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Battery going flat

Posted: Thu Apr 19, 2018 11:17 pm
by RossPat
I went to use the Ranger tonight but the battery was flat, 11.85volts.

I used the car on Monday, did about 150klms.

The same thing happened 2 weeks ago but the battery was @ 12.2 volts.

After the first time I kept a close watch on the volt and amp gauges through the OBDLink MX and all was good.

It then occurred to me that the battery issue only started after I installed the OBDLink.

So tonight I removed it from the car.

I thought it turned itself off after a certain time when not in use.

Well mine was very warm so I gather it wasn't off, the power light was on.

Re: Battery going flat

Posted: Fri Apr 20, 2018 2:16 pm
by RossPat
Took the car to my dealer and they took 90 minutes to test everything and say it's fine.

They did enable Dual Battery Mode or in simple terms, disable the smart charger.

Re: Battery going flat

Posted: Sat Apr 21, 2018 12:20 am
by janemar
I think the general concensus is to not disable smart charging especially on PX2's.

Just use a decent battery charger and charge it atleast once a month.

Re: Battery going flat

Posted: Sat Apr 21, 2018 8:16 am
by ira11y
janemar wrote: Sat Apr 21, 2018 12:20 am I think the general concensus is to not disable smart charging especially on PX2's.

Just use a decent battery charger and charge it atleast once a month.
Why do you think disengaging smart charge is a bad thing? Its certainly not a general consensus by any means. Do you understand how smart charge works?

Ross Patt - some OBDII's will stay active although I would have thought they would need to be running for a fairly significant period of time to cause any effect on the battery, I assume they would have relatively low draw although if the bluetooth is in constant search mode it will be pulling at its peak power usage.

How old is your car/ battery? is it the 700 or 880CCA version? If you are only doing short trips the Dual battery Mode will help keep the battery at full charge but if you are doing plenty of hours run time then it may be your battery is on the way out if its not the ODBII thats causing the issue.

Have you tried measuring the draw with the vehicle off and the OBDII connected/ disconnected to measure whats going on?

Re: Battery going flat

Posted: Sat Apr 21, 2018 8:45 am
by RossPat
As stated above, Ford tested the car charging system and could not fault it.

Car is only 9 weeks old and apparently disabling the smart charger is quite common.

There is no way a Ford dealer would disable smart charge it if could cause problems because they would be liable to fix them, for the next 5 years anyway.

Re: Battery going flat

Posted: Sat Apr 21, 2018 8:54 am
by ira11y
Ive had Dual Battery Mode enabled (or smart charge disabled) from delivery, done 80K Kms and never had an issue. Just because Ford say no issue, does not mean there is no underlying cause for the battery draining, if it was me I would be doing some testing myself to find where the current draw is coming from.

Re: Battery going flat

Posted: Mon Apr 23, 2018 8:44 am
by apsilon
Might want to have a search around here regarding disabling smart charge without having a second battery. There were definitely some concerns though I believe some of that has been addressed with newer versions of Forscan having some extra options. I haven't had time to look into it again.

FWIW I think something is wrong if you're getting a flat battery after a few days. I've left min sitting untouched for 3 weeks at one point and it still had 62% state of charge when I started it afterwards.

Re: Battery going flat

Posted: Mon Apr 23, 2018 4:06 pm
by RossPat
apsilon wrote: Mon Apr 23, 2018 8:44 am Might want to have a search around here regarding disabling smart charge without having a second battery. There were definitely some concerns
As was explained to me by the dealer smart charge is fine if you don't ad any accessories, but being a 4wd most fit lights etc.

Smart Charge does nothing/minimal until it detects the battery is down to about 12.2volts before it starts charging, and even then it rarely reaches 14.3 volts and so you could park your car with a 50% charged battery.

You leave home at night with 12.65volts in the battery but don't go far and arrive home with 12.3volts still in the battery so smart charge hasn't even kicked in.

Even if it does it hasn't been running long enough at a good charge rate to put a lot back, so if you stop your car with only 12.2v in the battery it is only 50% charged.

12.7 volts = 100%
12.5 volts = 80%
12.2 volts = 50%
11.3volts = 30%

All disabling smart charge does is revert the charger to a normal charger, the ones we have had for years and work.

A lot of Ford dealers disable smart charge if customers come in and they have fitted driving lights.

I turned on all my lights and I was pulling 68amps, obviously smart charge can't cope.

Re: Battery going flat

Posted: Wed Apr 25, 2018 6:13 pm
by saeb
I found another setting in the pre 2017 BCM's that tell the BMS to stop charging the battery at 94% or 95% SOC, cannot remember exact % now. I would expect this to work whether single or dual battery mode is enabled and I have never seen more on mine even with a 3 week old battery installed and driving for 500km straight in dual battery mode.

Some people have so I can not explain that. But from my finding over the past 2 weeks I will say its safe either way but disabled does use between .2 .5 lph more in fuel.