Auxiliary battery voltage
Submitted: Friday, Apr 11, 2025 at 15:49
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Member - nick boab
Hi folks : I have purchased a victron smart shunt battery monitor (Wi-Fi only) .I have not installed it as yet but I was wondering will this tell me the battery voltage in the auxiliary battery without any interference from main charging system or DC charger solar etc .
Or is there any way of determining the exact voltage in exhilary battery.
cheers
Reply By: Peter_n_Margaret - Friday, Apr 11, 2025 at 15:58
Friday, Apr 11, 2025 at 15:58
Which model(s) have you purchased?
Cheers,
Peter
OKA196 motorhome
AnswerID:
647763
Follow Up By: Peter_n_Margaret - Friday, Apr 11, 2025 at 16:17
Friday, Apr 11, 2025 at 16:17
https://www.solar4rvs.com.au/victron-smart-shunt-300a-bluetooth-battery-monitor
If this is what you have, then you need another cable...
"Key Features of the SmartShunt 300A
The SmartShunt isn't just a battery monitor—it's a leap forward in battery system management. It's equipped with Bluetooth for wireless communication, a VE.Direct port for wired data transfer, and additional connections for monitoring a secondary battery or connecting a temperature sensor. Whether it's for midpoint monitoring or simply keeping your system's footprint small, the SmartShunt has you covered."
Cheers,
Peter
OKA196 motorhome
FollowupID:
928858
Follow Up By: Member - nick boab - Friday, Apr 11, 2025 at 16:56
Friday, Apr 11, 2025 at 16:56
Thanks peter Shu05013005 300amp
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928859
Follow Up By: Allan B (Sunshine Coast) - Friday, Apr 11, 2025 at 17:39
Friday, Apr 11, 2025 at 17:39
.
Hi Nick,
You say….. "measure the auxiliary battery voltage without any interference from main charging system or DC charger solar etc ."
Just be aware that it is not possible to accurately measure the battery voltage in any way whilst the battery is receiving charge from any source or while discharging to a load. Whilst any charging is taking place the terminal voltage of the battery will be elevated by a small amount. Furthermore, the only way to determine the "exact" battery voltage is to measure it at some time after it has been charging or discharging. The wait time can be about 15 minutes for a lithium battery and an hour or more for a lead-acid battery.
But it all depends what you mean by "exact". The error during charge or discharge can be as much as 1 or 2 volts and during the resting time following charge or discharge it may be half a volt or so.
Normally it is sufficient to observe the voltage soon after charge, say 5 minutes or so to obtain a reasonably accurate value. Otherwise wait an hour to see a more accurate indication..
Why are you interested in a very accurate reading?
FollowupID:
928860
Follow Up By: Member - nick boab - Friday, Apr 11, 2025 at 17:52
Friday, Apr 11, 2025 at 17:52
Thank for reply ..sorry using wrong word :(
Dosen't need to be exact .
FollowupID:
928861
Follow Up By: Peter_n_Margaret - Friday, Apr 11, 2025 at 18:22
Friday, Apr 11, 2025 at 18:22
There are many other cheap and reasonably accurate other low cost ways to watch voltage on Ebay etc.
Voltage read-out
Cheers,
Peter
OKA196 motorhome
FollowupID:
928862
Follow Up By: Allan B (Sunshine Coast) - Friday, Apr 11, 2025 at 18:23
Friday, Apr 11, 2025 at 18:23
.
Nick……
OK then, what Peter said goes.
But please be careful…. about "exhilary batteries". I got all exhilarated composing my reply. Now I feel 'flattened'. Doh.
FollowupID:
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Follow Up By: The Explorer - Friday, Apr 11, 2025 at 18:41
Friday, Apr 11, 2025 at 18:41
@ Allan B - don't Start again - I dropped a Cell and suffered Attenuation after our last Connection.
Cheers
Greg
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Follow Up By: Allan B (Sunshine Coast) - Friday, Apr 11, 2025 at 22:17
Friday, Apr 11, 2025 at 22:17
OK Greg, I'll pull the plug.
FollowupID:
928868
Reply By: Member - peter g28 - Friday, Apr 11, 2025 at 19:16
Friday, Apr 11, 2025 at 19:16
I have a Victron Smart Shunt in my 12v set up in my camper trailer, it shows me via the Victron App the voltage as
well as the remaining time to full battery discharge which is very helpful when I am
camping off
grid.
I have attached a YouTube link that reviews the Victron Smart Shunt pretty
well.
Smart Shunt review
AnswerID:
647765
Follow Up By: Member - nick boab - Friday, Apr 11, 2025 at 21:57
Friday, Apr 11, 2025 at 21:57
Thanks peter , few good video's on this subject. Have been looking for info on setting for ledacid battery . Cheers
FollowupID:
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Reply By: RMD - Friday, Apr 11, 2025 at 21:32
Friday, Apr 11, 2025 at 21:32
G'day Nick
I have no doubt the Victron shunt (good KIT) will show you additional information but the phone has to be activated to read the system via it's Blueteeth.
The battery voltage can be seen/observed easily, I use a RED digital voltage meter as mentioned from EBAY, 3 digits, eg, 12.6v, no hundredths. That is for the Lithium AUX batteries. Another digital voltmeter BLUE numbers, is mounted below the RED one. Both have a switched earth, ie, Sw open to turn them OFF. These are mounted on RHS of Dash and are small but with a Glare shield around them they are easily seen while driving. This way I can instantly monitor both systems . Both voltages, Engine alt/battery and DCDC/SOLAR MPPT going into the AUX Lithiums. If anything is not working I can instantly see the voltages and maybe rectify any issue.
AnswerID:
647767