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Topic: battery life help (Read 618 times) previous topic - next topic

capt_carroll

Voltage questions, i have a home built controller that runs for exactly 2:25 hrs whether its on a (1) 12v 1300ma battery, or 2 12v 1300ma batteries (doubling the ma) or a 9.2v 3800 ma battery. my goal is to get to 3.5 hrs. my draw is 640-670 ma depending on load.

how do i extend the lfe time of the controller?

thanks in advance

johnwasser

I assume you meant to say Milliamp Hours when talking battery capacity.

> (1) 12v 1300 mA/h battery, or 2 12v 1300 mA/h batteries (doubling the mA/h) or a 9.2v 3800 mA/h battery.

The 9.2v battery SHOULD last nearly 6 hours with a 655 mA load.  Perhaps the battery is defective or your measurement system is wrong. 
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dc42

Are you certain that the reason the controller stops after 2:25 hours is always because the battery is flat, whichever battery you are using? This is about what we expect for the single 1300mAh battery, but not for the others. I'm wondering if there is a software problem.
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MarkT

Something isn't quite right - a 1.3Ah battery that is actually 1.6Ah is a rare find!

Its typical for nominal capacity to be just achieved with a new battery, and then the
capacity dwindles with the number of charging cycles.

Anyway the suspicious independence of uptime from the actual battery pack strongly
suggests a coding problem as has been mentioned - have you measured the battery
voltages at the 2:25 point BTW?

Are you sure about the load current?  Does it vary for instance?

(Note with lead-acid batteries over-discharge will ruin the battery - don't let the
votage fall below about 10.5V)
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capt_carroll

i ordered some A systems 123 batteries and together there set up for 7.2 v @ roughly 4000 maH and it lasted for around 6.2 hrs (far exceeded my expectations but a little on the costly side, but works awesome) so it was the nicd battery that was having issues but it still confuses me as to why the 12v batteries would push it for longer than 2.25 hrs, both of those batteries are actually 12.6v and 1500 maH.


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