I sent a question to Dometic and got a reply. Just wondering if they are making sense ?
To fill in the gaps, my fridge was hard wired to the vehicle battery until recently when my leccy mate wired it up to the leisure batteries and added a solar panel.
Waddya reckon ?
"
Dear Sir/madam
I am currently having problems with one of your fridges. I am not sure of the model so I am sending a picture.
It’s worked OK for 3 years on 240v but it seems to have a fault on 12v.
To explain. I have two 110 amp hour leisure batteries in my camper.
And I have a 150w solar panel fitted as well. I am holidaying in Lanzarote so obviously get 10 hours good sunshine every day.
The fridge is quoted as 100 watts in the manual.
But when I put the fridge on, it flattens everything in about 5 or 6 hours.
My electrical knowledge is minimal, but I have been told that the fridge should be drawing about 8 amps per hour (100w divided by 12v)
This should mean that my 2 leisure batteries should be able to supply power for about 18 hours. I let them charge for 3 days in the sun and the meters in the camper both showed them as fully charged.
And even without the leisure batteries, the 150w solar panel should be able to power just a 100w fridge, with the brilliant sunshine over here.
And ideas or tips would be gratefully received
"
===============================================
their reply...
"
Hello Craig,
Happy new year.
Thank you for your email to Dometic UK.
I will try to help in the best way I can how ever emails like this can be difficult to explain as normally the user is unable to understand the problem.
OK here goes....
Please remember firstly your 110 amp battery can not supply 110 amps. Lead acid battery's can only supply 60-40 % of the total amps stated before becoming to discharged to function.
So with your fridge consuming 100 watts at 12v, this equates to 8.3 amps being consumed every hour out of your battery, times this by say 6 hours (the time it takes to flatten a battery), this would mean the fridge has consumed 50 amps from your battery, so would mean that your have reached the 60-40% make mentioned above.
Please also note, battery's only have a life expectancy of around 2 years (If the voltage is not pulled below 12.1v at any point)- the issue hear is that everyone likes to think there battery's are maintained at this level but the reality of it is that most of the time the user does not know the level, or notice when the fail in voltage occurs.
OK now to explain the solar panel...
Your solar panel will also be adding power to the battery over this time, but solar panels are not 100% efficient. So the efficiency of your solar panel will also have an effect on the charge. Ie; An 150 watt solar panel providing 12v can produce 12.5 amps. However, if the solar panel is only 85% efficient, this means you would then loss 15% from the 12.5 amps produced. many of the cheaper models of panel don't even reach anywhere near the stated output of the panel due to impurity's in the cells and out components.
When using a panel to run a deveice, most solar manufactures state the panel must be 2x- 3x larger than the applience being opperated. We are not solar experts, and further questions regarding solar use must be taken up with your manufacture.
So with having read your email I would have assumed the fault is not with the product but the set up.
Please also note, because the set up has worked for three years, this does not mean the set up was running correctly, and then lead to a fault over time.
I hope we have been helpful?
You can use our website to locate an engineer to visist you for a check over of the product. www.Dometicapproved.co.uk.
Customer Services
Dometic UK Limited
Dometic House
The Brewery
Blandford
DT11 9LS
"
Thanks in advance of any replies
To fill in the gaps, my fridge was hard wired to the vehicle battery until recently when my leccy mate wired it up to the leisure batteries and added a solar panel.
Waddya reckon ?
"
Dear Sir/madam
I am currently having problems with one of your fridges. I am not sure of the model so I am sending a picture.
It’s worked OK for 3 years on 240v but it seems to have a fault on 12v.
To explain. I have two 110 amp hour leisure batteries in my camper.
And I have a 150w solar panel fitted as well. I am holidaying in Lanzarote so obviously get 10 hours good sunshine every day.
The fridge is quoted as 100 watts in the manual.
But when I put the fridge on, it flattens everything in about 5 or 6 hours.
My electrical knowledge is minimal, but I have been told that the fridge should be drawing about 8 amps per hour (100w divided by 12v)
This should mean that my 2 leisure batteries should be able to supply power for about 18 hours. I let them charge for 3 days in the sun and the meters in the camper both showed them as fully charged.
And even without the leisure batteries, the 150w solar panel should be able to power just a 100w fridge, with the brilliant sunshine over here.
And ideas or tips would be gratefully received
"
===============================================
their reply...
"
Hello Craig,
Happy new year.
Thank you for your email to Dometic UK.
I will try to help in the best way I can how ever emails like this can be difficult to explain as normally the user is unable to understand the problem.
OK here goes....
Please remember firstly your 110 amp battery can not supply 110 amps. Lead acid battery's can only supply 60-40 % of the total amps stated before becoming to discharged to function.
So with your fridge consuming 100 watts at 12v, this equates to 8.3 amps being consumed every hour out of your battery, times this by say 6 hours (the time it takes to flatten a battery), this would mean the fridge has consumed 50 amps from your battery, so would mean that your have reached the 60-40% make mentioned above.
Please also note, battery's only have a life expectancy of around 2 years (If the voltage is not pulled below 12.1v at any point)- the issue hear is that everyone likes to think there battery's are maintained at this level but the reality of it is that most of the time the user does not know the level, or notice when the fail in voltage occurs.
OK now to explain the solar panel...
Your solar panel will also be adding power to the battery over this time, but solar panels are not 100% efficient. So the efficiency of your solar panel will also have an effect on the charge. Ie; An 150 watt solar panel providing 12v can produce 12.5 amps. However, if the solar panel is only 85% efficient, this means you would then loss 15% from the 12.5 amps produced. many of the cheaper models of panel don't even reach anywhere near the stated output of the panel due to impurity's in the cells and out components.
When using a panel to run a deveice, most solar manufactures state the panel must be 2x- 3x larger than the applience being opperated. We are not solar experts, and further questions regarding solar use must be taken up with your manufacture.
So with having read your email I would have assumed the fault is not with the product but the set up.
Please also note, because the set up has worked for three years, this does not mean the set up was running correctly, and then lead to a fault over time.
I hope we have been helpful?
You can use our website to locate an engineer to visist you for a check over of the product. www.Dometicapproved.co.uk.
Customer Services
Dometic UK Limited
Dometic House
The Brewery
Blandford
DT11 9LS
"
Thanks in advance of any replies