Battery not charging yet alternator "strong"

[jvanzyl]

Hi All,
with battery (lifepo) fully charged up at 14.5V the car fires up no probs, I can go for drive and we're all good.
The ECU Master is tell me the voltage is sitting around 14v throughout the journey.

I then get back and shut down and the voltage is now 13.5V.

If I use an el cheapo battery/alternator tester it's telling me that the the alternator is producing a "strong" current and there's no problem.

The additional/different electronics that the car is running are:
- Chargecooler pump
- knackered power steering pump which I don't think is working anymore (does it drain massive amounts of power in this state??)
 - ECU Master black
 - Updated Sony radio
 - EDFC II (Tein adjustable suspension system)
 - Step down converter that I think is now broken and not producing anything buried up behind the door light that I used to plug in the dash cam.

Can anyone tell me what process you'd follow to figure out why my battery is not charging during driving?

Many thanks in advance.

John

[Ardent]

My 2p.

I don't know.
 But if doubts over power steering pump. If you pull the ps fuse that would isolate  that. Observe if any changes.

[Gaz mr-s]

Maybe I'm missing something, but if you go for a drive & at the end of it the battery measures 13.5V it has been taking charge. 
A healthy conventional lead-acid will drop to approx 12.6V after 2 or 3 hours. No idea about a Lithium.

[jvanzyl]

My 2p.

I don't know.
 But if doubts over power steering pump. If you pull the ps fuse that would isolate  that. Observe if any changes.

Good shout I'll try it.

Maybe I'm missing something, but if you go for a drive & at the end of it the battery measures 13.5V it has been taking charge. 
A healthy conventional lead-acid will drop to approx 12.6V after 2 or 3 hours. No idea about a Lithium.

Erm.. hang on.. I thought fully charged at 14.5v is what I was aiming for? I notice significant issues with starting if the voltage drops below 13v (if memory serves).

Err.. anyone else have any input?

[moredun]

Lead/Acid battery when fully charged should be about 12.5 to 12.8 volts

This should increase to 14.2 to 14.8 volts only when charging, anything higher and you risk cooking the battery.

LifePo4 battery should be 13.6 volts fully charged and 14.6 when charging. At 12.8 volts, you only have 20% battery capacity left and starting to get into the realms of battery issues.

[bobo83]

If the voltage when driving is 14V then the alternator is probably doing its job. If it wasn't, the battery wouldn't be able to provide these 14V yet show 13.5V after turning the car off.

Maybe the battery isn't holding charge as it was ? Maybe you have parasitic power draw (can be tested with a multi-meter) ?

[Carolyn]

The power steering pump could be drawing current, even with the fuse disconnected, depending on the nature of the fault???

You have idenitified at least two things that could be causing a drain. The pump and the step down convertor.  Just 'cos they aren't working doesn 't mean they have'nt got an internal short circuit.

How long have you had the battery?

[jvanzyl]

Hi All - ok so I've had the battery a couple of years, not long really.

I'll start with removing the step down converter, see what happens then and then I'll take out the fuse for the power steering.
Needs to google parasitic draw and how to test for it...

[Craigjm]

AT 13.5 its only .1 down on what it should be. Start with removing the step down converter and see what happens and the look at the power steering after that which I assume you will be fixing anyway?

[jvanzyl]

Right - apart from my other thread where I'm now having other "issues". I have removed the step down converter and all "seems" ok.. ish.. I have however discovered a little section in the ECU Master file where I can set the voltage target, it's default seems to be 13.5V but it has not been enabled. I may lift it to 14V and see where that gets me in terms of end voltage after a run...

[Carolyn]

14.2v  would be ideal.