Viva: Check this out with AM solar. And maybe someone can correct me if I am wrong, but I am pretty sure that you don't get enough volts from a 32 cell panel to effectively run a MPPT controller. In fact 32 cell panels are specifically made to be used to charge a 12 volt battery without the use of a controller. So forget about bulk, float and absorbtion charge modes which a charge controller will provide. And forget about charging a large amp hour deep cycle battery or battery bank. Check out below:
from:
http://www.alternative-energy-tutorials ... -need.html
"So How Many Cells Do We Need?
Most photovoltaic (PV) panel manufacturers make 12 Volt solar panels for battery charging with 32, 36, or 48 cells in the series string. They are all rated at about the same current, being composed of the same basic cell. The difference between these panels is one of voltage. The question for us to answer here is how their output voltages relate to the voltages we require for our 12V charging system.
32 Cells in Series
This size of photovoltaic panel has the lowest voltage rating of only 14.7 Volts (0.46 Volts times 32 cells). This is because it has the fewest number of PV cells in its series string. This panel design closely matches the charging curve of a standard 12 Volt lead acid battery. As the battery charges-up, its terminal voltage rises. When this battery is almost full its voltage is about the same as the PV cell's at around 14.7 volts. The 32 cell module simply hasn't enough voltage to continue charging the battery when its full so cannot overcharge the average, small, lead acid battery.
The applications suitable for these small 32 cell solar panels are in RV's, boats, garden lighting and summer cabins. These applications are characterized by their intermittent use and relatively small battery charging capacity.
In these these types of low power applications, a 32 cell panel can be used with or without a charge current regulator as the batteries will not become overcharged if left connect to the panel during long periods of non-use.
36 Cells in Series
This size of photovoltaic panel has an output voltage of about 16.7 Volts (0.46 times 36 cells). This is enough output voltage to be able to continue to charge a lead acid battery even though it may be already fully recharged. The 36 cell panel is suitable for a home based 12 Volt alternative energy system with high battery capacities as
it has the higher output voltage necessary to recharge deep cycle lead acid batteries.
However, a 36 cell solar panel will require some form of charge regulation to prevent overcharging the battery during periods of high solar intensities or when battery usage is at its lowest.
A 36 cell solar panel tends to be more cost effective in a typical home power application because it can produce a good amount of current or high voltages at elevated temperatures. The higher voltage produced by the 36 series wired cells will more effectively recharges a large deep cycle lead acid batteries.
High ambient temperatures will cause the voltage of any PV panel to reduce slightly, but the 36 cell panel has more than enough voltage surplus to still be an effective battery charger even at high ambient temperatures.
48 Cells in Series
A 48 cell panel is the big daddy of the PV industry. 48 individual photovoltaic cells connected in series produces an output voltage of about 22 volts. These large PV panels have sufficient output current capacity to charge a 12 Volt system, regardless of the battery's voltage or high temperature. However, these large panels do require some form of charge regulation in just about every application. They have the sufficient voltage necessary to raise a solar system's voltage, while charging full batteries, to well over 16 volts. This over voltage is high enough to ruin any electronic equipment rated at 12 VDC so some form of protection is needed.
Generally, a 48 cell solar module has very specific applications where high power and currents are required such as in pumping water or were long cable runs will have appreciable voltage losses even if large diameter cables are used. Another disadvantage of this PV panel is its size and additional cost compared to 32 and 36 PV cell panels. On the plus side, a 48 cell panel will perform better in very hot areas and areas with very low levels of sunlight throughout the year.
To learn more about "Photovoltaic Cells", solar panels and solar power, or to learn how to build your own DIY solar panel from individual solar cells to make Solar Power in your home a reality so you can save money on your utility bills, and to help you on your way consider Clicking Heresolar array and getting one of the solar books from Amazon about home made solar panel construction ensuring so that you have all the necessary information to get your solar power installation working efficiently and effectively the first time."
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