Dual Battery System not charging Auxiliary Battery

[drivesafe]

Who is running a dual battery system in there D3 and how is it performing.

The reason I ask is that I have found that although LRA originally provided me with voltage charging stats, I have found that not only are some D3s charging at even lower voltages, that these lower voltages are causing problems for quite a few Dual Battery Controllers, because the voltage is not rising high enough to turn the controllers on.

This problem has no effect on the D3 but it is stopping the auxiliary battery from being charged.

Cheers.

[jik22]

Who is running a dual battery system in there D3 and how is it performing.

Does that mean I shouldn't fit my SC40 yet, or that you'd like to know if it works when I do?

[discomaniac]

My SC80 still seems to working fine. Aux Battery in car is always charged. Caravan Battery Charges and Caravan Fridge works while driving and connected. No Problems that I am aware of.

[drivesafe]

Hi jik22 and discomaniac, I’m pretty sure you won’t have any problems with my gear but I am just following up on info that has come to me from a number of different sources.

What’s happening and because of the situation where it happens, my units, because of the way they work, should not be effected but this is what’s occurring and it occurring at the worst possible time.

The vehicle is started in the morning and as it is starting cold, the charge voltage quickly rises to around the 14 volt mark. This is well and truly high enough to turn on any battery isolator. Alls well so far.

Your off on your holidays and drive for a few hours then stop for fuel or a break.

After the break, ( during which time, most battery isolators have cut out because the motor wasn't running ) you start the motor and off you go.

Here’s where the problem is occurring, because the motor is still hot, once the motor is running, the voltage in the newer D3s is not rising much over 13.2 volts which means the other battery isolators are not cutting in again and the auxiliary battery is actually being discharged by the fridge and what ever else may be drawing power from it instead of getting power from the alternator.

The end result is that when you get to your days destination, your auxiliary battery is anything but charge up.

The reason for posting this thread is to try to get as much info as I can on this situation.

BTW a similar problem is also effecting auxiliary battery charging it new Toyota cruises.

Cheers.

[RichardK]

Interesting Tim, you would be aware of my past alternator problems as well as the auxiliary battery being replaced under warranty with a dead cell.
As the alternator charging problem has now been rectified (loose earth engine to body located ) the initial charge is indeed upwards of 14.4 V and will reduce to around 13.6. I will take some readings of the charge at the aux battery over the next few days and let you know.

Regards

Richard

[drivesafe]

Interesting Tim, you would be aware of my past alternator problems.

Absolutely, yours was the first and although in the end it was a similar but not the same problem, while you were sorting yours out, I started getting feedback from other source that seemed similar situations was occurring in newer versions of the D3.

Once yours was sorted ( and I am glad yours was sorted properly ) these other reports turned out to be a factory setting and not a problem.

Cheers.

[RichardK]

Tim,
The reading I had on Sunday morning was:

Main Battery Engine stopped-12.42
Engine running-14.15
Auxiliary Battery Engine stopped-12.45
Engine Running-14.21

Auxiliary started charging after about 15 seconds

Cheers

[bigmac]

Hi Drivesafe
my system is working well I was a bit worried the first night out as the fridge would not start up but no probs from then on
we have made it to Broome and start heading back in a couple of days
Bigmac

[drivesafe]

Good to hear bigmac and it should work well for you.

Even the dealers are now buying the kits and installing them.

Cheers and thanks for the feed back.

[feral]

Hi jik22 and discomaniac, I’m pretty sure you won’t have any problems with my gear but I am just following up on info that has come to me from a number of different sources.

What’s happening and because of the situation where it happens, my units, because of the way they work, should not be effected but this is what’s occurring and it occurring at the worst possible time.

The vehicle is started in the morning and as it is starting cold, the charge voltage quickly rises to around the 14 volt mark. This is well and truly high enough to turn on any battery isolator. Alls well so far.

Your off on your holidays and drive for a few hours then stop for fuel or a break.

After the break, ( during which time, most battery isolators have cut out because the motor wasn't running ) you start the motor and off you go.

Here’s where the problem is occurring, because the motor is still hot, once the motor is running, the voltage in the newer D3s is not rising much over 13.2 volts which means the other battery isolators are not cutting in again and the auxiliary battery is actually being discharged by the fridge and what ever else may be drawing power from it instead of getting power from the alternator.

The end result is that when you get to your days destination, your auxiliary battery is anything but charge up.

The reason for posting this thread is to try to get as much info as I can on this situation.

BTW a similar problem is also effecting auxiliary battery charging it new Toyota cruises.

Cheers.

Although I own a D2, this is exactly how things are happening with my auxiliary battery setup.

I have gone overkill on wiring - 18mmsq. using a Traxide SC40 coupled to a Fullriver 120amp/h.

I have a newish battery - 1.5 years - new 120amp alternator and the whole system does not work efficiently.

I have had my discussion with "12 volt power efficiency" and I am over it.

Why?

Just a couple of questions....

What voltage does a battery need to charge? = 13.8 or more.

What voltage should your alternator put out to charge that battery? = 13.8 or more.

Has anyone heard of this....

"To get heaps of current into a battery you need to supply it with 14.5 V or higher. Most vehicle alternators will not produce this sort of output wen the motor is warmed up (due to alternator temperature compensation.) So the battery will not absorb the full current output available from a vehicle alternator."


Why is my Commorore VT 2000 model has a voltage of 14.2 at the battery yet my D2 has 12.8 - 13.6 at the battery which is all dependent on the temperature. The only time I have seen 14 plus volts was when it was about 1 degree and that was at the cig lighter!

I have just been through to Alice Springs and the whole auxiliary battery set up was a disaster. Even after driving for 6 hours the aux. battery would be reading 12.4 at best. How long do you think the battery would last just running the Engel fridge. It lasted less than 4 hours before the cutout tripped out at 11.6 which means the aux battery is technically flat i.e after this point you are damaging the battery.

As you could possibly tell I am totally frustrated with this whole project. I have collected my research and the finding with my experience firmly confirm you cannot fully charge a battery (100%) by using your altenator. There are too many computers controlling the current for it to charge.

Over to you.