Measuring the power flow in a camper ... - Hilux 4x4 Forum
Measuring the power flow in a camper ...
Sat Aug 30, 2014 11:18 am
There are SO MANY facts, stories, old wifes tales, and blatant sales talk about the power flow in a camper that I embarked on a project to SEE what actually happens to the electrons running around in the wires ....
Step ONE - to utilize volt and ampere meters to see inside the wires -
This is actually not all that easy ... the current is just too high for ordinary meters, yet too low for hard core industrial meters.
And then our very own Pieter of 4x4Direct set about importing some meters. First batch was roaring success, and sold out in no time. I got some meters from the second batch.... sadly Murphy had a hand in this shipment and the meters and shunts were mismatched .... Pieter immediately set about re-ordering. But Murphy was sure to upset the apple cart, and the 3rd batch had the exact same mismatch as the 2nd batch.
But Murphy does not know the fisherman from the West Coast we call Pieter ...
Pieter now dug his heals in, and ordered a batch of note, and this has now cleared customs and is already installed in Elders
This time round Pieter elected to order THREE different types of meters, each with the correct shunt:
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Sat Aug 30, 2014 11:31 am
In a quest to uncover the mystery of how the power flows in a camper I decided to monitor the following :
- SOLAR - what voltage is available from the solar panel, at which amps.
- Ctek - what does the charger do to the power delivered from the solar panel (the cheaper shunt type solar regulators "throws away" the extra volts, and only keeps the available current. while the more expensive MPPT type does magic and increase the amps to reduce losses and charge the battery faster ... at least this is how the story goes .... let's see ...)
- BATTERY - and then for good measure I want to see what power is drawn from the battery by the fridge/compressor/lights/water pump/etc .... I also want to see what happens to the solar and ctek power when a load is applied to the battery ....
and thus I set about building a rig that could measure all three these items in real time and simultaneously .....
Nice box to house the three meters -
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This was placed next to the battery, to keep the extra wires to a minimum (wanted to limit the effect this may have on the final results) -
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I added a small switch to each circuit to be able to switch it off -
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and the final product -
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Sat Aug 30, 2014 4:39 pm
Ek se weereens as jy uitmaak van n ding dan maak jy uit.Well done Chris -jy kan jouself op die skouer klop
Sat Aug 30, 2014 5:24 pm
Lollie wrote: Ek se weereens as jy uitmaak van n ding dan maak jy uit.Well done Chris -jy kan jouself op die skouer klop
Jong jy moet vir Willy op die ander forum sien !!
Die ou bou sommer n proper computer om als te meet .... DAAI is nou n fensie kontrapsie.
My een is net lekker maklik, en practise - en ek WEET waar om te bypass as die goed rondneek in die bos ...
Sun Aug 31, 2014 7:55 am
Mooi Chris Lees die meters korrek?
george wrote: Mooi Chris Lees die meters korrek?
Ek glo so :)
Die Ctek se maksimum laai stroom is gelees teen 19A - ons weet dat die Ctek dit beperk tot n maksimum van 20A. Soos die battery gelaai het, het die stroom gedaal.
Die yskas begin teen ongeveer 5A, en wanneer die temperatuur daal sak dit tot 2,5A - presies soos die NL literatuur sê :) :)
En die solar panele se strome lyn ook perfek op met die toetse wat ek laas jaar gedoen het.
Chris ek sal like van so boksie...
Sun Aug 31, 2014 6:09 pm
ThysdJ wrote: Chris ek sal like van so boksie...
praat net ... ek ken n nice ou wat baie mooi meters verkoop.
en net vir jou - jy hoef nie eens postage te betaal nie
Nice project. Is there a way to use a single Volt/Amp meter and switch(es) to measure all of the above or at least multiple loads?
Mon Sep 01, 2014 3:13 pm
Nice one Chris. Wou ook al so projek aanpak... het die meters en shunts aan geskaf maar toe nooit daarby uit gekom nie
Mon Sep 01, 2014 4:07 pm
CasKru wrote: Nice one Chris. Wou ook al so projek aanpak... het die meters en shunts aan geskaf maar toe nooit daarby uit gekom nie
Hmmmm +1 Sit ook met alles, maar nog nie daarby uitgekom nie
Goeie werk Chris!
Mon Sep 01, 2014 6:06 pm
subok wrote: Nice project. Is there a way to use a single Volt/Amp meter and switch(es) to measure all of the above or at least multiple loads?
some people do it that way.
but then you need a two or three-way switch over switch .... and a PROPER DC switch over switch that can handle switching at 20A aint cheap !!
these meters are cheap enough that one don't have to struggle with switches :)
Mon Sep 01, 2014 6:17 pm
teken net eers daai circuit MOOI uit !!
direction of current flow from the solar panel - easy enough
direction of current flow from battery to fridge - easy enough
now look closely at the sketch to figure out the direction of current flow FROM the Regulator TO the battery ....
en om die volts reg te meet moet jy die rooi van elke meter op n ander punt Koppel ...
die res is redelik maklik - as jy eers uitgefigure het hoe om jou bestaande stelsel aan te rand om die meters in te skakel .... Ek het die 100A fuse holders gebruik - lekker om die shunt te Koppel, en BAIE maklik om te bypass as dit sou nodig raak -
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eintlik n LEKKER projek :)
ek lê agter in Elders besig met die werk. My peetkind, 3 jaar oud, sit op die bankie agter my .... hy kan nie lekker sien nie, so kom SIT op my om beter te sien - terwyl ek prober om die dun drade te soldeer. :)
Mon Sep 01, 2014 7:23 pm
Chris , het jy uit gefigure of mens die broshure se Ah kan glo
http://www.nationalluna.com/Datasheets/ ... ochure.pdf" onclick="window.open(this.href);return false;
Mon Sep 01, 2014 7:26 pm
Johan Kriel wrote: Chris , het jy uit gefigure of mens die broshure se Ah kan glo
hehehehe ..... is dit nou met of sonder die turbo knoppie ...
Johan die stroom het bo 5A gebly tot die temperatuur onder 10 grade was, toe sak dit tot 2,5A ... mens was ek bly .... en toe sak dit sommer tot 2,1A vir die laaste paar minute !!
Mens sal n reeks eksperimente moet doen om akkuraat kommentaar te kan lewer (en daai eksperimente gaan gedoen word).
here is the wiring diagram for my system :
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for those that want a bit more info, the attached pdf explains the process.
Fitting a V-A meter - small.pdf
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Wed Sep 10, 2014 10:49 pm
As julle moes kies, waar sal een VA meter die meeste waarde bydra? Tussen die battery en die yskas/liggies ens?
Thu Sep 11, 2014 2:54 am
Dan kan jy SIEN wat jou laste trek - jy mag dalk skrik as jy sien wat die compressor of die inverter doen .... en met iets soos die compressor is dit goed om te "skrik" - want jy KAN mos die kar laat idle vir daai paar minute :)
en die Volts WYS vir jou of daar gelaai word op daai stadium - so jy GOU sien of jou besig is om op empty te idle en of jy okay is ....
dit wat ek hier gedoen is HEELTEMAAL te veel !! Maar dis gedoen sodat ek kan eksperimenteer en n paar mites (myths) kan toets ...
Thu Sep 11, 2014 7:47 am
Tue Sep 16, 2014 9:54 pm
Ek is besig om die 20A meter te bestel, maar ek kort bietjie raad asb.
Waar kom daar fuses?
Hoe vêr kan die meter van die shunt af wees? My meter wil ek in die oorhoofse konsole sit by my radio en die dubbelbattery is in die enjinruim waar n hilux sn altyd sit.
Sit die skakelaar vir die meter op die positiewe lyn tussen die meter en die battery?
Ek sien die shunt 'onderbreek' die negatiewe stroombaan tussen die battery en die yskas. Beteken dit dat die drade dan dieselfde dikte moet wees as die oorspronklikes?
Wat ek dus eintlik wil weet is of mens op sekere gedeeltes in die stroombaan dun drade kan gebruik. (Dit lyk so as ek na die fotos kyk, maar wil net graag bevestig)
Wed Sep 17, 2014 7:03 am
Die "shunt" kom in die negatiewe lyn - net voor dit weer by die battery kom. Ek het n 100A fuse houer hier gebruik, sonder die fuse. Gebruik dan dieselfde dikte draad tot be die shunt en terug. Vir 20A ten minste 2,5mm2 draad, verkieslik 4mm2 (four millimeter square).
Die negatief word reeds beskerm deur enige fuses wat jy in die stelsel het.
PS - in my fotos sal jy sien dat my negatiewe drade nie almal ewe dik is nie - elkeen is gekies volgens die las wat dit dra. En die rooi draad is BAIE dun want dit sien slegs 75mA.
Jy moet ook dan n positiewe punt tot by die meter bring. Hier gebruik ek n DUN draad. In my geval is die meters BY die krag punte, dus het ek geen fuse gebruik nie - onthou dat n swak konneksie op die fuse jou lesing lelik gaan rond foeter !! Ek sou liewer n draad gebruik met ekstra isolasie .... maar hier moet jy kyk na jou stelsel en mooi kyk wat die kanse is vir n kort sluiting ...
So, dit het my die hele saterdag gevat - geen middagslapie - maar hy is in sonder dat die rook uitgekom het!!!
Ek het sommer die xstra battery uitgehaal om te kyk of die brackets nog reg is en ek moes natuurlik die dak-konsole verwyder om die ekstra meter te huisves.
Die foto is net nadat ek dit aangeskakel get met die yskas wat loop. Die voltmeter links is nou aan die sonpaneel invoerkant gekoppel sodat ek op n trip kan sien wat die sonpaneel aanvang. Sjoe maar dit was nou vir jou n klomp drade wat deur die bulkhead gaan, maar alles is waterdig en stofdig en ordentlik 'gefuse'. Ek het maar dik draad gebruik vir alles wat aan die shunt gekoppel is, want dis net oor twee meter kabel na die oorhoofse konsole toe.
Chris, baie dankie vir die instruksies!!!
Sat Sep 27, 2014 7:50 am
Are you by any chance selling these units? I am interested in one so I can monitor battery drain.
Sat Sep 27, 2014 8:28 am
Kobus dit lyk nou SPIEKERIES !!! :)
ronnie wrote: Hi Chris
Hi Ronnie I can re-sell it to you ...
But possibly better if you take a drive to the 4x4Direct shop in Brackenfell, they are around the corner(and up the road) from GoodHopeSpares.
BE WARNED - they have some nice toys there ....
Sat Sep 27, 2014 12:37 pm
Do you mean they sell that white box mounted near your DC to DC charger as a unit?
Sat Sep 27, 2014 1:09 pm
ronnie wrote: Do you mean they sell that white box mounted near your DC to DC charger as a unit?
No Ronnie.We just sell the meters
Sat Sep 27, 2014 3:32 pm
Hi Ronnie, sorry, ssems I misread your question.
4x4Direct only sell the parts.
The box you can buy from any electrical outlet, such as Bellville Electric.
the rest is just patience as you wire up the system
working 60+ hours a week it took me a good few weekends to complete my installation. If you have the time, it should only be 2 or 3 days worth of work - assuming your work will be interrupted every so often to buy one more lug ...
Thu Dec 04, 2014 9:41 pm
a question please. Did you only use 50A shunts? How do you determine which shunts to use?
Sorry two questions in one.i would like to do a similar system like yours.
Fri Dec 05, 2014 5:58 am
Cinco wrote: Chris
STUNNING PIC !!!!!!! :)
I used the following shunt and meter combinations:
solar panels - 20A
Between the Ctek and the battery - 20A
from the battery to the DB box - 50A
in each case look at the realistic max current and then select the shunt-meter combination to suit.
Fri Dec 05, 2014 9:04 pm
Ian please tell me more about that pic.
you may well enjoy these - http://www.grantatkinson.com/" onclick="window.open(this.href);return false;
I stand in awe of you guys. :) VERY lucky to Grant as a close friend. And know just how much goes into getting these specials pics.
Sat Dec 06, 2014 10:56 am
its not mine . cant remember where I got it.
Grants stuff is awesome.
my son is also a photographer but getting there.
Sat Jan 17, 2015 10:09 pm
I have spent hours rewiring and checking and cannot solve my problems with the meter set up.
I have installed my meters exactly as per your drawing with a few minor changes (mainly to do with switches).See the attachment.
My effort does not work.
1)Meter 3 (battery ) works correctly. It shows me the battery voltage and amps drawn if I connect a load.
2) Meter 2 (C-Tek)does not work at all. No lights come on. Is there a way to test if it is ok?
3) Meter 3 (Solar) works for both the alternator and the solar panel, but only if I have the negative from the solar connected to the body and the shunt connected to this. This way the solar panel and alternator both charge the battery. Obviously the wiring is wrong? If I connect exactly as per your drawing neither charge the battery? The Ctek just keeps resetting itself.
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Sun Jan 18, 2015 6:44 am
so easy to get this spagetti mixed up !!!!
Testing the meter - your battery meter works - thus this shunt IS connected correctly. Switch out the little plugs of the connecting leads - put the leads of battery meter shunt onto meter two - this SHOULD now work. IF so, this confirms you got your spagetti mixed up ....
DONT use common connection points for the different meters. This will quickly create bypass routes for the current !
Sun Jan 18, 2015 9:52 am
After many checks and rechecks I was moedeloos.
I eventually, out of desperation, starting checking all cables for continuity and found that the power cable to the Ctek meter had a break in it. Replaced that cable and all good!
Wed May 04, 2016 7:40 pm
I know I'm digging up history but I was reviewing your whole story again and from your test results with the C-tek you got over 20 amps when running both panels and alternator. Should that shunt, between C-tek and battery, be a 50 amp shunt and not a 20 amp?
Wed May 04, 2016 7:49 pm
Watch me put my foot in it now .....
IF memory serves me right, then this is what I did :
- PV solar - 20 A, as I pretty much knew it would not exceed 10A by much
- Ctek to battery - knowing this would regularly clock in at 20A I used the 50A shunt
- to the load side I had little choice, and had to go for the 50A shunt - the compressor would go past 20A ...
HOPE this is what I did ...
These units would have some safety factor. But I come from the era where we selected meters to operate at 50 to 75% range for optimal accuracy and longevity.
Ok thanks. I need to check my set up.