AC Fridge In Campervan -.Power Consumption Test

[wildebus]

Yes to the capacity but no to the weight, each of my battery’s weigh 13kgs so total is 26kgs. The Bosch PowerFrames they replaced weighed 26kg @ 90ah And I had 3 of them

ah, ok. So it would be 52Kg vs 210Kg (4 x Lithium vs 3 x Big AGM) - 150Kg difference when getting like for like capacity.
Are you payload limited in your van with it being a 4100kg GVW?
I know with mine the weight of the batteries is not that important as I still have around 600kg or spare when fully loaded AND with the batteries in place.

 

[Nabsim]

Van is rated at 4t dead Dave, rear axle is limiting factor I think, I know it was a struggle to get correct load rated tyres. Going to 16” would help a lot but it looked like there would be clearance issues at the front.

I am okay weight wise but only just, I carry a mobility scooter and handcycle as well as the genny, I also fill 2x25 litre water Jerry cans when travelling. Living in the van means I carry things I may not use very often as well but if you don’t carry you can’t use.

I wouldn’t be able to move your battery’s, I am good for maybe 30kg but then struggle to move with the weight lol

I had both my lithium fitted by December so have had the winter and 200ah is enough to last 2 days comfortably when no charge sources are available. I would have liked to go a bit higher on my B2B but costs went up a lot above 30amp so stopped there

I have spoken to you re mains charging and I do need to upgrade that before next winter. I can cope as I am with the 2 x 18amp Schaudt chargers but it means running the genny quite a bit. I am also looking at maybe connecting the immersion on the calorifier (1Kw) so have my eye on a Victron Multi but need to source funds first. Well need to source Caz another house first then see lol

 

[wildebus]

I can't really move my batteries either! They went in the back door and they have never been removed since!

I wonder if you could just add in a basic cheap non-intelligent battery charger with a set voltage output to help with bulk charging - in a similar way that an alternator would put out?

 

[Nabsim]

Well I don’t really need the intelligence as all I want us 14.4v (ish) and up to 80 amps. I can see what’s happening on my phone.
when I have looked though it’s either known brands that you know will do the job but at a cost or unknown rebadged Chinese stuff

 

[ScoTTyBEEE]

Well I don’t really need the intelligence as all I want us 14.4v (ish) and up to 80 amps. I can see what’s happening on my phone.
when I have looked though it’s either known brands that you know will do the job but at a cost or unknown rebadged Chinese stuff

Best bet buy one of these out of an ambulance, they cost over £700 new and contain 2 x 30A chargers which I assume you can hook up to one single battery. I'm using the same one in my van, you won't get a better charger for the money. Make sure it's a DUO 1230/30 like this one is listed as because mine are 1215/30, ie 15A and 30A. I'm using mine on lithium battery no problems as it has several configurations. I've attached the manual for you to peruse.

Pardon our interruption...

 

[wildebus]

You may be able to fit a new regulator pack. I carry one as a spare.
An interesting read Dave. Thanks for all the hard work. Though if you were to look at real world numbers with the assistance of your solar help your batteries will have much less of a hammering. I’m still torn over what to treat Betty too. For now I have some old Varna’s for testing.

Checked the Alternator output and not as I expected (actually a lot better!).

Added a high load to the Leisure Battery system (~200A). This enabled the Victron Cyrix-ct (VSR) and checked with a clamp meter what the alternator is sending to the Starter Battery at various engine revs.
So on the face of it, pretty good, yeah?

I have colour-coded the revs to match the colours on the Tachometer - it is marked green between 1600 and 2900 revs and is redlined at 3900 (but I very rarely go above 3000)
Can't directly relate the power recorded to the revs at the Leisure +12V end, but when the engine was running, it looks like getting between 45A and 60A contribution from the Vehicle +12V side.
I thought I would get more if I am seeing over 90A from the Alternator - but it maybe because the system samples the data once a minute and I was only at the different revs for as long as it took to note down the number on the Clamp Meter, I probably missed key parts. I think I need to repeat the test but holding the revs for at least 2 minutes at each point to get a good recording.

What I also need to do at the appropriate time is to check the output when the engine has been running for some time to see if the Alternator is overheating and cutting its output as I do think the output seems to be limited when it shouldn't be?

 

[SquirrellCook]

Two thoughts Dave. If you have a clamp current meter you could use it nearer your load?
I do wonder with graphs sampling times. Does it average the data or show as sampled peaks and troughs?

As for your alternator the built in fans are normally very good. Do you have a BMV on your starter battery? If so this would show for sure if the starter battery is topping up the alternator?

 

[wildebus]

Two thoughts Dave. If you have a clamp current meter you could use it nearer your load?
I do wonder with graphs sampling times. Does it average the data or show as sampled peaks and troughs?

As for your alternator the built in fans are normally very good. Do you have a BMV on your starter battery? If so this would show for sure if the starter battery is topping up the alternator?

The graphs tend to be based on the values sampled at the time. As you extend the time range shown, averaging comes into play and the lines get smoothed and you do tend to lose absolute peaks and throughs (this is most clearly obvious with solar yield)
I did put the clamp meter on the cable from Alternator to Starter Battery rather than Starter Battery to VSR, so I am sure those numbers I put in the alternator graph are genuine alternator numbers. Some of that will go to the engine systems I guess so less to the VSR (no headlights on or anything high current though), but there won't be tens of amps dropped unless there were the lights running (I deliberately upgraded the cable from starter to VSR to a 35mm2 cable to be able to easily carry any current the alternator could possibily provide and minimize any voltage drops).

I was thinking of maybe putting a BMV on the Starter Battery for a while to get an idea of what the alternator is doing as there would be no point in replacing it if it is working (not something I would want to leave there permanently though - too expensive!).
I think you have a BMV on the starter? what kind of currents do you see there when your engine is running?
I think my first step though will be to repeat the alternator test I did today but to leave it running at each RPM stage for longer to better capture the numbers

 

[SquirrellCook]

The BMV I have on the starter battery was about the paranoia of the starter batteries having a very low capacity. Even the new ones show low voltage at rest. I check the voltage daily and end up charging about every four days. They never take much. Just as well as I use the leisure side to charge them via a smart charger. On a good day I can get them back to float. As the output of the alternator I think I saw a flash of 40 once, but it dropped very fast. Due to no trips since Hereford I haven't had a chance to play. Just checked and I've still got 0.15 amps going somewhere?
Betty will have the same setup. Making use of the engine start capacity I run both eberspachers on that side.

 

[Nabsim]

Best bet buy one of these out of an ambulance, they cost over £700 new and contain 2 x 30A chargers which I assume you can hook up to one single battery. I'm using the same one in my van, you won't get a better charger for the money. Make sure it's a DUO 1230/30 like this one is listed as because mine are 1215/30, ie 15A and 30A. I'm using mine on lithium battery no problems as it has several configurations. I've attached the manual for you to peruse.

Pardon our interruption...

View attachment 2629

Not read the manual yet but is this just a charger? If so I can get a new Victron 30amp charger for similar price as I can get a VAT exemption on new parts. I really want more than 30 amp unless it was 30 amp per battery (2chargers). I have all charging sources using + on one battery and - on the other currently, would connecting to individual battery’s in a bank be a good idea?

 

[Nabsim]

If I am reading the manual right it supplies 15amps to one battery and 30amps to another? This raises two questions:
1. Does this mean I could have Part 1 to one battery in the bank and Part 2 going to the other?
2. If the answer was yes could I then connect a second unit so I would have 45 amps going to each battery?

if this is possible it then becomes a much cheaper option but think it may be wishful thinking on my part lol

 

[wildebus]

So I did another power test today....
To create a high load on the system, I put on a Fan Heater with a nominal 2kW output, plugged into the Multiplus 12/3000 - To run this heater, the inverter needs just under 2.2kW worth of input - which equates to around an 180Amp draw on the 12V system.

This was left running whilst I started the engine and then every couple of minutes increased the revs to a set amount, going upto 2,500. This allowed me to log each RPM step change and how it affected what the Vehicle system (Starter Battery & Alternator) contributed to driving the inverter.

The following chart (a chart? me? ) shows the results.

To explain the chart firstly ...
The Blue Area shows the total current being pulled by the Multiplus 12/3000 in order to run the Heater.
The Yellow Area shows how much current is being provided by the Vehicle system;
The difference between the top of the Yellow Area and the top of the Blue Area is the current being provided by the Leisure system.

The Green line is a map of the Engine RPMs at any time (values on right);
The Orange line is a map of the Alternator Output (in Amps) at any time (values on left)

So as the engine Revs increase, the Alternator output increases, although pretty well flattening out at around 95A.
The Alternator is putting out more current than the Vehicle system is providing, so that difference (gap between top of yellow area and the orange line) is going to vehicle demands, Starter Battery charging or are losses in the transfer. Given the gap increases as the output increases, looks like there are some losses there?
The Starter Battery itself is not generally providing any power and all power from the Vehicle System IS coming from the Alternator (I can tell this as the Starter Battery voltage is increasing all the time until 11:46 when the engine is turned off). Getting up to 77 Amps from the Vehicle system when the engine would be at typical 'cruising' speed.
The time from 11:46 to 11:50 is interesting... even though the engine is off, there is a (reduced) current still from the Vehicle area to the Leisure system. This is because the Cyrix-ct relay stays on for a period until the starter battery voltage drops below the set threshold for long enough. So during those couple of minutes the Starter Battery is actually providing power and its voltage drops significantly during that period (from 12.78V at 11:44 to 12.11V at 11:46). Once the Cyrix-ct relay turns off, the Starter Battery voltage recovers (back up to 12.64V at 11:50).


The reason I did this test is that I thought my Alternator was not able to put out a decent current and was on the way out. I would seem that its output is actually still fairly respectable in fact, although I would like to know where 20A of so (250W) is disappearing off to between the Alternator and the Leisure system

 

[SquirrellCook]

BMV on the starter battery me thinks

 

[wildebus]

BMV on the starter battery me thinks

That will tell me how much current is going into the Starter Battery. But I don't think it will tell me where all the power is heading?

SB Current (from BMV on SB) + LB Current (from BMV on LB) = x Current
Alternator Current (from Clamp Meter) = y Current
Difference between x and y = z . but where is z being used? Won't be much clearer except will know how much the Starter Battery is getting charged? (due to the Common earth for Vehicle and Leisure electrics - so for example, the Alternator output +ve IS going to the Multiplus +ve VIA the Starter Battery +ve connection when helping with the heater, but the -ve is via the chassis so bypasses both BMV Shunts)

 

[SquirrellCook]

Sounds like it needs sketching out and applying Kirchhoff's. Then after being more confused borrowing a thermal camera to find out what warming up

 

[ScoTTyBEEE]

If I am reading the manual right it supplies 15amps to one battery and 30amps to another? This raises two questions:
1. Does this mean I could have Part 1 to one battery in the bank and Part 2 going to the other?
2. If the answer was yes could I then connect a second unit so I would have 45 amps going to each battery?

if this is possible it then becomes a much cheaper option but think it may be wishful thinking on my part lol

The one I posted on ebay can do 30 amps to 2 separate batteries each, or 60 amps to 1 battery.

 

[Sprinter 1 cup]

This fridge thingy
240volts in van
yes or no? For cheap options

 

[wildebus]

This fridge thingy
240volts in van
yes or no? For cheap options

yes or no? to what?

 

[Nabsim]

Buying 230v fridge is definitely cheaper but you need power system to cope and inverter. If you already have suitable power source then yes it’s cheap option.

 

[Sprinter 1 cup]

yes or no? to what?

100 ltr at 240v AAA rated fridge compressor runds in the camber of the road, draws 50 amps or less in july a day 5am to 9.30 pm and you can put the inverta on timer.7 day timer via a relay .

I have neither 12v or 240v in my empty van build.