Safe minimum voltage for start up

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Mr Zero
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Safe minimum voltage for start up

Post by Mr Zero »

I'm interested in setting my Victron low-voltage cut-off switch to the lowest voltage that I can expect the Pinz to always start up. The switch supplies power to all non-essential accessories (fridge, off-road lights, accessory outlets, etc.). I have 2 Optima D31Ms (blue top/marine) batteries installed. I have gathered that a Pinzgauer will typically not start at voltages below 21.5V and appreciate that there are multiple variables to consider. However, on average what would be the lowest voltage that I could still expect the truck to always start up (without draining my battery repeatedly to find out)?
Jason @battlebornpinzgauer
[1975 Pinzgauer 710K 2.7L EFI, 1972 700AP Haflinger Pathfinder]
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rmel
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Re: Safe minimum voltage for start up

Post by rmel »

Consider the state of charge for a 12V AGM battery and that you might not
want to go below 50%. Attached table (typical), suggests about 12.0V/battery,
or 24.0V as your safe set point.

You may also want to check the open circuit voltage of your batteries after a
long drive and where the alternator took you to. It would not be too surprising
it's a bit below 100% charged (25.2V+) as these regulators were designed for
Wet cell batteries.
AGMDischargechart_grande.jpeg
AGMDischargechart_grande.jpeg (105.72 KiB) Viewed 915 times
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712MK

Driver: Ron // KO0Q
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Mr Zero
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Posts: 183
Joined: Fri Dec 11, 2009 1:28 pm
Location: Nevada

Re: Safe minimum voltage for start up

Post by Mr Zero »

Good info, Ron. I had started with a similar chart and assessed 24V as my safe point, but thought there might be some folks here with more smarts and experience than myself who might weigh-in on the topic. Thanks for the feedback.
Jason @battlebornpinzgauer
[1975 Pinzgauer 710K 2.7L EFI, 1972 700AP Haflinger Pathfinder]
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