense not only my 750amp/h domestic bank but also my 120amp/h starter.
It cost I recall about £68.00 that was 10 years ago, it monitored both, indicators told me what was going on, which was confirmed by my battery shunt monitor.
Quite contrary to the silly remarks I have a budget to keep to, and never been accused of profligacy, but where my safety is concerned I buy the best I can, there is no premium on safety.
A word to the, I hope, the wise.
Click to expand...

We stand corrected. Obviously, and from your extensive research, all Chinese equipment is rubbish, and all German equipment is excellent. Thank you for saving us the bother of thinking for ourselves. :rolleyes:
 
Freedom35 said:
My advice is based on the principle that you usually get what you pay for and with controllers in particular.
Click to expand...

And my advice is based on the notion that if something works well and gets good reviews from users there really isn't much point in spending more just for the sake of it. Mind you, buying a grossly under-specced piece of kit to save £48 doesn't make much sense either.
 
NormanS said:
We stand corrected. Obviously, and from your extensive research, all Chinese equipment is rubbish, and all German equipment is excellent. Thank you for saving us the bother of thinking for ourselves. :rolleyes:
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How could any reasonable thinking person possibly interpret my response in such a biased point scoring attempt is beyond ridicule.
I clearly outlined my experience. That does not imply, however clever the mental gymnastics perform, that Chinese products are rubbish and German are perfect.
If this person took the time to find out, my panels are CHINESE and very good they are. My controller is GERMAN because the Chinese one melted.
I did not mention extensive research, another figment of a rather excitable imagination.
I did not suggest I wanted to correct anyone or indeed infer or imply anyone here is incapable of thinking for themselves, I have far to much respect for those who take the time to share their experience and knowledge, and I at the very least expect, in this instance in vain, anticipate the same consideration. It would appear, but will nevertheless add to my belief that foolishness resides in us all, if not usually put into print in such a careless and I must say unthinking manner.
 
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