Thread: Defender flattening battery when left sitting

i thought the traxide isolators only isolate the batteries when both batteries are reduced to a pre-determine voltage therefore your aux battery will not be fully charged........

can you override the isolator so that you can start from the aux? not that that solves your problems as you still need to find the source that is flatening your start

Originally Posted by weeds

i thought the traxide isolators only isolate the batteries when both batteries are reduced to a pre-determine voltage therefore your aux battery will not be fully charged........

can you override the isolator so that you can start from the aux? not that that solves your problems as you still need to find the source that is flatening your start

They will actually isolate both ways (help Tim?). So if as the voltage drops to a determined level, it isolates the batteries. If the load is on the main side then it will just continue and flatten the main battery. I do carry a cable to link the two batteries, but because of the nature of this it only ever happens at home. So i just put the charger on it.

You need to think of everything in terms of amp hours. Ready to be shot down in flames but here's some thoughts :

Now your fully charged, new condition 100 amp/hour battery could, in theory, provide 1 amp for 100 hours, or 100 amps for 1 hour, or any variation in between ( actually it would'nt supply that high a current for that long due to other factors e.g heat )

So at .007 amps current draw, ( or 7 milliamps ) as you have measured, I worked out ( hopefully correctly ) that your battery should last 14285 hrs or 595 days. Actually 7 mA is quite low, that's less than 1 LED would draw, so I'm suspecting that number is not right if you're running a couple of things permanently. ( not sure what those anti rust devices draw ).

If you have read it incorrectly and it is actually .07 amps or something ( 70 mA) ,which sounds more realistic to me, the battery should last 59 days. ( 8 weeks )

However that would be a very flat battery at the end of that time - to get it beyond the point where it won't have enough residual "oomph" to turn the starter motor would be considerably less time. ( perhaps half that ?)

So a few possibilities :

1. your meter is reading incorrectly and residual current drain is a lot higher.
2. something of a higher current is switching in and draining your battery when you are not "looking".
3. your battery is not fully charged to begin with.

You can get little "float" or "trickle" battery chargers that will keep the battery topped up - even a little solar panel would help - I've seen thme in places like SuperCheap and even K Mart.

Try disconnecting your "electroninc rust proofer" thingy, and see if that improves things.

I leave my 110 for 3 or 4 weeks at a time and it starts happily, but it is bog standard and doesn't even have an alarm. If I try that with the Rangie, it will flatten the battery in 3 weeks so obviously more "stuff" drawing current.

Originally Posted by spudboy

Try disconnecting your "electroninc rust proofer" thingy, and see if that improves things.

I leave my 110 for 3 or 4 weeks at a time and it starts happily, but it is bog standard and doesn't even have an alarm. If I try that with the Rangie, it will flatten the battery in 3 weeks so obviously more "stuff" drawing current.

thanks for the ideas! I checked the charge this morning and it is charging like a Trojan. I drove it across town and it was consantly on 14.4 and only dropped to 13.9 at the end of the trip.

I will check all those things when I get the car back tonight or tomorrow.

Drive it more often!

Our Defender also only gets driven occasionally. I too have noticed voltage drops in the cranker.

I'll check the voltage after a country trip when I get home with the vehicle turned off. The voltage will typically be 13.2 - 13.00 Volts.

After say 2 weeks of no use - it can be as low as 12.4V. The deep cycle battery (also initially 13.2 - 13.00V) is at this same voltage - we have the traxide too.

I haven't ever found the traxide isolate the cranker when the vehicle is sitting idle under the house, but 2 weeks is about as long as I can go without a drive in it!

The Traxide should disconnect the main battery from aux battery well before the starting battery gets below the voltage needed to kick over the starter motor. ( light will start flashing when this happens ). Mine always does this OK.

As an extra comfort measure, you might like to consider a separate switch in the + line that goes from your main battery to the Traxide, so when you're leaving it or a couple of weeks, so you can completely isolate that side of things manually.

You need to be completely sure only "essential services" are running when you have it in storage.