# Strange SOC on 24v system **URL:** \ **Category:** DIY\ **Tags:** smart\_battery\_sense, marine, beginner\ **Created:** [21 April 2025 16:19 UTC](https://community.victronenergy.com/t/strange-soc-on-24v-system/29619 "2025-04-21T16:19:29Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Erwin](https://avatars.discourse-cdn.com/v4/letter/e/a88e57/32.png) [@Erwin](https://community.victronenergy.com/u/Erwin)\ **Post date:** [21 April 2025 16:19 UTC](https://community.victronenergy.com/t/strange-soc-on-24v-system/29619/1 "2025-04-21T16:19:29Z")
I have a 24v battery bank, with 4 AGM batteries of each 115Ah ( at 12v). In the settings, the voltage and the size of the bank are correct ( 330 Ah and 24 volt ), but where the used Ah shows 70 Ah, the percentage shows 90%… it looks like it’s calculating the percentage based upon 12 volt… but the Ah look correct ( no shore power for a week ) Any ideas what is going on? ---
**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:** [21 April 2025 16:43 UTC](https://community.victronenergy.com/t/strange-soc-on-24v-system/29619/2 "2025-04-21T16:43:42Z")
You need to read up on the Peukert effect. A simple overview is a 100Ah lead acid battery is specified to deliver 100Ah with a 5A load over 20 hours. With a 20A load it will deliver say 80Ah and a 100A load only 50Ah. When drawn down slowly, say at 1A you may get 140Ah and at 0.1A 180Ah. The battery monitor allows for this so the SOC and Ah drawn may not necessarily be the same. I am guessing that over recent days you have had a low current draw, at very low current consumption, the effective battery capacity is much higher than rated so SOC falls more slowly than Ah drawn. ---
**Author:** ![Erwin](https://avatars.discourse-cdn.com/v4/letter/e/a88e57/32.png) [@Erwin](https://community.victronenergy.com/u/Erwin)\ **Post date:** [21 April 2025 16:53 UTC](https://community.victronenergy.com/t/strange-soc-on-24v-system/29619/3 "2025-04-21T16:53:23Z")
Aha, I didn’t think of that. Since the discharge was around 0,5A this sounds like a plausible explanation. I will check the used Ah and the SOC when I have used more A than this time. The peukert setting is 1.25 Thanks for your reaction ---
**Author:** ![Erwin](https://avatars.discourse-cdn.com/v4/letter/e/a88e57/32.png) [@Erwin](https://community.victronenergy.com/u/Erwin)\ **Post date:** [22 April 2025 02:45 UTC](https://community.victronenergy.com/t/strange-soc-on-24v-system/29619/5 "2025-04-22T02:45:18Z")
Sorry, it is 4 x 165 Ah Victron AGM