navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address. Following continuous spam/hack attempts on the forum, "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: DC KWh or Ah meters ?  (Read 4394 times)
Dyslexicbloke
Full Member
***
Offline Offline

Posts: 159


Blue sky thinking ...


« on: May 06, 2011, 04:08:11 AM »

Hi folks,
dose anyone know of a supplier of KWh meters of even Ah meters that donít cost a fortune and will operate on a 12V battery bank.

I could probably program one into my little PLC but it wonít store ant sort of history and would loose the data every time I made a program change, which on a constantly evolving project would be a pain.

Alistair
Logged

Off Grid - Big Caravan and huge enclosed gazzebo.
300W PV 12V system.
400Ah of AGM Absolyte GP cells. (Second hand)
600W Inverter (Maplin's finest :-) )
CHP in the works - Chinese Horisontal Diesel [S195 Generic - Kukje]
VAWT testbed flying - Back to that when its warmer I think.
camillitech
Hero Member
*****
Offline Offline

Posts: 5477



WWW
« Reply #1 on: May 06, 2011, 08:14:46 AM »

How about this Alistair http://www.reuk.co.uk/Watts-Up-Meter.htm been thinking of getting one myself.

Cheers, Paul
Logged

http://lifeattheendoftheroad.wordpress.com/

'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SMA SI6.OH, 800ah Rolls, 9kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
Dyslexicbloke
Full Member
***
Offline Offline

Posts: 159


Blue sky thinking ...


« Reply #2 on: May 06, 2011, 03:33:31 PM »

Looks good thanks .... I'l have to save up though, generally I am doing things a shoestring and I just bought batteries  Tongue

Alistair
Logged

Off Grid - Big Caravan and huge enclosed gazzebo.
300W PV 12V system.
400Ah of AGM Absolyte GP cells. (Second hand)
600W Inverter (Maplin's finest :-) )
CHP in the works - Chinese Horisontal Diesel [S195 Generic - Kukje]
VAWT testbed flying - Back to that when its warmer I think.
davebodger
Full Member
***
Offline Offline

Posts: 137



« Reply #3 on: May 07, 2011, 12:51:20 PM »

Also check eBay - the Turnigy watt meter comes in at around £28 inc postage.
Logged

Soladin Grid-Tie 400Wp tracker in London NW5.
myozone
Sr. Member
****
Offline Offline

Posts: 299


Lizard peninsula - Cornwall


« Reply #4 on: May 07, 2011, 01:54:08 PM »

Apparently the Watts-Up has a better low-end reading <1 amp
Logged

'Don't live life by the perforations' !
Dyslexicbloke
Full Member
***
Offline Offline

Posts: 159


Blue sky thinking ...


« Reply #5 on: May 07, 2011, 03:43:21 PM »

You preempted the question why the 50% diference in price .... Thanks.

I'v been looking at how to plan my charging regime and I am going to be up around 75A during the bulk stage of a generator recharge or an EQ maintenance charge. It seems a big ask for something that can measure that to then be accurate at less than 10% of its full scale.

I might have to ponder that one a bit ... My other concirn is that all the units suggested are using a shunt which is likely to get seroiously warm at the maximum design current. The ones I looked at on eBay seem to be designed for RC stuff which is hardly going to be doing 75A for 2 Hrs. I know that some brushles motors for big RC stuff will have huge peek curents but I am worried about sustained high current use.

Anyone have any practical experiance of these things.

Alistair
Logged

Off Grid - Big Caravan and huge enclosed gazzebo.
300W PV 12V system.
400Ah of AGM Absolyte GP cells. (Second hand)
600W Inverter (Maplin's finest :-) )
CHP in the works - Chinese Horisontal Diesel [S195 Generic - Kukje]
VAWT testbed flying - Back to that when its warmer I think.
davebodger
Full Member
***
Offline Offline

Posts: 137



« Reply #6 on: May 07, 2011, 10:52:28 PM »

I would suggest reading Outtasight's thread http://www.navitron.org.uk/forum/index.php/topic,8368.msg88462.html#msg88462 which contains a mass of useful practical info.
He uses the battery wires as shunts so no additional resistance is added.
Logged

Soladin Grid-Tie 400Wp tracker in London NW5.
Dyslexicbloke
Full Member
***
Offline Offline

Posts: 159


Blue sky thinking ...


« Reply #7 on: May 08, 2011, 12:38:51 AM »

Thanks Dave ... I was planning to use the fuses as shunts, given that they are carfully manufactured to tight tollerances.

I have bought a few cheep, £3.00 each, DC current sensors and will be comparing the results with the shunt.
The ones I have are good for +/-80A it remains to be seen what the resolution and temperature stabillity are like.

Reading the thread you suggested now, always up for a bit if edumifying  ralph

Al
Logged

Off Grid - Big Caravan and huge enclosed gazzebo.
300W PV 12V system.
400Ah of AGM Absolyte GP cells. (Second hand)
600W Inverter (Maplin's finest :-) )
CHP in the works - Chinese Horisontal Diesel [S195 Generic - Kukje]
VAWT testbed flying - Back to that when its warmer I think.
Dyslexicbloke
Full Member
***
Offline Offline

Posts: 159


Blue sky thinking ...


« Reply #8 on: May 08, 2011, 03:04:43 AM »

Dave,
Thats one huge thread, seriously interesting though, Outtasight clearly knows what he is talking about.

I am somwhat hartened though, I am currently running two of the Maplin 60W (4X15) sets of pannels and 4X40W amorphous units I picked up on ebay.

I think I can claim to have a simmilar aproach to out of the box innovation, but I dont have nearly the budget to be employing all the gadgets, bells and whistles. Ah well my bulk charger, formally a 160A welder with a few mods, is doing the business when I need to top up from the genny.

I think that the whole MPPT concept warrents some investigation .... How would one go about that on the cheap?

Exhausted from reading  Undecided
Al
Logged

Off Grid - Big Caravan and huge enclosed gazzebo.
300W PV 12V system.
400Ah of AGM Absolyte GP cells. (Second hand)
600W Inverter (Maplin's finest :-) )
CHP in the works - Chinese Horisontal Diesel [S195 Generic - Kukje]
VAWT testbed flying - Back to that when its warmer I think.
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!