Humminbird Side Imaging Forums

General => General Discussion => Topic started by: tambrose76 on August 26, 2017, 04:32:39 PM

Title: 898 voltage offset
Post by: tambrose76 on August 26, 2017, 04:32:39 PM
Using a calibrated voltmeter, the feed to my 898 reads 1.6vdc higher than what the HB display says.  This reveals my main battery to maintain 12.2vdc after an 8hr rest and no other electronics to bleed it down. New battery, Guest algorithm charger on AGM setting, wiring intact, electronics technician. Why would the display read lower than the input voltage. Also, I see the Low Voltage alarm comes on during engine start, noting the current draw and resultant voltage drop to bark.  Why not a measurement of the last ten seconds (averaged) to preclude alarming but for the display voltage during fishing use?
Title: Re: 898 voltage offset
Post by: Bob B on August 26, 2017, 09:11:06 PM
How are you checking the voltage ..... If you remove the cable collector on the 898 there are pins on the power cable that can be accessed from outside the connector.  Check the voltage there with the unit powered on.

There is no calibration for the voltage reading.
Title: Re: 898 voltage offset
Post by: tambrose76 on August 28, 2017, 04:16:17 PM
The voltage at the pins, battery, bus bar are identically high compared to the display.
Title: Re: 898 voltage offset
Post by: Gimp on August 28, 2017, 04:47:10 PM
The voltage at the pins, battery, bus bar are identically high compared to the display.
The problem is you need to measure the voltage at the pins WHILE the battery is under load (i.e. while the unit and everything else that is connected to the battery is ON) The hard part is getting the volt meter onto the pins while the unit is on.

A battery under load will read lower that at idle. The more 'worn out' the battery is, the more the two measurements will differ.
Title: Re: 898 voltage offset
Post by: rnvinc on August 28, 2017, 10:01:22 PM
Turn the backlight the down to 1 and the readout voltage will be closer to your volt meter reading  ...

Rickie
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