Scrumbag Posted August 1, 2021 Report Share Posted August 1, 2021 Hi folks, Question, has anyone got a solution for battery back up for Freezers? Best wishes, Scrummy Quote Link to comment Share on other sites More sharing options...
martin_b Posted August 1, 2021 Report Share Posted August 1, 2021 Computer/ server UPS? (will be expensive.) When I kept marine fish I allways had a petrol generator around in case of emergency but it was so useful I kept it once the fish had gone. Quote Link to comment Share on other sites More sharing options...
GT3_richy Posted August 1, 2021 Report Share Posted August 1, 2021 Living in the sticks and having fairly regular power cuts, we have a small Honda petrol generator - life saver, if a bit of an investment initially. Quote Link to comment Share on other sites More sharing options...
Popsbengo Posted August 1, 2021 Report Share Posted August 1, 2021 1 hour ago, Scrumbag said: Hi folks, Question, has anyone got a solution for battery back up for Freezers? Best wishes, Scrummy Generator is a simple solution but auto-start is a complexity so if you're not at home when the power cuts you could have no benefit without. If you do want battery back-up have a look at marine inverters, typical set-up in boat uses around 200-300 Amp-hour of leisure batteries and an inverter (Mastervolt and Victron are the best but expensive, Sterling Power are adequate). Auto switch over to batteries is easy to achieve (and battery charging is simple when the mains is on. https://www.victronenergy.com/inverters-chargers Quote Link to comment Share on other sites More sharing options...
phoenix Posted August 1, 2021 Report Share Posted August 1, 2021 How much power does you freezer consume (i.e the watts on the rating plate), and how long would you anticipate it needing to run on batteries? Also is it a chest freezer or an upright because chest freezers keep their temperature longer because the cold air stays inside the box whereas with an upright, every time the door is opened the cold air Only then can you work out what size of battery pack you'll need Quote Link to comment Share on other sites More sharing options...
Scrumbag Posted August 2, 2021 Author Report Share Posted August 2, 2021 Sorry folks, should have given a bit of context. Our freezers are in a garage which has a communal electricity supply for the block. Occasionally the circuit breaker for the Garage gets tripped and it doesn't get reset until the estate manager / porter does their rounds on a Monday morning. So even a few extra hours of power would get the freezers through a weekend and less risk of loss. So, thoughts welcome. Scrummy Quote Link to comment Share on other sites More sharing options...
Popsbengo Posted August 2, 2021 Report Share Posted August 2, 2021 35 minutes ago, Scrumbag said: Sorry folks, should have given a bit of context. Our freezers are in a garage which has a communal electricity supply for the block. Occasionally the circuit breaker for the Garage gets tripped and it doesn't get reset until the estate manager / porter does their rounds on a Monday morning. So even a few extra hours of power would get the freezers through a weekend and less risk of loss. So, thoughts welcome. Scrummy doesn't sound like a generator is an option. What's the current consumption from the rating plate(s) ? The best way to work out the energy used would be to get one of those cheap plug-in energy monitors (https://www.amazon.co.uk/Decdeal-Electricity-Consumption-Analyzer-AC230V-250V/dp/B07QZYPQ4M/ref=sr_1_9?crid=36UT71OG4BIY8&dchild=1&keywords=energy+monitor&qid=1627893024&sprefix=energy+monitoring%2Caps%2C165&sr=8-9) and see what the typical drain is over a weekend. From that it's straight forward to work out the battery capacity you require. A good time to do it would be a warm summer's day - most draw on power Quote Link to comment Share on other sites More sharing options...
Richiew Posted August 2, 2021 Report Share Posted August 2, 2021 Basic ups system . Two sockets needed one for charging battery system and one to power the fridge and relay . Big enough relay contacts rated for amps draw of fridge . Wiring shows relay de- energised as in 240 volt fail . 240 volts come back on and relay energises and breaks dc power to inverter and the output of the inverter . Charger now tops up the battery. Should be able to get gear from caravan shop or electronic catalogue RS COMPONENTS Quote Link to comment Share on other sites More sharing options...
Popsbengo Posted August 2, 2021 Report Share Posted August 2, 2021 Richiew, do you have any formal qualifications for promoting that home-brew solution? It's unsafe. no fusing neutral link between inverter & incoming mains may well trip the RCD at the dis-board Incorrect choice of relay, in event of failure, could result in a back-feed of 240V AC exported out of the premises putting persons at risk of death there are regulations regarding auto switching systems connected to incoming mains services Please don't use this drawing. I am a fully qualified electrical engineer (not a sparky), this is not safe. Quote Link to comment Share on other sites More sharing options...
Richiew Posted August 2, 2021 Report Share Posted August 2, 2021 It’s only for basic understanding . Fusing in the plug s not good enough ?? . Of course real made equipment has lots of safety devices solid state switches fly back current diodes thyristors etc . Buy a purpose made bit of kit . Could run fridge off the inverter fed from batteries and 240 v charger as a straight through unit then don’t need relay and no problem s with mixing supplies?? How’s that idea Quote Link to comment Share on other sites More sharing options...
Popsbengo Posted August 2, 2021 Report Share Posted August 2, 2021 56 minutes ago, Richiew said: It’s only for basic understanding . Fusing in the plug s not good enough ?? . Of course real made equipment has lots of safety devices solid state switches fly back current diodes thyristors etc . Buy a purpose made bit of kit . Could run fridge off the inverter fed from batteries and 240 v charger as a straight through unit then don’t need relay and no problem s with mixing supplies?? How’s that idea No mate it isn't at all. Purpose made kit meets necessary design criteria for circuit interruption and protection. Your 2nd suggestion could work and could be safe but would be quite inefficient. There are purpose made inverter/chargers that can do, in principle, what you suggest but this can be an expensive solution. Quote Link to comment Share on other sites More sharing options...
Scotch_egg Posted August 2, 2021 Report Share Posted August 2, 2021 Given the Op’s situation, what about a device that alerts him to the loss of power so that action can be taken to put it back on easily enough. Quote Link to comment Share on other sites More sharing options...
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