Wednesday, 26 January 2022

Very Slow and The Parting

Back in July 2021 I purchased from China some T-Bolts for the camper trailer.  After waiting a month for delivery I eventually decided to make my own T-bolts and completed the trailer modifications.

T-Bolts

Order placed on 29 July 2021

Today the postie delivered a small package from China containing my much anticipated rivet nuts which are required to complete the ebike.

When the package was opened I found the T-Bolts!!  

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It’s only taken six months for them to be delivered by air freight.  They will go in my “might be useful one day” jar.  I now have to hope the rivet nuts don’t take the same time to arrive.

Yesterday afternoon I went for a 16km bike ride, primarily to test the two camera mounting positions.   The image shudders too much when the camera is fitted to the handlebar mount.  Less shuddering on top of the helmet, but I have to make a conscious effort to either keep looking directly ahead or moving my head very slowly. More practice is required.

Both Paul and Brian left comments on my post about the pool solar hot water system suggesting I consider a Temperature Switch rather than a thermostatic valve.   It’s an option I should have identified; but obviously age is catching up with me. This option would see a temperature switch monitoring the water temperature at the panel outlet.  The switch would be connected into the pump electrical supply.  When the water temperature reaches the set level the switch would close providing power to the pump.  As the hot water in the panels was replaced with cold the temperature would drop and the switch would open.

I think I’ve found a suitable (ie, cheap) temperature switch.

thermal switch 

Aliexpress $18.76 

The switch is for a motorbike radiator with a temperature setting of 83-77°C 

In a further effort to keep the cost down I’ve decided to take one of the two solar panels from the camper trailer array and use it to power the pool solar pump.  Back in 2017 I bought two 150W solar panels and; as usual for me; over-engineered the requirement.  When travelling the outback I usually only spend 1-2 nights in a location with the bulk of the battery charging being done by the 4WD alternator.  One panel should be sufficient for my camping needs.

The array has been split, rewired and I relocated the panel angle support brackets.

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An additional advantage is one panel is lighter to carry.

Meanwhile Jan has pointed out an issue with the swimming pool.  There is a large gap between the fibreglass coping of the pool and the underside of the cement coping pavers.  The gap is a consequence of the top of the fibreglass being bowed downward whilst the pavers are level,  Rain has been migrating the paving sand under the pavers into the pool. 

To prevent the loss of bedding sand and the pool filling with sand the gap needs to be filled.  I’m thinking of using aerosol insulation foam but need to check if it will have an adverse reaction with salt water.

4 comments :

Dave said...

Thinking of the solar

Are all the fittings, panel & pump suitable for the water in your pool?

To me i would take a look at how the cooling on your car works. The pump runs all the time (or at variable speed if an electric one in a very modern car) and the thermostat opens or closes as needed to direct water to the radiator to cool or internal loop to keep warm.
Think of the solar as the engine and pool as radiator.

I think if you only have a switch on the outlet, will it accurately sense the water temp when there is zero flow through it if the pump is off?

Could you set up a thermosiphon system and once the temp hits the right level the pump is engaged to boost throughput?

Final thought, use a temperature guage type fitting to sense the actual temp rather than on/off and then drive a variable speed pump. Faster when hot, slower when cool and off when daylight is lost, all done using a raspberryPi or similar

Brian and Diana on NB Harnser said...

https://www.amazon.co.uk/All-Purpose-Temperature-Difference-Controller-Differential/dp/B076M9KZFP

https://makingcircuits.com/blog/differential-temperature-detector-switch/

Or Ebay

Tom and Jan said...

Dave the 12V pump will be powered by the solar panel and obviously there will be no power and no heating of the water in the solar collectors unless there is sunlight. I don't want the 12V pump to run continuously because it will just push the water through the panels with giving them a chance to heat the water.

The temperature switch will cut the power to the pump until the water reaches the required temperature. There may also be some thermosiphon action. Also the main swimming pool pump may also push water up through the collectors. However I'm hoping the 12V pump will act as a stop cock when it's not running.

Tom and Jan said...

Brian, starting to look expensive and I love cheap!