Friday, Apr 27, 2012 at 14:53
You're welcome Simon,
as long as all panels are of the same wattage, there's no benefit of wiring 12V panels in parallel over wiring them in series.
Say you wire 2x12V panels in parallel (the typical folding panel configuration):
it only takes one cell to become shaded out, and you lose 50% of charging amps.
In a 2x12V series string, the same amount of shading reduces the charging amps by only 25%.
Of course your solar regulator needs to be of the true MPPT type for this.
As indicated above, only when you have a mix of different wattage panels, it is better to wire them in parallel.
Not that you would get maximum power from any of them, but you get good power, while in a series configuration you can't utilise the power from the smaller panel at all.
If wired in parallel our MPPT regulator achieves still higher charging amps compared to PWM, as long as the battery voltage is still low, and the ambient temps are also low. Once battery terminal voltage creeps up, and cell efficiency drops due to high operating temperatures, the MPPT advantage shrinks in this comparison.
Our MPPT solar regulator with modified multistage charging algorithm is capable of precisely charging the battery to 100% full, without applying unnecessary over-charging (which would cause battery dry out in the medium term).
It's very robust because it cannot get confused by any load currents during charging (e.g. by a fridge with constantly changing power drain).
Most if not all solar regulators in this price range don't get the absorption/float switch over right causing dry out, especially in a 24/7 situation.
And the best feature is the electronically limited max charging current of 10A.
This means the unit self protects itself from too big a solar panel connected to it. Now you can connect a high wattage panel for higher charging amps on overcast days or early morning/late afternoons.
Typical PWM solar regulators on the other hand would overheat when the max specced panel power is exceeded.
Yes, the remote control/display units are fairly comprehensive.
You can select display of incoming V,A,Ah,Wh, the same goes for the load, you get to see battery current (- signed means discharging current, unsigned means charging current), battery voltage. You also can observe the battery temperature, temperature coefficient display/adjustment.
You can also adjust the absorption stage end voltage for different types of batteries in 0.2V steps.
The only thing is SOC which is derived from the battery voltage, thus is quite inaccurate.
Another feature lets you remotely turn on/off any load connected to the MPPT solar regulator by pressing a button.
Use an inexpensive networking cable to extend the distance between the two by several metres (I think 12 metres is the specced maximum when using cat5 wire).
1.5m wire comes standard.
cheers, Peter
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