#182619  by Grant4747
 Thu Jun 23, 2022 10:41 pm
I am interested in purchasing a new portable Dometic pure sine wave generator https://www.smartmarine.co.nz/product/2 ... gJ0MvD_BwE mostly for battery charging through a Victron multiplus 12v/3000w inverter /charger 70amp as a backup to get through 3 months of inclement winter weather.

I plan on having a Dc to Dc charger also when occasionally on the Rd, we don’t want to run the engine just to charge batteries while stationary though.
We will have 600ahr lithium with 2400w solar

I guess what I’m asking …..is spending $1300 on this type of generator and capacity a good idea or not so much.
I don’t expect to charge the batteries to 100% just enough to keep us going until the next sunny day.
 #182620  by petercw
 Fri Jun 24, 2022 9:16 am
The shirt answer would be yes... But .. it depends what you are planning on using during 3 to 4 days of rain, cloudy days.
If you work out what that is in power usage by the time of the day then the answer will appear. Your overnight usage is of particular importance.. and what are your big users..
 #182624  by Nut17
 Fri Jun 24, 2022 9:50 am
We are pretty heavy users of our stored electrical energy, but with a little budgeting of our use we have found our set up more tan adequate. Your system has double our solar and 50% larger battery capacity of our set up and I would be surprised that any other charge source would be required - Even in Otago winter months. We can (with some energy use budgeting) survive up to five consecutive cloudy winter days before needing to hit the road and give the system a boost with my 80 amp DC DC charge set up.
See our specification in my signature below.
 #182629  by Grant4747
 Fri Jun 24, 2022 11:24 am
Thanks Chris looks like you’ve done the real life experimenting for us which I’d prefer over somewhat confusing figures.
Am curious to know in what order you’d drop off the user list.
Coffee machine? Toaster or change from induction cooking to gas.
I forgot to mention we live permanently in ours with a decent sized inverter fridge being the priority to run with a 5kw diesel heater equally so when we get to do some South Island touring in winter.
We would like to buy a combination induction gas hob like yours and to prioritise power use over gas so we don’t introduce more moisture and fumes than we need to.
Hot water is likely to be gas only in winter and sun power only in summer.
We aren’t the type that has to have every creature comfort all of the time so can and will adapt where necessary.
My thoughts if we are going to spend some serious money on upgrading our little power station we should utilise it as best as possible and try to design it for most weathers, situations, and geographic locations.
 #182633  by Nut17
 Fri Jun 24, 2022 4:09 pm
Over the summer months we are able to heat most of our hot water requirements as well as cooking with induction, boiling the kettle, hair dryer, toaster, microwave, etc. all either direct 12 volt or via our 3000 watt PSW inverter. Our fridge is a 12 volt compressor model and has approximately the same energy requirements as the Samsung inverter model we had in our Jayco. (55 - 70 AH / 24 Hrs.) We simply resort to gas for hot water and stove top cooking and limit the use of the microwave and toaster when in conservation mode. The coffee machine takes priority though and it does only consume 3 AH to brew a double shot long black from cold ;)
With our recent trip to Ngawi, we had three days and nights with very little solar from the heavy overcast conditions. Our 400 AH battery had dropped to 225 AH remaining by mid morning on the third day. We could have survived two more days without panicking :-T An hour on the road back to Martinborough put 100 AH back into the battery with the combo of about 30amps from overcast solar and 80 amps from the DC DC charging.
 #182636  by DunSpannerin
 Sat Jun 25, 2022 7:52 am
Nut17 wrote:
Fri Jun 24, 2022 4:09 pm
..... Our fridge is a 12 volt compressor model and has approximately the same energy requirements as the Samsung inverter model we had in our Jayco. (55 - 70 AH / 24 Hrs.)
Hi Chris
I am reading this usage as 70/24 or 2.92 AH. What make and model fridge do you have

 #182637  by Nut17
 Sat Jun 25, 2022 9:28 am
This is the fridge I installed last December. Dometic RUC 6408X https://www.dometic.com/en-nz/outdoor/n ... x-_-186741
It has a variable speed compressor so is impossible to calculate total energy requirements without measuring the total used over elapsed time. It typically consumes about 30 - 35 AH from sun down to sun up. It does have much longer without the sun at this time of the year, but the much cooler ambient temperature compensates for this.
My preference would still have been to install a Samsung inverter 230v fridge the same as I fitted to our last Jayco caravan, but the rebuild of cabinetry to accommodate it was too prohibitive. The Dometic RUC6408x has the identical cabinet measurement and rear ventilation requirement to it's 3 way gas sibling that we removed. This made the installation a pretty simple job.
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