Thread: Battery/charging issue

Hmmm. I’d suspect it but also:
What’s the voltage on the engine side when it’s running and the voltage on the aux side?
Leave it with the dual setup disconnected etc. and see if the primary still goes flat. If it does then you know it’s not to do with the aux?
My TD5 alternator had an issue but it was revealed with lots of smoke from under the bonnet rather than a civilised flat battery!
Cheers,
Dave

Hi Simon, just a suggestion, disconnect the negative ( - ) lead off your auxiliary battery.

Then turning your ignition, but DO NOT start the motor.

With your ignition on, turn your headlights on.

With everything on, measure the voltage at your cranking battery.

I suspect you may have dropped a cell in the cranking battery and with everything on, you may see 10.5v on the cranking battery.

The fact your charger is not working on the cranking battery seems to point to a dud cranking battery or possibly a diode gone in your alternator.

Originally Posted by travelrover

Hi team

I suspect I know the answer to this but thought I would bounce it off the brains trust for an informed answer.

My Td5 ute has dual batteries and a Rotronics charger/isolator which was installed when I bought it new in 1999.


Rotroincs.jpg

I have know for some time that the auxiliary battery was dead but not got around to changing it. Latterly the primary battery has been dying overnight so I assumed the auxiliary was pulling it down. I would charge it for a few hours and no dramas.

Last Friday I stopped in at the sparkie and got a new auxiliary battery. He tested the primary which I bought from him less than three years ago and he said it was good. Yesterday (Saturday) I used the vehicle on and off all day with no problems. However this morning I tried to start it and nothing, lots of relays clicking and dash lights flashing. I tried to charge via a 7 stage Protecta charger and it didn't want to know about it. The power LED flashed red (nothing in the manual about that) and wouldn't charge. The voltage was 12.3. I tested the auxiliary and it was 12.8v so I jumped the two together and still nothing, chattering relay's...

Am guessing as both batteries were declared in good health 48 hours ago the Rotinics box has gone cactus. So if i disconnect everything from that I should be at least able to start? If this is the case I will replace it with a Traxide SC80.

Any other suggestions as to the cause?

Cheers - Simon

I have a couple of Projecta chargers and the red LED indicates a fault (either faulty battery or wrong polarity) IF you have dropped a cell in your cranking battery your alternator will be working overtime ALL the time in a vain attempt to charge the cranking battery and with a simple dual battery isolator (which I imagine the Rotonics unit is) your aux battery May have 12.8v But bugger all "Grunt" left in it to start the car regardless of jump starting from it because the alternator is putting all its power into the cranking battery and until that battery is up to speed NOTHING will flow to the aux battery.

Thanks trout1105

Yes I figured the flashing red led was a fault, just interesting it didn’t come up even when the sparkie tested it on Friday with something a little more sophisticated.

What you say certainly makes sense. I’ll head back to the sparkie in the morning for a chat!

Thanks again!

Disconnect your isolator and then try your battery charger on the auxiliary battery.

This should tell if the charger is working or not.

Originally Posted by travelrover

..... The power LED flashed red (nothing in the manual about that) and wouldn't charge. ......

There are a few different flashing red status lights on Projecta chargers.
From the Projecta manual for some current products:

Slow flashing - incorrect polarity connection or not properly connected up.

fast flashing - faulty battery

slow flashing(plus green LED on) - faulty battery or a load on the battery and charging is timing out.

It's not unusual to have a battery that has no cranking power but still shows some surface charge on it.
I have one in my shed, out of my dads car. volts comes up good, but a battery test shows 100 CCA out of 570 something like 20% SoH or thereabouts.
Would start the little diesel Pug when hot/warm, but not when cold.

I'm thinking(if they fit) .. swap batteries around. Will be the simplest way to check if the stating battery is really ok or not, in that if swapped, you shouldn't have any starting issue.
The potentially half dead current starter battery(now as the aux), will still get a charge, but will drop voltage overnight until the cutout point of the isolator on the start battery.

The now new start battery(formerly the new aux) will till start the car tho ... isolator should do it's job to protect the start battery. If not .. then you now know you could have a few issues compounding the current situation.

Originally Posted by AK83

There are a few different flashing red status lights on Projecta chargers.
From the Projecta manual for some current products:

Slow flashing - incorrect polarity connection or not properly connected up.

fast flashing - faulty battery

slow flashing(plus green LED on) - faulty battery or a load on the battery and charging is timing out.

It's not unusual to have a battery that has no cranking power but still shows some surface charge on it.
I have one in my shed, out of my dads car. volts comes up good, but a battery test shows 100 CCA out of 570 something like 20% SoH or thereabouts.
Would start the little diesel Pug when hot/warm, but not when cold.

I'm thinking(if they fit) .. swap batteries around. Will be the simplest way to check if the stating battery is really ok or not, in that if swapped, you shouldn't have any starting issue.
The potentially half dead current starter battery(now as the aux), will still get a charge, but will drop voltage overnight until the cutout point of the isolator on the start battery.

The now new start battery(formerly the new aux) will till start the car tho ... isolator should do it's job to protect the start battery. If not .. then you now know you could have a few issues compounding the current situation.

Thanks AK83

Yes this is fast flashing so looking more toward a dead battery. As mentioned off to the sparkie for a chat this morning.

12V Digital Battery Load Tester Car AGM GEL Battery Analyzer Tool 100-1100CCA AU 712755960705 | eBay

I bought one of these a few years back.
Not a state of the art tool But good enough to give you a good idea of a batteries health and saves a lot of guess work