We have a 2018 T@B 400 with 2 6-volt AGM batteries, a 190 watt solar panel on the roof, and a Victron battery monitor. We brought it for service a week ago and picked it up today. Unfortunately, I didn't think to turn off the battery at the cutoff switch, and the battery was quite run down. With a full day of sun and driving, the monitor now reads 11.5, but at the same time reads 100% SOC. I admit that I don't understand this. 11.5 is, to my understanding, clearly not 100%, so we're boondock camping with out using battery currently. What's going on here? I've already tried turning off the battery switch and turning it on again after resting it for a half hour, but it still said 11.5 and 100% charged.
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@Sharon_is_SAM the batteries are original 2018, so I guess they could be nearing the end. We've only let them run lower than is healthy twice, though, and we don't get out all that often. I'll try to plug in on Monday when we're back home and see if they fully charge. Until then, we're stuck with whatever the sun will give us!
Thanks!
2013 Tundra TRD 5.7L
Massachusetts
2013 Tundra TRD 5.7L
Massachusetts
Cheers
There are 4 main things that need to be properly configured to prevent this from happening.
Battery capacity - matches the Ah of your battery bank (Harris AGM is 224 Ah)
Charged voltage - Victron suggests that is set to the "Absorption voltage level - which is 13.6 volts", but I set mine to 14.2 with AGM
Tail current - Minimum setting is .5%, which is where I had mine set
Charged detection time - default is 3 minutes, I suggest 5 minutes.
The SOC is reset to 100% when the following conditions are met.
When the Charged voltage reaches the level specified with a charge current that is less than the Tail current setting for the amount of time specified in the Charged detection time setting.
So, using the numbers that I used, the voltage has to reach 14.2 (or higher) with a Tail current of less than .5% (.005 x 224 = 1.12 Amps) for a period of at least 5 minutes. When those 3 things are met, that is when the SOC resets.
I think the defaults are as follows
Charged voltage - 13.2
Tail current - 4% (which is 8.96 Amps)
Charged detection time - 3 minutes
Using these settings and the same logic statement I listed above; you can easily see why the SOC resets to 100% long before the battery is 100% SOC. I had this issue early on with the BMV-712
Victron has some of the best (if not the best) stuff in the market, but their USA support is less than good.
Hope this sheds some light for all you "Tabbers and Victron users". As I mentioned before; I am going to miss this forum and the people on it but since I am no longer (okay in 10 days) a TAB owner, there isn't a reason to lurk
Brad
2022 Black Series HQ19 aka "Cricket"
2021 F-250 Tremor with PSD aka "Big Blue"
Concord, NC
@Deb55 - it took me a while to understand the nuances of the BMV. As much as we want a “plug and play”, we do need to understand that the equipment needs to be tweaked from time to time. I have had residual current that was stuck on the monitor that required a reset. The Tail current concept is important. As Dutch61 noted, the Tail current (positive amp value) is one of the things that tells the BMV that you have reached your charging goal and the monitor can label the Charged voltage as 100%. This value and the Charged detection value can be impacted by changing cloud coverage - a cloud shades the panel, drops the Amps and if the time value is too brief, it will prematurely call it 100%. I read some marine articles that were very helpful in understanding the settings.
2013 Tundra TRD 5.7L
Massachusetts
Cheers
TV: 2005 Toyota Sienna LE (3.3L V6)
RV: 2018 T@B 320S, >100 mods
224
14.2
50%
2.0%
5 min
1.16
90%
.10 amps
3 min
Is this what I should use for my settings to get a correct reading?
Right now, my camper is plugged into shore power and the battery switch is on, so I assume I'm fully charged. Should I do anything else or change any of those settings? This is a bit beyond my technical knowledge, but I'm obsessive enough to want to know what my correct SOC is when we're on a trip. Thanks!
Cheers