Is it OK to use a granny charger as my main charger?

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hungerdunger
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Post by hungerdunger »

My circumstances aren't typical of the usual ID.3 user: we have a 9kWh solar panel setup, and have recently installed a 9.5kWh battery backup system to maximise the use of our solar generation. I have also been thinking of getting a charger before the 31 March deadline, but I'm having second thoughts.

I can see that as we enter the spring, the panels and battery combined can provide a steady source of energy through the day as long as the weather is fairly bright, so yesterday for instance I could have plugged the granny charger in around 9am and left it chugging away at 2.3kWh until 5pm and still have left a fair amount of charge in the battery. Additionally we can't get the car closer than about 15 metres to the house so to run the supply to a proper charger we'd have to dig up our garden. Being retired we are not heavy users of the car, so as long as we don't get a prolonged spell of very dull weather we could probably manage on the granny charger for the majority of the year.

However I seem to remember reading somewhere that prolonged use of the granny charger is not recommended although I can't remember why - and whether it was to do with my domestic supply or the car itself. Can anyone advise me?
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steviebabes
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Post by steviebabes »

I don't think it will harm the car but I believe charging at under 7kW is less efficient so in the long run will use more electricity. As the power from your panels is free I can't see this being a problem.
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sidehaas
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Post by sidehaas »

I'm no expert myself but have picked up quite a bit of advice on this via the forums since ordering our car (particularly the speakEV forum.)
The basic answer is that it's not a great idea to run 10A (the usual rating of a granny charger) through a 13A socket for hours at a time because it can cause the plug and socket to overheat and cause a fire risk. People seem to only recommend it for emergency or very occasional use and suggest that ideally you should reduce the current to 6A if doing it regularly to create some extra safety margin. The ID3 let's you reduce charging current very easily (there is an option in the in-car menu) but only being able to charge at 6A would be pretty limiting - a full charge would theoretically take 40 hours.
That said, there are people doing what you suggest.
Some of them using imported granny chargers bought off Amazon that allow it to run at the full 13A... it won't take you long to find photos of burnt-out sockets on speakev if you go looking.
Have you looked up the maximum type 2 cable length you can get? It might not be necessary to bring the charger to the car. You can certainly get 10m cables, not sure about 15m+. If you can find one long enough from a reputable supplier it would be much better than a granny charger on an extension lead.
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Utumno
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Post by Utumno »

In your place I would be doing the following :-

1) Purchasing the highest quality “granny” charger I could afford, being certain to check that the BS1363 plug is monitored for temperature while charging
2) Employ a qualified electrician to run tests on the socket and circuit I intend granny charging from, to be certain the household electrical system supporting the “granny socket” will remain safe when charging for hours.
3) Comparing the costs of simply adding something like a Zappi system into the solar/battery mix you already have versus the expense in options 1&2.
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QPRfan
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Post by QPRfan »

Currently I have a Leaf and every year, for the past 4 years, from March to September I probably use the granny charger 95% of the time to utilise the solar I am generating.

It has never caused me an issue.

When (if) my ID3 arrives I plan to continue with thgis method
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Alanpyle
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Post by Alanpyle »

I have to park my car 13m from my house,I bought a 15m charge cable and I can plug it in and put the cable away in 5 min max each way& I am disabled with Arthritis
steviebabes
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Post by steviebabes »

If you are worried about overheating a 13A socket fit a 16A commando (caravan EHU type) socket on your outside house wall. Cut the 13A plug off and fit a 16A commando plug. If you need to use the granny lead at someone else's house you can get short 13A plug to 16A socket patch leads quite cheaply and carry this with you.
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Daveion
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Post by Daveion »

I charged my car predominately via a granny from Jan-Nov 2021. The granny was supplied with the car and a home charger wasn't possible at my house but never had any problems at all.
My longest charge was 16 hours and I charged 2 or 3 times a week. I made a number of checks on the plug but it never got more than slightly warm.
Its important to have a good quality socket so the pin to socket contact doesn't allow any arcing.
I have a Masterplug double outside socket IP65.
My granny charging amounted to around 4,000 miles.
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hungerdunger
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Post by hungerdunger »

Thanks everyone for your replies and advice. As my granny charger is conveniently plugged into an existing 13A socket in an outbuilding I'm thinking I'll probably stick with it for a year or so to see how it goes. Even though it means losing the grant, it will certainly avoid a lot of disruption.

As regards the advice to get a good quality granny charger, I bought the VW one when we bought the car. I'd like to think that for the price it's good quality, but I'm willing to be corrected.
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Utumno
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Post by Utumno »

hungerdunger wrote: Sun Feb 27, 2022 11:41 pm Thanks everyone for your replies and advice. As my granny charger is conveniently plugged into an existing 13A socket in an outbuilding I'm thinking I'll probably stick with it for a year or so to see how it goes. Even though it means losing the grant, it will certainly avoid a lot of disruption.

As regards the advice to get a good quality granny charger, I bought the VW one when we bought the car. I'd like to think that for the price it's good quality, but I'm willing to be corrected.

The VW charger is a good quality one. I'd still recommend you get a sparky in to check that the outbuilding circuit is safe to push 10A for hours at a stretch though unless you're already certain it's fine, as sometimes circuits can overheat and cause all sorts of problems to the house electrical system, possibly resulting in an electrical fire. It's very rare, but it's possible.
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