As part of my slow, but moving, change transitioning to almost full solar reliance I am considering a 36V system, the caravan will remain 12V (too hard to change) but 36V will be used to power a 36V/240V inverter which will then provide 240V for everything.
My question is:
Is anyone using a 36V system and what inverter are you using and does it have EMC emissions approvals or an Australian RCM approval?
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Back in the day many homesteads ran 32volt systems - Normally attached to Lister Deisel gensets. It was apparently the preferred system for the old Sunbeam shearing gear.
I am uncertain whether 32volt household appliances are still available for purchase.
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Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan
Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.
As part of my slow, but moving, change transitioning to almost full solar reliance I am considering a 36V system, the caravan will remain 12V (too hard to change) but 36V will be used to power a 36V/240V inverter which will then provide 240V for everything.
My question is:
Is anyone using a 36V system and what inverter are you using and does it have EMC emissions approvals or an Australian RCM approval?
Just interested as to why 36V Mike? Just a quick google says 36V mainly used for golf carts, electric boat motors and some power tools.
Apart from running an inverter, what else could you use it for, as you say caravan is 12 V. Is the 36V inverter better, I'm thinking it would draw more power.
Pardon my ignorance and dumb questions, just wondering why?
Cheers Bob
-- Edited by Bobdown on Friday 27th of January 2023 03:01:40 PM
My experiments to date lead me to believe the optimum battery capacity for my situation is around 3.5kWh to 4kWh. A 120Ah lithium battery has a usable capacity of around 1.3kWh so three of them would be ideal but, of course 3 x 12 = 36V - hence my interest. I could go for four 12V batteries (48V) but this adds $1k, 15kg and extra room to the situation. Another alternative is to go for 12 individual cells, which is probably a better solution.
Going to a higher voltage has the significant advantage that it reduces current; eg. a 1500W microwave requires 125A at 12V but at 36V only 42A. This has the advantage that it makes the electrical installation much easier, reduces the fire risk and improves reliability.
Unfortunately 36V is not a common DC supply voltage so I may end up with 48V anyway but I thought I'd put feelers out to see if anyone is using it.
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Edit:
To expand; I'll leave the caravan at 12V as it's far too much trouble to change all the caravan internal stuff (radio, lights etc) to anything else and will continue to do as current which is to let the original caravan roof mounted solar panel do its thing but, via a time switch, use the external system to provide 240V for two hours (whatever?) per day to the caravan to top up its 12V system. This is a little wasteful of energy but, generally, I have enough solar not to worry about that.
-- Edited by Mike Harding on Friday 27th of January 2023 06:26:02 PM
__________________
"I beseech you in the bowels of Christ think it possible you may be mistaken"
Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland
>Run the van 12V through a 36V to 12V step-down converter.
I would not do that; a 36V/12V power supply will have losses at least equal to those of an inverter and is an unnecessary expense and complication. Better simply to use 240V to run the whole van, as I do currently, and allow that to charge the van's 12V battery.
>Have the solar panels in Series Array to solar controller at 36V.
I prefer panels in parallel for my style of bush camping.
>The question being... What is the overall benefit over a complete 12V Parallel system?
12 volt systems have a number of downsides:
High current with consequent power losses in cables
Increased fire risk due to high currents
Very low tolerance to voltage drop caused by those high currents or sagging batteries
To be honest Dick0 it's hard to thing of a single benefit to a 12V caravan system and I'm sure the only reasons cars/caravans run on 12V is historical and the fact it only needs one battery. Most trucks, I think?, run on 24V or 48V.
I'll continue to examine the 36V route but I'm wondering if it may not be worth absorbing the extra battery dollar/weight/space cost and going to 48V which is a more common DC supply voltage. Watch this space :)
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"I beseech you in the bowels of Christ think it possible you may be mistaken"
Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland
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Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan
Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.
12, 24 and 48 is well covered with equipment, other voltages, not so much.
I have a 5000VA system running on 24 volts and can't see any technical reason for going to 48V
Their system looks very good and well designed however it is aimed at caravan/RV OEMs and it will be very expensive I have no doubt. Interestingly they run at "51.1 volts" - why such an odd voltage I do not know but it is sensible, caravans/RVs should be wired at 48V with a few 12V cigarette lighter sockets available.
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"I beseech you in the bowels of Christ think it possible you may be mistaken"
Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland
