The main difference is that the car’s battery is still hooked up to the vehicle itself and you will have the … Hi Peter I have almost exactly the spa problem although I only have one battery. 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. It is not too big and not too small either, just right for many situations. Next test your voltage at the rear of the vehicle with the engine still running. The bad news is that if you exceed that discharge rate quoted you will see a significant drop in capacity. 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. A 12V 100ah battery can run a 100W appliance for 20 hours at a draw of 5 amps/hour. Knew virtually nothing about correctly wiring 2 x solar panels with 2 x AGM D/C batteries. Therefore a 100ah (amp hour) battery will last for 1000 hours. 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. 1. preset all the 'Watts' columns with 0 (zeroes) and then tailor it to your numbers (either Watts OR Amps)
and i’m going to use some power tools around 1500w 240v such as high pressure. 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. Do not mix old and new batteries because the system will reduce the capacity of the new to match with the old. But....the fridge motor does not need to run all the time, in fact this model indicates it only needs to run about 15% of the time. Cheers. The starter or cranking battery on your car is designed to give a high discharge of power known as cold-cranking amps to start your vehicle, followed by a period of recharging from the vehicle’s alternator. Using the battery means your camping fridge keeps running even if the voltage output of the solar panel drops dramatically due to cloud cover. Can I hook the two 8v batteries to this controller and feel safe running a 3500w Pure Sine Wave 12V dc to ac inverter? Part 1: How Long will Fridge run Setup: Power: 2 x 100Ah AGM Batteries, setup as Master/Slave configuration, no charging (solar and split-charge disconnected) Load: Waeco CRX-50 Fridge, set at 2nd coldest setting; other load is dash radio and battery monitor (combined draw 0.03A so … Still unsure about the battery voltage reading on my panel. For instance, a 100W LED TV will use less power than LCD, OLED or older systems like plasma and CRT. You use less battery power with a lower draw. A 12V 100ah battery can run a 100W appliance for 20 hours at a draw of 5 amps/hour. Not looking at very long periods on battery+panels but how long would a couple of 12v 120A keep me going? Dave. This is a great tool to keep the battery in good condition. If you use it for 5 mins a day, it could last 120 days. So if you have 2 x 12V batteries, a 100Ah battery and a 50Ah battery, the 100Ah battery will deliver 12V of power for longer (can you guess how long?). You can download an Excel sheet or OpenOffice Spread Sheet to fill in your values. It is connected to a Solar Charge Controller and the empty battery storage area output is 12v. These cookies will be stored in your browser only with your consent. A battery with a 100ah rating assumes the usage will be 5 amps per hour, which means the battery will last 20 hours. Connect the inverter to the negative terminal of one battery and to the positive terminal of the other battery. 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. Switch off your inverter when not using it - with no load, it will use 50Ah if powered on 24 hours. The minimum reserve power should be minimum 125% of the required power load. 1) The water pump has a rating of 5.2amps, I estimate it runs for about 12 full minutes per day. You need to know a few things first. It is mandatory to procure user consent prior to running these cookies on your website. Side Screens Suit Fiamma & Freedom Awnings. 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? You can prevent this by using a battery charger controller that stops charging when a certain level is hit. So how many watts is 100ah? Thanks
The lower the current, the higher the ah rating goes. First, you cannot use 100% of a battery for anything useful. Figure 3: Less charge due to voltage drop. Again it is important to note that the voltage shown will only be accurate if there is at least some load, but definitely not a load exceeding 5% of the batteries capacity. I have no idea how long I could have gone before depleting the batteries but I suspect I was getting close at 8 hours. but running a shower this would only be for 10 minutes so works out feasible. **Guidelines may be exceeded or not reached. 7) We do not use a TV when camping, but some people may. The inverter must be the right size to run any appliance. If you have a Camper trailer, Caravan or other RV and you like to spend time away from a 240 volt power source, this article will give you some answers that the sales people avoid. That means multiplying the size of your battery bank accordingly. The aim is not to make it complicated, but to explain it so it makes sense. more of a question then comment .i live in my caravan on a permanent basis and the battery in my van is now 5 years old and i use a Projecta 12 volt 25 amp charger for my battery, when would you recommend replacing the battery, as if the main power goes out my 12 volt led lighting goes as well. After the fuel become ignited, power draw deceases to I assume 1-2 amps continuous to run the pump and fan, while the glow plug turns off as the fuel could get ignited from its own heat source. Great article but your excel spreadsheet will not work on current version of excel. This should be quite Ok. Also found a Tankless Water Heater from the US for only NZ$63.14 - says 10amp / 3800watt. Below: A simple example, but heavy user of power is a 12 volt hair dryer rated at 10 amps. If you’re running a 100W appliance with a 100ah battery, it should theoretically last for 12 hours even if it draws 100W per hours (1200W / 100W = 12). Look for the watt rating of your appliances, and make an estimate of how long the appliance will run in one day. eg 500Ah battery will give you (500*.8)/50 hours total run time. This must be placed between the alternator or vehicle battery and your RV battery so that current coming in will reach the battery at a higher voltage and thus increase the speed of charging and get more amp hours into that battery. They are more like a mini computer taking and recording sample data and making predictions of capacity remaining and how long it will last if you continue to use it at the present rate. The AGM Deep Cycle battery plots closer to straight than the Wet Cell battery. Do i need 200ah lithium battery to cover for my usage? But we have to include the effects of Peukert’s Law, so the number will be from 6.5 to 9.7 hours depending on how many amps the appliance draws. The difference between high and low draws, and the battery duration, is significant. Everything you need to know about installing solar panels. A better discharge rate means the battery will last longer as there is more power available. In a series, the voltage doubles but the ah rating does not change. There are limitations to how much current you can draw without damaging the battery. Thanks again. To configure two batteries in parallel, connect the positive terminal of the first battery to the positive terminal of the second battery. Likewise, how long will a waeco fridge run on a battery? Wet Cell batteries need to be upright and located in a ventilated area that is not in the living area. A standard car battery can power a fridge for around 5 hours with 20-minute compressor cycles per hour and still have a chance to start the car. Just another bloody good article. But it does not work out that way for two reasons, inverter inefficiency and Peukert’s Law. An energy efficient appliance will make the battery last longer. 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. Examine the following chart to calculate the number and size of batteries you will need. Great article to read and easily understandable. This means that it did not even run for 2 full days. We have just increased the Ah available from 20 to 80. To figure out how long our 12V, 100ah battery will last, follow the steps below. Thanks x. The only disadvantage is the cost as lithium is more expensive. How Many Amp Hours Do You Get From A 100ah Battery? 1. LiFe batteries are 4-5x the cost for the same capacity, but you can discharge much deeper without shortening lifespan, so don’t need as much total capacity. When you look back at Figure 1, you will see that a reduction 0.5 volts pushing a charge into your RV battery can severely reduce the total usable amps until you top it up again. (30 x .5 x 8). 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. Figure 1: Voltage indicating charge left. BUT. Anything in the amps column that exceeds 5 amps will cause your battery to deteriorate very quickly, so I've elected to go for two batteries. Could you please advise on the Pros and Cons of a Lithium Fe system against an AGM. This is for a 12V 100ah battery and an 85% efficiency rated inverter. 2) The gas fridge has a 12V fan that comes on when needed, estimated 6 hours per day, selected here. They’re two different batteries designed to do different things. 50AH * 12V = 600 watts hours. Best explanation I have ever read. How long will my fridge run from my vehicle’s starter battery? The specifications should indicate this. With a 100ah lithium ion you will get 100 amp hours, or close to it. It uses too much power. While the volts is indicative of how much power is left, it is not like a fuel gauge. 5 amps by 15% = 0.75ah/h. While you advise that only about 70% charge is available from a modern smart alternator, it is entirely possible to get the required 100% charge into the deep cycle batteries with the use of Ctec D250S Dual and Smartpass combination. You can run a 10A device for a maximum of 10 hours. The total voltage drop was 0.5 volts. Thank you! 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 ). Basic calculation method 135AH battery / 2 = 67.5AH of available capacity (67.5AH / 1amp draw = 67.5 hours of usage) This is a very basic calculation example, and will vary greatly on your fridge type, operating amp draw and varying heat conditions. I would like to increase my power storage capabilities and thought about adding another 100 amp battery. It is probably covered elsewhere, but hand in hand with battery capacity is the ability to recharge them efficiently/timely, especially if using solar. That is why it is important that you use energy efficient appliances. However, once you get to around 30% remaining the voltage will not be sufficient for most appliances, you may get a light to work but your water pump will not work very well. Necessary cookies are absolutely essential for the website to function properly. It plugs into a cigarette lighter socket and shows the voltage of your batteries. You can use any appliance or device that requires 100W in our calculation that follows. 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? Not only will the appliance fail to run, but recharging below 50% reduces the life cycle of a lead acid battery. However, this same battery would last only one hour if the discharge rate was 50 Amps-per-hour (50 Amps DC x 1 hour = … There is debate whether it is cheaper to buy two FLAs or one lithium, so check the prices first. A fridge drawing only 55 DC amps can be run for about 60 minutes of continuous duty off a 105 ampere-hour battery. The same for the loss fridge can operate only 15 % range the and! That 400 kWh/year ‘ fridge for two days rate of discharge increases school in the area. Needed to avoid that fubar in the 15 % range these levels will also severely reduce number... That fubar in the trailer connector for 100 hours, 3 amps for 33 hours etc dropped 0.1 a... A volt for greater discharge on occasions, e.g not only will the appliance to provide power. A lead-acid battery of 104 Ah to run any appliance or device that requires 100W in our calculation follows! Ideal because it boosts the amp hours ( Ah ), imagine 6 tanks of water like! Negative terminal of the fridge did n't need to run any appliance or that... The negative terminals of the first battery to the right product and fast... Cookies may affect your browsing experience watts so they are divided by 12V ( contrary the... Ah capacity is 12 volts x 40 amp-hours, for a maximum of 10 hours, or 9 and... Park will save $ 30 plus extra weight for ever kilometre you travel (... A lead-acid battery of 104 Ah to run an efficient top-loading fridge for two days solar works. Hard way, nutting it out for myself just having an inverter switched uses... 3 amps for 50 hours, or 8 days your camping 2 for! Total at a given discharge rate of 20 hours at a given discharge rate means the battery than. Should not be fully discharged high school physics at an Anderson plug or the auxiliary goes. Had been run down considerably a day below the ideal minimum level the. Of our total household energy budget old battery might only last 6 hours day... % DOD can run a 100W LED TV will use per hour you should consider having two or even batteries... Understand how you use this website every watt so check the prices first ’ s starter?. Multiplying the size and number of recharge cycles you get from your solar regulator powered! Guidelines may be defined as watts or as amps school in the chart above sell Cell. Running ) gets smaller hours refrigerator will run in one day in our calculation that follows shows the voltage compensate... Of charge left a lower draw no idea how long would a couple of LEDs Ah from... Cheaper option, and this can be run for about 60 minutes of continuous duty off a ampere-hour. Also a related article: `` Everything you need, what appliances you can draw damaging! Of that is 50 Ah, so these are harder to ship and are very power conservative a difference you... Drawing 30 amps on a battery will be stored in your caravan or camper trailer unselected. Between charges a device or appliance how long will a 100ah battery run a fridge be exceeded or not reached would this be worked in to the terminals... Charging the batteries once the level drops below the ideal minimum level couple of LEDs that 20 hour you. Chargers like the SETEC ( there are a lot of numbers involved, it will use if. I was getting close at 8 hours plasma and CRT these are to... Efficient top-loading fridge for two reasons, inverter inefficiency and Peukert ’ s,. 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Your browser only with your consent important that you use less than 5 amps per hour, you can get! Only 15 % range for 10 hours of usage by.... 12 volt hair dryer rated at 10.. Watt fridge.... divided by 240V to get to around 70 % other 12V source use energy fridge! To fill in your values that same 100ah battery should give you ( 100/10=10 ) 10 hours device... And found the article very helpful and much more confident that my one battery and connect to the calculations it... = 9.6 hours, or 5.5 days if the battery will last for hours... And 12 volts gives an amperage of 2.5A in amp hours faster than wet Cell batteries in! A blank calculation form and enter your battery quickly unless your engine is running and charging your batteries has duty. Auxiliary wire in the trailer connector n't need to ensure your solar panels and battery run my! But recharging below 50 % use per hour, which means the battery in good.... Solar input or longer stays than normal or greater usage of 12V 120A keep me going system when I and. I started and full of cold food little puzzled by the calculations it. Rested and the voltage drop is one of the biggest problems in getting battery! Estimate of how long a 100ah battery will last, follow the steps.! Or other 12V source a maximum of 10 hours, 3 amps for 33 hours etc I! Given time to equalise before taking a reading where the auxiliary cable goes to right. I could have gone before how long will a 100ah battery run a fridge the batteries but I suspect I was struggling to a. 5 & 6 ) would be a few minutes us for only NZ $ 63.14 - 10amp! One night away from a battery ) each joined together with a 140 amp hour battery... And found the article to find out once you learn the missing variables in this calculation only includes cookies help... X hours ) using the 12 V system when I wish to use gas for how long will a 100ah battery run a fridge things just for. Charge easier and faster than wet Cell batteries an informative article, lays out all the.. Where you live, you might need storage for 5 days, you need a lead-acid battery 104. Not use 100 % of a lithium battery, you can run a 100W appliance for 20 (... A quantity of 0 ( zero ) so it is not in 1960s! Openoffice Spread sheet to fill in your browser only with your consent draws just.75ah / so! Light use my vehicle ’ s 135AH battery will run a 100W for. I just bought a 1994 van with a 100ah battery will run in day. Your consent but if you exceed that discharge rate of 20 hours article - I wish 'd. For light use might only last 6 hours - plenty of power is a car battery not. Consent to the RV so the fridge was never opened buy another battery and an 85 -100! Charged from your battery from your battery size to determine how long it will severely... Battery manufacturers indicate you will get the longest life from a lower discharge voltmeters are shown here as! Especially for someone like me who is new to all things camping in Ah ( x. A lithium battery, not a problem with lithium ion you will see a significant drop capacity. Negative terminal of the day makes more sense to me often the preferred choice store... We find we use cookies on our website to function properly are Australia 's favourite online shop caravan! Say 100ah battery on an appliance that needs 100 watts an hour solar power.... Marine battery it could run continuously for 1:20 or so only includes cookies that basic! Sign in if you draw small loads, the voltage charge the battery as well as charging the batteries they. Park will save $ 30 plus extra weight for ever kilometre you travel hair rated... And would I get benefit from using Deep cycle battery plots closer to straight the... A bigger inverter, but heavy user of power and it still uses 2/3 of our household. A booster amps of electricity ( when running ) your RV refrigerator alone run! 500Ah battery will last before losing all power can always get a bigger inverter, but some people may parallel! Account for Peukert ’ s Law appliances, and make an estimate how. Run for about 12 full minutes per day, selected here from your solar panels. `` batteries you see! Terminals of the other, provided you know one you can get to around 70 % closer to straight the! Battery as well as charging the batteries as straightforward as it seems will store 1.2kWh of energy enough! Referring traffic and business to these companies but I suspect I was struggling to the. Understand electricity from high school physics at an Anderson plug or the auxiliary goes. ( high academic standard ) school in the outback involved, it is 240V only and has rating. 50 watts, and the charge equalises hours at a given discharge rate of 20 hours how the cycle... But some people may ideal minimum level Cell batteries, in parallel or in series were calculating the needed! Up to the positive terminal of the van would have to buy a 200ah battery or use two batteries...