Attaching a USB charger on Factory Blank switch on Corolla 121

[dtaluthge]

Hi Everyone,

I want some help in a DIY project. I just bought a USB charger from ebay as shown in the below picture. And I want to fix this into blank switch next to the steering wheel but I don't know which wires to splice. I don't want this to be always on just key on accessory mode.

Link to USB charger

Thanks

 

[dtaluthge]

Thank you everyone for giving their ideas and opinions. I managed to complete my DIY project with success. 

Edited September 4, 2016 by dtaluthge

[Rumesh88]

Wire it in parallel with the cigarette lighter.

[Davy]

The cigarette lighter is not that far away.  But if the fuse box of the 121 is closer (above the pedals maybe), you can locate the fuse that powers the cigarette lighter and tap into it. You can get a compatible fuse tap from eBay and do a clean job without cutting any wires.

 

 

Just an alternative suggestion to Rumesh88's.

[nilnuwan]

what is the little switch next to the location (not the power mirror switch)?   

Maybe you can get 12+voltage from there  and then connect ground(black wire) to the vehicle ground (nearest bolt or somthing).

[Dushyantha]

Just a suggestion . since ur somehow going to tap into the wiring system. why not wire Your DVR to an accessory switched 12V supply and buy good 12v phone charger that goes in the cigarette lighter . that way you can get your DVR wires off the dashboard and also charge your phone with a more reliable charger .

[Davy]

A USB port's voltage on a PC is 5V and the amperage is 500mA or 900mA (USB 2.0 and USB 3.0 respectively). If the phone can be safely charged by plugging it into a PC, then surely it can be charged through any USB port that outputs 5V and amperage between 500mA and 900mA.

Having said that, some phone chargers supplied originally with phones nowadays have ratings higher than 900mA. My phone's charger for example says 5V 2A. Charging it plugged into a PC takes quite a long time.

I think most people ruin (by ruin I mean shorten the lifetime of the battery) their phones with car USB ports and adaptors is because they used a USB adaptor with a higher charge rate than the battery should be charged at. When buying a charger, it is important to check if the charger or adaptor is suitable for the devices you plan to plug into it.

I have a Belkin USB adaptor that plugs into the cigarette lighter of my car and the rating of that is 5V 600mA or something. So almost any phone can be safely charged. I could have gone all the way up to 2A, but my wife's phone came with a charger with a 750mA rating I think.

The eBay link that OP has shared says that the ports output 5V 1.2A/2.1A. So if you charge a phone that is meant to be charged with a 5V 500mA power source for example, obviously the lifetime of the battery will suffer.

My 2 cents.

Edited August 31, 2016 by Davy

[terrabytetango]

This is a pretty good idea. I had this done to my van a long time ago, I stripped a usb car charger, took power from the cigarette lighter connection (I think) and then fitted it to one of the many blank switches. The charger had a 7805 regulator which limited the current, but back then all I had was an HTC Tattoo and a 4th gen Ipod classic.

Phone batteries being ruined by car chargers is a myth; the power regulation circuitry is in the device itself. Giving the device less current will only lead to longer charge times, and if the power is insufficient, the device will simply refuse to charge. Newer devices support quick charging, but have a set of parameters it verifies by first testing the power supply if it's capable of providing the amount of current required. Plugging in a device which only requires 500mah to a charger providing 2Ah will not affect the battery in any way, as the device will only draw 500mah.

[Davy]

4 hours ago, The Stig said:

Well the amperage is only part of the story. You can't compare the current that comes from a pc to that of a car. Pc components are extremely sensitive to current fluctuations therefore the power supply unit has many layers of voltage protection and filtering circuits to ensure that the power stays stable. A cars power supply will always fluctuate since the voltage changes on the load to the alternator and other equipment. Voltage fluctuations are bad for batteries,  the low end car chargers do not have any filtering circuits. You can just crack open one and see how basic the circuits are. Also genuine chargers have a cutoff circuit that detects when the phone battery is full and switches to a trickle charge pattern. 

 

Yes, agreed. There maybe significant voltage drops and spikes especially when the car is being started, switched off and when the load on the alternator changes. However, I think the small regulator circuit behind a good USB port deals with the fluctuations and delivers a pretty clean voltage given that it's a "proper" adaptor.

 

39 minutes ago, terrabytetango said:

Plugging in a device which only requires 500mah to a charger providing 2Ah will not affect the battery in any way, as the device will only draw 500mah.

All rechargeable batteries have a C rating - the rate at which a battery should be charged/discharged. And this generally related to the capacity of the battery. For example, if a battery with a capacity of 500mAh needs to be charged at a rate of 1C, this means that it should be charged at 500mAh for 1 hour. If the C rate is 0.5, it should be charged at 250mA for 2 hours. Just to list a few examples. Exceeding the C rating is not always good for the battery. Researched all this while hunting for a charger for the RC car.  

But yes, I believe all modern phones have mechanisms to prevent over-charging and to control the charge rate (C).

[dtaluthge]

5 minutes ago, Rumesh88 said:

Wire it in parallel with the cigarette lighter.

Even i was thinking of that.. but i am looking for an easy way without dragging wires all the way from cigarette lighter to there. 

[dtaluthge]

50 minutes ago, Davy said:

The cigarette lighter is not that far away.  But if the fuse box of the 121 is closer (above the pedals maybe), you can locate the fuse that powers the cigarette lighter and tap into it. You can get a compatible fuse tap from eBay and do a clean job without cutting any wires.

 

 

Just an alternative suggestion to Rumesh88's.

This would be a good idea... Just googled and found that CIG fuse is just under there.. I'll update whether it's a workable solution when I get home..

[Crosswind]

USB works on 5V. Vehicles run on 12V. Does this have a 12V-5V converter?

[Davy]

2 minutes ago, Crosswind said:

USB works on 5V. Vehicles run on 12V. Does this have a 12V-5V converter?

I believe the USB port has a small resistor behind it to bring the voltage down to 5V. USB ports that plug in directly to the cigarette lighter work in the same way.

[dtaluthge]

13 minutes ago, Davy said:

I believe the USB port has a small resistor behind it to bring the voltage down to 5V. USB ports that plug in directly to the cigarette lighter work in the same way.

Red wire goes to the fuse where should i connect the black one? 

LOL sorry for being a noob

[Rumesh88]

1 hour ago, Crosswind said:

USB works on 5V. Vehicles run on 12V. Does this have a 12V-5V converter?

Yes. They have a small switched mode converter.

[Rumesh88]

49 minutes ago, dtaluthge said:

Red wire goes to the fuse where should i connect the black one? 

LOL sorry for being a noob

Connect it to the chassis ground. 

[Crosswind]

1 hour ago, Davy said:

I believe the USB port has a small resistor behind it to bring the voltage down to 5V. USB ports that plug in directly to the cigarette lighter work in the same way.

I've had pretty bad experiences with USB ports and FM modulators that plug in to cigarette lighter sockets. I hope OP wouldn't burn anything by doing this.

[The Stig]

Ummm im going to say this is a bad idea. These cheap chinese chargers don't have tricle charging circuits and cutoffs builtin, you will ultimately ruin your phones battery. Just buy a good branded one like belkin or anker. 

[dtaluthge]

1 hour ago, Crosswind said:

I've had pretty bad experiences with USB ports and FM modulators that plug in to cigarette lighter sockets. I hope OP wouldn't burn anything by doing this.

 

1 hour ago, The Stig said:

Ummm im going to say this is a bad idea. These cheap chinese chargers don't have tricle charging circuits and cutoffs builtin, you will ultimately ruin your phones battery. Just buy a good branded one like belkin or anker. 

Since I'm connecting my Car DVR with CIG lighter i have no option other than connecting my phone into this... and i dont want humongous gadgets near the CIG lighter because this is a manual car. But this gadget looks pretty decent comes with a inbuilt fuse also and not gonna charge my phone unless its really necessary. 

Thanks for advise BTW

[dtaluthge]

16 hours ago, nilnuwan said:

what is the little switch next to the location (not the power mirror switch)?   

Maybe you can get 12+voltage from there  and then connect ground(black wire) to the vehicle ground (nearest bolt or somthing).

Actually this is not a picture of m car... This is a random google picture

3 hours ago, Dushyantha said:

Just a suggestion . since ur somehow going to tap into the wiring system. why not wire Your DVR to an accessory switched 12V supply and buy good 12v phone charger that goes in the cigarette lighter . that way you can get your DVR wires off the dashboard and also charge your phone with a more reliable charger .

I will look into that over the weekend...

2 hours ago, Davy said:

A USB port's voltage on a PC is 5V and the amperage is 500mA or 900mA (USB 2.0 and USB 3.0 respectively). If the phone can be safely charged by plugging it into a PC, then surely it can be charged through any USB port that outputs 5V and amperage between 500mA and 900mA.

Having said that, some phone chargers supplied originally with phones nowadays have ratings higher than 900mA. My phone's charger for example says 5V 2A. Charging it plugged into a PC takes quite a long time.

I think most people ruin (by ruin I mean shorten the lifetime of the battery) their phones with car USB ports and adaptors is because they used a USB adaptor with a higher charge rate than the battery should be charged at. When buying a charger, it is important to check if the charger or adaptor is suitable for the devices you plan to plug into it.

I have a Belkin USB adaptor that plugs into the cigarette lighter of my car and the rating of that is 5V 600mA or something. So almost any phone can be safely charged. I could have gone all the way up to 2A, but my wife's phone came with a charger with a 750mA rating I think.

The eBay link that OP has shared says that the ports output 5V 1.2A/2.1A. So if you charge a phone that is meant to be charged with a 5V 500mA power source for example, obviously the lifetime of the battery will suffer.

My 2 cents.

Thanks for the advice... I will look into what I can do for this over the week end... 

It would be great if someone can suggest a reliable small scale digital multi-meter from Ebay 

Thanks everyone for the support

[The Stig]

4 hours ago, Davy said:

A USB port's voltage on a PC is 5V and the amperage is 500mA or 900mA (USB 2.0 and USB 3.0 respectively). If the phone can be safely charged by plugging it into a PC, then surely it can be charged through any USB port that outputs 5V and amperage between 500mA and 900mA.

Having said that, some phone chargers supplied originally with phones nowadays have ratings higher than 900mA. My phone's charger for example says 5V 2A. Charging it plugged into a PC takes quite a long time. 

Well the amperage is only part of the story. You can't compare the current that comes from a pc to that of a car. Pc components are extremely sensitive to current fluctuations therefore the power supply unit has many layers of voltage protection and filtering circuits to ensure that the power stays stable. A cars power supply will always fluctuate since the voltage changes on the load to the alternator and other equipment. Voltage fluctuations are bad for batteries,  the low end car chargers do not have any filtering circuits. You can just crack open one and see how basic the circuits are. Also genuine chargers have a cutoff circuit that detects when the phone battery is full and switches to a trickle charge pattern. 

 

2 hours ago, dtaluthge said:

 

[terrabytetango]

6 hours ago, Davy said:

All rechargeable batteries have a C rating - the rate at which a battery should be charged/discharged. And this generally related to the capacity of the battery. For example, if a battery with a capacity of 500mAh needs to be charged at a rate of 1C, this means that it should be charged at 500mAh for 1 hour. If the C rate is 0.5, it should be charged at 250mA for 2 hours. Just to list a few examples. Exceeding the C rating is not always good for the battery. Researched all this while hunting for a charger for the RC car.  

But yes, I believe all modern phones have mechanisms to prevent over-charging and to control the charge rate (C).

Yup, I'm familiar with C ratings, been in the R/C hobby since 2008, just as Lipos and brushless began to become mainstream. However, none of that applies to mobile devices, the internal charging circuitry takes care of all of that, and that's how it has always been for a very long time, going back to even analog mobile phones in the early 90s. The external power supply i.e. mains adapter or usb cable, is just that, a power supply, and no more.

[MV-5]

15 hours ago, terrabytetango said:

Yup, I'm familiar with C ratings, been in the R/C hobby since 2008, just as Lipos and brushless began to become mainstream. However, none of that applies to mobile devices, the internal charging circuitry takes care of all of that, and that's how it has always been for a very long time, going back to even analog mobile phones in the early 90s. The external power supply i.e. mains adapter or usb cable, is just that, a power supply, and no more.

Yes, charger is integrated in the device,but it is not good to assume that it can tolerate the external voltage fluctuations.

[terrabytetango]

On 9/1/2016 at 3:33 PM, MV-5 said:

Yes, charger is integrated in the device,but it is not good to assume that it can tolerate the external voltage fluctuations.

The power supplies can deal with quite a bit of voltage fluctuation. The chargers I use for my Lipos can deal with anything from 12-20V DC.