I want to get an electric van but need to restrict the amperage draw.

Thread Starter

David Quartermain

Joined Sep 6, 2018
7
Van will be parked at bottom of yard with only a 10amp supply (220v) charger requires a 13amp supply. I realise if you lower the draw the charging time will increase and that is not an issue. I would like to almost trickle charge at 5amp so can still have lighting. I can't see how slower charging will reduce battery life but Nissan only make a 13amp charger that will overload the circuit.

Ideas please?.
 

crutschow

Joined Mar 14, 2008
23,352
If you can't get a lower current charger, then I think you need to boost the supply up from 10A to 13A.
What limits the supply to 10A?

What is the charger output (battery) voltage?
 
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Hymie

Joined Mar 30, 2018
708
Although the charger may have an input rating of 13A, it may not draw that current in use. Therefore I’d recommend you measure the actual current draw which might be within your 10A supply rating.
It won’t damage your 10A supply if during measurement the circuit is loaded at 13A for a short period.
 

Thread Starter

David Quartermain

Joined Sep 6, 2018
7
Hi,

It's a smart charger that draws what is required and can be up to 13amp. The issue is the supply cannot be upgraded (50m run and buried) plus need to make sure it will only pull 5 amp as I have lights and a small fridge. Nissan do not make a smaller charger.

Van will be parked up 14Hrs per day so I realise half the ampage requires double the time but no issue just need to restrict so can only draw 5 amp to avoid overload on delicate circuit.

Thanks
 

oz93666

Joined Sep 7, 2010
669
As Hymie says the 50 m cable will certainly be able to handle 13A , but because of the length 220V will not arrive at the other end , this is not a problem , the charger will still function ....

Don't look for problems that don't exist , try the existing wiring first with the Nissan charger ,it will almost certainly work and not effect your other lights and fridge . You may have to change fuses to 15A.
 

Thread Starter

David Quartermain

Joined Sep 6, 2018
7
As Hymie says the 50 m cable will certainly be able to handle 13A , but because of the length 220V will not arrive at the other end , this is not a problem , the charger will still function ....

Don't look for problems that don't exist , try the existing wiring first with the Nissan charger ,it will almost certainly work and not effect your other lights and fridge . You may have to change fuses to 15A.
 

ericgibbs

Joined Jan 29, 2010
8,734
hi,
If a 12V battery charger required a 13Amp supply from a 220Vac, taking into account the step down ratio of the charger transformer.

Stated max: 220Vac * 13A = 2860W
Actual max charge: 15Vdc *10A = 150W

Assume 100% conversion.
So actual draw from the 220V supply 150/2860 = << 1 Amp

It would be possible to sit down and work out the figures exactly, but for this application I would expect the maximum mains current for the charger would be less than 1 Amps.

E
 

Thread Starter

David Quartermain

Joined Sep 6, 2018
7
50m run not 50mm cable. Cable is 1.5mm, hope that clarifies.

I am not a qualified electrical engineer but that is not heavy enough.

I hope we have crossed wires (excuse the punn) as I certainly hope you are not advising anyone to upgrade their breakers without checking thickness of cable.

David
 

Thread Starter

David Quartermain

Joined Sep 6, 2018
7
hi,
If a 12V battery charger required a 13Amp supply from a 220Vac, taking into account the step down ratio of the charger transformer.

Stated max: 220Vac * 13A = 2860W
Actual max charge: 15Vdc *10A = 150W

Assume 100% conversion.
So actual draw from the 220V supply 150/2860 = << 1 Amp

It would be possible to sit down and work out the figures exactly, but for this application I would expect the maximum mains current for the charger would be less than 1 Amps.

E
hi,
If a 12V battery charger required a 13Amp supply from a 220Vac, taking into account the step down ratio of the charger transformer.

Stated max: 220Vac * 13A = 2860W
Actual max charge: 15Vdc *10A = 150W

Assume 100% conversion.
So actual draw from the 220V supply 150/2860 = << 1 Amp

It would be possible to sit down and work out the figures exactly, but for this application I would expect the maximum
hi,
If a 12V battery charger required a 13Amp supply from a 220Vac, taking into account the step down ratio of the charger transformer.

Stated max: 220Vac * 13A = 2860W
Actual max charge: 15Vdc *10A = 150W

Assume 100% conversion.
So actual draw from the 220V supply 150/2860 = << 1 Amp

It would be possible to sit down and work out the figures exactly, but for this application I would expect the maximum mains current for the charger would be less than 1 Amps.

E
Electric vehicle is 40+kw at high voltage dc (over 200 volt dc) not 12v standard car battery.
 

oz93666

Joined Sep 7, 2010
669
50m run not 50mm cable. Cable is 1.5mm, hope that clarifies.

I am not a qualified electrical engineer but that is not heavy enough.

I hope we have crossed wires (excuse the punn) as I certainly hope you are not advising anyone to upgrade their breakers without checking thickness of cable.

David
As I thought this is 1.5 mm square twin cable , used in the UK for lighting circuits ... this is perfectly adequate for carrying the current , and there is no danger at all in upgrading the breakers .... the only question is , what voltage will be seen at the end when carrying 15A, ...enough I believe .

When used for house wiring this level of current would not be permitted for 1.5mm because it is often laid under thermal insulation in the roof , this prevents the small amount of heat in the wire from escaping and temperature can build up ...But in your situation 20A is no problem.
 
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Thread Starter

David Quartermain

Joined Sep 6, 2018
7
As I thought this is 1.5 mm square twin cable , used in the UK for lighting circuits ... this is perfectly adequate for carrying the current , and there is no danger at all in upgrading the breakers .... the only question is , what voltage will be seen at the end when carrying 15A, ...enough I believe .

When used for house wiring this level of current would not be permitted for 1.5mm because it is often laid under thermal insulation in the roof , this prevents the small amount of heat in the wire from escaping and temperature can build up ...But in your situation 20A is no problem.
 

Thread Starter

David Quartermain

Joined Sep 6, 2018
7
Sorry, but this is frightning me now. 1.5mm should carry no more than 10a. Anything over 6a and less than 30a should be 2.5mm according to regs. Allow the drop over 30+ meters 10+ amp upgrade breaker and boom.

Just want to restrict a 10a+ current draw to 5amp. Any ideas?.
 

Alec_t

Joined Sep 17, 2013
10,367
Can you run another 1.5mm cable in parallel with the existing one? At £23.51 for 50 metres UK price, that would probably be a lot cheaper and less work than trying to build some current-limiting gizmo.
It's unknown, too, whether the Nissan charger would play nicely with such a gizmo trying to throttle its input current,
 
Last edited:

ebp

Joined Feb 8, 2018
2,332
Depending on the design of the charger, it is highly probable that a reduction in its AC input voltage will result in an increase in its current demand. This makes the issue of voltage drop in the line even more of a problem.

"Can you run another 1.5mm cable in parallel with the existing one?"
I would be very surprised if this would conform to regulations.

Short of modifying the charger circuit, it is very unlikely that there is anything you can do to reduce the maximum input current.

It might be feasible to come up with a circuit that would detect current demand by the other loads and turn off the charger. Some sort of timing function might be required to prevent the charger from being cycled on and off too frequently, since it probably does something in terms of a multi-stage charging process that begins anew each time it is turned on.
 

dendad

Joined Feb 20, 2016
3,008
Measure the actual current draw is a good idea.
The charger most likely has output current limiting built in. So, see if you can adjust that to a lower setting. If the charger is supplying less current to the battery, it will draw less from the mains. Will the manufacturer help with a schematic or technical advice?
A rough way to do it could be a series resistance on the output leads. That resistance will need to be pretty high power and the value found through trial and error. An enclosed (for safety) but ventilated open coil of steel fencing wire is often used for high power custom resistors. Stainless steel wire is even better as it will not corrode.
Also, if the car is kept at a fairly charged state, the current will not be so high. Max current will only be needed for flat batteries.
 

ebp

Joined Feb 8, 2018
2,332
It might be helpful if we had a model number for the charger, though I kind of doubt if there is much in terms of detail for spec's for it since it is a consumer buy-it-and-use-it product.
 

oz93666

Joined Sep 7, 2010
669
According to this wire table, a 1.5mm square copper wire (2.25 sq mm area) should be able to readily carry 13A.
It will give about a 10V drop at the output of a 50m cable (100m wire length) at that current.
There ... that's all you need to know ... 10V drop is nothing ... Everything will work fine with the cable you already have ...
 

oz93666

Joined Sep 7, 2010
669
Sorry, but this is frightning me now. 1.5mm should carry no more than 10a. Anything over 6a and less than 30a should be 2.5mm according to regs. .
You must understand how these regs were established and why ... It's all about dissipating the small amount of heat produced in the cable by the current .... If you wrap the cable in a foot of rockwall then even 1A is too much , after a day the cable will be too hot . ... Regulators imagine the worst case likely to be encountered which is the cable lying on plasterboard with 100mm rockwall insulation on top during a Heatwave (40C) !!! under such conditions 10A is the limit ... so to be extra safe they say 6A ....

Your cable is in a metal pipe? underground ... all the heat is quickly dissipated .... I would guess 50A would not cause problems
 
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