Solar Cell to usable USB 5V, 1A project - Page 1
Forum section: electronics / projects

author: ninjastrike
author_rank: Contributor
timestamp: August 09, 2014, 08:25:23 pm
content: Hello all,I've been trying to figure out how to power a portable device using solar cells(via standard USB).Since im producting 1.0 - 1.1V and about 8.5A, i'm thinking of using the Texas Instruments TPS61202 to convert this 8.5A and 1.0 V to a usable 5v andthe Texas Instruments TPS2513A-Q1 to be able to drive my USB charger.Could anyone tell me if i'm going in the right track?http://www.ti.com/product/tps61202http://www.ti.com/product/tps2513a-q1Cheers!

author: Psi
author_rank: Super Contributor
timestamp: August 09, 2014, 09:54:07 pm
content: i imagine 1.0V cells are intended to be connected in series rather than used by themselves.Boost converting 1.0V up to 5V is never going to be very efficient.Have a look at the input voltage vs output current graph in the datasheet for TPS61202.With 1.0V input the maximum output current is under 200mA.

author: ninjastrike
author_rank: Contributor
timestamp: August 10, 2014, 10:46:18 am
content: Hey PSI, yea that's true. What do you think the most efficient way to convert this energy?

author: wiss
author_rank: Frequent Contributor
timestamp: August 10, 2014, 01:01:27 pm
content: What is your reason to not have several solar-cells in series?

author: ninjastrike
author_rank: Contributor
timestamp: August 10, 2014, 02:35:14 pm
content: I want to be able to use it when i'm out say for a camping trip. So size is a design constraint.Specifications :Monocrystalline photovoltaic cell6" x 6"4.4W @ (STC): 1 000 W/m2, 25 °C0.55V / 8ABased on these specs, I would at most be connecting two cells in series.

author: wiss
author_rank: Frequent Contributor
timestamp: August 10, 2014, 04:25:06 pm
content: Unless you already have the cells I would go with something like this (not very cheap...)http://se.farnell.com/bp-solar/msx-01f/solar-panel-1-2w/dp/654012While googleing I also found this:http://www.kjell.com/sortiment/el/batteriladdare/mobilladdare/apple/powerpack-1900-mah-p42041about 10 USD, 20h of charging-time is hardly impressive and supposedly only iphone/ipad but considering the prise...

author: mij59
author_rank: Frequent Contributor
timestamp: August 10, 2014, 04:42:51 pm
content: Quote from: ninjastrike on August 09, 2014, 08:25:23 pmSorry, the same problem as with the LTC3105, can't handle high input current, as mentioned in the previous thread.

author: ninjastrike
author_rank: Contributor
timestamp: August 11, 2014, 02:09:30 pm
content: Quote from: mij59 on August 10, 2014, 04:42:51 pmAre there some sort of current limiters which will be able to either disappate the energy that can be placed in the circuit?

author: ninjastrike
author_rank: Contributor
timestamp: August 11, 2014, 02:10:31 pm
content: Quote from: wiss on August 10, 2014, 04:25:06 pmI've got 10 cells lying around, I want to build it and enjoy the whole process.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: August 11, 2014, 02:23:29 pm
content: This seems to be ok (20Euro)http://www.aliexpress.com/item/5v-1a-solar-panel-5-watt-monocrystalline-solar-cells-solar-panel-camping-solar-powered-phone-charger/1772087476.html

author: mij59
author_rank: Frequent Contributor
timestamp: August 11, 2014, 02:33:56 pm
content: Quote from: ninjastrike on August 11, 2014, 02:09:30 pmYou don't want to waste energy, there's already not much to work with.Even assuming 100% conversion efficiency, 5V 1A at the output, means at 1V an input current of 5A.

author: wiss
author_rank: Frequent Contributor
timestamp: August 12, 2014, 10:21:40 am
content: Did you find this one?http://www.eleccircuit.com/step-up-dc-converter-1-2v-to-5v-5v-for-micro-computer/Never tried it, might work...