hi,

Just bought an axpert 5kva and a pylontech us3000 this is purely for backup . Should I get another battery? Us 3000 or us2000? 4,5 hours loadshedding with average of 400w at any time

That  battery is good for 35A at around 50V, or about 1.7kW. So as long as you stay under that, you don't need another battery (that of course means the full 5kVA rating of the inverter will never be used). At 400W, plus the roughly 50W or so self-consumption of that inverter, times 4.5 hours, plus a bit of a fudge factor since inverter is not 100% efficient, you're looking at around 2.2kwH discharged from your 3.5kWh battery, or 60% DoD. So it looks okay to me.

Edit: Well, I may be a bit hasty in saying you'll be fine. The inverter maker wants a certain amount of battery capacity installed, usually, and this is not only about how much current you can reasonably draw, it would also sometimes be necessary to keep things like ripple down. Also it may affect the warranty. Technically I think you'd be fine, but I'm only about 85% sure 🙂

Edited August 6, 20205 yr by plonkster

Thank you,should i go for another US3000 at R20 k or a US2000 at around 15k? 

1 hour ago, Shockin said:

Thank you,should i go for another US3000 at R20 k or a US2000 at around 15k? 

I'd go for the US3000. The smaller battery has 2.5kWh storage, of which ideally you should use just 80% or so, and as you can see from the quick number I calculated... you're either going to run out or discharge too deeply each time with the US2500. Go for the larger one, or two of the smaller ones (that would be even better, of course, but carries an extra 10k price tag).

Am i understanding the specs correct for the pylon us3000. The recommended discharge is 37A but can go to 74A and still be within the warrantee of the battery, (74A with say 48V battery = 2550W) It should be able to run a kettle of similar watts without problems?

3 hours ago, Gerrie said:

recommended discharge is 37A but can go to 74A and still be within the warrantee of the battery

Correct. Most LFP batteries can handle 1C discharge without a problem, but recommended is C/2 (half that). A kettle takes about 5 minutes or so to boil water, so this should be okay I'd think.

So  had to do some sneaky work so wife doesn't find out but I am now the owner of two pylontechs US3000 batteries, now to start putting everything together 

17 minutes ago, Shockin said:

So  had to do some sneaky work so wife doesn't find out but I am now the owner of two pylontechs US3000 batteries, now to start putting everything together 

Dude... I once saw a motorcycle advertised on gumtree. Beautiful machine, almost brand new. The seller explained that his reason for selling is that apparently "Do whatever the f... you want" doesn't mean what he thinks it does.

🤣🤣🤣🤣🤣🤣🤣🤣

On 2020/08/06 at 4:52 PM, Shockin said:

So  had to do some sneaky work so wife doesn't find out but I am now the owner of two pylontechs US3000 batteries, now to start putting everything together 

They always find out...sooner or later. Then its rations for the longest time.

19 minutes ago, Delta9 said:

They always find out...sooner or later.

Then you are doing something wrong. You have to learn how to lie honestly. 😂😂

Just what is it with women? They complain when there is no power to do washing. Then they also complain when you spend money on a system big enough to wash and tumble dry.. 🤔

14 minutes ago, Solaris said:

Then you are doing something wrong. You have to learn how to lie honestly. 😂😂

Just what is it with women? They complain when there is no power to do washing. Then they also complain when you spend money on a system big enough to wash and tumble dry.. 🤔

Your pain is my pain...

On 2020/12/01 at 11:08 AM, PaulinNorthcliff said:

Your pain is my pain...

Y'all are doing something wrong. I get thanked on a regular basis for the equipment that sits on our roof and and inside a spare cupboard. When the loadshedding starts I even get a cup of coffee in bed (because we can still make coffee).

1 hour ago, Bobster said:

When the loadshedding starts I even get a cup of coffee in bed

Bobster, you’re the man!!