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Solar Power – eCharger project – UPDATE #2

FIX & UPGRADE – Restoration and increase of Solar Panel energy production

Project Re-cap

The project from 2 years ago, detailed here, built a solar energy charger using these system elements:  Solar Panel, Charge Controller, Battery, Inverter. Last year, an upgrade was performed to increase the batteries to provide more storage capacity, as described in Update #1.

Solar Panel Failure

The system has operated satisfactorily for almost exactly 2 years, but then it was observed that no energy was being produced. After investigation, it was discovered that the solar panel had developed a fault. The panel was a flexible’ model, and by slightly bending it, energy was intermittently produced. Hence clearly there was an internal breakdown of connectivity. 

Solar Panel Replacement & Upgrade

Since a replacement was needed, it was decided to purchase a more robust, ‘fixed (i.e. non-flexible) solar panel, which has a solid frame and securely mount onto a brick wall. Taking advantage of the overall lower cost of fixed vs flexi panels, it was decided to opt for an increase to 100W for the replacement.

RatingInformation
Rating Information

This will bring the advantage of producing more energy during sunny periods, which will compensate for the need to mount the panel on a wall where it receives slightly less direct sunlight hours. 

100W Solar Panel
100W Solar Panel (mounted)

The installation of the replacement panel was relatively straight-forward, using ‘Z-brackets’ to affix to the wall.

zbrackets
Z Brackets

It came with MC-4 connector terminated cable ‘tails’, which were plugged into the existing positive and negative connections.

Connector Block & MC4 tails
Connector Block & MC4 tails

Power generation was resumed immediately, with an extremely healthy 4A (roughly double of the previous 50W panel, as expected) confirming the success of the remedy. 

Charge Display
Charge Display

Conclusions

Alas, it transpires that the originally chosen ‘flexi’ type of solar panel is not very ‘robust’ and consequently is only warranted for 1 year. It is somewhat disappointing that only such a short life-span is achieved, especially since it had been mounted on shed-type roof without experiencing disturbance or damage. 

Happily, the replacement ‘fixed’ type of solar panel is warranted for 10 years, so should operate for a considerably longer time. And given that like-for-like it is less expensive, then it is concluded that this should be selected to ensure maximum lifetime and collection capacity for the same outlay. 

@YellowsBestLtd we are always looking to expand our portfolio services for #business development and #enterprise support, and increase the mix of solutions for #sustainable systems and maintenance of new and legacy #technologies and products for our customers. Please get in touch to discuss your requirements; we look forward to hearing from you.

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Solar Power – eCharger UPGRADE

Project Re-cap

Last year’s project, detailed here, built a charger that collected and stored solar energy for use by an eBike, also for charging additional Li-ion or Ni-Cad batteries for other equipment as well as powering LED lights for illumination of the work space.

These 4 main elements were put together to create the solar charging ‘system’: Solar Panel, Charge Controller, Battery, Inverter. The resultant assembly captures energy from the sun via the solar panel, ‘conditioned’ by the controller and stored in the battery. This therefore provides an ‘off-grid’ 12V DC power source, or via the inverter as 240V AC ‘mains’ subsitute.

Experience from use

What wasn’t certain at the time of the project construction was how much energy would be available to be captured (estimates indicated sun 2-3 hours per day, weather and time-of-year dependant), how much could be efficiently stored and what would be needed to charge the eBike (understood to require around 3-4 hours for a full charge) and/or for the other uses. 

It had been assumed that there would be sufficient sunlight during summer days to adequately charge the storage battery, but at other times of the year the energy might be lacking, requiring additional solar panels for more energy generation.

The experience gained from use indicated that more solar panels were not needed, as enough energy was being captured, resulting in a fully charged battery (indicated by the charging stopping, despite it being sunny) when not being used for eBike charging. What was noticed however was that if the eBike had been used for a medium to long ride, requiring moderate to high charging afterwards, that insufficient energy was available from the storage battery to power the inverter (indicated by an audio alarm) long enough to fully charge the eBike.

The resulting conclusion was that the storage capacity was needed to be increased, to capture more sunlight energy to be available for charging purposes.  

Storage Upgrade

It was decided to purchase a second 12V 110AH 800CCA AGM-type battery, of identical make and specification as the original, thereby doubling the storage capacity (although since its advisable to allow for discharge of only 50% of the stated rating, the total energy available is taken to be 110AH). This compares with the capacity of the eBike battery, which is 36V 11AH (400WH).

Twin AGM batteries

It is important to note how additional batteries are added to a solar energy system. The choice is between series or parallel connection. 

Series would result in a doubling of the operating voltage to 24V. This would bring some advantages in terms of lower current rating for wiring gauge with the same power, and a simpler daisy-chaining method of connection. However, this is only possible if the other system components are rated for 24V operation.

For this upgrade, it was chosen to add the additional battery in parallel, thereby keeping the operating voltage at 12V (suiting the controller and the inverter) whilst providing more current. The parallel connection requires the battery terminal connections to be separately wired to the inverter and controller connection points, and for safety an additional fuse was added so that each battery is separately fused to protect against a short-circuit.

Twin batteries and inverter in use

Conclusions

Limited experience to date of the upgraded 2-battery-storage Solar power system finds that there is now sufficient energy available to completely charge the eBike even after a long ride, without incurring a low-energy warning from the inverter.

Charge controller with 2A input

The conclusion is reached that due to the usage pattern of occasional eBike charging compared with the daily solar energy collection, that more battery storage is a more appropriate choice over more solar panel energy generation. This is re-enforced by the fact that on poor-weather days, although there is a lack of available solar energy, the eBike is unlikely to be used, so the energy usage requirements are also low!

eBike fully charged

If will be interesting to monitor the performance of the upgraded system through the seasons of another year.

@YellowsBestLtd we are always looking to expand our portfolio services for #business development and #enterprise support, and increase the mix of solutions for #sustainable systems and maintenance of new and legacy #technologies and products for our customers. Please get in touch to discuss your requirements; we look forward to hearing from you.

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