So, first off I admit that I don’t trust electricity, I think it’s sneaky and just sits in the electric pipes and lays in wait to get you when you least expect it. Despite its inherent treacherous nature I wired up an eBox-WIFI -01 to my MPPT solar charge controller. I would now like someone who actually understands this stuff to explain what all the readings actually mean. Thank you.
I took it out and weighed it just now ‘cos the capacity went up to 70% but it still weighs the same so the magic smoke must be very very light, I really should have paid attention in the “Elementary Electrics for Aircraft Engine Men” in RAF basic training.
Your solar panel is producing 49.82 watts of power at 15. 57V (volts). The controller is limiting the output to 13. 72V. It is splitting the output to charge your battery which is charging with a current of 3.59A (amps) . Their is a lamp also receiving output but only using 0.27W
thanks for that, that makes more sense now. The lamp at 0.27W is, I think, May be the actual WIFI box itself and it’s power on light. The capacity figure is confusing me, in the pic it shows 54%, does this mean the battery is just over half fully charged? And if that is what it means then I’m even more confused as I’ve just checked again and now the capacity shows as 42%. Obviously with the sun getting lower it’s charging at a lower rate but how can that affect the battery capacity.
The reason it doesnt weigh any different is the electrons redistribute themselves around the battery when its charged. They are all piling up on the negative terminal in order to leap out at you.. Should be a bit lighter the more you charge it if it gasses at all .... The first picture showing energy flow says theres nearly 50 watts coming from the solar panel(s) and that all but 0.27 of a watt (going off to the load output of the solar controller) of that is charging the battery. All is good and happy. The charge estimate for the battery is taken from looking up the voltage in a table of values for when it is charging and another table of values when it is not charging. Its a very rough estimate, and the more knackered the battery, the bigger the difference in the "charging" and "discharging" estimates will be - if it shoots up to 14.2 volts immediately on charge when it was reading e.g. 12.5volts and 50% charged before charging, when it starts charging the estimate will say 100% but that same battery could be down at 11 volts or 0% in a very short time when the sun sets or goes behind a big cloud. My knackered battery hit 100% in about half an hour from starting the engine, but would only deliver about 10AH of charge before hitting 0% and 11 volts. Even more annoying was a quick load test showed it could still have started the engine . If the battery is "good" then the difference in voltages between charging and discharging will be smaller, so the estimates get closer in value.. So 42% vs 54% is basically both about half-charged. At the end of a sunny day you would want that number to be higher, ready for the night. If it keeps dropping day after day at the end of the day, then eventually you will be damaging the battery if it doesnt get charged up during the day. Need bigger solar panels or less load or sunnier weather to use the solar panels.
Thanks Mike I’d thought of that so I left the plastic cap on the terminal when I put the negative wire on. The sun’s gone out now and the capacity shows 37% but with a full battery icon and the voltage now is 13.01. The battery was showing less and less on the capacity figure as the sun went down but it’s a brand new 100Ah AGM battery and I fitted it yesterday and apart from a tracker there is no load on it at all. #stillconfusedaboutcapacity.
As it is an AGM battery, the on-charge voltages would be a bit higher. A well charged AGM battery just after being charged would be nearer 14 volts or even a bit over, so 13 volts after being charged is not very well charged. Hence 37%. The problem is that at this time of the year, it may take several cloudy-bright days to deliver 100AH into the battery. Thats just because the 100 watts figure quoted is for full sun at 1000 watts per square metre, and that does not happen in the autumn this far north. Not all the energy that goes into the battery gets stored as charge, some of it gets converted to heat, so again it takes even longer to fully charge the battery. This is the reason that the temperature sensor on the Epever controller should be unplugged from hanging out of the bottom of the controller and fixed on extension wires to the battery terminal of the leisure battery, where it measures how hot the battery is. If the battery temperature is over 40 degrees C you should not recharge lead acid or AGM batteries, the charger will watch the temperature of the battery and shut off- AGM batteries can go into a smelly thermal runaway if they are charged when they get hot.
Punch the reload button on the unit and reset it Bob. These Bluetooth things are a bloody nightmare.. We've all sat happily oblivious to the dark arts of power management for years and now we have the ability to see the light. Which for me mainly at the moment appears to be the proverbial one on the front of the loco. My lithium BMS has now become nearly as compelling as TLB for an evenings entertainment, which consisted last night of turning things on and off to the appropriate soundtracks of oohs and ahhhs. Mrs Monkey remains stoic, but comforted in the knowledge we can now run the hairdryer and straighteners....
Ah slowly the mist is clearing, so the 49W figure from the solar panel indicates it’s only getting about half the sun energy it needs for full efficiency ? Does that go up or down depending on solar energy falling on the panels? I think I’m going to stick my hookup onto it for the night and see what figures come up in the morning after a night charging on shore power through my CTEK.
It’s on again now and before I’d connected this monitoring box I was blissfully unaware of what was happening and didn’t care as long as the beer was cold in the fridge.
Exactly. Mike makes a good point about the season. I disconnected the AGM from the bus 2 nights ago because even with the 180w panels, we were down to 12.2 volts going into the evening.. Bearing in mind we're living in the bus at the moment I didn't want to be facing down the wrath which would have been induced from a non functioning propex. It's got chilly. So swapped the AGM for a lithium and now I can't stop watching the app! Is your panel around 100w, I can't recall, its been a while...
No I’ve got two 100w panels but where the bus is parked now it’s in shade all morning plus I didn’t actually wire it in until about 11 this morning from brand new out the box. I’ve just set the hookup up and selected AGM on the CTEK and it’s quite quickly gone through the first three stages of charging. I’ll see what the morning brings…..oh wait…it’s my dentist appointment, that’s what the morning’ll bring.
Hi to achieve optimum output from your panel it needs to be between 30 --45 degrees angled and South to South west facing this achieves about 75% of its output on average throughput the year if it's unshaded obviously ..if your panel is flat on your roof you will get no where near that but it will be enough to charge your leisure battery ..I think MikeDjames quoted 1000watts per square meter he must have meant 100 watts hope this helps a bit
Its all helping thanks, I decided it’s about time I was a bit more informed about caring for leisure batteries as I’ve just shelled out £139 on one. Although having said that I can’t be doing too bad as my last one was about eight years old before it gave up the ghost.
Pretty straight forward on a house FWIW we see about 15 to 20 percent loss of input on a Westy, elevated to flat. No worries, just let us know what's going on around 2.30...
Nope, still confused…It’s been on hookup since last night and now reads 12.94V Full battery icon and 35% capacity. I just can’t get what this capacity figure is actually showing me.
Do you have to tell the controller what capacity of battery you have fitted? I’m wondering if it thinks you have a bigger battery fitted than you actually have
I’m not sure, I’ve told it the voltage and the type of battery but didn’t see anywhere to tell it the size/capacity.
