Octopus Twintelligent Go will be launched soon, lol

 

The same diversity rules apply. Depending on your current loading, you might need a main fuse upgrade, or just a smart charger with dynamic load limiting.

 

I had a second wall box installed a couple of years ago, no problem. I have 100A main fuse and am not on a looped supply. Both wall boxes feed off the incoming supply after the meter but before the domestic CU.

 

Yeah i think the fuse will need sorting, its only 60A. I dont really have any large electrical loads, no electric shower, no induction hob, the only other thing is the home battery which charges up overnight.

 

I have 3 evs in my household. I maintain them using a 7kw podpoint and an external 13 amp socket with 10 amp granny chargers.

I use to have a good fixed rate deal so could charge at anytime so had no issues with all doing 40 to 120 miles a day. How I have 6 hours of 7.5p kWh rate and find it a challenge but only 1 car is doing high mileage now with 80 to 120 miles a day. It’s challenging but doable, with using the weekends to get the cars all charged up for the week ahead.

I do have the idea of a second 7kw charger, especially to maintain the cheap rate with a compatible charger and the stories of podpoint chargers failing soon after warranty. But in no rush.

I am lucky I got an upgrade to 100amp when I needed the cable to the fuse checked just before the podpoint install and it’s not looped.

 

There are options, you could have a second charger limited to 3.6 kW to give you 20 kWh to a 2nd car or two if need be if all 3 cars are doing 70 miles plus per day, the question does arise, what happens when you get a heat pump and make a cup of tea at 3 in the morning!

 

Just wondering how folks have got on with having a second charger installed.

The rules have seemingly been tightened up a lot since my old Rolec was installed 6+ years ago.

Am i going to have a fight on my hands? How have others got on?

Few people need more than one charging point even if they have more than one BEV. Most people only need to charge their BEV once-or-twice a week. Even those households where both people put in mega milages the first person home from work can plug straight in and you can then swap the cars over before you go to bed. imagine the first person getting home at 6pm plugging in and charging for 4hrs at 7.4kW adding c.30kWh and c. 120miles of range. At 10pm the cars can be swapped over and the 2nd car can charge for 8hrs adding 240miles of range. I can’t think of a single household where this wouldn’t be sufficient.

 

Just wondering how folks have got on with having a second charger installed.

The rules have seemingly been tightened up a lot since my old Rolec was installed 6+ years ago.

Am i going to have a fight on my hands? How have others got on?

Just had a 22kW Zappi installed (alongside my existing 7kW PodPoint), with no issues.
But we have a 3-phase supply - not sure if 3 x 60A or 3 x 80A.
That might be an issue if we ever managed to use both chargers at full power simultaneously, but I certainly intend to avoid that.

 

Yeah, my car needs charged most nights, joys of a 95 mile commute. Typically takes 35-40kwh. Thus we'd quite like a second charger for the second car. 3.6kw would probably be fine though.

The main trick being fitting everything into the 6 hours of cheap rate...

 

Is there an EVSE with two sockets? It might be sufficient to have one EVSE if both cars can charge via timers?

 

There are ones on the market but I think they just drop to 3.7kw when using both. He doesn't have enough hours to pull the rates he wants.

The biggest problem is the poor efficiency of his main EV 35-40kwh for 95 miles. If he had a more efficient EV a twin output charger might work.

 

Interesting page here:

https://www.smarthomecharge.co.uk/features/do-you-need-two-home-charge-points-if-you-have-two-evs/

 

You'll need to install your new charge point with CT clamp to reduce its speed when it detects high load. You then charge using your existing dumb charge point and use the new charge point with the car that drives less daily.

Or use existing charge point and a granny charger for the shorter range car. 32 amp + 10 amp is still comfortably under 60 amp.

 

You'll need to install your new charge point with CT clamp to reduce its speed when it detects high load. You then charge using your existing dumb charge point and use the new charge point with the car that drives less daily.

Or use existing charge point and a granny charger for the shorter range car. 32 amp + 10 amp is still comfortably under 60 amp.

He also has a home battery that he charges overnight so over a 6 hour period that might be another 7A presuming it's a 9.5kWh battery. He might also be heating water in the cheap rate as well.
I guess long-term he will probably get a heat pump too.

So realistically he either needs to upgrade the supply or accept some charging outside the cheap window (which is still cheaper than petrol) on the second EV. This might only need to be a few hours in the week as the charger should be available on the cheap rate Fri or Sat night.

Or as said get a main car that does more than 2.5m/kWh. A Tesla seems a good fit if doing 95 miles a day.
He must have been spending £15-£20 a day on his old ICE car so a little power at 30p or whatever doesn't seem a bad tradeoff.

 

The biggest problem is the poor efficiency of his main EV 35-40kwh for 95 miles

Its winter 🤷Very lucky to get over 3mi/kwh at this time of year. It took 33kwh last night. But 42 the night before probably because it didnt get plugged in over the weekend and had some local running about on there too.

You'll need to install your new charge point with CT clamp to reduce its speed when it detects high load. You then charge using your existing dumb charge point and use the new charge point with the car that drives less daily.

Or use existing charge point and a granny charger for the shorter range car. 32 amp + 10 amp is still comfortably under 60 amp.

Yeah granny will be the starting point, i also have a commando-equipped unit i used to use at work back when i had the LEAF before, but obviously no handy commando socket to connect it to.

Problem i ran into previously is that the DNO no longer do Adhoc fuse upgrades. They want a form filled out with a list of all the equipment existing and proposed and a maximum demand calculation done.

 

Its winter 🤷Very lucky to get over 3mi/kwh at this time of year. It took 33kwh last night. But 42 the night before probably because it didnt get plugged in over the weekend and had some local running about on there too.



Yeah granny will be the starting point, i also have a commando-equipped unit i used to use at work back when i had the LEAF before, but obviously no handy commando socket to connect it to.

Problem i ran into previously is that the DNO no longer do Adhoc fuse upgrades. They want a form filled out with a list of all the equipment existing and proposed and a maximum demand calculation done.

Yes there’s a difference between 3.5m/kWh in the car and what actually is used from the wall. Including the loss in the EVSE and the cars onboard charger, with winter motorway driving etc…

I have similar issues. We have 9.5kWh house battery, and heat water with immersion overnight. My wife has a 65 mile daily commute, needs a daily refill if not a full 4 hours. Still I will have no desire to get out of bed at 3AM to swap cables between cars. We use a combination of granny charging and podpoint.

We had Octopus check meter and tails etc and they were happy we could have a 100amp fuse, but UKPN disagree and only gave us 80amp.
Now I need to figure out how to configure the GE stuff and the podpoint so that they know they can have 80amp, as well as figuring out why octopus and UKPN seem to disagree on whether our installation will be ok for 100amp.

 

Ah home battery, can that reduce its charge rate in order to not go over?
For example, I have 5 kW V2H for Leaf, only do 30-100%, so instead of 2.5 hours, I would prefer to do do 2.1 kW for 6 hours. Unfortunately the V2H charger doesn't support this with scheduling.

Another idea, get Ohme or Zappi installed and be on IOG. Then rely on smart scheduling to get extra slots. Does it re-roll allocated time slots when it senses reduced charge rate? You'll need to manually disable battery when extra IOG slots are active.

But as Gav said, to solve root of your problem, you really need main fuse upgraded.

 

I guess i'll get back onto SPEN and see if i can get the fuse upgraded.

On a typical night i could imagine 32A into the main car, 10A into the home battery and 16A into the second car. So right against the 60A limit just with that load. Even 80 would make things more comfortable.

I also wondered if the main charger was limited to say 25A, would intelligent octopus realise it wasnt the full 32A and adjust its schedule accordingly?

 

On an 80 amp fuse you could have 2 32amp chargers with one having a ct clamp limit of 75 amps and one set at 80. Might be worth asking if they can upgrade you to 3phase to give yourself headroom for the future if you would be charging most nights

 

Yeah I think if I can get an 80A fuse I should be fine, the LEAF will be happy charging at 16A anyway.

3 phase upgrade is likely to cost thousands, dont think that makes much sense. Maybe further down the line when the gas boiler gets replaced with a heat pump and the gas hob ends up being swapped out for induction etc etc.

 

Get a quote for 3 phase, at the same time as you ask for a fuse upgrade. You might be surprised! ...probably not, but you lose nothing by asking. If nothing else, you'll have another figure to plug into your spreadsheet when calculating the cost of a heatpump.

FYI, I installed a 3kw induction hob myself. It came with a plug top, and works just fine off the oven circuit, which already had a double socket for the oven and gas hob sparker. In 3kw mode, I can only use 2 burners at a time, but since I've never used more than 2, that's not an issue. It cost £160 from Amazon, making it an absolute no brainer. Should I need more, I can move a jumper and call the helpdesk to upgrade it to 6kw, but running a fat cable there will be very difficult, so I'll leave it.

 

Why do you need a second charger? I've got two EVs and manage very well with just the one. Only a couple of times I've had to be up at 1:30am to swap the cable from one car to the other. Still ended up with two fully charged.

 

I have two 7kW charge points, having second fitted wasn't an issue, plus I have 30kWh batteries for the house, they all charge together no problem in my five hour cheap slot. Max load has been about 19kW. 100A fuses so 23kW roughly max load, I often run the dishwasher at the same time. No issues.

 

Challenge is you now can't really get 100a fuse upgrades now. If you didn't have a 100a fuse already then you would need 3 phase for that load if upgrading the fuse now.

 

No need for three phases with that load. My fuses were upgraded from 80A to 100A in early January, all new cabling to the street supply. 25kW is the absolute maximum load on my supply. My DNO is UKPN. no charges for the upgrade and no charges for 12kW export allowance either.

 

Also I do have a three phase supply to my house, but only currently use one.

 

That's possibly why you have 100 amp fuses then. Even though your using one phase only they will have checked the local grid before installing it or it would have been upgraded from an old 3phase cut-out when these were the normal install to a house. They generally don't upgrade single phase only supplies above 80 amp fuses though.

 

Haha. 24kW at 250v is 100A. 100A fuse upgrades are routine for my DNO, and my systems are all fine. I think I'm qualified to confirm.

 

Indeed, but two 7.2kw (14.4kw) chargers and a 30kw battery just doesn't add up to 24kw its potentially 44.4kw. Throw in domestic consumption like your dishwasher and you've got issues.

Admittedly it's been 50years but I can still do math. But if it works for you caveat emptor.

 

It's a 30kWh battery, I don't charge it at 30kW. That's about 6kW max, but usually around 5kW as I don't need to charge it that quickly

 

OK that helps. 6kw 25amps. Add to the chargers a total of 85 amps leaving a whopping 15amps for domestic usage. Yeah that's how it works then.
Still pushing the envelope though.
Do you sell your 'deemed' pv export power? Having a home battery is good isn't it.

 

The battery's great! I sell everything I generate at 12p, as I can buy overnight at 4.5p. My battery lasts easily throughout the whole peak period, even over Christmas with all the cooking and dismal weather the lowest it got to was about 22% 🙂.

I also get FIT generation payments on 4kW of my arrays, so overall throughout the year I make a good profit and have no net electricity bill.

 

5 hour window 4.5p EDF? Me too till May.