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Discussion Starter #1
Apologies in advance for my lack of understanding of how electricity works and potential garbled terminology.

I have an e golf and hope to get a longer range ev (70 kWh battery) next April so will need to charge two cars.

Currently using a 3 pin plug to charge.
I have a cable suitable for 32A ready to go but what would be ideal is a charger with 2 outputs so when both in use would draw 16A per output but when only one is being used it would draw 32A. This would allow me to charge more 'rapidly' should I need to.
I realise I could have two 16A chargers but what I'm after is the best of both worlds.
Any help gratefully received.
Thanks.
 

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That doesn't answer the question in the title. Are you a politician? :)
I can neither confirm nor deny that accusation. :p
My point was that "load balancing" is what OP is asking for.

PodPoint do a dual 7kW unit, but may require extra hardware to load balance.
 

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Apologies in advance for my lack of understanding of how electricity works and potential garbled terminology.

I have an e golf and hope to get a longer range ev (70 kWh battery) next April so will need to charge two cars.

Currently using a 3 pin plug to charge.
I have a cable suitable for 32A ready to go but what would be ideal is a charger with 2 outputs so when both in use would draw 16A per output but when only one is being used it would draw 32A. This would allow me to charge more 'rapidly' should I need to.
I realise I could have two 16A chargers but what I'm after is the best of both worlds.
Any help gratefully received.
Thanks.
This would require a 60 Amp supply if both 7.2kw chargers were used at the same time, I know in ireland that's the standard supply into domestic houses. So you would need load balanced units, these reduce the supply to the vehicle if a domestic appliance draws a lot of current ie an electric shower or an induction hob.
You have to talk to an electrician that knows your house wiring.
Maybe you could get away with one 16 amp and one 32 amp.
Good luck
 

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The question really is why.... are you trying to keep your max draw to 7kw for house wiring/supply?

There are grants on home charge points - is there anything preventing you from having one fitted? Our pod point was £359 fitted and monitors the whole house load so if it gets over a set level of amps for the entire house, the pod point will reduce the power going to the car.

A combination of a 7kw pod point and a 16A charger plugged into a commando socket would work well, then you can choose which vehicle is in which?

Thanks.
 

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Discussion Starter #7
Thanks for all the replies. I realise that to charge from both outputs at 7.2kw would require 60A+, and I also realise that what I’m after might only exist in my fevered imagination.

OLEV grant is allowed for 2 chargers per household but as I don’t think I have capacity for more than 32A it looks like my only option is for 2x16A rather than the mythical intelligent charger with two sockets that will interchange from 3.6 to 7.2kw depending whether two vehicles are plugged in or just one.
 

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stegen does a smart evse controller that will allow load balancing up to 4 cars i believe. you would need 2 of those


plus 2 x contractors and 2 cables (or 2 sockets if you wanted un teathered)

A bit of knowledge is required to put it all together its not rocket science

(also with his new sensor box you can make it charge with just excess solar is you have panels!)
 

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Discussion Starter #9
The question really is why.... are you trying to keep your max draw to 7kw for house wiring/supply?

There are grants on home charge points - is there anything preventing you from having one fitted? Our pod point was £359 fitted and monitors the whole house load so if it gets over a set level of amps for the entire house, the pod point will reduce the power going to the car.

A combination of a 7kw pod point and a 16A charger plugged into a commando socket would work well, then you can choose which vehicle is in which?

Thanks.
Thanks for this. If I understand you correctly would t this require 48A? If one charger is running at 7kw and the other we’re to run at 3.6kw. The problem is I don’t in all honesty know how much spare capacity I have. I think most domestic properties have 100A supply so presumably if I only needed 40-50A most of the time this would work and with load balancing (such as you mention on you Pod pPoint charger all might be well?

Is there a simple way to assess your household load? Sorry to be such a numpty!
 

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I believe Tesla's charge points can do this load sharing/balancing..but they're not cheap.

Thanks for this. If I understand you correctly would t this require 48A? If one charger is running at 7kw and the other we’re to run at 3.6kw. The problem is I don’t in all honesty know how much spare capacity I have. I think most domestic properties have 100A supply so presumably if I only needed 40-50A most of the time this would work and with load balancing (such as you mention on you Pod pPoint charger all might be well?

Is there a simple way to assess your household load? Sorry to be such a numpty!
I'd charge 2 cars at 32Amp overnight, as I know the house uses < 250W during that time.

I 'future proofed' with the following (80Amp main house fuse):
32 Amp pod-point (£359)
32 Amp commando socket (£cheap) with type 2 EVSE (£199 from Octopus)
 

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Is there a simple way to assess your household load?
Podpoint do that when they work out if your house is suitable for a charge point.

Basically think about any big electrical loads and how big your master fuse is (60, 80 or 100A), e.g. Electric shower, Electric heating (underfloor or storage heaters), Cooker(s), etc. Small stuff like lights, tv, etc doesnt really matter too much.

Having the pod point with the monitoring clamp just keeps it simple, the installer said it had enabled them to fit charge points to properties with 60A fuses and other electrical loads.

Cheers.
 

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There are a number of ways to do this, but the best way is to look at any large loads that are likely to be running at the same time and decide whether you can add a diversity factor to them. For example, an immersion heater and EV charger could both run at the same time (makes sense if you have a cheaper time of day tariff) but you may feel that you will not run your oven at the same time. Even if you do an oven is generally not heating the whole time and standard rules mean that you only have to consider half of its normal load - so instead of say 13 amps (~3kW) you can count it as 1.5kW. Alternatively, if you have a smart meter run around your house and turn everything on at the same time and take a measurement from that!
Things are further complicated in the you can place load restrictors onto some circuits (typically EV charging ones) and prevent the peak current being excessive.
If you are using an OLEV grant the contractor has to do all of these checks before they claim the grant.
What I am confused about is why you only have one cable capable of 32A. In our house we have a total incomer of 100A and two 32A chargers without load restrictors despite twin ovens and an immersion heater - but with diversity it is within allowances. The only stupidity is that when we rewired our house about 12 years ago we disconnected the incomer for a couple of weeks and Western Power refused to reconnect us due to the local transformer being undersized for a 100A connection. After lots of shenanigans we won, the transformer is still the same, and we now are potentially pulling its full capacity into our property without any help from the neighbours (who aren't EV drivers but have things such as immersion heaters). Clearly the transformer can operate way above its rated capacity.
 

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The Zappi team can do some set up using the current clamp. They have made setups for houses with 40A incoming fuses to keep watch the total home load doesn't exceed this. I would send them an email.
 

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Discussion Starter #14
There are a number of ways to do this, but the best way is to look at any large loads that are likely to be running at the same time and decide whether you can add a diversity factor to them. For example, an immersion heater and EV charger could both run at the same time (makes sense if you have a cheaper time of day tariff) but you may feel that you will not run your oven at the same time. Even if you do an oven is generally not heating the whole time and standard rules mean that you only have to consider half of its normal load - so instead of say 13 amps (~3kW) you can count it as 1.5kW. Alternatively, if you have a smart meter run around your house and turn everything on at the same time and take a measurement from that!
Things are further complicated in the you can place load restrictors onto some circuits (typically EV charging ones) and prevent the peak current being excessive.
If you are using an OLEV grant the contractor has to do all of these checks before they claim the grant.
What I am confused about is why you only have one cable capable of 32A. In our house we have a total incomer of 100A and two 32A chargers without load restrictors despite twin ovens and an immersion heater - but with diversity it is within allowances. The only stupidity is that when we rewired our house about 12 years ago we disconnected the incomer for a couple of weeks and Western Power refused to reconnect us due to the local transformer being undersized for a 100A connection. After lots of shenanigans we won, the transformer is still the same, and we now are potentially pulling its full capacity into our property without any help from the neighbours (who aren't EV drivers but have things such as immersion heaters). Clearly the transformer can operate way above its rated capacity.
There are a number of ways to do this, but the best way is to look at any large loads that are likely to be running at the same time and decide whether you can add a diversity factor to them. For example, an immersion heater and EV charger could both run at the same time (makes sense if you have a cheaper time of day tariff) but you may feel that you will not run your oven at the same time. Even if you do an oven is generally not heating the whole time and standard rules mean that you only have to consider half of its normal load - so instead of say 13 amps (~3kW) you can count it as 1.5kW. Alternatively, if you have a smart meter run around your house and turn everything on at the same time and take a measurement from that!
Things are further complicated in the you can place load restrictors onto some circuits (typically EV charging ones) and prevent the peak current being excessive.
If you are using an OLEV grant the contractor has to do all of these checks before they claim the grant.
What I am confused about is why you only have one cable capable of 32A. In our house we have a total incomer of 100A and two 32A chargers without load restrictors despite twin ovens and an immersion heater - but with diversity it is within allowances. The only stupidity is that when we rewired our house about 12 years ago we disconnected the incomer for a couple of weeks and Western Power refused to reconnect us due to the local transformer being undersized for a 100A connection. After lots of shenanigans we won, the transformer is still the same, and we now are potentially pulling its full capacity into our property without any help from the neighbours (who aren't EV drivers but have things such as immersion heaters). Clearly the transformer can operate way above its rated capacity.
I'm pretty sure we have 100 amps incoming also. The 32 amp cable to which I refer is one that was run from the consumer unit into the garden when we had an extension built on the off chance that we would require an external power supply. This is a 6mm armoured cable which I'm told will handle 32 amps although I'm not sure whether or not it will handle even more. The reason I
feel restricted to this outgoing cable is that that it would mean significant disruption to trench another cable under paving and from the back of the house all the way round to the front.
 

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I have a cable suitable for 32A ready to go but what would be ideal is a charger with 2 outputs so when both in use would draw 16A per output but when only one is being used it would draw 32A. This would allow me to charge more 'rapidly' should I need to.
If one is not made commercially, it ought to be as such a charger would be of use for minor destination charging.

Basically, each charger tells the car (by a control wire in the lead connecting the charger to the car) the maximum it can draw, and this maximum can be preset (? by DIP switches) so that a single design of charger can be used for varying maximum currents.

Also, each charging outlet has a contactor which connects the mains to the charging lead when all the pre-charging checks have been carried out.

It should therefore be possible to have a dual charger half which allows 32A current to be drawn unless the contactor of the opposite half has been activated, when the current draw is restricted to 16A.

A more sophisticated system (which is used by Zappi) is to sense the total current in the supply lead, and restrict the charging current on each half accordingly. This allows the charging current on one half to rise above 16A as the charging current drawn on the other half reduces as that car approaches a full charge. (Alternatively, one side can be arranged to have priority and the second side is controlled to let that car have what is left of the 32A supply availability).

PS. According to my old (1991) edition of the Wiring Regs, a 6mm2 armoured cable has a maximum current rating of over 40A, so it is probably worth having a word with your local electrician as to what your cable can actually carry continuously.
 

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Discussion Starter #16
I’m going to cut and paste most of these replies and send to my electrician mate who is new to the ev charging game. Thanks so much to all for your replies.
 

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Discussion Starter #17
If one is not made commercially, it ought to be as such a charger would be of use for minor destination charging.

Basically, each charger tells the car (by a control wire in the lead connecting the charger to the car) the maximum it can draw, and this maximum can be preset (? by DIP switches) so that a single design of charger can be used for varying maximum currents.

Also, each charging outlet has a contactor which connects the mains to the charging lead when all the pre-charging checks have been carried out.

It should therefore be possible to have a dual charger half which allows 32A current to be drawn unless the contactor of the opposite half has been activated, when the current draw is restricted to 16A.

A more sophisticated system (which is used by Zappi) is to sense the total current in the supply lead, and restrict the charging current on each half accordingly. This allows the charging current on one half to rise above 16A as the charging current drawn on the other half reduces as that car approaches a full charge. (Alternatively, one side can be arranged to have priority and the second side is controlled to let that car have what is left of the 32A supply availability).

PS. According to my old (1991) edition of the Wiring Regs, a 6mm2 armoured cable has a maximum current rating of over 40A, so it is probably worth having a word with your local electrician as to what your cable can actually carry continuously.
Thanks very much for your reply. Very useful and I think is exactly what I’m after.
 

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I have a cable suitable for 32A ready to go but what would be ideal is a charger with 2 outputs so when both in use would draw 16A per output but when only one is being used it would draw 32A. This would allow me to charge more 'rapidly' should I need to.
On a Leaf, you can set the (6kW) charger to use only 3kW. Won't the Golf do the same ?
 

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Discussion Starter #19
On a Leaf, you can set the (6kW) charger to use only 3kW. Won't the Golf do the same ?
I’m sure it can and I think it’s done automatically. But what I need is a charger that can chop and change according to available current.

I’m using a 3 pin plug ATM which draws 10A @240v so charges at 2.4kw (if my 1978 o level physics serves me well)
 
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