LifePo4 Discharge Rate

S

skusku

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Hi
Just referring to NON loadshedding hours in below:

So with Lifepo4 batteries only able to discharge at half the watts compared to what they will deliver (ex 4.8kwh 48V - Is only able to handle 50A at 48A continiously) Ie. 2400W
Thus you buy a 5KW Inverter and you buy 1x 4.8kwh Lifepo4 battery. You can run your fridge/tv until you have used your 4.5kwh usable energy, but plug in the hairdryer and there the 5kwh battery is unable to handle the current.
So effectively you need 2x 4.8kwh with a single 5kw inverter.
Getting very expensive or am I missing something?
Just wondering how the installations are done
 
RedViking said:
I would not plug in the hairdryer then.

Will tell my wife even though she looks like hurricane katrina, she is still the most beautiful wife in my life.

Cheaper than another battery I think.
Click to expand...
Well, depends on the divorce settlement after she is denied the use of the hairdryer...
 
skusku said:
Hi
Just referring to NON loadshedding hours in below:

So with Lifepo4 batteries only able to discharge at half the watts compared to what they will deliver (ex 4.8kwh 48V - Is only able to handle 50A at 48A continiously) Ie. 2400W
Thus you buy a 5KW Inverter and you buy 1x 4.8kwh Lifepo4 battery. You can run your fridge/tv until you have used your 4.5kwh usable energy, but plug in the hairdryer and there the 5kwh battery is unable to handle the current.
So effectively you need 2x 4.8kwh with a single 5kw inverter.
Getting very expensive or am I missing something?
Just wondering how the installations are done
Click to expand...
Add solar panels?

Also, look at the product data sheet. Many LiFePo4 batteries are 1C nowadays
 
Yes
The batteries can only discharge x amount continuously, lithiums get very warm and they are protecting themselves with the BMS in place.
 
Wait, a tv and fridge will idle along at around 250 Watts so it shouldnt be a problem, there is a gremlin elsewhere that hasnt been mentioned
 
skusku said:
Hi
Just referring to NON loadshedding hours in below:

So with Lifepo4 batteries only able to discharge at half the watts compared to what they will deliver (ex 4.8kwh 48V - Is only able to handle 50A at 48A continiously) Ie. 2400W
Thus you buy a 5KW Inverter and you buy 1x 4.8kwh Lifepo4 battery. You can run your fridge/tv until you have used your 4.5kwh usable energy, but plug in the hairdryer and there the 5kwh battery is unable to handle the current.
So effectively you need 2x 4.8kwh with a single 5kw inverter.
Getting very expensive or am I missing something?
Just wondering how the installations are done
Click to expand...
You need a 1C battery:
Hubble AM-2 (5.5kW)
4 x Hubble S-100 (4.8kW)
Fusion Batteries I think are 1C (4.8kW)
 
skusku said:
Hi
Just referring to NON loadshedding hours in below:

So with Lifepo4 batteries only able to discharge at half the watts compared to what they will deliver (ex 4.8kwh 48V - Is only able to handle 50A at 48A continiously) Ie. 2400W
Thus you buy a 5KW Inverter and you buy 1x 4.8kwh Lifepo4 battery. You can run your fridge/tv until you have used your 4.5kwh usable energy, but plug in the hairdryer and there the 5kwh battery is unable to handle the current.
So effectively you need 2x 4.8kwh with a single 5kw inverter.
Getting very expensive or am I missing something?
Just wondering how the installations are done
Click to expand...
You need a battery of 1C or higher. Most decent
lithium iron phosphate batteries will give you at least 1C in those that are 4.8Kwh and below.

These would generally have a 50A maximum charge a rate and a 50A maximum discharge rate for the 2.4kwh battery (for the 48V battery) while the 4.8Kwh will have a maximum charge rate of 100A and a maximum discharge rate of 100A (again for the 48V).

Those above 4.8Kwh would generally be below 1C.

The above is a general guidline and does not hold true for all makes and models.
 
anyone have experience with blue nova lithium batteries?

any good?
 
wingnut771 said:
You need a 1C battery:
Hubble AM-2 (5.5kW)
4 x Hubble S-100 (4.8kW)
Fusion Batteries I think are 1C (4.8kW)
Click to expand...
So does that mean one can use 1x 1C (4.8kwH) battery with a 5Kw inverter and plug in the hairdryer + Fridge+ Freezer and the battery would be able to handle it?

Koosvanwyk said:
You need a battery of 1C or higher. Most decent
lithium iron phosphate batteries will give you at least 1C in those that are 4.8Kwh and below.

These would generally have a 50A maximum charge a rate and a 50A maximum discharge rate for the 2.4kwh battery (for the 48V battery) while the 4.8Kwh will have a maximum charge rate of 100A and a maximum discharge rate of 100A (again for the 48V).

Those above 4.8Kwh would generally be below 1C.

The above is a general guidline and does not hold true for all makes and models.
Click to expand...
"maximum discharge rate of 100A" all datasheets I can find the maximum is not recommended. Its like saying my car's top speed is 220km/h. This doesn't mean I can drive 440km in 2 hours. Maximum time is like a minute or two I would guess. If someone has the lights,fridge,freezer,tv's etc connected and its running at 2500w and now its winter and they plug in a heater of 1800W for an hour, I am not sure if the batteries would be able to handle it?
 
skusku said:
So does that mean one can use 1x 1C (4.8kwH) battery with a 5Kw inverter and plug in the hairdryer + Fridge+ Freezer and the battery would be able to handle it?


"maximum discharge rate of 100A" all datasheets I can find the maximum is not recommended. Its like saying my car's top speed is 220km/h. This doesn't mean I can drive 440km in 2 hours. Maximum time is like a minute or two I would guess. If someone has the lights,fridge,freezer,tv's etc connected and its running at 2500w and now its winter and they plug in a heater of 1800W for an hour, I am not sure if the batteries would be able to handle it?
Click to expand...
As long as the hairdryer + fridge + freezer is less than 4.8kW the battery should cope. However, as with all these things, the longer you put the battery under more strain the shorter its expected life. The recommended rate is for max life expectancy, but the max rate is what the BMS will allow.
 
skusku said:
So does that mean one can use 1x 1C (4.8kwH) battery with a 5Kw inverter and plug in the hairdryer + Fridge+ Freezer and the battery would be able to handle it?


"maximum discharge rate of 100A" all datasheets I can find the maximum is not recommended. Its like saying my car's top speed is 220km/h. This doesn't mean I can drive 440km in 2 hours. Maximum time is like a minute or two I would guess. If someone has the lights,fridge,freezer,tv's etc connected and its running at 2500w and now its winter and they plug in a heater of 1800W for an hour, I am not sure if the batteries would be able to handle it?
Click to expand...
You are correct, using full discharge rate is not recommended as it impacts battery life. Most charges cycles that I have seen assume average discharge of 0.3c or below.

Best would be to install an energy monitor before the DB board and monitor usage for a week or two to determine average and maximum consumption at different times of the day.

For instance, in my case, during the evenings when lights are on, all appliances are on (2 TVs, Playstation, laptops charging, hifi connected to TV, routers, NAS etc, the standard things) we use between 450W and 600W (0.08c in my case). What I have learned is that appliances hardly ever use their maximum consumption. All lights fittings are 3.5w which helps a lot and appliances are mostly A+++ rated.

Switch on the kettle and that goes to 3000W, so we stopped using the electric kettle and only use gas.
1
We invested in low energy consumtion applicances, heat pump tumble dryer, A+++ front loader, same for vacuum cleaner etc. Switch on all these at the same time and the 500W above goes to 2000W and then stabilises at 1800W as they heat pump tumble dryer gets going (0.25c in my case).

I guess what I am trying to say is if you go the solar route it is much more than just installing the system, it requires other changes to accommodate the parameters of the system.


Edit: I just checked, switching on the hairdryer adds 2000W
 
Last edited:
Koosvanwyk said:
You are correct, using full discharge rate is not recommended as it impacts battery life. Most charges cycles that I have seen assume average discharge of 0.3c or below.

Best would be to install an energy monitor before the DB board and monitor usage for a week or two to determine average and maximum consumption at different times of the day.

For instance, in my case, during the evenings when lights are on, all appliances are on (2 TVs, Playstation, laptops charging, hifi connected to TV, routers, NAS etc, the standard things) we use between 450W and 600W (0.08c in my case). What I have learned is that appliances hardly ever use their maximum consumption. All lights fittings are 3.5w which helps a lot and appliances are mostly A+++ rated.

Switch on the kettle and that goes to 3000W, so we stopped using the electric kettle and only use gas.
1
We invested in low energy consumtion applicances, heat pump tumble dryer, A+++ front loader, same for vacuum cleaner etc. Switch on all these at the same time and the 500W above goes to 2000W and then stabilises at 1800W as they heat pump tumble dryer gets going (0.25c in my case).

I guess what I am trying to say is if you go the solar route it is much more than just installing the system, it requires other changes to accommodate the parameters of the system.


Edit: I just checked, switching on the hairdryer adds 2000W
Click to expand...
Just using hairdryer as an example, but lots of women have 3000W+ hairdryers. Kettles and microwaves are the other main problem always.
 
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