# Soc will not show an accurate percentage **URL:** \ **Category:** DIY\ **Tags:** backup, bluesolar\_pwm, beginner\ **Created:** [22 April 2025 20:54 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767 "2025-04-22T20:54:22Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [22 April 2025 20:54 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/1 "2025-04-22T20:54:22Z")
I can’t get my smartshunt to show an accurate reading. System ends up going dead at “48%” I can’t seem to figure out what the isssue is. I input all the settings from the battery manufacturer ---
**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\ **Post date:** [22 April 2025 21:11 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/2 "2025-04-22T21:11:15Z")
Not enough information to help out. Tell us what batteries you have, type, voltage, Ah rating, number in series and parallel and a screenshot of your settings. Do you have 2 batteries in series and have put in 2 x battery capacity. In series you do not multiply battery capacity, so your batteries would run out at indicated 50% because that would be 0%. ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [1 May 2025 13:46 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/3 "2025-05-01T13:46:35Z")
![IMG_3379](https://europe1.discourse-cdn.com/victron/original/3X/2/0/203cc51dfbb6d96445c78c80c76694a5e72b1997.png) ![IMG_3382](https://europe1.discourse-cdn.com/victron/original/3X/e/3/e3de8f4a2ef34eff009aff87a7667f142490b513.png) ![IMG_3385](https://europe1.discourse-cdn.com/victron/original/3X/5/7/578e99eb413e46736c8e61740cca3d896e305e27.png) ![IMG_3591](https://europe1.discourse-cdn.com/victron/original/3X/3/c/3c6aa16a24a6f96c78128175bbd383f8fb8d572a.png) ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [1 May 2025 13:48 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/4 "2025-05-01T13:48:51Z")
I have 4 200ah 12v lifepo batteries in series x 2 so 8batteries total. Wired for 48v ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [1 May 2025 13:50 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/5 "2025-05-01T13:50:03Z")
The bottom photo is from today. It does again but at 56% I then set the soc to zero ---
**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\ **Post date:** [1 May 2025 16:32 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/7 "2025-05-01T16:32:25Z")
The SmartShunt should he working reasonable well. The discharge floor for lithium is typically 10% or 20%. If your system is going dead at 48% then you have some serious problems. Have you checked that each of the 12V batteries in series are balanced because one poor pack going off line because it is not balanced would be an issue. You really ought to do a monitored draw down if you are losing power at 48%. The other possibility is you have not wired the shunt up properly a d you have some power draw from the battery that is not being measured or you have a large zero error. See the manual for zero current calibration and this link for wiring. > [@Shunt / battery monitor not reading the correct SOC/ Amps, missing solar, decreasing daily or other misreading problems](https://community.victronenergy.com/t/shunt-battery-monitor-not-reading-the-correct-soc-amps-missing-solar-decreasing-daily-or-other-misreading-problems/87): > > This topic covers the SOC / Amps reported by BMV battery monitors, SmartShunts, Lynx BMSs and Lynx Shunts and will just be called shunt below. It is also assumed that the shunt is monitoring the domestic / house / cabin battery bank and not engine start / bow thruster / winch / caravan mover battery banks. The problems may be one or more of the following The SOC decreases daily despite the solar charger or other charger(s) working. The SOC increasing when discharging and falling when charging… ---
**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\ **Post date:** [1 May 2025 16:46 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/9 "2025-05-01T16:46:34Z")
That would explain the 50% discrepancy. ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [1 May 2025 21:18 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/10 "2025-05-01T21:18:32Z")
It was doing this before I changed the battery floor to 48% I was just playing around at this point ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [1 May 2025 21:19 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/11 "2025-05-01T21:19:26Z")
The batteries are connected to balancers ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [1 May 2025 21:20 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/12 "2025-05-01T21:20:37Z")
All the negative power flows through the shunt. ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [2 May 2025 05:19 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/15 "2025-05-02T05:19:44Z")
Yes. And yes… now I actually tried to remove the smart shunt all together. Batteries are at 52v and the inverter won’t stay on for more than a few seconds before displaying the Low battery alarm. The loads connected are minimal and this system has been working completely fine for over 6 months. No issues until now. ---
**Author:** ![structureandslate](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@structureandslate](https://community.victronenergy.com/u/structureandslate)\ **Post date:** [2 May 2025 05:23 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/16 "2025-05-02T05:23:00Z")
![IMG_3608](https://europe1.discourse-cdn.com/victron/original/3X/2/1/21884880602cc87ae5e0f014a7ac3dbeeff4a499.png) ![IMG_3609](https://europe1.discourse-cdn.com/victron/original/3X/a/d/ad61e1c7f8618de84368f3f811319ee882c7badf.png) ---
**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\ **Post date:** [2 May 2025 07:32 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/18 "2025-05-02T07:32:21Z")
Are both battery strings working, disconnect them from each other, then see if they are showing the same voltage. Use them individually to see if they both work, making sure to recharge them to the same voltage before reconnecting. It is not unheard of for the SmartShunt to loose accuracy but the failing at 50% points towards one battery bank not contributing. ---
**Author:** ![anon39974850](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@anon39974850](https://community.victronenergy.com/u/anon39974850)\ **Post date:** [11 June 2025 17:03 UTC](https://community.victronenergy.com/t/soc-will-not-show-an-accurate-percentage/29767/19 "2025-06-11T17:03:16Z")
To followup on an earlier post of @pwfarnell The batteries: 1.) Self built or retail 2.) Detailed spec of above (cell type, BMS, manufacturer if retail). System: Please provide pictures of your shunt and associated wiring to your battery (all bank elements), and to your system distribution board.