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Hi,

Since taking delivery of my BMW 330e a few months ago I have been relying on plugging the granny charger into a 13A socket in the garage and running the charging cable out under the garage door. I then leave the charging plug tucked away in the corner of the driveway when I go out. With winter round the corner I feel it is time to get a proper charger and have a few questions I hope people can help with.

Firstly there is the question of which make to go for. I'm thinking Rolec or Pod Point. Benefits of the former seem to be the low price and the fact I could get a unit which includes a 13A outdoor socket for the jetwash. Plus it seems to be easier to repair. Downsides are the looks and the past reliability issues.

Pod Point looks nicer and is more expensive but I like the fact it integrates with the Pod Point app which I already use for public charging.

Any views on which is best?

Then there is the question of location. My house is on a corner plot so I have a garage and driveway at the front and another garage and driveway at the back. Currently I park my car at the back and charge as described above with the granny charger powered from the back garage. Ideally that is where I would install the new charger too. And the consumer unit in the back garage has spare capacity for a new circuit. However, the back garage is fed by an underground cable that comes off a 32A MCB in the house. Apart from a wireless access point and two IP cameras there's never anything else running in the garage at the same time as I'm charging - so in theory I have enough spare capacity to go for a 7kW charger (especially as the car only charges at 3.6kW). But would an approved installer be allowed to fit one or would they force me to go for a 16A unit? Desire to future-proof means I'd prefer to get the 7kW unit if possible.

My other option is to install the charger on the front driveway and power it from the front garage. This is where the main electricity supply enters the house and it's on a 100A main fuse so no worries there. However, I'd need to install an extra CU in the front garage just for the charger as the existing CU is full. And the other drawback is I would need to park my car on the grass (which is not ideal in winter) or risk getting blocked in by Mrs Autolycus if I park on the drive in front of the garage.

So the question here is - if I can't get a 7kW charger installed on the back drive, is it worth parking in a less convenient location on the front drive just so as I can get the beefier charger?

Thanks in advance for any advice.

David.
 

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I guess it all depends on your charging requirements. 3.3 kW will charge you at appx 12 miles/hour, 7 kW at 25 miles/hour. If your car (present, or future if planning on staying at this house) can charge at 7, but all you have is 3.3 and you've come home with empty battery, and want to dash out again soonish, you'll be biting your fingernails & urging the bloody thing to get a move on! The future seems to be pure EV, and I reckon most if not all will be 7 kW charging capable, and when those cars arrive & you've got one, you'll be weanting to upgrade sharpish, so why not bite the bullet & invest in a 7kW one now?

If all you do is overnight charge, then a 3.3 kW one will get you 100 miles range in 10 hours, so is probably okay for the current gen of cars (30-40 kWh-ish). But to fill a 60 kWh battery from empty will take about 65 kWh from grid, so at 3.3. kW that's 20 hours charging - rather a long time to wait.

I chose a 7 kW Rolec to future-proof myself, and it's probably helped me, as I've had no unreliability probs in 3 years running it at 3.3 kW! I believe the new ones have a better RCBO in which should mean unreliability is a thing of the past.
And as mine lives inside my gge, I'm not fussed whether it's elegant or not. And I can, & have, modified it myself internally - they're simple to fix if things go wrong. Happy with mine.
 

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PodPoint will certainly fit a 7kW if you ask them. While it does need its own breaker (C32 or C40 for preference), there appears to be a DIP switch bank inside where the installer can cap the maximum the charger will supply to fit in with any odd wiring constraints.

If you fit a 7kW charger and then plug a 3.6 vehicle into it, the two will talk to each other and negotiate the safe upper limit for charging. In your case, the PodPoint (or Rolec) would offer "up to 7" and the car would ask for (and be given) "up to 3.6".

If your back garage is supplied off a C32 in the main house CU and you want to charge there, PodPoint may simply ask you to sign a waiver to "not use any other circuits in the garage when charging and only charge at night". By this they actually mean "don't roll home from work, plug the car in then fire up the TV, dishwasher and cooker while the tumble drier is doing its thing".

While in the ideal world you would be best off running a new CU off the 100A fuse on a 10mm cable to a C40 breaker to deliver a clean 7kW, you are fine with a 6mm cable off a C32 breaker and being sensible since your (current) car is only a 3.6kW device anyway.
 

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You need to investigate the cable to the garage. If that can handle more, you can upgrade the MCB on the CU. If it can't, how easy would it be to run an upgraded cable to the garage? Is there an underground conduit that you would allow you to pull through a new cable?
 
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