The Honda PCX / Forza / ADV150 / SH Forums

Hi peeps. I have a 2017 Honda Pcx 125. The battery drains to 0 after about 3 days of standing with the ignition OFF. I checked to see if there is a drain current from the battery with a meter and it is a steady 160mA. If I calculate the resistance which would be drawing that current it is 75 Ohms. Is this normal, or, can you give me some help as to what may be causing this problem???

Thanks
Colin

Definitely not normal. Some wire somewhere is shorting a bit. Maybe you can figure out a way to get standing currents through the various fuses - that might help with what circuit was the perp.

How old is the battery?
Was there anything added to the original wiring?

If the battery is original, take it out of the bike, charge it, and then test it under stress to see if it has any problems holding a charge.
If there is a newly added electrical item, that would be where I would start.
If not, you may find that this is going to be a slow search process.

There are a lot of items that could cause problems...switches, wires that have rubbed against the frame, even lights.

You may have to disconnect one item at a time, waiting 3 days, checking the battery again. Then on to the next item. It is a slow process if you are not an electrician.

Hi, thanks for the reply. The battery is only 2 months old, so, nearly new. I had Tried what you said, charged it and it held the charge out of the scooter. Now as you advise, it's a process of elimination to isolate the problem via fuse pulling. It's a pain, but I have to do it to find where the problem is.

If I find it I'll let you know as it migt help somebody else in the future.

Cheers

Colin

What electrical modifications have you made to the system? Any additional lights or other devices?

If you could make little wires that could slip on/in side of a fuse slot, you could then use your multimeter as an ammeter to figure out fairly quickly which circuit is the issue. I have not taken the time to see if I could get meter probes directly into the fuse locations, but that would be even faster.

There should be no current draw when the bike is turned off unless you have added something such as an alarm system with a motion sensor. That is why it is important to know if anything new was added, even if you don't think it could be causing the problem. When the bike comes from the factory the wires have been wrapped in a protective "sheath ", for lack of a better term. Honda had problems with their early motorcycles and learned from that. Very few of the wires are now exposed.

That being said, the switches and plugs are still accessible. What is the history of this bike, such as does it stay out in the weather, unprotected?

If the bike is not being used as your primary or only transportation, pull one fuse at a time and let the bike set to see if the battery still discharges. There are only 4 fuses as far as I know. Once you have isolated the circuit, pull out the wiring diagram and start checking wires for continuity. If you put your multimeter lead on a wire that is supposed to be a hot lead and you touch the other to a ground there should not be any reading on the meter with the bike turned off.

Hopefully you have a wiring diagram. If not, let us know. I am sure there is one around here. I may even have one.

Hi guys, I have found the leakage current of 16ma to be on the fuel pump/ignition 10A fuse circuit. I checked the manual and max leahage on post 2013 models is 0.4ma maximum!!! So, now I have to start digging about to see exactly what the configuration of the wiring system is for these circuits. Bike is less than 2 years old and I am the 3rd owner. No Mods' have been made it is stock. With the 10A ignition/fule pump pulled, current drain goes to zero and battery doesn't discharge. So by my calculation I have a resistance/impedance of 750 Ohms somewhere that is the culprit. If you have any ideas on that it would be helpful???? Of now to see if I can get the wiring diagram and figure out what's going on... Thanks to all once again who are helping me with this.

Colin

So, I gave up on the troubleshoot. This is because when I get my head together and think about this in terms of theory, then WIth a 7Ah battery having a leakage current of 0.016A the battery should last around 468 Hours ( approx 20 days) with zero usage. So whatever flattened the battery must be something else. I suspect maybe a fault with the battery internal resistance or maybe I bought a new battery with a fault on it????? I think I have a headache now.. lol

Are you sure that this bike didn't have a history that involved it being hotwired and stolen? It could explain the problems you are having.
As far as I know, once the bike is turned off and the key removed there should be absolutely NO current bleed anywhere. If you pull that fuse when not using the bike and the battery stays charged, look for the problem in that circuit. Something is bleeding your current, and it could be anything associated with that circuit.

Do you have a wiring diagram? You are going to need one.

colbecoz wrote:So, I gave up on the troubleshoot. This is because when I get my head together and think about this in terms of theory, then WIth a 7Ah battery having a leakage current of 0.016A the battery should last around 468 Hours ( approx 20 days) with zero usage. So whatever flattened the battery must be something else. I suspect maybe a fault with the battery internal resistance or maybe I bought a new battery with a fault on it????? I think I have a headache now.. lol

After a charge and the bikes battery cables disconnected from the battery - does it lose the charge after a day or so ?

Just in case you do not have one, here is a wiring diagram. I have a service manual for 2013 thru 2017 and this is the diagram for the after 2013 models. I hope this helps you. I had to shrink it in order to add it to this thread. Hopefully it is still readable.

1. Battery drain somewhere.

2. Battery f*cked

Big money on 2.

you you wrote:1. Battery drain somewhere.

2. Battery f*cked

Big money on 2.

+1

Well, a huge thanks again to everyone who helped me with my problem, and to Mel46 for the wiring diagram which helped greatly. I think I tracked the problem down to the accessory socket which had a USB charger plugged in to it. I disconnected/removed the plug and all seems good now. Battery holding charge now. This was a bit of a pain in the ass, but with your help, it seems to be OK now.. THANK YOU ALL SOO MUCH.... Colin

Mel46 wrote:Just in case you do not have one, here is a wiring diagram. I have a service manual for 2013 thru 2017 and this is the diagram for the after 2013 models. I hope this helps you. I had to shrink it in order to add it to this thread. Hopefully it is still readable.

Honda_PCX150_wiring.jpg

THANKS MY FRIEND.. Colin

Hi, my 2012 pcx125 drains battery after 3 or so days without use.
I've checked and pinpoint the drain to a circuit running through a 10 amp fuse marked "backup" in the fuse box.
The issue is that when I remove this fuse my amp meter indicates no drain. The bike runs and all seems to work without thus fuse but I don't have z wiring diagram and the ones here I can't read properly .
Any advice, ideas would be greatly appreciated,
Thanks
Ernest

It's possible you have something draining the battery, like a stuck brake lamp switch or something. In that case, you may need to trace the circuit.
But the easiest and 1st thing I'd recommend is the battery. Modern batteries are extremely efficient and dependable.. But I've had new replacements that were defective and would not hold a charge.
All modern bikes have some 'load' to operate the electronics, for clocks, digital readouts, etc. Your phantom load that disappears when the fuse is pulled could be this and depending on your diagnostic meter's setting, simply too small a drain for your meter to detect. Under normal conditions and the battery is in good working order, even 3 weeks/months idle time wouldn't be a problem for the battery.
I'd recommend having your battery fully charged, then load tested to see how capable it is under load to hold its voltage.
A 12v static reading on a battery does not mean it's Good if it quickly breaks down under load.... any load no matter how small.