3rd build, biggest I’ve done yet so any help appreciated

[Ro0ke]

That fan must be huge.

It’s not massive but it’s bigger than what you see in average domestic setting. It has a 6” duct on it which goes over the exhaust of the car to expel fumes while the cars warming up.

 

[Ro0ke]

I see no power for the inverter in your calculations inverters draw power all the time and will depend on the inverter.

That’s a really good point, I overlooked that, thank you.

 

[John Frum]

Oh course the efficiency makes sense.

so would my inverter have to have a continuous rating high enough to cover the surge of the motor? My inverters going be huge.

Depends on how long the inverter can sustain its surge rating.
Typically high frequency inverters have no practical surge capacity.
Low frequency inverters do but they cost significantly more.

 

[John Frum]

If I DIY the battery which is a possibility if I go lithium I could potentially have a look in the BMS settings. But I think for ease and more of a fit and forget, I might go acid.

Do we have any recommendations for an inverter?

I'm don't know much about lead acid batteries.
In my opinion they only make sense now for applications where LFP are precluded for one reason or another.
This link describes a charteristic of lead acid batteries which I'm glad I don't have to deal with.

Peukert's law - Wikipedia

en.wikipedia.org

There are plenty of folks here who know and love lead acid batteries.
If you go that way I'm sure they can help.

 

[Ro0ke]

Depends on how long the inverter can sustain its surge rating.
Typically high frequency inverters have no practical surge capacity.
Low frequency inverters do but they cost significantly more.

I never even knew about high frequency and low frequency inverters, managed to
find this one 9kw peak for a a few seconds.

3000W 24V low frequency pure sine wave off-grid inverter (peak power 9000W) 5060297341854 | eBay

This 3000W 24V low frequency is perfect for powering your household appliances by converting 24V DC (direct current) into 230 VAC (alternating current) without access to mains electricity. Output wave: pure sine wave.

www.ebay.co.uk

Also just found this one which is similar but need to look at reviews etc

VEVOR Pure Sine Wave Power Inverter Power Inverter 3000w Nominal 24v Dc Charger Lcd | VEVOR UK

Discover Pure Sine Wave Power Inverter Power Inverter 3000w Nominal 24v Dc Charger Lcd, 3000VA Hybrid Inverter and Comprehensive Setting LCD at lowest price, 2days delivery, 30days returns.

m.vevor.co.uk

With regards to batteries still unsure I need to work out cost I would rather go with lithium but ready made LFP batteries are going to be too expensive for now.

Another question would 2x 400watt panels with 3 hours of sunshine a day nearly charge 2x 240Ah batteries in series? Think that works out 2.4kwh a day but I’m not sure how to factor in inefficiencies.

 

[John Frum]

I never even knew about high frequency and low frequency inverters, managed to
find this one 9kw peak for a few seconds

* can I post eBay links here? *

Sure as long as you are not an affiliate or vendor.

With regards to batteries still unsure I need to work out cost I would rather go with lithium but ready made LFP batteries are going to be too expensive for now.

LFP batteries are cheaper when cycle life is considered.

Another question would 2x 400watt panels with 3 hours of sunshine a day nearly charge 2x 240Ah batteries in series?

I will leave the PV side of things to others.

You mention batteries in series, what is your planned system voltage?

 

[Ro0ke]

Sure as long as you are not an affiliate or vendor.

LFP batteries are cheaper when cycle life is considered.


I will leave the PV side of things to others.

You mention batteries in series, what is your planned system voltage?

Yeah I agree I could diy two 12v batteries with their own BMS’ I have some experience with it so shouldn’t be an issue, just cost and wait times.

My planned system voltage is 24v

Also I’ve added the links into the post above

 

[John Frum]

Yeah I agree I could diy two 12v batteries with their own BMS’ I have some experience with it so shouldn’t be an issue, just cost and wait times.

My planned system voltage is 24v

Also I’ve added the links into the post above

I don't recommend putting batteries in series.
If you want a 24 volt system buy or make 24 volts batteries.
It avoids the issue of drift within the series.

 

[Ro0ke]

I don't recommend putting batteries in series.
If you want a 24 volt system buy or make 24 volts batteries.
It avoids the issue of drift within the series.

Ok awesome advice thank you. I take it I can get 8S BMS’? I’ve only used 4s which was the same as the overkill branded one

 

[Bluedog225]

It’s not massive but it’s bigger than what you see in average domestic setting. It has a 6” duct on it which goes over the exhaust of the car to expel fumes while the cars warming up.

The reason I commented is because something like this is less than 600 watts. Fans tend to be pretty low watts. Wanted to double check on something that big.

 

[Ro0ke]

The reason I commented is because something like this is less than 600 watts. Fans tend to be pretty low watts. Wanted to double check on something that big.

View attachment 93415

Yeah that is true it surprises me as well, it’s tagged at 550watt on the fan but shows more on the clamp meter, it’s not even that old either.

 

[Bluedog225]

if it’s running through ductwork, that could make a difference.

 

[Ro0ke]

if it’s running through ductwork, that could make a difference.

I think you’re correct could be making the motor work that bit harder.

 

[John Frum]

Ok awesome advice thank you. I take it I can get 8S BMS’? I’ve only used 4s which was the same as the overkill branded one

overkill makes an 8s bms.