# How Many Batteries Is Needed For 3000 Watt Power Inverter

3000-watt power inverters are a very popular class of power inverters used during blackouts, emergencies, camping, for off-the-grid, medical and security systems, and similar.

Most 3000-watt power inverters are very simple to use, however, dimensioning required batteries or battery packs can cause some issues in terms of reliability and runtime.

Published: January 24, 2022.

## 3000 Watt Power Inverters Energy and Power Requirements

Power inverters are not ideal units and have a certain energy loss during energy conversion.

Good power inverters feature an energy efficiency of ~85%, although there are units with better energy efficiency - such units are usually more expensive ones.

Thus, if the power inverter features a continuous output power of 3000 Watts, the required battery power is:

PBat = PInv / Energy Efficiency % = 3000 Watt / 0.85 = 3530 Watts

Also, power inverters usually feature a surge output power that is ~2x larger than the continuous output power, thus requiring the battery to provide much more power for a very short time (usually just a few seconds):

PBat = PInt / Energy Efficiency % = 6000 Watt / 0.85 = 7060 Watts

Thus, if we want to power 3000 Watt power inverter that features energy efficiency of 85%, the battery (or battery pack) must be able to provide ~3600 watts continuously and ~7200 surge watts.

This solves power requirements. But, what about energy requirements?

Power inverters usually don't operate at full power all the time - if that is happening, then the power inverter is seriously underpowered.

Energy requirements are usually given in the form of continuous power during a certain time, for example, 1000W for 3 hours.

In that case, the energy that the battery must provide is calculated using these formulas:

PBat = 1000 W / 0.85 = ~1200 Watt

EBat = PBat * T (h) = 1200 Watt * 3 hours = 3600 Wh = 3.6 kWh

In this example, if we want to power a 3000 Watt power inverter with surge power of 6000 Watt and energy efficiency of 85%, we need a battery that is able to provide 3600 Watts continuously, 7200 surge Watts and that features an energy capacity of at least 3.6 kWh.

3000 Watt power inverters are usually 12V units, but there are also 3000 Watt power inverters that accept 24V, 36V, or even 48V.

Battery currents can be easily calculated:

IBatCont = P(W) / U(V) = 3600W / 12V = 300 Amps

IBatSurge = P(W) / U(V) = 7200W / 12V = 600 Amps

IBatAverage = P(W) / U(V) = 1200W / 12V = 100 Amps

Note: as one can see, when powering 3000W inverters using 12V batteries, currents are rather strong!

Battery actual capacity can be calculated using following formula:

Actual Capacity = Required Energy (Wh) / U(V) = 3600 Wh / 12V = 300 Ah

Actual Capacity vs. Nominal Capacity: nominal capacity of the battery is battery capacity measured when the battery is discharged for 20h. However, when the battery is discharged faster, especially lead-acid batteries, actual capacity decreases - 1h actual capacity can be as little as 50-70% of nominal (20h) capacity for lead-acid batteries.

Lithium deep discharge batteries are less sensitive to discharge current in terms of capacity loss, but if a certain current is reached, the built-in Battery Management System (BMS) disconnects the lithium battery to protect it from overcurrent discharge.

Personally, for most applications lithium batteries are a much better choice than lead-acid batteries - for more about these batteries, feel free to check out our Best 12V, 24V, 36V, and 48V Lithium Deep Cycle Battery For a Power Inverter article.

For example, Ampere Time 12V 300Ah battery is one of the best batteries in its class and supports:

- maximum continuous current of 200 Amps,

- maximum surge current of 400 Amps for 5 seconds,

- connections of four batteries in series and four batteries in parallel in order to create larger battery packs.

In order to power 3000W power inverter in our example, we would need at least two such batteries connected in parallel - such battery pack would support:

- maximum continuous current of 400 Amps, which is more than the required 300 Amps,

- maximum surge current of 800 Amps for 5 seconds, which is more than the required 600 Amps,

- actual capacity is 600 Ah, which is more than the required 300 Ah.

If such battery pack is too large, note that Ampere Time 12V 200Ah battery features the same current limits, but provides an actual capacity of 400 Ah when two batteries are connected in parallel - still more than enough for our example.

Of course, there are other 12V lithium batteries that can be used to power 3000W and similar power inverters:

 Model Battery TypeChemistry Group SizeCapacity (Ah) Discharge Currents Parallel / Series Connections Weight (lbs/kg) Aicipow PDAC-12100 Deep CycleLiFePO4 31100 100A cont. P: up to 4S: up to 4 26 lbs; 11.8 kg Aicipow PDAC-12200 Deep CycleLiFePO4 4D (6D)200 100A cont. P: up to 4S: up to 4 58 lbs; 26.3 kg AIMS Power LFP12V50A Deep CycleLiFePO4 -50 50A cont.100A 10s ? 17.75 lbs; 8.04 kg AIMS Power LFP12V100A Deep CycleLiFePO4 31100 100A cont.200A 10s ? 30.2 lbs; 13.7 kg AIMS Power LFP12V200A Deep CycleLiFePO4 4D (6D)200 160A cont.350A 10s ? 77 lbs; 34.9 kg AIMS Power LFP12V50B Deep CycleLiFePO4 -50 50A cont.100A 10s P: up to 4S: up to 4 15.5 lbs; 7.0 kg AIMS Power LFP12V100B Deep CycleLiFePO4 31100 100A cont.200A 10s P: up to 4S: up to 4 28.5 lbs; 12.9 kg AIMS Power LFP12V200B Deep CycleLiFePO4 4D (6D)200 200A cont.400A 10s P: up to 4S: up to 4 62 lbs; 28.1 kg Ampere 12V 50Ah Plus Deep CycleLiFePO4 -50 50A cont.100A 5s P: up to 4S: up to 4 14.3 lbs; 6.5 kg Ampere 12V 100Ah Deep CycleLiFePO4 31100 100A cont.280A 5s P: up to 4S: up to 4 24.25 lbs; 11 kg Ampere 12V 200Ah Plus Deep CycleLiFePO4 4D (6D)200 200A cont.400A 5s P: up to 4S: up to 4 52.3 lbs; 23.7 kg Ampere 12V 300Ah Plus Deep CycleLiFePO4 4D (8D)300 200A cont.400A 5s P: up to 4S: up to 4 63 lbs; 28.54 kg Ampere 12V 400Ah Plus Deep CycleLiFePO4 8D400 250A  cont.750A 5s P: up to 4S: up to 4 86.2 lbs; 39.1 kg Banshee LFP-31M Dual PurposeLiFePO4 31100 1200 CCA P: ?S: up to 4 24.2 lbs; 11 kg Battle Born BB5012 Deep CycleLiFePO4 -50 60A cont.100A 30s P: yesS: up to 4 17.6 lbs; ~8.0 kg Battle Born BB10012 Deep CycleLiFePO4 31100 100A cont.200A 30s P: yesS: up to 4 29 lbs; 13.2 kg Battle Born BBGC2 Deep CycleLiFePO4 GC2100 100A cont.200A 30s P: yesS: up to 4 31 lbs; 14 kg Bioenno Power BLF-12100WS Deep CycleLiFePO4 31100 100A cont.200A 5s (not recommended) 28.1 lbs; 12.8 kg Chins 12V50Ah Deep CycleLiFePO4 -50 50A cont.150A 5s P: up to 4S: up to 4 13.8 lbs; 6.3 kg Chins 12V100Ah Deep CycleLiFePO4 31100 100A cont.300A 5s. P: up to 4S: up to 4 23.9 lbs; 10.8 kg Chins 12V200Ah Deep CycleLiFePO4 4D (6D)200 200A cont.600A 5s P: up to 4S: up to 4 49.4 lbs; 22.4 kg Chins 12V300Ah Deep CycleLiFePO4 4D (6D)300 200A cont.600A 5s P: up to 4S: up to 4 67.3 lbs; 30.5 kg Chins 12V400Ah Deep CycleLiFePO4 4D (6D)400 250A cont.750A 5s P: up to 4S: up to 4 86.4 lbs; 39.2 kg Eastup 1250750 Dual PurposeLiFePO4 34R/97R50 750 CCA930 MCA ? 15.43 lbs; ~7.0 kg Eastup 12751000 Dual PurposeLiFePO4 94R75 1000 CCA ? 18.5 lbs; 8.4 kg Eco-Worthy 12V50Ah Deep CycleLiFePO4 -50 60A cont. P: unlimitedS: up to 4 11.9 lbs; 5.4 kg Eco-Worthy 12V100Ah Deep CycleLiFePO4 34100 - P: up to 4S: up to 4 23 lbs; 10.4 kg Eco-Worthy 12V150Ah Deep CycleLiFePO4 31150 150A cont. P: unlimitedS: up to 4 36.7 lbs; 16.6 kg Eco-Worthy 12V200Ah Deep CycleLiFePO4 -200 120A cont. P: unlimitedS: up to 4 52.9 lbs; 24 kg ExpertPower EP1250 Deep CycleLiFePO4 -50 50A cont.100A 10s ? 13 lbs; 5.9 kg ExpertPower EP12100 Deep CycleLiFePO4 31100 100A cont.200A 2s ? 22.6 lbs; 10.3 kg ExpertPower EP12200 Deep CycleLiFePO4 4D (6D)200 150A cont.200A 3s ? 48.3 lbs; 21.9 kg GLI GLIBATT12050 Deep CycleLiFePO4 2650 50A cont.500A 5s(?) P: yesS: up to 4 12 pounds; 5.5 kg GreenLiFE GL50-50AH Deep CycleLiFePO4 2150 50A cont. Yes 15 lbs; 6.8 kg GreenLiFE GL80-80AH Deep CycleLiFePO4 2780 80A cont. Yes 28 lbs; 12.8 kg GreenLiFE GL100-100AH Deep CycleLiFePO4 31100 100A cont.1000A 5s Yes 31 lbs; 14 kg GreenLiFE GL260-260AH Deep CycleLiFePO4 8D260 100A cont.2600A 5A Yes 80 lbs; 36.24 kg JITA 12V100Ah Deep CycleLiFePO4 31100 100A cont. P: up to 4S: up to 4 23.8 lbs; 10.8 kg JITA 12V200Ah Deep CycleLiFePO4 4D (6D)200 200A cont. P: up to 4S: up to 4 48.9 lbs; 22.2 kg JITA 12V300Ah Deep CycleLiFePO4 4D (6D)300 200A cont. P: up to 4S: up to 4 59.5 lbs; 27 kg JITA 12V400Ah Deep CycleLiFePO4 4D(6D)400 200A cont.400A 5s P: up to 4S: up to 4 83.7 lbs; 37.9 kg Kunmo LF-12100 Deep CycleLiFePO4 75100 100A cont. ? 25.3 lbs; 11.5 kg Lossigy 12V100Ah Deep CycleLiFePO4 -100 50A cont. P: up to 10S: up to 4 23.8 lbs; 10.8 kg Lossigy 12V200Ah Deep CycleLiFePO4 4D200 100A cont. P: no limit (10?)S: up to 4 46 lbs; 20.9 kg Lossigy 12V300Ah Deep CycleLiFePO4 4D (6D)300 200A cont. P: up to 10S: up to 4 72 lbs; 32.6 kg Lossigy 12V400Ah Deep CycleLiFePO4 4D (6D)400 200A cont. P: up to 10S: up to 4 95 lbs; 43 kg Mighty Max ML100-12LI Deep CycleLiFePO4 30H100 100A cont.200A 15s P: up to 4S: not allowed 29.54 lbs; 13.4 kg Mighty Max ML4D-LI Deep CycleLiFePO4 4D (6D)200 - P: up to 4S: not allowed 48 lbs; 21.8 kg PacPow 12V 100Ah Deep CycleLiFePO4 31100 100A cont.300A 10s P: up to 4S: up to 4 27.56 lbs; 12.5 kg Pionergy 12V200Ah Deep CycleLiFePO4 4D (6D)200 200A cont. P: up to 4S: up to 4 46.1 lbs; 20.9 kg Pionergy 12V300Ah Deep CycleLiFePO4 4D (6D)300 200A cont. P: up to 2S: up to 4 71.2 lbs; 32.3 kg Power Queen 12V100Ah Deep CycleLiFePO4 31100 100A cont. P: up to 4S: up to 4 25.25 lbs; 11.0 kg Power Queen 12V200Ah Deep CycleLiFePO4 4D (6D)200 100A cont. P: up to 4S: up to 4 48.28 lbs; 21.9 kg Power Queen 12V300Ah Deep CycleLiFePO4 4D (6D)300 200A cont. P: up to 4S: up to 4 62.8 lbs; 28.5 kg Renogy RNG-BATT-LFP-12-50 Deep CycleLiFePO4 -50 50A cont. P: yesS: not allowed 14.77 lbs; 6.7 kg Renogy RBT100LFP12S-G1 Deep CycleLiFePO4 -100 100A cont. P: yesS: not allowed 26 lbs; 11.8 kg Renogy RNG-BATT-LFP-12-170 Deep CycleLiFePO4 -170 125A cont. ? 46.3 lbs; 20.97 kg Scream Power 12V100Ah Deep CycleLiFePO4 31100 ? P: ?S: no 24.3 lbs; 11 kg Scream Power 12V400Ah Deep CycleLiFePO4 -400 400A cont.800A peak ? 81.4 lbs; 36.9 kg Vatrer 12C 100Ah Deep CycleLiFePO4 31100 100A cont. P: up to 4S: up to 4 33 lbs; 15 kg Vatrer 12V 200Ah Deep CycleLiFePO4 4D200 100A cont. P: up to 4S: up to 4 48.5 lbs; 22 kg VMAXTANKS LF27-12100 Deep CycleLiFePO4 27100 125A cont.350A 3s P: up to 4S: up to 4 25.3 lbs; 11.5 kg VMAXTANKS LFPU1-1245 Deep CycleLiFePO4 U145 45A cont.100A 3s P: up to 4S: up to 4 10.8 lbs; 4.9 kg VMAXTANKS VPG12C-50Li Deep CycleLiFePO4 U150 50A cont.100A 5s150A 3s P: up to 2S: not allowed 12 lbs; 5.5 kg Waterblade LFP 100-12.8 Deep CycleLiFePO4 -100 80A cont.400A 1s ? 29 lbs; 13.2 kg Weize FPLI-12100AH Deep CycleLiFePO4 31100 50A cont.100A 3s P: up to 4S: up to 4 26.4 lbs; 12.0 kg Weize TPLI-12200AH Deep CycleLiFePO4 4D (6D)200 100A cont.200A 3s P: up to 4S: up to 4 27.6(?) lbs; 12.5(?) kg Wingda W100-12V100AH Deep CycleLiFePO4 31100 50A cont. P: up to 4S: up to 4 23.8 lbs; 10.8 kg Wingda W200-12V200AH Deep CycleLiFePO4 4D (6D)200 100A cont. P: up to 4S: up to 4 48.9 lbs; 22.15 kg Wingda W300-12V300AH Deep CycleLiFePO4 8D300 200A cont. P: up to 4S: up to 4 70.54 lbs; 31.95 kg Zooms 12V 100Ah Deep CycleLiFePO4 31100 100A cont. P: up to 4S: up to 4 25.35 lbs; 11.5 kg Zooms 12V 200Ah Deep CycleLiFePO4 4D (6D)200 200A cont. P: up to 4S: up to 4 49.6 lbs; 22.5 kg Zooms 12V 300Ah Deep CycleLiFePO4 4D (6D)300 200A cont. P: up to 4S: up to 4 62.83 lbs; 28.5 kg

When calculating the number of required batteries in order to power 3000 Watt power inverter, it is a good practice to over-dimension the battery pack - in most situations, energy requirements can only grow...

And whatever You do, stay safe - these units are easy to use and maintain, but they are not toys and can provide huge currents that can do some serious damage, injuries, or worse...

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