Solar charge controller and fully charged batteries?

ibbo said:
A 50w panel will be marginal to run the cooler. I had one the same, and had 2 x50w panels to run it. One each side of the spray hood to try and ensure a reasonably continuous charge. I ended up with a 100w one sat on the deck as well to keep the batteries up for a UK summer.

I could then leave the fridge on full time. The 50w x 2 was hardly able to keep up. UK South coast.
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Yes I agree my 50w panel is marginal. But we tend to only be on the boat for a few days , usually just a long weekend when it should be fine. But I am fully expecting I might need to supplement with a moveable panel....or overnight mains marina charge.... no plans to leave it running when off the boat. But thanks for your real world experience. First to sort my solar mystery!
 
The two batteries are on a 1-2-both switch and I simply elect which battery to use for the day. Obviously if I used the Both setting the batteries would not be isolated from each other but I do not use that setting. The solar connections go direct to each battery from the controller.
The possible problems I have introduced are installing a planar heater in 2020 direct from the batteries and the 12volt power socket and USB, which is recent. However the heater is seldom on and the solar controller issue has only recently showed up. Since the fridge is seldom plugged in (cigarette lighter socket) the only permanent connection between the batteries is the LED light on the USB switch. And I did pull the fuse from the 12v power/USB socket for a week or to see if it had any impact on the solar controller- it didn't seem to make a difference. I realise now these are possible issues.
 
If the two batteries were connected together and the charge controller was connected to both I was wondering what effect that would have on the charge controller .
Your only issues is whether there is current going into your batteries from the charge controller.
 
LadyInBed said:
SPECIFICATION says
Current Type - AC/DC
Q&A says
Hello Review48,
You can do DC voltage using the leads but not DC current.
That says to me that you have to use the clamp for dc current, you can't use the leads!
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The specification is not helpful and some of the the answers in Q&A very doubtful, even some from Screwfix Product Support

There is an answer from Screwfix Product Support which says
badge_productsupport.png
Hello Allyallsorts,​
​
The DC measurement can only be tested by the use of the test leads.​
​
Thank you for using Q&A.​

Think you will find that the clamp feature will only measure AC current. The leads are of a non-contact type so they cannot be used to measure current, neither AC nor DC.

.
 
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VicS said:
The specification is not helpful and some of the the answers in Q&A very doubtful, even some from Screwfix Product Support

There is an answer from Screwfix Product Support which says
badge_productsupport.png
Hello Allyallsorts,​
​
The DC measurement can only be tested by the use of the test leads.​
​
Thank you for using Q&A.​

Think you will find that the clamp feature will only measure AC current. The leads are of a non-contact type so they cannot be used to measure current, neither AC nor DC.

.
Click to expand...
The above is basically correct. The "Lap" meter will only measure ac Current via the clamp it will measure DC Voltage with the leads. The other meter mentioned UNI T will measure DC with the clamp.
 
Finally back to the boat this weekend and the focus was on sailing not my batteries. The sailing was good! I tried to get some current readings using my clamp meter but have no idea as to what readings to expect. My meter is a Mastech MS2108A and I used the 40A setting. Was I wasting my time trying to get current readings from the solar controller? The highest reading I got was 0.06A to battery one. (Sunny day about 6pm with panel flat on the deck)

Also I have reset the battery priority charging to 50 % to each battery, rather than 90/10. And set the controller to sealed batteries rather than flooded. One battery read 12.6, battery two 12.25volts which obviously indicates drain or simply not getting any charge from solar. Thanks for any replies.
 
FairweatherDave said:
Finally back to the boat this weekend and the focus was on sailing not my batteries. The sailing was good! I tried to get some current readings using my clamp meter but have no idea as to what readings to expect. My meter is a Mastech MS2108A and I used the 40A setting. Was I wasting my time trying to get current readings from the solar controller? The highest reading I got was 0.06A to battery one. (Sunny day about 6pm with panel flat on the deck)

Also I have reset the battery priority charging to 50 % to each battery, rather than 90/10. And set the controller to sealed batteries rather than flooded. One battery read 12.6, battery two 12.25volts which obviously indicates drain or simply not getting any charge from solar. Thanks for any replies.
Click to expand...

Very difficult to tell from the pic's but looks like 40 amp is ac (Wiggly line) and the 400 amp is DC straight line??? Just had a look here
https://www.manualslib.com/manual/1186068/Mastech-Ms2108a.html?page=7#manual
Looks like it is an ac measurement only NOT DC.
 
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FairweatherDave said:
Finally back to the boat this weekend and the focus was on sailing not my batteries. The sailing was good! I tried to get some current readings using my clamp meter but have no idea as to what readings to expect. My meter is a Mastech MS2108A and I used the 40A setting. Was I wasting my time trying to get current readings from the solar controller? The highest reading I got was 0.06A to battery one. (Sunny day about 6pm with panel flat on the deck)
Click to expand...

Make sure you only have one wire (either positive or negative is fine, but not both) in the jaws of the clamp.

If you try and measure the current with both the positive and negative wires in the clamp, the two currents will cancel each other out.
 
Thanks for all the replies. Alex, I couldn't get your link to work but the symbols on the meter are the same for 40 and 400 A, ie a straight line above a squigly one. And VicS has the correct page in the manual so that looks good news for DC. But his question about if a PWM controller's pulsed output confuses the meter? And thanks Noelex, I was only measuring a single wire, trying to hold it steady in the centre of the clamp space (equidistant from the arms.) As for the L.i.B banana plugs method, for me that sort of (re)wiring is only something I would contemplate if I wasn't getting by, as we are on a swinging mooring. I'd see that as a winter job. What does the forum think of 0.06 Amps from a 50w panel?
 
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