Power outages using a battery with a power inverter.

[DHouse]

Good afternoon all, Can anyone tell me how long a 12V 100Ah LifeP04 100A BMS, max 1280Wh battery with a 1100 watt DC 12V to AC 120V Modified Sine Wave 1000w Power Inverter will run my tanks that each pull approximately 400 watts (heater and pumps) before needing to be recharged?

 

[Dan_P]

Good afternoon all, Can anyone tell me how long a 12V 100Ah LifeP04 100A BMS, max 1280Wh battery with a 1100 watt DC 12V to AC 120V Modified Sine Wave 1000w Power Inverter will run my tanks that each pull approximately 400 watts (heater and pumps) before needing to be recharged?

If I understand correctly, you have a supply of 1280 watt-hours and a demand of 800 watts. 1280/800 = ~1.5 hours

 

[Dipi]

First we need to get the eletrical current your tank is pulling. For that, we divide 400W (power your system is consuming) by 12v (battery voltage), which gives us 33A. Since your battery has a capacity of 100Ah you should get about 3h max for one tank, but i would consider less, since there are some inefficiencies. The 1000W of the power converter means how much power it can handle, but this number also needs to be corrected by the power factor, which usually is 0.5. Therefore, you are good to go, but there is no much room for raising your power consumption.

 

[VintageReefer]

The formula is
(Battery watt hours x .8 ) / watts = number of hours it will run

I use 3 of these

So for you (1280 x .8) / 400 = 2.56 hours for one battery running one tank

The secret with batteries like this is to be efficient. You do not run your entire tank on one. Bare minimum. One pump for circulation. I run a dc return pump that’s adjustable. Normally it runs using 40 watts. When I use the battery generator I cut speed 50% so it uses 20 watts. Heater shouldn’t be needed for normal power outages of a few hours

 

[DHouse]

The formula is
(Battery watt hours x .8 ) / watts = number of hours it will run

I use 3 of these

So for you (1280 x .8) / 400 = 2.56 hours for one battery running one tank

The secret with batteries like this is to be efficient. You do not run your entire tank on one. Bare minimum. One pump for circulation. I run a dc return pump that’s adjustable. Normally it runs using 40 watts. When I use the battery generator I cut speed 50% so it uses 20 watts. Heater shouldn’t be needed for normal power outages of a few hours

Thanks for the input. That certainly helps.

 

[DHouse]

First we need to get the eletrical current your tank is pulling. For that, we divide 400W (power your system is consuming) by 12v (battery voltage), which gives us 33A. Since your battery has a capacity of 100Ah you should get about 3h max for one tank, but i would consider less, since there are some inefficiencies. The 1000W of the power converter means how much power it can handle, but this number also needs to be corrected by the power factor, which usually is 0.5. Therefore, you are good to go, but there is no much room for raising your power consumption.

Thanks!

 

[DHouse]

First we need to get the eletrical current your tank is pulling. For that, we divide 400W (power your system is consuming) by 12v (battery voltage), which gives us 33A. Since your battery has a capacity of 100Ah you should get about 3h max for one tank, but i would consider less, since there are some inefficiencies. The 1000W of the power converter means how much power it can handle, but this number also needs to be corrected by the power factor, which usually is 0.5. Therefore, you are good to go, but there is no much room for raising your power consumption.

Thanks!

 

[REEFRIED!]

I am not doubting the math in this thread but that run time seems low to me. There is definitely only 1280wh available. If you are pulling 400w you would get three-ish hours of run time. However the heater (which I am assuming is the most draw) won’t be running for that entire time. Allowing you over three hours.

 

[The_Paradox]

I am not doubting the math in this thread but that run time seems low to me. There is a YouTube video where a guy builds a setup similar. (I believe with the same battery you mentioned) and he gets 8+ hours. He is using an 800w heater. His draw is definitely more than 400w. He tested the inverter set up with the entire tank running

Think how fast two old school 55w halogens will drain a battery when left on.

I can plug a microwave in and run it for days off one battery… if the duty-cycle is 0.01%

 

[VintageReefer]

I am not doubting the math in this thread but that run time seems low to me. There is definitely only 1280wh available. If you are pulling 400w you would get three-ish hours of run time. However the heater (which I am assuming is the most draw) won’t be running for that entire time. Allowing you over three hours.

You need to factor for the loss that happens using the internal inverter to convert DC battery storage into AC power. The loss is 20%

You are correct that the heater won’t be running that entire time. I should have mentioned that the OP will get 2.56 hours of run time. The heater probably comes on and off for a few minutes at a time, and will not be running constantly. It depends on the ambient temp

Running a heat source such as a heater that’s several hundred watts off a battery is not going to last as long as you would think. But if if ran a 25w dc pump the op could get 40+ hours