What kind of battery charger should I buy

[theseeleys]

I've got a 2013 cmax with its 4th dead battery in less than a year!  I'm apoplectic, and my local Ford dealer (who has the cmax again for his 4th attempt to fix the problem permanently) is well aware how mad I am!

 

But I'm also trying to learn, and this board is very helpful.  I've seen several msgs saying that buying my own battery charger and plugging it in at night might be one "fix".  Certianly not the permanent fix I'm entitled to, but hey!  If Ford can't solve the problem and this might, I'll think about it!

 

My immediate problem now is: I'm not an auto techie at all!  So when I googled on auto battery charger I got overwhelmed by the choices.

 

Can someone please give me some advice on the kinds of things I should consider?  Size, voltage, type, any particular manufacturers to avoid or use, etc?

 

Thx.

[plus 3 golfer]

AFAIK, no one has demonstrated that a battery charger prevents a no start condition.  If you want to go through the hassle of connecting and disconnecting a charger everyday make sure you get a "float charger / smart charger" not a "trickle" charger.  A float charger will maintain the battery at full charge while a trickle charger can overcharge a battery since it won't have the circuitry to reduce charging current which is not good for battery life.  Since we don't know what the current draw is overnight that depletes the charge of the battery such that the battery won't start the car in the morning, one probably should buy a smart charger capable of putting out at least 10 A or higher (not cheap).  Even 10 A may not be enough to prevent discharge of the battery overnight if the current drain on the 12 V battery is significant.

 

Another alternative is a jump start battery.  The jump start battery is only connected to the battery terminals, if the car will not start. I believe this is what tow drivers use when jump starting cars.  I believe at least one owner tried using a small, inexpensive jump start battery when his car would not start and it did not work.  Commercial jump start batteries are not cheap and really not very portable for a typical car owner.   If the 12 V battery is completely dead, one might need a commercial grade jump start.  

 

The alternative I use as a hedge against a no start is a set of battery jumper cables. I carry a set in my C-Max even though I've never had a no start.  Of course one needs a second vehicle to connect the jumper cables to.  Jumper cables have been used to successfully to start a C-Max.

 

So, decide which alternative you want to deal with 1) nuisance of connecting a smart charger daily, 2) carrying around a smaller jump start which may not start the car. or 3) carrying a set of jumper cables (assuming you have another vehicle at home to jump start the C-Max).  Then, there is the decision on how many $$$ does one want / need to spend to ensure a start if one selects option 1) or 2). 

[ptjones]

It sounds like you plan on doing this at home, so I would recommend what I did the only time I had a dead 12v from leaving the ACC on. At home in the garage I don't lock the doors so I can open the hood easily and connect up regular battery charger to + post and neg post under the hood. If you need to look at Owners Manual. After 15min. I was able to start ICE with charger still connected. This way you never have to connect it up until you need it. I think the simplest solution should always work. Worst case you might have to allow it to charge longer than fifteen minutes. :)

 

Paul

[kaptnk228]

Our battery problem is solved for now:  

 

Cause:

 

1. Failed dc/dc charger that floats 14.3-5 Volts on battery when car is started.

2. The culprit for the battery drain was a high amp fuse!!  It caused the charging voltage to drop to 13.5 V (no alarm but there should be one) and to drain battery when car is off

3.  No battery low or charging system alarms to tell you.

 

As soon as it failed it told the dealer not to just replace the battery but figure out what caused it to drain.  The fuse was the difficult one.  An infrared camera might have picked up the hot element.  I told them to follow the current to the component that was draining the battery.  It took 2 weeks but we are working again and enjoying our C-Max.

 

Ford still have to fix the NO ALARM problem.  Until that is fixed we will run a volt meter in the 12 V socket to monitor the battery/charging system.  This should be part of the standard instrumentation ofthe car.

 

You may have another cause but I suspect this fuse problem is causing a lot of batteries to fail.

 

IMHO the battery is NOT the problem but the symptom of something else not working properly.  If you monitor the charging system via the 12 V plug or use the ETM you can check if your charging system is working. ie 14.3 V + and not below the 14.0 value when running.  You can try to check the green light on the battery after a trip to see what color it is.  Red is not good, black you most likely need a new one.

 

My wife and I love this little car.  Now we must get Ford to fix the alarms via IMHO a software programming error of a set point of 12.0 Volts verse 13.0 V and please put a voltage meter on the dash board instrumentation.  ie just like the ETM will be fine.  I don't want to have to drive in ETM all of the time.

 

retired P.Eng.

 

21 Nov 2014

 

Two weeks and all is well.  Still awaiting the battery monitoring system update.  No more battery problems so far.  suspect fuse link may be defective which caused our problem.

 

I would have loved to give a better explanation but ford did not give me the proper part name.  Just that it has very large cable size around 4-6 which is huge.  We were told that we would be receiving a report in the mail but nothing so far.  Must send a letter to ford.

 

19 December 2014  Still working great.  Using a voltage meter to monitor charging system.  Wish it was put on the dash as part of the instrumentation cluster

Edited December 19, 2014 by kaptnk228

[ArizonaEnergi]

Wow! A hot fuse - who would have guessed that! Sounds like you may have found the problems that lead to a lot of dead batteries!

[RobMax]

About this fuse, I'm sure we would all appreciate an exact description of where it is, what it does, etc, just in case any of us ever have a similar battery drain problem. Thanks!

[wab]

"As soon as it failed it told the dealer not to just replace the battery but figure out what caused it to drain. The fuse was the difficult one. An infrared camera might have picked up the hot element. I told them to follow the current to the component that was draining the battery. It took 2 weeks but we are working again and enjoying our C-Max."
 
This is a very common mistake usually made by younger/inexperienced technicians.
 
"What did you find?"
"I found a hot fuse and replaced it"
Wrong answer
 
A hot fuse is about to fulfill it's reason for being in the circuit, protecting expensive parts, wiring harness, maybe the whole car!
 
"What did you find?"
"Found a hot fuse, tested the circuit, replaced a defective module THEN replaced the fuse"
Correct answer

Edited November 18, 2014 by wab

[MichaelM]

My thoughts also @wab. A fuse either opens or passes current. It's a circuit protection device but has little or no influence on the actual operation of the circuit. I think poster was fortunate to have discovered the circuit running over-current leading him to the defective module. He is right that infra-red may have led him directly to the components much quicker. 

Edited November 18, 2014 by MichaelM

[homestead]

Fuses can also go resistive, this causes them to lower voltages on that circuit. If it is a charging circuit then it could lower the charging voltage. In this case the fuse would also get hot. One possibility to consider .

[SPL Tech]

I dont understand why the technicians have such a difficult time troubleshooting parasitic drain, unless it's an intermintant problem. I used to troubleshoot this problem all the time and it was not difficult. Basically you put a multimeter in series with the 12V- cable on the battery, and set it to the 10ADC mode to measure amperage. If the value is high, say above 0.2A, then something is killing the battery. The higher the current value, the faster the battery will drain. Anyway, you start pulling out fuses one by one until the value drops. Once it drops, you identified what is causing the drain. Look the fuse up in the manual to see what it connects to. It wont give you an exact identification most of the time, but it can get you quite close.

[wab]

Fuses can also go resistive, this causes them to lower voltages on that circuit. If it is a charging circuit then it could lower the charging voltage. In this case the fuse would also get hot. One possibility to consider .

 

True but extremely rare.

I've seen one, a co worker found it.

 

I dont understand why the technicians have such a difficult time troubleshooting parasitic drain, unless it's an intermintant problem. I used to troubleshoot this problem all the time and it was not difficult. Basically you put a multimeter in series with the 12V- cable on the battery, and set it to the 10ADC mode to measure amperage. If the value is high, say above 0.2A, then something is killing the battery. The higher the current value, the faster the battery will drain. Anyway, you start pulling out fuses one by one until the value drops. Once it drops, you identified what is causing the drain. Look the fuse up in the manual to see what it connects to. It wont give you an exact identification most of the time, but it can get you quite close.

 

That's the cmax problem, a VERY intermittent problem.

[plus 3 golfer]

Fuses can also go resistive, this causes them to lower voltages on that circuit. If it is a charging circuit then it could lower the charging voltage. In this case the fuse would also get hot. One possibility to consider .

IMO, its more likely the fuse assembly (loose connection, dirty connection, bad assembly and so forth) went bad.

 

When I look at the wiring diagrams there are two fuses in the circuit from the DC/DC converter to the 12 V battery.   First, there is the Battery Fuse Assembly (150 A) that is attached to the positive terminal of the battery and the second is a fuse (175 A) in the High Current Battery Junction Box in the rear that is the primary converter fuse.  The fuse assembly attached to the battery terminal has a non serviceable fuse inside.  

 

I also still question what happened and did the converter really fail.  It wouldn't surprise me if the dealer simply checked the battery first and found it to be okay and then found the charging voltage at the battery was not to spec.  So, as is common these days one replaces parts and hopes it fixes the issue.  

 

IMO, this "hot fuse" problem can cause a significant enough voltage drop in the 12 V battery charging circuit to not keep the battery fully charged.  Given the right conditions its possible that at times the car will not start.  There is no question that other failed components (electric water pump, bad connectors not properly sealed) have caused no starts.  But this "hot fuse" issue may explain why people have seemingly random and many no starts but when the no start is checked by the dealer, they can find nothing or find the battery is no longer good and replace the battery.