We don't plan to do a lot of unpowered site camping but would like the option. hubby uses a CPAP machine so we need some kind of power supply.we can get one from the mob that supplies the CPAP machine but now we don't know what to use as the power source. so is it best to use a battery or a power/ jump start thingie? not sure if the inverter from the CPAP mob is a pure sine wave one but it seems from what I read here that it's the best to use. we have no idea what we are looking at when we go looking/ shopping and frankly don't have a lot of faith in staff at various stores- I get the feeling they just want to sell us whatever is in stock.
We have a little fridge as well but not too concerned about running that as we could always use an esky type setup on the odd nite that we go unpowered.All advice would be gratefully accepted as we really don't have a clue!
My first thoughts are that the safest option would be a pure sine wave inverter. A 300 watt unit would be fine. Supercheap have them available for I think around $130 (don't hold me to it, best check it out). Assume that an inverter is not pure sine wave unless it is specifically stated. Also consider that you may wish to use the inverter for other purposes.
That said, If the CPAP supplier also supplies an inverter that they say is ok then you should be able to take their word it is. Also ask about any warranty issues just in case they insist on using "their" inverter.
Re the Jump Start Thingie I suggest you go for the largest available to get the maximum capacity. I have a 1900 amp Unit from Supercheap that they claim has an amphour capacity of 30 ah. I have tested it with my Bushman fridge and found this figure to be realistic. As I'm not familiar with the power requirements of the CPAP I'm unable to give you any idea how long it would be before you have to recharge it.
The best option for a car fridge is an Engel/Waeco style compressor type unit (or a "Bushman" such as mine) connected to a dual battery system installed in the car. You could then also use this to power the inverter for the CPAP machine. If your budget doesn't extend to this at this stage then your fallback position is the esky as you suggest. Powering the bar fridge off the inverter as well would not be an option as it would probably risk flattening the battery before the night was out. The inverter may not have enough "grunt" to start the fridge anyway.
As for your other post re power to the tent, I'm sorry I cannot help as last time I suggested an option that was sensible. practical, and safe, I was caned mercilessly by the forum's resident nitpicker.
Thanks for that info re Supercheap. It's a pity there isn't a mandatory standard to prevent the selling of these non-isolated inverters.
I'm not challenging your claim (I'm not in a position to do so) but purely as a matter of general interest I'd be interested to know where you obtained this information. Is it a warning that comes with the inverter or the result of an independent test.
That said, I'd play it safe and assume an inverter isn't isolated unless it were specifically stated that it were.
-- Edited by jimricho on Wednesday 30th of November 2011 07:39:07 AM
