advertisement


Electric cars and voltage drops and hifi

H

hal9001

pfm Member
Given the move to electric cars and therefore domestic charging points I'd like to share with you what might be a potential problem for the future. My neighbour has bought a hybrid vehicle and told me that because we share the same incoming mains infrastructure that there might be some work required to install the charging point. I'd get written confirmation of what was to be done. Fair enough. The charging point went in but I didn't get any notification of what had been done (if anything). OK.

I have a power regenerator that has incoming voltage reading which is normally rock steady @ 230V. Now when the car is charging the voltage can bounce around between 218 and 230V although I need to gather a bit more data on this. 216V is the nominal minimum limit.

My first question is that if you are running a current hungry amp is there going to be a problem running it at the bottom the voltage range? I would expect 220V to be fine but what happens if it goes down to 216 or less? I have passed this onto Northern Powergrid for comment as it's up to them to ensure the correct voltage is supplied on the mains.

It begs a follow up question. Can our electrical infrastructure handle the the move to electrical cars without it causing long term problems for hifi enthusiasts with power hungry kit? Should we be looking at running our power amps off batteries? Is this even possible? I seem to remember a manufacturer bringing their own electrical supply to hifi shows but this was a huge and expensive bit of kit. Wonder if it can be done now with the current battery technology?
 
Hi Hal, may i ask where are you living? voltages are nominally 240V+. Ours here in London is never less than 245V, and in my previous property, a village in Northumberland it was 248V.
 
UK mains usually 240V but some areas where new infrastructure has been put in place may have been brought down to 230V I guess.

I was at a bake off once where a power amp went completely haywire and started making loud cracks and the music going on and off etc and it turned out that the mains had gone down to IIRC 218V. Luckily it was an SET and not powerful enough to damage the speakers.

The main issue is the drop out voltage of linear regulators and this was what was to blame here. SMPS will generally be completely unaffected by it and indeed many are rated to run from 90 - 240V!!

It's a perennial compromise with linear regs... make it run pretty cool and efficient on UK 240V mains and it probably won't work in an EU country with 220V mains.... make it work at 210V to allow for EU 220V mains on a bad day (when a car is being charged up maybe!) and it will need larger more expensive heatsinks for the regs and run a bit toasty warm on UK 240V mains....
 
I am in the middle of nowhere in rural Lincolnshire. 230V is normal here. I'm also wondering how a power amplifier in particular copes when the voltage is jumping around so much! I thought we had been reduced from 240 to 230V to fall in line with the EU. It might go back up in again after tomorrow.
 
The EU requires, as far as I know, 230V, plus or minus to cover the U.K. at 240V. The voltage is allowed to vary quite a lot, but the frequency must remain very tightly controlled.
 
hal9001 said:
I am in the middle of nowhere in rural Lincolnshire. 230V is normal here. I'm also wondering how a power amplifier in particular copes when the voltage is jumping around so much! I thought we had been reduced from 240 to 230V to fall in line with the EU. It might go back up in again after tomorrow.
Click to expand...

They supposedly harmonised at 230V but actually just widened the tolerance so that nominal 220V and 240V would both be in spec pretty much whatever. I can`t see that changing anytime in the near future.
 
Earlier on reading a solid 230v. Now the car is charging reading between 219 and 223V. Even if the absolute value isn't completely accurate that's still roughly a 10V drop.
 
Barrymagrec said:
If that drop is on the shared incoming cable and it`s due to the new car charging circuit that`s a pretty duff installation and should be looked at.
Click to expand...

Oh I don't know... I pointed out in a thread on electric cars a few months back that the fast charging of vehicles requires colossal amounts of electricity and that if there was a rush on electric car dealerships the UK's electricity supply wouldn't cope with it. We are maybe talking in terms of charging one car in an hour taking similar to a whole street of 20-30 houses running electric fires and immersion heaters at the same time.... Now if even one in 3 households in that street bought electric cars with fast charge points and all put them on charge at the same time:eek:
 
Arkless Electronics said:
Oh I don't know... I pointed out in a thread on electric cars a few months back that the fast charging of vehicles requires colossal amounts of electricity and that if there was a rush on electric car dealerships the UK's electricity supply wouldn't cope with it. We are maybe talking in terms of charging one car in an hour taking similar to a whole street of 20-30 houses running electric fires and immersion heaters at the same time.... Now if even one in 3 households in that street bought electric cars with fast charge points and all put them on charge at the same time:eek:
Click to expand...
That's my point exactly. If the infrastructure can't support fast charging how can they push us into buying electric cars? Hifi is on nobody's radar so the writing might be on the wall for Class A, valves etc.
 
hal9001 said:
That's my point exactly. If the infrastructure can't support fast charging how can they push us into buying electric cars? Hifi is on nobody's radar so the writing might be on the wall for Class A, calves etc.
Click to expand...

Are there post Brexit farming policy changes we've not been told about?
 
Barrymagrec said:
If that drop is on the shared incoming cable and it`s due to the new car charging circuit that`s a pretty duff installation and should be looked at.
Click to expand...
I've taken it up with Northern Power grid but as long as it's above 216V they wont give a monkey's. I don't know what the process is for installing a charging point but there IS a process. You can't just plug the thing into the mains. Will ask my neighbour what he did. I'm not mentioning hifi. They won't know what I'm talking about.
 
Barrymagrec said:
If that drop is on the shared incoming cable and it`s due to the new car charging circuit that`s a pretty duff installation and should be looked at.
Click to expand...
Maybe, but I'm not so sure, as long as you are referring to the supply side.

As long as the voltage delivered stays within the range 216 V to 253 V as delivered to the property over the distribution grid, then that's all the power company is obliged to maintain. Home equipment should be designed to cope with that, even the OP's current-hungry amplifier. But I don't know about specific cases.

Series resistance is normal in the mains supply grid. Hence there are always voltage drops of some amount compared to what's generated. The power generators know all about this, of course. In UK, 10% of properties have a mains grid series resistance exceeding 0.25 Ohms and 2% exceed 0.46 Ohms (source: IEC report TR 60725). And the OP is "in the middle of nowhere in rural Lincolnshire" so maybe one of that 2%.

With high power consumption from fast car battery charging a bigger than usual drop in voltage is to be expected. Charging a 75 kWh electric car battery over 10 hours, for example, adds 7.5 kW to consumption. At the 2% level that will drop an additional 15 V relative to "normal" when charging is happening. That's actually not as bad as the 230 V to 218 V the OP reports and it still looks within regulated limits.

If the OP has a rather higher than UK average electricity consumption then the voltage drop might exceed the limit and the power company might respond. But I guess that's unlikely to be the reality.
 
Voltage touched 214V this evening so outside of the designated range.Average drop is about 10 to 11V so now reading 219/220V. I would expect the amp to cope with this but I've emailed the manufacturer to check.
 
You must log in or register to reply here.


advertisement


Back
Top