Battery options

Drivesafe,

I've noticed with My D4 using an Optima D34 and the Traxide USI 160 system that the car usually tells me the voltage is low and please start the engine, after the fridge etc has been draining the battery for a while. No problems starting the car but I assume this is because the batteries remain connected together until the voltage drops just below the message threshold before being isolated. Would this be the case?

On our Cape York trip we had no problems running the Waeco 50l fridge and LED camping lights off the sytem for even 2 days without starting the engine.

Bob

Hi Bob and on a trip you will experience this because the cut-out level of my isolators is 12.0v but the low battery messages commence once the battery voltage gets down to 12.2v

As soon as you got home and started you usual city driving the messages should have stopped. Correct?

Yes. Just as I thought the cut off voltage is just below the message voltage. It will accasionally also trigger around the city with the fridge on all the time but never with no load on the dual battery.

FYI, I noticed that the D4 has no trouble supplying 65 Amps to the D34 battery when I use my ARB twin compressor attached to the D34 battery. The compressor draws 65 Amps and I measured 65 Amps going into the battery with the engine idling, as expected.

Bob

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Originally Posted by drivesafe

Toyotas

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Don't swear at me! :p

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Originally Posted by BobD

I've noticed with My D4 using an Optima D34

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Hi Bob - do I read that correctly that you're using an Optima D34 as a crank battery? or are you using the OEM DIN100 Calcium battery with the D34 as Aux?

No. I have the standard Calcium starting battery and the Traxide second battery kit (USI 160) with the Optima D34.

Sorry if the criptic message gave you false hope!!

Bob

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Originally Posted by BobD

It will accasionally also trigger around the city with the fridge on all the time.

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Hi again Bob and if you get a chance, the next time you get the low battery message, when driving around town, if you notice the message before you start your motor, get a voltage reading from your auxiliary battery.

Your cranking battery will be fine as it’s protected by the isolator, but your auxiliary battery is not protected from over discharging.

With my system, because the current load is shared over both batteries, if should take a while to discharge the batteries down to where the isolator cuts out.

But once the isolator does cut out the auxiliary battery is then providing all the power for the fridge and as the auxiliary battery is pretty small in the first place, you may find your auxiliary battery will discharge to a very low state in a short period of time.

If this happens a lot, you may end up shortening the auxiliary battery’s life span.

Just a suggestion but if you are not using the fridge around town, it may pay you to turn it off between uses.

Yes, thanks Drivesafe.

The only time the fridge is in the car is when I am getting ready for a trip or on a trip, so no worries with the battery life. We only notice the message occasionally once we put the fridge in the car ready to leave in a few days, usually if the car has been sitting around for most of the day. I understand that if the starting battery is below 12.2V or at 12V then the Optima is at that level or lower. The Waeco cuts out at 10.5V at the fridge which is some protection from gross discharging of the aux battery, especially with the voltage loss that occurs from the battery to the fridge when the compressor is running. So far the fridge has never stopped running in the D4 so at least we haven't reached a voltage which is that low!

Sorry to hijack the thread a bit komodo!

Bob

Go for youre life!
Its interesting information.

Thanks komodo.

It's interesting that despite the relatively low AH's of the Optima battery the combination that the Traxide kit gives never runs out of power in normal use. We were running three 24W LED light bars for two or three hours plus the Waeco fridge 24/7 and there was never any lack of power for the auxilliary stuff or starting the engine, even after two nights with the car sitting unused all day.

Bob