Solar powered arduino pro mini with waterpump

Hi.
I am looking controll a waterpump with an arduino pro mini and have it all run on solar.
The arduino will be in power down state with low-power library and only wake up every 3 hours, (i will also remove the onboard LEDs)
it will then check if its light or dark, and if dark it will check soil moisture to see if watering is needed.

i estimate that the waterpump will run for about 30 min per day.

The specifications are:

1 adruino pro mini.

2x AA NiMh batteries / or 1x 18650 3.7v Lithium battery

1-2 solar panels (gives 6v 100mA at decent sunlight, estimating to get that for about 5h per day)

1 waterpump 3-6v with about 500-600mA when running ( http://www.ebay.com/itm/1PC-Micro-Brushless-Submersible-Aquarium-Pump-Water-Pumps-DC-3-6V-120L-H-Low-/111968821009?hash=item1a11dc9f11:g:aqgAAOSwhDdXDt21&vxp=mtr )

1 p2n2222 transistor to controll the pump.

1 dc-dc step-up boost converter to supply pump with 5v (http://www.ebay.com/itm/121142828799?rmvSB=true)
takes about 5mA when active.

by my calculations the arduino will take like 6-8mAh per day. (sleep and sensor)
the pump will take about 300mAh per day + ~2.5mAh from step-up converter.

so it would run fine if i get 350mAh per day from the solar so 4hours decent sun would do.

and now afew questions:
1, Are my power consumption calculations correct? will this project have enough power to run?
2, Would an pro mini 3.3v or 5v be best for this project?
3, Can the arduino run on the 2.4v from 2x NiMh batteries or do i need to add another and make it 3.6v?
4, A, If i have more than 3.3v should i have a stepdown regulator or use the built-in one (connecting power to raw)
4, B, If i should have a regulator how do i wire this up to supply arduino with correct power and also charging the battery from solar?

5, Is there anything i have missed? do you have any recommendation?

I don't have much experience with this, but I believe you'll need a charge controller for the solar.

The below video might help, this guy made a charge controller that only pulls 5.5 mA.

VIDEO

-Chase

Leothlon:
so it would run fine if i get 350mAh per day from the solar so 4hours decent sun would do.

There will be all sorts of inefficiencies in your system. I suggest you plan on getting about 4 times as much solar energy as you think you will need. Base your calculations on the days in the year with least sunshine energy.

If you live in a country with day-long cloudless sunshine maybe that could be reduced to 3 times.

You may find useful info on this JRC solar website

...R

Robin2:
There will be all sorts of inefficiencies in your system. I suggest you plan on getting about 4 times as much solar energy as you think you will need. Base your calculations on the days in the year with least sunshine energy.

If you live in a country with day-long cloudless sunshine maybe that could be reduced to 3 times.

You may find useful info on this JRC solar website

...R

ok, well the system will only be running summertime (it's to keep the flowers and stuff living while away at our vecation home) so i am counting on long days with alot of sun (atleast 5h with 100mA supplied from solar + atleast 3-4h with 50mA).
Also on cloudy days i'm expecting that the soil wont dry out as much and the pump then not needing to run as much those days.

but i do have 4 extra solar panels that i can connect if i need more.

@cbrum11
I think that charge controller is for charging 12v car batteries with huge solar panels (like running your house on solar) dont think its needed for an normal arduino project.
(except with lithium batteries for wich i would use something like http://www.ebay.com/itm/Micro-USB-1A-5V-18650-Lithium-Battery-Charger-Protection-Module-Charging-Board-/131559338360?hash=item1ea18c3178:g:XhUAAOSwu4BVqfaF )