Battery maximum output

Exiled_Tyke

Mikeyboy01443 said:

Exiled_Tyke said:

Discharge rates are limited to preserve battery life. I can change them for my (Solax) battery but wouldn't want to ask I presume the manufacturer has chosen a fair balance between maximising power and looking after the battery.  I'm also limited to about 2.7kW. If the sun is shining I'm find but otherwise I start to import  - but it's not a great deal.  

Charging also follows a similar pattern. It starts off at a maximum rate (which I'm never at risk of wanting to exceed) but then reduces as it gets close to maximum. 

Do you have a single battery setup? My dual battery solax can charge / discharge at 5kw+

Yes.  I tried to get an extra one about a year ago but they've changed the specs on the new ones so they are not compatible with each other.  I'd have to get rid of the one I've got and buy two.  

zeupater

Qyburn said:

zeupater said:

Reed_Richards said:

My battery, which has a 6.5 kWh capacity (LG RESU6.5), seems to have a maximum output of about 2.67 kW.  I'm not sure if this limit is set by the battery or by the inverter but it's a bit irritating because it means even if the battery is fully charged I cannot boil a 3 kW kettle without importing some electricity.  I don't recall ever seeing this issue discussed here so I don't know if this issue is normal or not.  If it's something that can vary then it should be quite an important consideration when choosing an inverter & battery conversation.  Thoughts?  

Hi

First thought ... if it's an issue, buy a ~1kW kettle - it's the cheapest & most easily addressable solution by far!

HTH - Z

There are plenty of 2200W or 2400W kettles available. Having said that, have you measured yours? Our Russell Hobbs is sold as "3000W" but actually draws 2700W.

Hi

Yes, of course it's been measured ... years ago, that's why we use a 1kW kettle in the first place as it better matches solar PV generation conditions and reduces electron imports!. Yes, the lower power results in it taking longer to boil, but it's really not noticeable most of the time because of being able to plan priorities (put just enough water in the kettle & turn it on first!) and multitask (get mugs, spoon coffee, add milk, get biscuits, wipe spilled coffee granules from side and do a multitude of things that would otherwise need to be done anyway !) whilst it's boiling .... 

The issue described was the battery system seemed to be topping out at ~2.67kW, so, considering it was already supplying household baseload and whatever else was being powered, putting an existing 3kW kettle on resulted in energy being imported .... whereas a kettle rated at ~1kW provides considerable headroom to allow for other powered devices, anything within the 2kW to 2.67kW would not, hence the logical (& low cost!) suggestion ...

HTH - Z (Owner of ~1kW kettles since the early days of PV ... )

Reed_Richards

After a very long wait I finally got a response from Goodwe, the manufacturer of my inverter.  They say that the inverter is limited to a maximum charge and discharge power of 2500 W.  

1961Nick

zeupater said:

Reed_Richards said:

My battery, which has a 6.5 kWh capacity (LG RESU6.5), seems to have a maximum output of about 2.67 kW.  I'm not sure if this limit is set by the battery or by the inverter but it's a bit irritating because it means even if the battery is fully charged I cannot boil a 3 kW kettle without importing some electricity.  I don't recall ever seeing this issue discussed here so I don't know if this issue is normal or not.  If it's something that can vary then it should be quite an important consideration when choosing an inverter & battery conversation.  Thoughts?  

Hi

First thought ... if it's an issue, buy a ~1kW kettle - it's the cheapest & most easily addressable solution by far!

HTH - Z

A boiling water tap is very efficient & typically draws 1-1.5kW. The small heat loss is more than covered by the energy wasted by the typical overfilling of a kettle.

zeupater

1961Nick said:

zeupater said:

Reed_Richards said:

My battery, which has a 6.5 kWh capacity (LG RESU6.5), seems to have a maximum output of about 2.67 kW.  I'm not sure if this limit is set by the battery or by the inverter but it's a bit irritating because it means even if the battery is fully charged I cannot boil a 3 kW kettle without importing some electricity.  I don't recall ever seeing this issue discussed here so I don't know if this issue is normal or not.  If it's something that can vary then it should be quite an important consideration when choosing an inverter & battery conversation.  Thoughts?  

Hi

First thought ... if it's an issue, buy a ~1kW kettle - it's the cheapest & most easily addressable solution by far!

HTH - Z

A boiling water tap is very efficient & typically draws 1-1.5kW. The small heat loss is more than covered by the energy wasted by the typical overfilling of a kettle.

Hi

Agree, but would it conform to what was described in costing close to £10 (cheapest) and simply plugging into the wall (easily addressable) ?

We've actually got a 'One Cup' kettle with built-in filtration in a cupboard somewhere, cost ~£100 & great for boiling just the right amount of water, but like it's predecessor  proven itself extremely prone to limescale issues ... not too bad if the replacement is effectively 'plug & play', but could provide quite an issue if the solution to having a cuppa in the next few days actually relied on the calendar availability of an expensive plumber to fix/service what is in effect a 'fixture' ... 

HTH - Z

1961Nick

zeupater said:

1961Nick said:

zeupater said:

Reed_Richards said:

My battery, which has a 6.5 kWh capacity (LG RESU6.5), seems to have a maximum output of about 2.67 kW.  I'm not sure if this limit is set by the battery or by the inverter but it's a bit irritating because it means even if the battery is fully charged I cannot boil a 3 kW kettle without importing some electricity.  I don't recall ever seeing this issue discussed here so I don't know if this issue is normal or not.  If it's something that can vary then it should be quite an important consideration when choosing an inverter & battery conversation.  Thoughts?  

Hi

First thought ... if it's an issue, buy a ~1kW kettle - it's the cheapest & most easily addressable solution by far!

HTH - Z

A boiling water tap is very efficient & typically draws 1-1.5kW. The small heat loss is more than covered by the energy wasted by the typical overfilling of a kettle.

Hi

Agree, but would it conform to what was described in costing close to £10 (cheapest) and simply plugging into the wall (easily addressable) ?

We've actually got a 'One Cup' kettle with built-in filtration in a cupboard somewhere, cost ~£100 & great for boiling just the right amount of water, but like it's predecessor  proven itself extremely prone to limescale issues ... not too bad if the replacement is effectively 'plug & play', but could provide quite an issue if the solution to having a cuppa in the next few days actually relied on the calendar availability of an expensive plumber to fix/service what is in effect a 'fixture' ... 

HTH - Z

Funny you should mention that as I've just been servicing the Sister in law's Quooker...

70sbudgie

Is there much range of output powers of battery inverters? In the above I have seen 1.2kW, 2.5kW and 3kW mentioned.

I am considering retro fitting AC coupled batteries, but want to get a "future proof" design, where the batteries could supply a heat pump or provide an emergency top up of my EV. I don't know what size heat pump we would need, but my EV charger is a standard 7(.4?)kW. 

All the battery chat I've found, apart from this thread, seem to quote battery energy capacity, not their charge /discharge powers, even if the conversation veers towards power.

Netexporter

The Givenergy All-in-One has a 6kW output (7kW 10 second peak). The gateway that goes with it will handle 18kW, so you can have three AiOs in parallel and completely separate from the mains.

70sbudgie

Is that an AC inverter or PV hybrid? (All in one suggests hybrid). 

And what does AiO stand for?

Reed_Richards

After a very long wait I got a reply about my battery maximum output.  It turned out that the limit is imposed by the inverter and is stated if you read the spec. carefully enough.  The same limit applies to both charging and discharging, 2.5 kW in my case.  Note that this limit is not the same thing as the inverter maximum output.