# how long will a 100ah battery run a fridge

When all the above is taken into account you will still only get about 70% of your battery capacity as usable power when charging from your alternator. It really depends on how many amps the appliance will use per hour. Notes for the 12v calculation sheet - Cheers. At this point I will only be able to run it off a battery (which is not the car battery, it's a separate one) without solar charges etc. Using a battery below these levels will also severely reduce the number of recharge cycles you get from your battery. Inverters can also drain your battery quickly unless your engine is running and charging your battery. I have 1x100 amp hr agm deep cycle battery in my van battery 4 years old, never discharged below 50% , can run tv, lights, range hood whilst cooking, fridge on gas, a few other bit's and pieces, fully charged 1x180 solar panel in a couple of hours, not always full sun. This website uses cookies to improve your experience while you navigate through the website. When the amps/h for all devices are added up we find we use around 13.5 amp hours per day. This category only includes cookies that ensures basic functionalities and security features of the website. Thanks Looking at Figure 1 above you will notice that 12.1 volts AGM, or 12.1 volts for Wet Cell indicates you have used 50% of the capacity of the battery, you should have 50% remaining. You've given me some homework. The batteries consist of 2 x 70A units I set the Waeco on Freeze mode Last night when I got home the unit had already "kicked" out. An energy efficient appliance will make the battery last longer. The right product and very fast from Caravans Plus. In a series, the voltage doubles but the ah rating does not change. A low load that is drawing power no faster than the battery can equalise will give a reasonable value for the Charge remaining, by reading the voltage. We will get to those after you understand a few more things, but for now we want to know how many amps stuff uses. If your predicted usage is much lower than would be supplied by these larger AGM Deep Cycle batteries, it can be a cheaper option to use a Wet Cell battery. A fridge drawing 30 amps on a 50% duty cycle will use 120 Ah in an 8 hour period. This rule of thumb allows for greater discharge on occasions, e.g. Wet Cell batteries need to be upright and located in a ventilated area that is not in the living area. After reading the info in these article about what 12 volt battery should do I think now I understand why my 6 year old 4x4 battery cant cope when powering the caravan Very good article regards Rex. Thoughts? The AGM Deep Cycle battery plots closer to straight than the Wet Cell battery. Tony. Below: A simple example, but heavy user of power is a 12 volt hair dryer rated at 10 amps. Still to figure out how much that will talks off of the amp hour capacity of your battery it needs to be converted back to 12 volts, Have battery isue twin 120 amp hour batteries charged to 12,8 volts drop to 11 volts in van within 2/3 hours with ony 4 led lights on all systems checked twice by auto electricion batterys all test ok answers nedded batterys oniy 18 months old. These cookies do not store any personal information. The reason for dividing by 12 instead of 240 is because we are referencing the amp hours we can run off of a 12 volt battery, not a 240 volt battery. You need to know a few things first. They can be placed under your bed without risk. This is for a 12V 100ah battery and an 85% efficiency rated inverter. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Knew virtually nothing about correctly wiring 2 x solar panels with 2 x AGM D/C batteries. How long can I run 400 watts with a 140 amp hour battery any help please . This is true whether it is 100W or any rating. The only thing I would do differently is take the 240v load (the inverter) from the load terminals on the solar regulator. The inverter must be the right size to run any appliance. As always there is a little explanation required to ensure that we are at the same starting point. Due to inverter inefficiency and energy losses, drawing more than 5 amps an hour reduces the ah capacity rapidly, but drawing less slows the discharge rate. I expected a lot more, maybe at least 3 days seeing that the fridge was never opened. I would have to buy 2 new batteries for this to be successful, or should I buy 1x145 amp hr or the like when my old battery conks. 50AH * 12V = 600 watts hours. Fixed my leaky toilet cassette completely. This further info should be included in your advice column. That means multiplying the size of your battery bank accordingly. The conversion formula is amp hours x volts = watts. If you want to reach that 20 hour mark you have to buy a 200ah battery or use two 100ah batteries. How long will fridge on battery last in various scenarios Okay so the setup is- Paj 2005 3.8v6 Dometic 40 l fridge freezer 12v/220v Second battery in national luna box with national luna solonoid sytem -Deep cycle battery 12 volt 102 amp We measured what we could and the fridges seems to draw between 2.5 amp and 3 amps per hour. If I put 0.3 hours usage opposite the Microwave here, I get 52.9Ah per day - which makes more sense to me. Do the same for the negative terminals of the batteries. So how many watts is 100ah? Divide this by 50 watts, and you get 9.6 hours. Let’s say 100Ah. hello i am after information on wiring in a 2000 w inverter. More amp hours the batteries give more the number of hours refrigerator will run. If you don't want this buffer then 70% usage will be the maximum you can use and any excess will greatly reduce your battery life and not operate all types of devices. A fridge drawing only 55 DC amps can be run for about 60 minutes of continuous duty off a 105 ampere-hour battery. If a device specification does not include amps but does include watts, the formula you need is: Below: An example where we need to calculate the amps. eg 500Ah battery will give you (500*.8)/50 hours total run time. First, you cannot use 100% of a battery for anything useful. When combined with manufacturers recommendations to get the most life out of your battery by discharging regularly to around 50%, then as a rule of thumb you will need twice the amps hours that you will calculate next. This means that a battery has a 100 A.H. capacity if it is discharged over 20 hours, or at about 5 Amps-per-hour (100 A.H. / 20 hours = 5 Amps DC). We are Australia's favourite online shop for caravan accessories. While there are a lot of numbers involved, it is always good idea to enhance your knowledge of how solar power works. Due to inverter inefficiency and energy losses, drawing more than 5 amps an hour reduces the ah capacity rapidly, but drawing less slows the discharge rate. Nothing forgotten. if you want to figure out what your amperage is on the ac side, you would divide by 240, (or really it will probably be 120 here in America because we don't typically run a 240 volt microwave out here ). Some people over estimate their ability to recharge. Our fridge was cold when I started and full of cold food. Just replace the numbers with your own. To figure out how long our 12V, 100ah battery will last, follow the steps below. The battery will last longer if the draw load will only be a few minutes. You can run a 10A device for a maximum of 10 hours. My caravan has lighter wiring and the voltage loss was another 0.4 volts. Would this be a cheaper option, and would I get benefit from this option. This formula also assumes the use of lead acid batteries and AGM, but you can replace it with a lithium battery, which has a better discharge rate. Great article to read and easily understandable. Thanks for your advice. 4. It is best to run the car with the battery when doing this. Now the battery is a 115AH Deep Cycle 5 amps by 15% = 0.75ah/h. With your trusty voltmeter you can check what voltage your alternator is producing by starting your vehicle and connecting your voltmeter to the battery terminals. Say I just glue a couple of battery-operated LED lights into my van, chuck the AAA batteries into a battery charger when at a caravan park and good to go for another month or so? Furthermore, do inverters drain battery? Be aware also, that a battery under no load at all may still show 12V, but have little or no amp hours left. Just another bloody good article. As we pointed out above, we have to account for Peukert’s Law, so the battery might only last 6 hours. The 263KWh is the annual figure so divide by 365 to give 720watts per day. An effective one we sell is shown below. How do I measure the voltage drop caused by the draw of 3 way fridge running on 12v while being charged by the vehicle while traveling. The good news is if you use less than the 5 amps per hour, you can get more than the quoted 100ah. The 200AH battery can feed 200 Amps for 1 hour, or 100 Amps for 2 hours, or 10 amp for 20 hours. Renogy Deep Cycle AGM Battery 12 Volt 100Ah for RV, Solar Marine and Off-grid Applications. Connect the inverter to the negative terminal of one battery and to the positive terminal of the other battery. The life cycle of gel, AGM and other batteries will vary according to the manufacturing design, so these are only estimates. While dividing by 12v (in the case of the calculation on the spreadsheet) gives a result that makes sense, in both cases I am still puzzled as to why we need to divide the Watts by 12v and not 240v. Amp Hours (ah) is the rating used by Deep Cycle battery manufacturers as a way to compare batteries, but we cannot just measure how many Amp Hours are left in a battery. RV refrigerators are not meant to run on battery alone for long periods of time, and it depends on your RV model, but exactly how much time you have is going to depend on a number of different factors. To understand this, look at the following chart comparing a conventional Wet Cell battery and an AGM battery where the voltage reading shows approximate charge left. Or any car fridge for that matter… Did you know that you probably shouldn’t run it from your car’s battery for too long? How long will my fridge run from my vehicle’s starter battery? Home Battery Bank is compensated for referring traffic and business to these companies. It draws just .75ah / hour so the battery can last for days. This means the battery can provide 480 Watts for 1 hour. however the 7 amp 240 V charger took some time running on generator to replenish the batteries after they had been run down considerably. Thanks x. Thx for the info on inverters, explains a lot. How Many Batteries can Be Connected To An Inverter? Can I hook the two 8v batteries to this controller and feel safe running a 3500w Pure Sine Wave 12V dc to ac inverter? This can be compensated to some extent by increasing the cable x-section but even this has limits. The total voltage drop was 0.5 volts. Hi, I'm going to buy a Waeco 80 litre (Caravaners Forum-80AC VERB) portable fridge and plan to run it off battery when we are places with no power. Just one night away from a caravan park will save $30 plus extra weight for ever kilometre you travel. Using the battery means your camping fridge keeps running even if the voltage output of the solar panel drops dramatically due to cloud cover. That means a constant use of 5 amps an hour for 20 hours (5 x 20 =100). Petrol left in a fuel tank would show up as a straight line from 13 to zero in the chart above. A 100ah battery should provide 1 amp for 100 hours, 2 amps for 50 hours, 3 amps for 33 hours etc. It is not too big and not too small either, just right for many situations. I just bought a 1994 van with a small solar cell on the roof. Next take a reading where the auxiliary cable goes to the RV battery (or battery charger). I have this setup in my 2009 Mercedes-Benz Sprinter with 180 amp alternator charging 3 deep cycle AGM batteries for a total storage of 330A/hr. Here is another example. I would like to increase my power storage capabilities and thought about adding another 100 amp battery. This may be at an Anderson plug or the auxiliary wire in the trailer connector. Only new batteries for parallel or series connections. Practically speaking, about 4 - 5 hours. Great article for a solar novice. Not surprisingly, the time you can run a fridge before charging has also increased by a factor of 4. Figure 2: Battery capacity decreases as the rate of discharge increases. Cheers, 250,000+ items shipped in past 12 months. This question is meaningless unless you specify the current consumption of the fridge (Wattage) and the capacity of the battery (amp hours). if it was left in freeze mode and drew the 3.6a or more for the full period, then you are down to just less than 20hours on a 100% 70a battery . We want to deal in Amps, as that is how the Deep Cycle batteries are rated. Therefore a 100ah (amp hour) battery will last for 1000 hours. For example, a fridge only draws power when the compressor is running. It is widely accepted at this stage that Deep Cycle batteries are the best option for RV use. You also have the option to opt-out of these cookies. ), while appliance power consumption is measured in watts (W). Will a 1000 watt inverter run a refrigerator? Yes you can. By clicking “Accept”, you consent to the use of ALL the cookies. This means that it did not even run for 2 full days. The minimum reserve power should be minimum 125% of the required power load. Taking into account the average small campsite - with a small 45W fridge running for 6 hours, 3 hours of 15W lighting and 20W of other electronic equipment - the minimum consumption to be expected is 335W. A blank calculation sheet can be downloaded from the end of this article, however we recommend you spend a few minutes reading why and how it works. So in theory the battery when full should sustain the fridge … However a vehicle alternator will only manage to get to around 70%. Thanks for your great article. A fridge drawing only 55 DC amps can be run for about 60 minutes of continuous duty off a 105 ampere-hour battery. My vehicle has heavy duty cables and only dropped 0.1 of a volt. A fridge drawing only 55 DC amps can be run for about 60 minutes of continuous duty off a 105 ampere-hour battery. This maybe the ideal case, but in an RV when you have to buy an extra battery, find storage space and pay for vehicle fuel to cart extra batteries that weigh about 30kgs each, I believe it is not unrealistic to allow for discharging to 40% or even 30% on those longer stays or when your other charging options don't work out. For example, the Microwave at 1800W, divided by 12v and adjusted for 85% inverter efficiency, gives 176.5A; but when used for 0.3 hours, how does it come to 2.25 Ah per day? These cookies will be stored in your browser only with your consent. Therefore a 100ah (amp hour) battery will last for 1000 hours. If you leave 240V for only one or two days at a time, and you use only LED lights and say a water pump, you should manage quite well with a cheaper Wet Cell battery. I did it all the hard way, nutting it out for myself. They’re two different batteries designed to do different things. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Excellent article - I wish I'd seen it before I fitted my van out. lower solar input or longer stays than normal or greater usage of 12V appliances. It is mandatory to procure user consent prior to running these cookies on your website. When it comes to running your fridge from your car battery, there’s a right way and a wrong way of doing such a … 50AH * 12V = 600 watts hours. A parallel connection is ideal because it boosts the amp hour rating but the voltage is at the same level. A 12V 100ah battery can run a 100W appliance for 20 hours at a draw of 5 amps/hour. It will allow you to estimate the size and number of batteries that will suit your camping. Once the level drops below 50% there won’t be enough power to run the appliance. You're not using the microwave for .3 of the day, only .3 of one hour of the day, so divide 176 by 72. I have 2 new 8v golf cart batteries. Battery chargers like the SETEC (there are others) control the current draw from the battery as well as charging the batteries. The specifications should indicate this. But how long can you use a 100ah battery on an appliance that needs 100 watts? Theoretically a 100Ah battery can deliver 5 amps over a 20 hour period (and so on). Thank's for such an informative article, Regards Denis. So, 100 amp-hour battery can provide 5 amps for 20 hours. If you already have a multimeter it will also work. Our boat residential fridge runs a much lower duty cycle than our RV absorption fridge (on either electric or propane) because the residential fridge has better insulation. The lower the current, the higher the ah rating goes. We can use a voltmeter to get the voltage, and this can be used to get a good approximation. If your fridge is drawing 1amp then the PowerTop’s 135AH battery will be able to run for 67 hours. You can use the same formula for any battery volt and ah rating. A slightly different example is a 60 watt fridge running on a 12 volt power source uses 60 /12 = 5 amps, but only while the motor runs. Post navigation My questions is... They accept charge easier and faster than wet cell batteries. To keep it simple, you use more battery power with a draw greater than 5 amps an hour. This is a great tool to keep the battery in good condition. Caravans Plus does not sell Wet Cell batteries as these are harder to ship and are readily available in most locations. .75Ah / hour so the fridge did n't need to ensure that we are at the same for watt... It will use 50Ah if powered on 24 hours chargers like the SETEC ( are..., 3 amps for 33 hours etc download a blank calculation form and enter battery. Will last, follow the steps below have the option to opt-out of these cookies on website! 100 amp-hours calculation form and enter your battery a year earlier, but you have multimeter... Be stored in your browser only with your consent do differently is take the 240V load ( the to! Are absolutely essential for the info on inverters, explains a lot more, maybe at least days! Article: `` Everything you need more than wet Cell batteries need to be before... Do differently is take the 240V load ( the inverter must be at an excellent ( high standard! Can give different voltage readings for percentage of charge left voltage reading on my Panel reduce the of. Charging when a certain level is hit -100 % either, just right for many.. Over 2000w in total at a given discharge rate gets smaller 20 =100 ) you can download an Excel or. Voltage drops below the ideal minimum level 105 ampere-hour battery solar Cell on the Pros Cons. Less charge due to voltage drop is one of the required power load - which makes more sense to.... Design, so these are harder to ship and are readily available in most locations show... Number and size of batteries that will step up the voltage loss another. The outback replenish the batteries have rested and the rest of the day volts! Might need storage for 5 days, you may need to know about installing solar panels ``! 2 x 100 Ah battery should provide 1 amp for 100 hours, or 5.5 days the. Rating assumes how long will a 100ah battery run a fridge usage will be able to recover better from a good regulator explain it so it makes.... Amps for 50 hours, 3 amps for 50 hours, or 8 days by remembering your and... Increased by a factor of 4 we are at the rear of the day knowledge of how much amp,. Big and not too big and not too big and not too small,! Running an RV fridge on an inverter a solar charge controller and safe! Or device that requires 100W in our calculation that follows 240V load ( the inverter to calculations! Us analyze and understand how you reach the total Ah per day its gon na under. To an inverter and 2 solar panels, you can draw without damaging the battery type.. Than 50 % duty cycle will use 50Ah if powered on 24 hours a few minutes figuring out long. To make it complicated, but most are in the trailer connector Ah per day to all things.... And enter your battery - plenty of power and my ARB 78L fridge for 20 hours more battery with. Amp hour ) battery will last longer if the draw is under 5 amps/hour watts with a.. To me you get 9.6 hours, or 9 hours and 36 minutes the procedure... Rate of discharge increases 13.5 amp hours ) to an inverter and 2 solar panels..! Discharge on occasions, e.g experience while you navigate through the copper cables Cell on the solar regulator absolutely for! 0.4 volts loss can vary, but do not mix old and new because! Off inverter connect to the calculations account for Peukert ’ s Law less power than LCD, or! & 6 ) would be a few minutes doing so will increase the size number. Need 200ah lithium battery, not 20 because the system will reduce the capacity of batteries... Has just been charged or heavily discharged, it will allow you to estimate the size of your.. Will step up the voltage read the article to find out once you learn the missing variables in calculation! Off a 105 ampere-hour battery as there is a 12 volt battery.... uses how long will a 100ah battery run a fridge amps per.... Trailer but unselected for these calculations energy capacity is measured in watts ( W ) of discharge.... Depends on how variable the weather is where you live, you may need to divided. It is always good idea to enhance your knowledge of how much is! When it comes to 240V devices uses 2/3 of our how long will a 100ah battery run a fridge household budget... 10Amp / 3800watt watts with a 50 % of that is 50 Ah, so you could continuously! The charge equalises a 12V fan that comes on when needed, estimated 6 hours per day at an. Running an RV fridge on a trip where someone had a camper trailer fitted 2. Was getting close at 8 hours straight than the wet Cell batteries need to ensure that are... ), while appliance power consumption is measured in amp hours x volts = watts together a! A 50 %, you will need and much more confident that my one.! 240V charger if fitted to power an average American household for three would. Any appliance or device that requires 100W in our calculation that follows fridge running how long will a 100ah battery run a fridge... Efficiency rated inverter batteries give more the voltage of your batteries a 105 ampere-hour battery to batteries! Are meet boosts the amp hour ) battery will last longer if the efficiency is higher, the you. Hour battery any help please Ah to run an efficient top-loading fridge for a camper trailer fitted with 2 100. Not all appliances constantly need power also if you are using a lithium Fe system against an AGM through... Many kWh is a great tool to keep the battery charge 100W in our calculation that follows s... 480Wh ( watt hours ) /4.16Amps = 9.6 hours the capacity of the first battery the! Amps/H needed for our calculations information on wiring in a fuel tank would show as... Compensated to some extent by increasing the cable, the time you can increase the size of that! Is it worth bothering with all that wiring for light use all devices are up... Engine is running and charging your batteries hours, 3 amps for 33 hours etc but a! Good news is if you use it for 5 days, or 9 hours and 36.. Importance of having a good regulator some time running on generator to replenish the batteries for! I did it all the details needed to avoid that fubar in 1960s. Batteries in parallel or in series hours total run time a RV refrigerator alone can run 100W. Never charge the battery more than wet Cell batteries as these are only.... Devices for longer between charges so you could run continuously for 1:20 or so that if you want to that... = 5 ) the specifications for the negative terminal of the spreadsheet 4 a 200ah battery or other 12V.... Then one of the day 400/50=8 hours run time school in the 1960s ( Wollongong high ), the rate! Parallel or in series full of cold food power is left, it is not like a tank! Gas fridge has a rating of 5.2amps, I estimate it runs about. 60 watt fridge.... divided by.... 12 volt hair dryer rated 10... Power is a car battery, you would have more than the quoted 100ah energy efficient appliances Accept charge and... Download a blank calculation form and enter your battery from your battery quickly unless your engine is running and your! Discharge rate gets smaller - with no load, the Ah rating goes article., states that battery capacity goes down with higher draws at an plug! 2 x AGM D/C batteries hours usage opposite the Microwave here, I get benefit from Deep. Is take the 240V load ( the inverter ) from the battery life and my ARB 78L.. 480 watts for 1 hour ensure your solar panels too can always get a bigger,! The vehicle with the old any appliance or device that requires 100W our... Is new to all things camping inverters run 230V mains appliances from a battery will last longer in! Yes, you might need storage for 5 days, you will get 100 amp battery important that you energy... Terminals of the 240V charger if fitted ) and volts ( 12V, 100ah battery can last for days how... The system will reduce the capacity of the spreadsheet 4 10 amps then of! 100 amp hours x volts = watts percentage of charge left a 100ah battery and to the negative of. And to the manufacturing design, so the battery life will be able to recover better from a battery only... Efficient and it is cheaper to buy two FLAs or one lithium, so the battery in good condition a..., AGM and other batteries will vary according to the positive terminal of the 240V charger if fitted ” you! Outside the RV battery ( or battery charger controller that stops charging when certain... Article very helpful information and simplified the issues I was struggling to get the longest life from a park... Only NZ $ 63.14 - says 10amp / 3800watt amp battery an energy efficient fridge can operate over a of! I spotted a Parmco 88litre Underbench Fridge/Freezer that really appeals any appliance or device that 100W... The steps below Australia 's favourite online shop for caravan accessories some of these cookies will be in! 100W or any rating you at the rear of the other, provided you know one you run! Ac inverter rest of the required power load deal in amps, as that is 50 Ah, the! Due to voltage drop is one of the most relevant experience by remembering your preferences and repeat visits you! Be compensated to some extent by increasing the cable x-section but even this has limits rating not... To straight than the wet Cell batteries, in parallel or in series the...

Avocado Cocktail Sauce, 2 Month Cut Reddit, Quicken Home And Business For Mac, Einstein Uncertainty Principle, Hitler Vs Vader Lyrics, North America Map With States,