question

Todd Landfried avatar image
Todd Landfried asked

Multiplus 24/3000/70 showing incorrect SOC, shuts down at 100% charge, doesn’t recognize generator

This is weird. We have a four-month-old Multiplus 24/3000/70 that has recently been reporting false SOC numbers and shutting down at 50% even when the charge controllers are floating. If you flip the rocker switch On to Charge Only back to On it agrees with the controllers.

Also, in cases where the generator does need to come on (e.g., at 50% charge), the Multiplus sees it, but goes into float mode. It doesn’t change to bulk charge unless you flip the rocker switch from “On” to “Charge Only” and then back to “On.” The firmware version is 465.

Any thoughts?

MultiPlus Quattro Inverter Charger
2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Alexandra avatar image Alexandra ♦ commented ·

How is the SOC determined? Are you reading this information through a GX device, using a BMV or is it just the multi using volatge? What type of batteries are they?

0 Likes 0 ·
Todd Landfried avatar image Todd Landfried Alexandra ♦ commented ·

It’s in the inverter, there is no BMC or GX in this system.

0 Likes 0 ·
1 Answer
JohnC avatar image
JohnC answered ·

Hi @Todd Landfried

You don't say what pv chargers(s) you're using, but looking back at your older posts, probably independent dc-coupled units.

Now unless there's some new-fangled way of linking to the Multi, you'd need a GX box to give the Multi enough info to calculate an SOC. It can't sense external batt charge itself, just what it's own charger provides. Nor can it see batt dc loads that aren't going through itself.

So I suspect your SOC is incorrect, and will remain so whilst ignorant of pv charge. And if you're using an assistant or something to make decisions from that SOC, then I suggest you turn it off.

But the Multi can see V, and that may explain some of your other observations, like genny charge kicking off in Float. It's already seen it's own charger's Absorb limits achieved by the pv, so bypasses that phase. Never tested that myself, but I'm told that's what happens. Rather than a reset when you run the genny, try raising it's Abs V to slightly above that of the pv chargers.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.