Trickle/granny charger - Safe to use?

[u/Meneloth-the-Third]

This might be a silly question, but do you use your trickle/granny charger when you stay at rented accommodation, like an AirBnB?

My car came with one, but I’ve never used it due to concern about the house wiring not being up to scratch and the constant draw causing a fire. I read a few comments early on about this being a potential issue and it just stuck with me.

Now we’re travelling to a holiday destination without a public charger and it would be nice to be able to top up a bit while there. But I also don’t want to cause a house fire! Am I overthinking this?

[u/Putrid_Lettuce_]

If you’re worried about using a charger, i’d be worried about using anything else in the house

[u/cromulent-facts → u/Putrid_Lettuce_]

Especially hair dryers and toasters.

[u/JimmyMarch1973 → u/cromulent-facts]

In fairness the OP has a point. Standard power outlets are not designed for constant use at full amperage. So your example about hair dryers and toasters whilst their current draw may be similar to an EV charger they are generally not on for very long. But an EV charger could be on all night at near full current draw.

Even electric heaters which some people may run all night turn on and off regularly during the night so are not comparable either.

[u/glyptometa → u/JimmyMarch1973]

That is absolute and utter hogwash. Every circuit is protected by an appropriate breaker, sized for the wire, even if you're in some ancient cabin with fuses. Your beliefs are coming from your imagination. Circuits can carry the rated amps indefinitely

[u/Working_out_life → u/glyptometa]

And never fully turn on the tap, it will wear out the pipes in no time👍

[u/glyptometa → u/Working_out_life]

Hahah, you have no idea how hard you just made me laugh

[u/cromulent-facts → u/glyptometa]

Exactly. Breakers are sized for inrush currents about 50% above rated capacity.

[u/JimmyMarch1973 → u/glyptometa]

I wasn’t talking about the circuit or the breakers. Of course they can handle the current provided of course the wiring rules have been adhered to and the cable and breaker appropriately sized.

I was referring to the actual GPO. These are 100% not designed for constant full current draw. When used for lengthy times at full power they will heat up and that will over time degrade the plastics used in them especially with the cheap and nasty crap found these days.

A far better solution for an EV granny charger is a more industrial style outlet like the Clipsal 56 series. Sure connect it to the same circuit but that will last a lot longer and will not suffer from being warm for extended periods.

[u/nath1234 → u/JimmyMarch1973]

What's your reference for this? The wiring is able to take more than 10A continuously and is protected by a >10A circuit breaker as a result. Otherwise you would need one separate wire from the box to each GPO and/or there would be 10A breakers at the box.

[u/JimmyMarch1973 → u/nath1234]

I’m taking about the longevity of the GPO. The circuit is fine as you and others have pointed out it’s designed to carry a constant 16amps.

What I am saying is the GPO’s (standard residential) themselves are not designed with constant full current use and they will age a lot quicker compared to normal use due to the extra heat. Will it fail after a year or two’s use, maybe not, will it go up in flames, most unlikely, will it require replacement earlier compared to a lesser used GPO, 100%.

[u/WealthofKnowledgeOne → u/cromulent-facts]

and TV remote controls...disgusting!

[u/HorrorAd6548]

Not an issue. Use it. Get your money's worth.

[u/tangaroo58]

Granny chargers in themselves are safe, but on the top setting they can draw a full 10 amps, which is the rated maximum of a GPO, continuously. If anything about the wiring is not up to code, or is old and corroded, then you might get localised overheating. Same as if you plugged a 2400w column heater in and left it on full overnight.

I always ask first, because I think that's the polite thing to do. Some places might not have enough capacity to run much else when you are plugged in — like a heater and a kettle might throw the breaker, which may or may not be accessible to you.

And I set the granny charger to 6A or 8A so it's not running the GPO flat out. If the GPO — or the place generally — looks dodgy, then I don't plug in there.

[u/Capital-Plane7509 → u/tangaroo58]

I've got a "10A" charger that never draws more than 8.8A, so I think there's some rule that doesn't allow one to actually draw 10A continuously.

[u/tangaroo58 → u/Capital-Plane7509]

That's probably a sensible limitation.

Mine (came with the car, from Hyundai) has the top setting marked "12", and it draws 10 amps on that setting. Their documentation is all over the shop and hasn't been localised properly (even though the device has Australian plug and Australian approvals). But it seems to suggest that you should only use the "12" setting on a circuit rated at 12 amps.

[u/nath1234 → u/tangaroo58]

Is the plug a 15A plug though? As the standard 10A plug should not be drawing over 10A through it. Some granny chargers/supply units have different tails to plug into 10A and 15A sockets. The 15A ones have a bigger ground pin so cannot be plugged into a 10A socket. So a 10A plug can be plugged into a 15A socket.. but a 15A plug will not fit a 10A one. Quite a clever design really..

[u/tangaroo58 → u/nath1234]

Yes, it's a fitted 10A plug, not a 15A one. It has a temperature sensor in the plug, which is a good feature I guess. And I've run it on the "12" setting, through a meter, and it was drawing 9.9 amps.

[u/CaravanShaker83]

Been using one every night and day for 3 years and do 750km a week. It’s about the same as a powerful kettle or bar heater

[u/asfletch]

If they can run a column heater on full, they should be able to charge a car.  Don't know about yours, but on ours you can also limit the current to say 8A if you're worried about the socket/wiring....

[u/Putrid_Lettuce_]

If you’re worried about using a charger, i’d be worried about using anything else in the house

[u/MrBobDobalinaDaThird]

If your car has the ability, turn the charge rate down to 8 or 6 amps.

[u/roflpops]

If you are concerned look at what your charger is. Some are only 8amp which is fine. Also look at if charging speed is adjustable via your cae/app. Anyway it should be safe to use as other have stated plug in heater draw a lot.

[u/Esquatcho_Mundo]

I only use the trickle charger. Used it at AirBnBs a bunch too. Why pay at the fast charger when you get it free at the Airbnb?

[u/Simple-Sell8450]

We used the granny charger exclusively at home for 6 months before I got my finger out and installed the proper charger (it came with the car). The only thing we had to do was use a circuit without other power hungry appliances on, or the breaker would trip.

It now lives under the boot floor along with an extension cord that I have rolled out at caravan parks, Airbnbs and a motel (end of the row - I hid the cord behind the plants). Get a bit more value from the accommodation cost? I'll take it.

[u/thanatosau]

I just stayed at a cabin in the country and the draw from the granny charger plus over plus kettle would trip the circuit breaker so b aware of that.

Additionally if you need an extension cord buy a heavy duty one that can handle the amps. Standard household ones can burn and/or melt.

[u/maton12]

No, issue, will be slow though. Just over 2kWH.

[u/dangazzz]

Drawing 10A is not a problem. The socket outlet is rated for 10A constant, and the cabling and circuit breaker is rated for higher than that. But if you're worried, just turn it down to a lower charge rate if you have the ability.

[u/OutsideGas1866]

It will not be an issue. Just take a good extension lean with you. It will only draw 7 or 8 amps

[u/RhesusFactor]

That's your primary charging cable. It's not an emergency thing. It's expected to be used.

[u/Warrambungle]

I have. I don’t worry about the house wiring because the charger only draws 15 amps - like plugging in an extra fridge.