Navitron Renewable Energy and Sustainability Forum

Green Building and Design => Energy Efficiency & Insulation => Topic started by: clivejo on February 21, 2020, 12:58:06 AM



Title: 12VDC Central Heating Pump
Post by: clivejo on February 21, 2020, 12:58:06 AM
I am looking for a 12V DC pump to replace a standard 230VAC central heating pump.  I want to replace a lot of "wall warts" on always on equipment and powering them from a 12V battery to reduce the base line drain, mainly my wifi router, switches, monitoring and automation etc.

A quick search on eBay is showing 200-400 for one directly from Germany, there must be something cheaper on the market?!?


Title: Re: 12VDC Central Heating Pump
Post by: sunandwindy on February 21, 2020, 10:37:05 AM
My Mercedes Sprinter van has an electric pump to circulate the coolant. There's a few different styles here (https://www.ebay.co.uk/sch/i.html?_osacat=0&_odkw=mercedes+sprinter+water+pump&_from=R40&_trksid=m570.l1313&_nkw=mercedes+sprinter+electric+water+pump&_sacat=0)


Title: Re: 12VDC Central Heating Pump
Post by: Nickel2 on February 21, 2020, 11:36:01 AM
Would it be worth investing in small-scale solar? One panel, cheap charge controller, battery, small inverter could run the lot most of the time.
Alternatively one of the modern circulating pumps? (I have a wilo yonos in my GCH), It uses 20W from the mains / solar home-grid.


Title: Re: 12VDC Central Heating Pump
Post by: biff on February 21, 2020, 12:43:47 PM
Welcome back Clive,
        Running a C/h pump in DC will deprive you of the latest technology from the likes of Grunfoss who sell C /H pumps that can operate on 10watt to 25watt.  I would think that a dedicated battery bank  a small UPS  400WATT  smart APC   would be a good way forward. I could give you your pic of 3 of such and that would mean
That your present plumbing valves would stay as they are.
     You could even Invest in a little modified wine wave chespie that would be much easier run.
       The Merc pump is s good idea  but their alternator is between 14v x 180amp to 14v to 220amp, so that is what is powering the pump in the actual Merc.
As I said  Grunfoss AC can run on 25watt and lower.
      Biff


Title: Re: 12VDC Central Heating Pump
Post by: Philip R on February 22, 2020, 01:07:58 PM
What is the pumping duty, is it for central heating or something smaller like solar thermal?

Might be too small but how about a Lowara D5 High efficiency DC pump? Runs on low voltage DC and has invertor drive, so waterproff motor windings and no brushed to wear out.
Philip R


Title: Re: 12VDC Central Heating Pump
Post by: biff on February 22, 2020, 06:00:22 PM
Hi Phillip,
     Clive wants it to replace a standard central heating pump,,
   Your item seems good,
                             Biff


Title: Re: 12VDC Central Heating Pump
Post by: clivejo on February 22, 2020, 09:20:59 PM
Central heating, about 10 big and 4 small rads.  I have one running on mains at the minute, and yes it only draws between 10-25w depending on the speed, But I am wanting to install 12V battery any-ways to power my other baseline loads.  It really is a sad state of affairs that these wall warts draw 2-10W to power low voltage loads of about 500mW.





Title: Re: 12VDC Central Heating Pump
Post by: Nickel2 on February 23, 2020, 07:29:35 AM
If you do not already have one, it is well worth buying a plug-in power meter such as this one: (others are available)

(https://i.postimg.cc/SjrqPdH5/Typical-power-meter.jpg) (https://postimg.cc/SjrqPdH5)

They can be found from a hundred sources on the interweb.

Wall-warts are moderately efficient, probably in excess of 90%, so will take 10% more from the mains on top of the power you draw from them; i.e: 500 mW + 50 mW = 550 mW.
A lot of them do not have a very good power-factor, so may not give an accurate true-power reading on your domestic meter.
I bought one of these and went around the house doing exactly 24 hour readings for each appliance, to find the electrical vampires that suck in the night.
The biggest draw in my house is the fridge-freezer, (Bosch upright), that quietly slurps the electrons. Measure the temperature and adjust to best specified level, avoiding rapid-freeze.
 GCH pump is Wilo Yunos that takes 20W.
The guzzlers of energy are: Washing machine 1.45 kWh per load, Drier 1.5 kWh per load, Microwave oven, 1.5kW any time it is on.
Microwave ovens are very inefficient, but are usually only used for short duration, so tend to get overlooked.
All house lights are now LED because they pay their way within a year.
My workshop still uses grid for the bigger machines.
However, look after the pennies and the pounds will look after themselves; look after the mW and the kW will look after themselves. (or something)


Title: Re: 12VDC Central Heating Pump
Post by: Iain on February 23, 2020, 09:05:28 AM
Hi
If you get a plug in power meter just check it can reflect the power factor otherwise you can get some unreliable readings especially at the lower end of the scale.

From our sponsors

https://www.navitron.org.uk/catalogsearch/result/?q=Powermeter


Iain


Title: Re: 12VDC Central Heating Pump
Post by: Nickel2 on February 23, 2020, 10:25:49 AM
There you go! Power-meter on your doorstep, right under your nose, look no further. Very good price as well, compared to the available others.


Title: Re: 12VDC Central Heating Pump
Post by: Justme on February 23, 2020, 01:34:40 PM
We looked at this 11 years a go.

The answer is still the same. A high efficiency mains AC unit from Grunfos.

The DC ones just looked Micky Mouse & not like they would last long.

Our current one is an Alfa 1 that can run from 3 to 34 watts.

Been reliable now all this time & on lowest settings.

Ok our heat demand is low with just 5 small rads of around 300-500 watts output each & via 10mm pipes.


Title: Re: 12VDC Central Heating Pump
Post by: clivejo on February 23, 2020, 05:01:30 PM
Yes, I do have one of those plugs for measuring the power.  My PIR LED flood light, for example, use 3W of power all the time, day and night.  I have since installed a timer, but even that draws 0.7W.

My pumped shower unit draws 3.5W just sitting there doing nothing, so I installed a manual pull switch, which is supposed to be turned off after use!

It just surprises me how much energy is wasted by these items sitting on standby and how much energy they waste by using very inefficient designs/voltage droppers and they are everywhere!  I basically have a 100w baseline being drawn all the time!!  I am trying to reduce that to zero and power the essentials (telephone, internet, security, automation) by battery and avoid the inefficiency of some of these voltage droppers.





Title: Re: 12VDC Central Heating Pump
Post by: Iain on February 23, 2020, 05:46:39 PM
Hi

Yes, I do have one of those plugs for measuring the power.  My PIR LED flood light, for example, use 3W of power all the time, day and night.  I have since installed a timer, but even that draws 0.7W.

My pumped shower unit draws 3.5W just sitting there doing nothing, so I installed a manual pull switch, which is supposed to be turned off after use!

It just surprises me how much energy is wasted by these items sitting on standby and how much energy they waste by using very inefficient designs/voltage droppers and they are everywhere!  I basically have a 100w baseline being drawn all the time!!  I am trying to reduce that to zero and power the essentials (telephone, internet, security, automation) by battery and avoid the inefficiency of some of these voltage droppers.


Just check your powermeter reflects the actual power factor. If it doesn't then you could be chasing phantom loads for ever.
Some units only measure voltage and current. These are combined to give a reading so can be drastically out when power factors are involved.
Regards Iain


Title: Re: 12VDC Central Heating Pump
Post by: Justme on February 24, 2020, 05:14:52 PM
Yes, I do have one of those plugs for measuring the power.  My PIR LED flood light, for example, use 3W of power all the time, day and night.  I have since installed a timer, but even that draws 0.7W.

My pumped shower unit draws 3.5W just sitting there doing nothing, so I installed a manual pull switch, which is supposed to be turned off after use!

It just surprises me how much energy is wasted by these items sitting on standby and how much energy they waste by using very inefficient designs/voltage droppers and they are everywhere!  I basically have a 100w baseline being drawn all the time!!  I am trying to reduce that to zero and power the essentials (telephone, internet, security, automation) by battery and avoid the inefficiency of some of these voltage droppers.





Most plug in meters dont measure the lower watts very well.

Your plan of using a battery will increase energy used as charging / converting looses energy.