question

kevgermany avatar image
kevgermany asked

VRM Calculation Wrong

VRM is reporting incorrect figures. See screen shot. Same/similar numbers on CCGX.

There is no load on AC, despite what VRM says.

DC load is actually about 3-15W, one LED plus an Orion feeding a 12V battery at 1A. Fan is running on the Easysolar.

Numbers are usually reasonable, when there's no shore power.

Easysolar 24/1600

CCGX

Orion 24/12 (can't remember the amperage)

screenshot-20221020-084827.png


VRM
2 |3000

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

2 Answers
marekp avatar image
marekp answered ·

@kevgermany

Those levels as so low that I am not surprised.

This "nonexistent" AC-out load could be the EasySolar's power draw.

AC-out loads are not measured but calculated.

I have seen systems without DC-loads but when DC-load was selected the values on VRM for it were positive.

3 comments
2 |3000

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

kevgermany avatar image kevgermany ♦♦ commented ·

Even so, I'm out by close to 150W

0 Likes 0 ·
marekp avatar image marekp kevgermany ♦♦ commented ·
@kevgermany

At that low power the efficiency of AC/DC conversion of MP is below 90%.

(850-36)x0.9=732.6

622+56=678

732.6-678=56.4 <- this is what you are "missing"


0 Likes 0 ·
kevgermany avatar image kevgermany ♦♦ marekp commented ·
Thanks
0 Likes 0 ·
Sarah avatar image
Sarah answered ·

Having a shunt installed as a DC energy meter to measure the DC load made a huge difference to the accuracy of this measurement on our boat.

2 |3000

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