Compressor Fridge power usage

shakey55 · Senior Member

Compressor Fridge power usage

Mike Harding · Guru

shakey55 wrote:
The following morning, before the sun gets onto the solar panels I again check battery level and it is down to 12 or 12.1.
What are your thoughts.

Your batteries are dying of old age.

shakey55 · Senior Member

Mike Harding wrote:
shakey55 wrote:
The following morning, before the sun gets onto the solar panels I again check battery level and it is down to 12 or 12.1.
What are your thoughts.
Your batteries are dying of old age.

Thanks Mike, I thought this may be the case, but had fingers crossed that it was not.

When I replace, and not in the position to covert to lithium, as I would have to purchase batteries, solar controller and batterycharger (at least this is what I think).

Are the good and bad AGM batteries. Do you have any experience of what are good and bad brands.

-- Edited by shakey55 on Sunday 19th of March 2023 08:17:32 AM

BAZZA44 · Senior Member

I use Fullriver AGM ( expensive ) next choice Ritar

Barry

TimTim · Guru

Hi Shakey55,

From my experience and from a few friends, I would recommend here.

https://www.aussiebatteries.com.au/

If, you went LiFePO4 then yes you may have to upgrade you solar controller depending on the model that you have. Let us know and we can take a look.

When you say charger Im unsure whether you mean a DC to DC charger or a 240v charger. If you mean the latter you can generally get away with not having one as lithium batteries have a very slow self discharge rate so in storage they are generally not needed. I dont use one even though I have one for other purposes.

We all make different choices based on many factors so there is no right or wrong but my recommendation would be to go to LiFePO4 if at all possible.

Good luck and enjoy your trip.

Tim

-- Edited by TimTim on Sunday 19th of March 2023 09:01:14 AM

Possum3 · Guru

I've had great deals at Aussie Batteries and Solar - usually 2 - 5 delivery in Australia See www.aussiebatteries.com.au/

They do package deal for batteries and loom at very good pricing AGM's and Lithium. Quality Assured.

Mike Harding · Guru

As mentioned: Fullriver and Ritar are good as are Powersonic.

Steer clear of the cheap ones and they must weigh about 30kg per 100Ah or prorata.

Cuppa · Guru

It is certainly possible that your batteries have age/use related loss of capacity.

However before reaching that conclusion there are a couple of pieces of information required about the charging side of things rather than the storage side.

1. How much solar do you have & have you been getting plenty of sun.

If the answer is 'not a lot' then your 13.8v may not signify that your batteries are in float mode. It depends upon whether your charger is saying it is in float, or whether you are assuming this from the voltage reading. If the charger is saying they are in float then I would concur with Mike Harding that your batteries are getting to the end of their life & have lost a significant amount of their capacity.

If however you are going on the voltage alone, then it is possible that your charging is not keeping up with consumption. In order to know (by voltage) whether the batteries are in float at 13.8v , you need to know whether they have already been up to 14.4v to 14.6v in bulk charging mode, BEFORE dropping down to 13.8v. If that has occurred then the 13.8v is 'in float'. If it hasn't then it means your batteries are undercharged & charging is not keeping up with your fridge demands.

It is a big 'hungry' fridge & 80Ah per day would need approximately 400w of roof mounted solar +5 hours of good sun daily to keep up. If less solar or less sun you could be seeing the 13.8v voltage dropping overnight to 12.0v or 12.1v (Note: If your solar is freestanding & you are 'obsessional' about moving it multiple times during the day to follow the sun AND you have panels stood up at an angle rather than laying flat, you might get away with 300w).

If the batteries were at their full capacity (360Ah when new) & only the fridge running, you should see the batteries at around 12.5v minimum early in the morning a bit before first light. This is the best time to check - if you get up for an early morning wee, make it routine to check battery voltage - noting whether the fridge is running at the time or not. If you do this regularly your familiarity with the the 'norm' will quickly tell you when something isn't right).

So at 12.0v or 12.1v it is clear that your batteries have not reached full capacity the previous day - either because a) they are old & knackered & no longer have sufficient capacity or b)because they were not fully charged the day before.

Indicators of a) are - voltage rises to 14.4v+ before dropping back to 13.8v and/or there is a float mode indicator which is on.

Indicators of b) are - voltage does not rise to 14.4v prior to dropping back to 13.8v, and there is no float mode indicator.

You can do a load test to check capacity, but it's not practical whilst the system is needed to be in use. Any battery place can do a quick load test which takes a just a minute or less, but this is destructive to the batteries (esp. deep cycle batteries) & not recommended. To do a proper load test they would need your batteries for 24 hours.

On balance: If I were in your position & you have had sufficient solar & sun, I'd bite the bullet & get new batteries.

I was in a similar position to you in 2021 with 360Ah (3 x 120Ah) of AGM's failing. I had decided to replace them as we were headed to remote areas where replacements could take weeks to get & cost would have been much higher, so got the battery place to do the quick load test just for interest sake. It turned out that one of the 3 batteries had dropped a cell, & the other two with reduced capacity were struggling to keep up, just as you describe. They had lasted for 9 years & 10 months, including 5 years in full time use. I chose to replace them with the same again rather than going to Lithium as the only benefit I would get with lithium would have been a significant weight reduction, but the additional cost of lithium plus the cost to change my dc to dc charger (& the hassle of changing it due to difficult access) made the cost of weight reduction too much, considering we had managed ok with the weight for many years.

Best brand are Fullriver (I got over 12 years out of previous Fullrivers) but my batteries are Ritar, which I consider 'best value', as they are significantly cheaper than Fullriver. So I replaced my 3 Ritars with 3 new Ritars of the same capacity.

-- Edited by Cuppa on Sunday 19th of March 2023 09:44:00 AM

shakey55 · Senior Member

Cuppa wrote:
It is certainly possible that your batteries have age/use related loss of capacity.

However before reaching that conclusion there are a couple of pieces of information required about the charging side of things rather than the storage side.

1. How much solar do you have & have you been getting plenty of sun.
Not sure on solar, as came with the van. Possibly only 200w fixed panels, is there a way of determining size. I also have a 200w portable
If the answer is 'not a lot' then your 13.8v may not signify that your batteries are in float mode. It depends upon whether your charger is saying it is in float, or whether you are assuming this from the voltage reading. If the charger is saying they are in float then I would concur with Mike Harding that your batteries are getting to the end of their life & have lost a significant amount of their capacity.

If however you are going on the voltage alone, then it is possible that your charging is not keeping up with consumption. In order to know (by voltage) whether the batteries are in float at 13.8v , you need to know whether they have already been up to 14.4v to 14.6v in bulk charging mode, BEFORE dropping down to 13.8v. If that has occurred then the 13.8v is 'in float'. If it hasn't then it means your batteries are undercharged & charging is not keeping up with your fridge demands.
I had power connected yesterday and bulk charge was (when I looked 14.2)

It is a big 'hungry' fridge & 80Ah per day would need approximately 400w of roof mounted solar +5 hours of good sun daily to keep up. If less solar or less sun you could be seeing the 13.8v voltage dropping overnight to 12.0v or 12.1v (Note: If your solar is freestanding & you are 'obsessional' about moving it multiple times during the day to follow the sun AND you have panels stood up at an angle rather than laying flat, you might get away with 300w).
Yes from what Ive read it may be a hungry fridge, but not a lot I can do about that, it came with the van. Still works fine, so not replacing just yet. Van is parked out doors and when sun is shining my solar controller is always reading 13.8, never any different, although Im not religiously checking

If the batteries were at their full capacity (360Ah when new) & only the fridge running, you should see the batteries at around 12.5v minimum early in the morning a bit before first light. This is the best time to check - if you get up for an early morning wee, make it routine to check battery voltage - noting whether the fridge is running at the time or not. If you do this regularly your familiarity with the the 'norm' will quickly tell you when something isn't right).
So at 12.0v or 12.1v it is clear that your batteries have not reached full capacity the previous day - either because a) they are old & knackered & no longer have sufficient capacity or b)because they were not fully charged the day before.
Indicators of a) are - voltage rises to 14.4v+ before dropping back to 13.8v and/or there is a float mode indicator which is on.
Indicators of b) are - voltage does not rise to 14.4v prior to dropping back to 13.8v, and there is no float mode indicator.
You can do a load test to check capacity, but it's not practical whilst the system is needed to be in use. Any battery place can do a quick load test which takes a just a minute or less, but this is destructive to the batteries (esp. deep cycle batteries) & not recommended. To do a proper load test they would need your batteries for 24 hours.
On balance: If I were in your position & you have had sufficient solar & sun, I'd bite the bullet & get new batteries.
I was in a similar position to you in 2021 with 360Ah (3 x 120Ah) of AGM's failing. I had decided to replace them as we were headed to remote areas where replacements could take weeks to get & cost would have been much higher, so got the battery place to do the quick load test just for interest sake. It turned out that one of the 3 batteries had dropped a cell, & the other two with reduced capacity were struggling to keep up, just as you describe. They had lasted for 9 years & 10 months, including 5 years in full time use. I chose to replace them with the same again rather than going to Lithium as the only benefit I would get with lithium would have been a significant weight reduction, but the additional cost of lithium plus the cost to change my dc to dc charger (& the hassle of changing it due to difficult access) made the cost of weight reduction too much, considering we had managed ok with the weight for many years.
Best brand are Fullriver (I got over 12 years out of previous Fullrivers) but my batteries are Ritar, which I consider 'best value', as they are significantly cheaper than Fullriver. So I replaced my 3 Ritars with 3 new Ritars of the same capacity.
Thanks Cuppa, Ill get a test done, but its looking like I will replace all three batteries so I know they are new and how old they are. Have not totally made my mind up on AGM or Lithium, obviously lithium will be the more expensive route as I will also need to change controller and charger. Agree its expensive way to save weight

-- Edited by Cuppa on Sunday 19th of March 2023 09:44:00 AM

shakey55 · Senior Member

Thanks to everyone for comments and advice

Cuppa · Guru

shakey55 wrote:

Not sure on solar, as came with the van. Possibly only 200w fixed panels, is there a way of determining size. I also have a 200w portable

You can get a rough idea by measuring your panels if unable to view the label on the underside. I believe 180w per sq metre of panel size is average. Or just measure your panels & look online at the physical sizes of panels, find something close to yours & you'll know the approx wattage you have. There is a bit of variation between cheap & not so cheap panels, but it'll get you in the ball park.

Whenarewethere · Guru

Once you have worked out the area of the panals & then how many watts.

Then calculate the loss of wattage due to the angle of the sun. In this example only 63.39 watts.

In this example I have used a 150 watt panel & sun up 25° from the horizon (or if the panels are level). So type in your smartphone calculator the following:

Cuppa · Guru

I still go by the rule of thumb from Collyn Rivers.

If panels mounted flat, or close to it, on a vehicle roof, expect to get around 70% of the panel's nominal output in perfect conditions.

Eg.
120w panel divided by nominal voltage & multiplied by 70%

120w divided by 12v =10Amps

10A multiplied by 70% = 7 Amps.

Obviously output will vary through the day depending upon position of the sun to panels but this has worked well for me over the years in terms of determining how much solar I need to do what I want. My brain is not a maths brain.

Whenarewethere · Guru

Cuppa wrote:
My brain is not a maths brain.

That's why I use the calculator on the smartphone!

Whenarewethere · Guru

Non reputable manufacturers seem to have a habit of saying their solar panel produce X amount of watts per square metre but they are often using the actual cell performance, not the panel performance.

By the time you factor in the dead area around the cells. Watts per Square metre drops a fair bit.

_MG_1837 (1).jpg

If one packs all the actual solar cells together (Photoshop) they take up 72.7% of this panel.

So in this example if you thought you had 200 (which would be generous unless you have A grade cells) watts per square metres. You actually only have 145 watts per square metre.

Then by the time you factor in all the other things like third rate cheap hardware, too thin wiring, dirty panels, controller not next to the battery. There is not a lot left for your batteries.

shakey55 · Senior Member

TimTim wrote:
Hi Shakey55,
From my experience and from a few friends, I would recommend here.

https://www.aussiebatteries.com.au/

If, you went LiFePO4 then yes you may have to upgrade you solar controller depending on the model that you have. Let us know and we can take a look.
When you say charger Im unsure whether you mean a DC to DC charger or a 240v charger. If you mean the latter you can generally get away with not having one as lithium batteries have a very slow self discharge rate so in storage they are generally not needed. I dont use one even though I have one for other purposes.
We all make different choices based on many factors so there is no right or wrong but my recommendation would be to go to LiFePO4 if at all possible.
Good luck and enjoy your trip.
Tim

-- Edited by TimTim on Sunday 19th of March 2023 09:01:14 AM

Tim Tim

I have older controller and AC to DC charger.

If I go Lifepo4 is it just as simple as taking out old controller and putting in new one with same wiring. As for replacing AC to DC with a DC to DC charger, what is needed to be done here.

-- Edited by shakey55 on Wednesday 22nd of March 2023 06:32:50 AM

-- Edited by shakey55 on Wednesday 22nd of March 2023 06:34:37 AM

Aus-Kiwi · Guru

Keep the fridge 3/4 full . Even if its a few bottles of water . It acts like a cold sink. Does fridge run at night ? Once cold it shouldnt come on too often or for long . Unless seals are leaking . Solar should have batteries charged by about 11am ..or theres not enough solar ? Battery shouldnt go lower than 12.2 imo . If they do ? You need more batterys . I got away with 400 watt solar / 200AH AGMs . Now have 300 lithium . No issues now . When I used AGMs ? I didnt use the top expensive brands . They lasted 7 years .. Big part is not to cycle them too deep .

Cuppa · Guru

shakey55 wrote:

I have older controller and AC to DC charger.
If I go Lifepo4 is it just as simple as taking out old controller and putting in new one with same wiring. As for replacing AC to DC with a DC to DC charger, what is needed to be done here.

You'll need to check this, but I believe the PL20 is adjustable which may make it suitable for use with Lithium. Size wise (amps) depends on amount of solar.

A DC to DC charger does not have to replace an AC charger, you can use both, but either will need to have a lithium profile to be useful. And to make use of Lithiums abbility to charge fast you would need a higher amp (read - more expensive) charger. Lower amp ones will work, but not much, if any quicker than with lead acid batteries.

DC to Dc chargers like Redarc's BCDC chargers are combine solar regulators & dc to dc chargers & do the same job as the VSR (aux battery solenoid to protect starter battery from being discharged by your fridge etc). So you could repace your PL20 with, for example a Redarc BCDC1240N which would give you up to 40 amps charge as you drive, & do the job of your PL20 &leave room for more solar if /when you decide to get it. If Your AC charger has a lithium charging profile, you could use it. If it doesn't you will have to be advised by te battery manufacturer as to whether their Lithium BMS (inbuilt Battery Management System) will handle it. You may not need a mains charger, depends how often & for how long you generally drive. Handy to have a mains charger though.

Warren-Pat_01 · Guru

I have seen some suppliers stamp the delivery date on the battery with metal punches - if you can find some numbers on the case, that might give you the age of the batteries.

I know you haven't the time but I would be inclined to discharge each battery down to 12.25v & then charge & monitor (volts & amps) each battery separately using a 240v powered smart charger.

Regarding Lithium, I've seen where some batteries "Have their own battery control system built in so the earlier charging system can be utilized" - how that works, I don't know.

shakey55 · Senior Member

Warren-Pat_01 wrote:
I have seen some suppliers stamp the delivery date on the battery with metal punches - if you can find some numbers on the case, that might give you the age of the batteries.

I know you haven't the time but I would be inclined to discharge each battery down to 12.25v & then charge & monitor (volts & amps) each battery separately using a 240v powered smart charger.

Regarding Lithium, I've seen where some batteries "Have their own battery control system built in so the earlier charging system can be utilized" - how that works, I don't know.

Thanks Warren

Im away at the moment on power so no concerns. When I get home next week I will do that to each battery and see how I go. Not sure about lithium with BMS. Ive seen it mentioned and will be researching

Does it mean that you can use any charging profile, as the battery willl look after the charging rate - I dont know, perhaps some else can explain if this is what it does, but is it best to have a proper charger with lithium profile?

TimTim · Guru

shakey55 wrote:

Im away at the moment on power so no concerns. When I get home next week I will do that to each battery and see how I go. Not sure about lithium with BMS. Ive seen it mentioned and will be researching

Does it mean that you can use any charging profile, as the battery willl look after the charging rate - I dont know, perhaps some else can explain if this is what it does, but is it best to have a proper charger with lithium profile?

Hi Shakey,

All LiFePo4 batteries have a BMS. Generally all they do is prevent over charging and discharging of the individual cells and the battery as a whole.

It is best to have a MPPT charger with a LiFePO4 profile or a charger where you can put in a user profile. Similar to your EPever MPPT.

There are plenty of people that use an AGM charger but you need to be able to turn off equalisation mode.

Good luck.

Tim

shakey55 · Senior Member

Ive decide to replace my AGM batteries.

What are peoples thoughts on Giant batteries from Aussie Batteries.

They have 140 amp AGMs at $259 each if I buy two or more

www.aussiebatteries.com.au/batteries/deep-cycle-agm/140ahx-12v-agm-deep-cycle-battery+FACEBOOK+ONLY++LITHIUM&fbclid=IwAR0ac0fG76K8nQ9VcChuuH6RuZ3S4PuBnYuw-_-4akTW3VCQMyDlTMqsftc_aem_ATgB9QiZmJKokjjGkv2O-IzTEGgNwJT-AokGJ1lQxvzQuhDCXyEyJnwfUdyAK1ZChenGY2pM3o5AGsE-eIoz7OVlK5X_8fBnJBzfVUgh6njSE3eDUbQ3cy06zTLCDBauaZL2jHAJkpj8k0OPt1KV7TRQ

THEY ALSO MAKE THE FOLLOWING CLAIM - your thoughts

With a GIANT POWER 140AH AGM BATTERY, you get massive battery capacity. Unlike some of our competitor's batteries who recommend only using 30-50% of the battery capacity with Giant Power, you get more value from your AGM Batteries. When your camping and running a 12v fridge, most battery manufactures will recommend running the battery down to 50%, which is normally about two days of autonomy. With Giant Power Batteries, you get double the power usage due to the thicker lead plates and quality construction this means you get up to four days power autonomy.

-- Edited by shakey55 on Sunday 2nd of April 2023 06:34:27 AM

-- Edited by shakey55 on Sunday 2nd of April 2023 06:35:17 AM

Possum3 · Guru

As I advised previously; I've had great deals at Aussie Batteries and Solar - usually 2 - 5 delivery in Australia See www.aussiebatteries.com.au/

They do package deal for batteries and loom at very good pricing AGM's and Lithium. Quality Assured.

shakey55 · Senior Member

When replacing all batteries, is there anything I need to do with solar as it will probably be daylight when I do the changeover. Im just not sure

Possum3 · Guru

With any power system there is a probability of "residual" take precautions such as turning off all appliances, turning off 240v at source ensure that tools don't touch positive and negative terminals together or any "Ground/Earth".

Cover solar panels with opaque cloth if not able to "switch off" with fitted isolation switch.

Insulated tools and gloves can help reduce potential shock to you and your vans system/s.

shakey55 · Senior Member

When I receive my new AGM batteries should I charge each battery befor installing?

Cuppa · Guru

shakey55 wrote:
When I receive my new AGM batteries should I charge each battery befor installing?

Won't do any harm, but no need if they are going to be getting charged from your solar, unless you are going to be needing to use them straight away, in which case it would be helpful.

It wont matter if they are at different State of Charge (SoC) as once you have connected them they will all level out & behave as one large battery. If you have a battery monitor you will want to wait until they are fully charged before you calibrate the monitor. (ie. set it to the combined capacity of your batteries).

You can also charge them as one once installed from a mains charger if you have one. That's the easiest way.