Discharge test halted by high temp sensor??? Why did this happen?

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edgargw22 asked Dec 7, '19

Discharge test halted by high temp sensor??? Why did this happen?

I was about an hour into a discharge test of my lithium system and the BMV-712 shut it down about an hour later (see chart) because of high temperature. The ambient temperature was about 70F. The battery bay ambient temperature was about 64F. I had a constant load (convection microwave set to Mix High 325 drawing about 1300W). The internal temperature of the batteries was 70F, according to my Bluetooth utility, at the end of the test. The BMV-712 temp input comes from the battery temp sensor that's connected to the POS battery terminal.

Why would I get this elevated temperature from the battery post while internal battery temperture is staying cool. TIA...

Other equipment includes: (2) Victron LiFePO4-Smart 12,8/300Ah with Bluetooth and Victron MultiPlus 12|3000|120-50|120V.

BMV Battery Monitor Temperature Sensor

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Answer 1 · 2019-12-07T21:37:07Z

wkirby answered · Dec 07, 2019 at 09:37 PM

The battery terminal could get hotter due to a poor connection.
Check the connections at the terminals and the wiring to ensure those are sound. Is the wire guage the correct size?

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edgargw22 commented · Dec 08, 2019 at 07:56 PM

I have 4/0 cables from the batteries to the Victron Lynx Distributor and to the Victron Multiplus 3000. I pulled out my torque wrench and checked that all posts had at least 85 foot pounds.

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klim8skeptic ♦ edgargw22 commented · Dec 08, 2019 at 08:06 PM

Hi Edgar,

A battery terminal temp of 27c (80f?) is only luke warm. Not anything to get concerned at.

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