[Brett]

I've been out of the loop for awhile (15 years) and the freight from the East Island may be the killer

ah well then, yeah that probably won't help

http://www.fastlec.com.au/p/Clearance-Sa...17-252-168

or
http://www.fastlec.com.au/p/Clearance-Sa...00/WM3-420

are two I've found that might be ok plus are not going to kill me in price.

[hvalentim]

The controllers I have opted for now are similarly priced (I think). I've been buying the 5A model - on ebay the item number is 261392830593, http://www.ebay.com.au/itm/261392830593?...1439.l2649

According to this fellow that may not be a true MPPT charge controller:
CMTP02 – disassembling this solar charge controller

This one would seem a bit more promissing: Solar Panel Battery Regulator LCD 10A 12V/24V MPPT Charge Controller Three-time

Product Homepage
Manual here

But the peculiar way they use to describe it makes me think it may almost certainly be just a PWM with a twist. They do not seem to provide maximum accepted voltage as well which is odd.

MPPTs work by tracking the I-V curve of panels and picking at any given moment the best volts/amps compromise.

[werk_ag]

Hi,
I have another query with regards, to TX power supply, on the TX pcb the power supply connection has the following pins marked :

+Bat
12v
GND

As far as I am aware these connections also have something to do with showing the battery voltage in the software, So would I be correct when wiring this to the battery that you would have :

GND to negative/black terminal on battery
+Bat/12v to positive/red terminal on battery

I am hoping that I have understood this properly If not please let me know.

regards

tyntop

The TX unit is not connected directly to the battery.
Connect GND and 12V to the output of the solar charger / regulator, and the + Bat to battery positive terminal.

When the TX unit is powered from an 12V AC/DC adaptor, connect +Bat and 12V together to positive pin from adaptor.

[Brett]

nice finds. The CMTP02 I have is definitely better than the PWM variant I bought previously, so even if it's a PWM type the algorithm is much better. I might try out one or two of those other variants from that seller (like 281134380669 ) and see if there's much difference.

The one big thing that they all don't really do well is manage voltages on the battery charge cycle based on your battery chemistry. It'd be great if you could set / adjust proper charge parameters for the battery you use, but then again that's a 5x or more price increase and impossible to justify for a project like this.

[werk_ag]

This one would seem a bit more promissing: Solar Panel Battery Regulator LCD 10A 12V/24V MPPT Charge Controller Three-time

I did not buy one of those because even for the 10A version, they recommend batteries> = 100Ah, and solar panels> = 50W.
I was afraid it would not work well with smaller solar cells and panels.

[hvalentim]

I have been doing some testing using a 80W solar panel and a 20A solar regulator which I already had lying around. Now, the thing is: the solar regulator is a 10 year old linear model which most of the time (when the Sun is shinning bright) produces a permanent voltage oscillation of around 2v (say it constantly goes from 15,6v to 13,6 volts to 15,6v to 13,6v....). This happens both in the battery charge and DC supply parts.

I am wondering if the 7809 will help handling/curbing this. Would it just mimic this oscillation in the 9v output or will it somehow attenuate the gap? What about the Arduino? Can this mangle the reference voltage (and consequently the readings)?

[uncle_bob]

I am wondering if the 7809 will help handling/curbing this. Would it just mimic this oscillation in the 9v output or will it somehow attenuate the gap? What about the Arduino? Can this mangle the reference voltage?

The Voltage regulator does does just that. It takes any input voltage within it's operating parameters (something like 11 to 30v) and gives a steady output regardless of it's input.

They do get hotter the higher the voltage they have to drop.

[AllanG]

I am wondering if the 7809 will help handling/curbing this. Would it just mimic this oscillation in the 9v output or will it somehow attenuate the gap? What about the Arduino? Can this mangle the reference voltage (and consequently the readings)?

The output of the 7809 will remain constant even if the input voltage changes. If I remember correctly, the 7809 should handle input voltages from around 11 to 35 volts.

Hope this helps.

[meteoestarreja]

You should check the regulator (7809) datasheet. Usually they can handle somewhere around 30 to 40V peak, you should check yours just for safety, but I'm guessing that you don't need anything else

[meteoestarreja]

The output of the 7809 will remain constant even if the input voltage changes. If I remember correctly, the 7809 should handle input voltages from around 11 to 35 volts.

We where replying at the same time, but it looks like my answer isn't wrong