I'm fitting 2w LED dimmable lights. Cable size and 12voltplanet cable specs?

[roooms]

I'm wiring the new lights in the back of the van and now realise this isn't my area of expertise. Along with most things that need to be done on the van

I will be running four 2w LED dimmable puck lights from Marvix on a single circuit. They will be connected to an Acegoo dimmer switch which manages all the dimming and memory itself. (see picture)



When it comes to cable size, I'm concerned I'm misunderstanding things. If the four 2w LEDs total 8 watts at 12 volts (confirmed by testing the draw on my river 2 max), does that mean in total they will draw 0.67 amps? Does that mean the whole circuit can use fuses and wire rated for 1amp? That seems low and based on other wiring diagrams I've seen, I was looking at using a 5amp fuse and 1.5mm2 cable.

That leads me to the second question. I'm looking at 1.5mm2 cable on 12voltplanet and it says it is rated at 16.5amps. A quick search suggests 1.5mm2 is rated somewhere between 10amps and 14amps. Is this reasonable or should I be factoring in significant safety margins?



I'm looking to charge the river 2 max from a 12v socket while driving and it says it will draw 8amps/100watts max from the car input. I've seen this pull 90-100watts from a spare car battery but the 1.5mm2 cable and 14AWG connectors I was using to connect a 12v socket got very hot but should be ok up to 15amps.



Can anyone help educate me on this?

Thanks!

 

[Deaky]

The fuse is to protect the cable not the lights. 1.5mm cable will be fine as will a 5a fuse

 

[roadtripper]

You also need to use the calculator for voltage drop which is more important in low voltage wiring.

Generally the cable ratings are for the cable not melting, it can get uncomfortably hot at those current levels and hence why you may see lower advised current levels.

 

[roadtripper]

I'm looking to charge the river 2 max from a 12v socket while driving and it says it will draw 8amps/100watts max from the car input. I've seen this pull 90-100watts from a spare car battery but the 1.5mm2 cable and 14AWG connectors I was using to connect a 12v socket got very hot but should be ok up to 15amps.

It's generally accepted that whole traditional "cigar lighter" style connections can peak at 15 amps they are not safe over 8 amps for sustained current due to overheating.

A few seconds flashing a heater coil to temperature to light a smoke is very different from 3 hours of flat out charging.

If you want to do this you are much better fitting a dedicated fused feed using a more suitable connector like an Anderson SB50 or PowerPole.

 

[roadtripper]

See also @Dellmassive threads on using the less current limited solar inputs to charge faster if you use more suitable connections.

 

[roooms]

The fuse is to protect the cable not the lights. 1.5mm cable will be fine as will a 5a fuse

Thanks Deaky. But does that mean I could use 1mm or even 0.5mm with this load? That’s obviously cheaper and 0.5mm can handle 11amps according to 12voltplanet (see below) still with a 5amp fuse for protection.

 

[roooms]

It's generally accepted that whole traditional "cigar lighter" style connections can peak at 15 amps they are not safe over 8 amps for sustained current due to overheating.

A few seconds flashing a heater coil to temperature to light a smoke is very different from 3 hours of flat out charging.

If you want to do this you are much better fitting a dedicated fused feed using a more suitable connector like an Anderson SB50 or PowerPole.

Thanks roadtripper.

The ecoflow river 2 max comes with a “cigar lighter” cable for car input charging. It says it’s limited to 8amp input but still seemed to be excessively hot on the van wiring to the point I’d be worried. 15amp rating is almost 100% safety margin. Am I doing something wrong or could it be cheap cable/connectors?

 

[roooms]

See also @Dellmassive threads on using the less current limited solar inputs to charge faster if you use more suitable connections.

Yeah these have been great threads to read. I’m considering a solar panel but haven’t taken the plunge yet.

 

[roadtripper]

Thanks roadtripper.

The ecoflow river 2 max comes with a “cigar lighter” cable for car input charging. It says it’s limited to 8amp input but still seemed to be excessively hot on the van wiring to the point I’d be worried. 15amp rating is almost 100% safety margin. Am I doing something wrong or could it be cheap cable/connectors?

Nothing wrong it's just running everything to the limit - hence why if you are going to do this regularly rather than just occasionally topping up it's better to have a dedicated feed with better cables and connectors.

The 8amp limit doesn't mean it stays cool, it just means it doesn't melt...

 

[roadtripper]

Your EcoFlow River has an XT60 input connector.

So if you were to get the solar cable (or make your own) you could use that to connect a dedicated feed to your leisure fusebox and charge at 13A (which is the solar limit)

You'd have to go into the app and change the mode from either CAR or AUTO to SOLAR from memory to enable the high current limit at 12v - and you must turn that back if you wanted to use the car charging cable in another vehicle.

 

[Deaky]

Thanks Deaky. But does that mean I could use 1mm or even 0.5mm with this load? That’s obviously cheaper and 0.5mm can handle 11amps according to 12voltplanet (see below) still with a 5amp fuse for protection.

View attachment 247069

I wouldn't go any thinner personally because you'll get significant voltage drop on the cables with all the joint's off to the lights and the switch

 

[roooms]

Thanks for the replies in this thread. If I had to document my current (no electrical pun intended) understanding, I'd go with...

1. Determine the maximum amp draw of the load(s) on the circuit when everything is on.
2. Multiply the maximum draw by 1.25 to find the most appropriate fuse to place at the "head" of the circuit.
3. Use a voltage drop calculator to find the most appropriate wire depending on the typical length factoring in voltage drop and the magic 3-4% rule. Double-check that the wire amp rating is more (ideally twice or more) than the fuse rating.
4. Using chassis earth points will reduce the resistance as it's calculated over the length of the positive and negative wire. Chassis earth points in the rear of the van will significantly reduce total circuit length and therefore resistance.

 

[DXX]

Thanks for the replies in this thread. If I had to document my current (no electrical pun intended) understanding, I'd go with...

1. Determine the maximum amp draw of the load(s) on the circuit when everything is on.
2. Multiply the maximum draw by 1.25 to find the most appropriate fuse to place at the "head" of the circuit.
3. Use a voltage drop calculator to find the most appropriate wire depending on the typical length factoring in voltage drop and the magic 3-4% rule. Double-check that the wire amp rating is more (ideally twice or more) than the fuse rating.
4. Using chassis earth points will reduce the resistance as it's calculated over the length of the positive and negative wire. Chassis earth points in the rear of the van will significantly reduce total circuit length and therefore resistance.

Sounds good.

 

[roooms]

So I think I've bought all I need for this now, then realised again that I don't understand electrics properly.

I'll have two lights (total of six) on each dimmable switch/button. In trying to avoid voltage drop and wire issues, I was going to ground to the chassis local to the LED lights rather than run a negative back to the battery as shown in the picture. All the switches and lights would be fed from a common positive running from under the passenger seat along the b/c/d pillar line on the passenger side.

But can I do this if I am using the dimmer switch? Will it work as in picture B or do I need to wire it up like picture A (by running more cable)? If anyone can answer my question that would be awesome.

 

[roadtripper]

You just need a complete circuit, either will work in a vehicle that uses the chassis as negative like the T6.

You still need to find a usable ground point though, don't just go using any bolt or drilling. You may end up wiring like A anyway just with the negative going to the ground point rather than the battery.

 

[roadtripper]

This may help if you're a T6

https://www.t6forum.com/threads/vw-t6-earth-points.12961/

 

[roooms]

Thanks @roadtripper I have some ground points visible behind each rear-quarter panel dedicated for this purpose. They have the same ground point nut as under the seats and have a number of black wires terminating there already. Some of the previous LED lights terminated there but didn't have the dimmer function which is what concerned me.

 

[roadtripper]

The dimmer function will just be via PWM (Pulse Width Modulation) - essentially they just flash on and off extremely fast (so you can't see it like TV/cinema) and the longer they are "on" for the brighter they appear.

The problems you can have is if you try and run them off another lighting circuit that the van is already doing PWM on for dimming as then the dimmer controllers are turned on and off very fast, but you are giving them clean DC from the battery.

 

[roooms]

That makes sense. Thanks again!

I realise my B diagram suggested very local earth points and maybe you assumed I was just screwing into the chassis near each light. Definitely not. The three sets of lights will actually all terminate at the same ground point behind the passenger rear quarter panel, close to the tailgate. It saves adding another 2.5-3 metres to each circuit.