120v Fridge Questions
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kerismatic
Member
highdesertranger said:
Dedicated battery just for the fridge. Not worried about the other stuff right now.
kerismatic
Member
Weldman said:
Got one! That was the plan all along. Good to know someone else thinks so too.
Seminole Wind
Well-known member
kerismatic said:
i have a very similar dorm fridge 3.2 cf 2 door fridge freezer. dont know about yours but mine is a manual thermostat, no electronics. so there are no phantom loads, if the fridge is off there is no consumption.
mine runs a consistent 0.7 amps @ 120v ac (from inverter) amp hours per day vary depending on how i use it. 35-40 amp hours out of the battery (including inverter over head and conversion inefficiency) when only storing cold/frozen food and just going in and out a couple times for meals. goes up to 50-55 amp hours is i use it for freezing purchased meat or making ice blocks alot and chilling room temp beverages
i run it off my victron phoenix inverter 375 watts pure sine wave. when i first plugged it in the inverter would not start the fridge. it would trip around 7 amps draw on the start up surge. we ran it off a generator and saw if was pulling about 9 amps start up draw. then we installed a "hard start kit" http://tinyurl.com/y4whm9k9 and my little 375 victron inverter starts it every time with about a 6 amp surge.
i have a very large battery bank, but would not run the fridge on less than a pair of golfcart batteries to have some overhead incase of rainy days or parking in the shade. also as the batteries get older and lose capacity they will still get the job done just with less extra reserve.
i would consider in a good sunny climate 200 watts as my minimum solar for such a system, especially if panels are laid flat and on a pwm controller. in the best conditions. if in the northern areas for the winter or in cloudy areas i would up the solar considerably and have an alternative charge source as well, engine alt or genset.
as you mention not wanting solar yet, i would highly recommend a decent "battery to battery" charger in the 30-60 amp range. these will recharge your batteries much quicker than just coming direct off the alternator of the car/truck and will get them fully charged instead of taking hours and hours of driving and still not fully recharging the house batteries.
if your trips include driving each day with just over night stops you could get away with the smaller battery to battery charge and a smaller rv type battery to get you through the night. but if you want to stay camped in one spots a few days then at least a pair of golf cart batteries and a larger battery to battery charger will let you have a couple days between having to run/drive your rig
Seminole Wind said:
Thanks for the info here, I had not seen these smaller 'hard start' kits...the larger capacity ones I have seen are for roof air units and they cost around $300.
Seminole Wind
Well-known member
ya, this one was under $15 and super simple install just unplug wires from compressor plug the unit wires onto the compressor and then plug original wires on to unit. took longer to read the instructions. the company has other sizes and was helpful when i contacted them to confirm i had selected the right size
kerismatic
Member
Seminole Wind said:
Yes very good info!
It gives me ideas to explore and that causes me to learn a lot more.
I can't just do what someone says, I need to understand it as much as possible and question everything. So I really appreciate all the details!
Seminole Wind
Well-known member
kerismatic said:
happy to help. if you get into it enough. there are ways to compensate for the horrible power factor these small fridges are subject to and in the process shave around 30% off your daily amp hour consumption from the battery. i did all the math and figured out the parts i need for mine but i have not ordered them yet. i will post up when i get around to it and let folks know if it worked
A note: Some inverters have a power saver or 'sleep' mode. On my 700 watt PSW GoPower, about every 4 seconds it pulses the AC output line, looking for a load. If one is found, then the inverter kicks on and operates the load. When the load is removed, about 10 seconds later, the inverter resumes power saver mode. The threshold is adjustable from (IIRC) around 20 watts to about 150 watts, more or less.
This means that it can power a fridge that has a mechanical thermostat, like my little dorm fridge, ONLY when the thermostat calls for the compressor to engage.
It works VERY well.
You can deactivate the power saver mode so that the inverter will stay in normal mode, so you can operate small electronic items that won't or can't trigger the unit, like a small lamp or radio, electic toothbrush, laptop charger, phone charger, whatever.
This means that it can power a fridge that has a mechanical thermostat, like my little dorm fridge, ONLY when the thermostat calls for the compressor to engage.
It works VERY well.
You can deactivate the power saver mode so that the inverter will stay in normal mode, so you can operate small electronic items that won't or can't trigger the unit, like a small lamp or radio, electic toothbrush, laptop charger, phone charger, whatever.
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