Hi, the time remaining on my Smart Shunt seems to be off by a lot.
My capacity at 92% (of 687ah) is 632ah. In the screenshot, I’m pulling 14.97A. 632Ah / 14.97A is roughly 42.2 hours remaining. Shunt says 37 hours remaining. What’s up with that? The unit thinks it’s on the latest firmware - v4.19 and bt firmware v2.52 , bootloader v1.8.
Am I missing something or is this just wrong?
Thanks for reading!
What is your setting on discharge floor remaining time takes in to account the setting of discharge floor if for example your setting is 10% the time remaining is calculated for 90% of your Amp setting
Thanks, my discharge floor is currently 0%.
How long was the load applied, and how constant is it?
Time remaining calculation takes a bit to calculate correctly. If my compressor fridge starts, it only runs for a minute. In that minute the time-remaining figure barely is able to get to a steady number
As noted above, the time to go uses an average current. This is taken over the time range specified in the battery setting “Time to go averaging period”, default 3 mins. All explained in the manual.
Yeah, I guess that explains it. Thanks
I have installed many Victron I/C on boats in the last 20 years. I always disable the TTG feature on whatever battery monitoring device that is installed. In a dynamic environment like a boat, RV, etc., this value if essentially meaningless and is extremely dependent on the load during the last 3 minutes (default). I teach the client to use either Ahr remaining or SoC.
And why did you set your discharge floor at 0%. I am personally uncomfortable going <10% for this setting.
@CharlieJ re discharge floor setting. It’s Lithium - it’s meant to go to 0% - and as long as ones low cell voltage cutoff is set appropriately, why carry around the weight of that extra 10%, or whatever, if it will never be used. I’m totally ok with a full cycle.
@vanlifeftw LFP batteries have the capacity to be discharged to 0% SOC but they are not “meant to go to 0%.”
Here is an excerpt from the Smart LFP NG manual:
The discharge floor prevents full discharge and
should be chosen so that there is always enough
energy in the battery for self-discharge before the
battery can be recharged.
Example: A 10% discharge floor still provides
enough stored energy for the self-discharge of
a 200Ah battery to last about 9 months without
recharging
As an analogy, diesel engines can be run at WOT but it is not advisable to run at WOT for extended periods.
At the end of the day, it is your installation but my advice is to be conservative and set the discharge floor at 10%.
As a full time van person, let me say that you are making my argument for me. But hey, if I ever leave my van for 9 months, thanks, I’ll take that under consideration. 
