What Would Be Causing This?

[GorillaToast]

The distribution panel on my boat is a Blue Seas traditional metal panel with AC/DC breakers, both AC and DC analog voltage meters, and a DC ammeter. The entire system is less than a year old, wiring the ncluded. All circuits are properly fused. 4 6v house bank batteries, and a starter battery are charged via a 140w solar panel controlled by a mppt controller. An ACR sends the charge to both banks as needed.

The problem of is with the DC ammeter.

With the DC main breaker on, and flipping on various circuits, I can see the needle move showing positive current readings. However, if I flip the AC main on, the needle moves to the left below the scale. The meter is wired correctly as per the Blue Seas installation diagram.

Has anyone experienced this odd meter behavior, and found a solution?

Thanks.


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[skipmac]

When you turn on the AC main does that include turning on a battery charger? If so, the meter could be showing charge going back into the batteries.

[StuM]

Originally Posted by skipmac

When you turn on the AC main does that include turning on a battery charger? If so, the meter could be showing charge going back into the batteries.

That would be my guess too.

[GorillaToast]

Aha! It does occur when the charger is on.

So, should I not worry about it?


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[skipmac]

Originally Posted by GorillaToast

Aha! It does occur when the charger is on.

So, should I not worry about it?

Probably not but I guess there's a slight chance of damaging the analog meter movement if trying to push it too far negative. On the other hand, you can tell when the charger is working.

[Xthewater]

You can put a blocking diode on one leg of the meter to prevent that reverse affect if there's concern about meter damage.

[KadeyKrogen38]

I would contact Blue Seas for info and advice. DC meter should not act this way. It should show the increased voltage being supplied by charger, not the other way.

[Xthewater]

Originally Posted by KadeyKrogen38

I would contact Blue Seas for info and advice. DC meter should not act this way. It should show the increased voltage being supplied by charger, not the other way.

Ammeter shows current both leaving and entering batteries whereas voltage just shows raising and lowering.

[transmitterdan]

Draw out the wiring diagram and post it here. Maybe we can recommend a simple change. An analog meter should not be damaged by being driven negative but it isn't wired right either based on what you see.

[unclemack]

DC ammeter:

Engine alternator or charger coming on line should deflect needle to the right.
Switching on a load should deflect it leftward.

Needle right of centre, batteries are being charged.

Needle left of centre batteries are being discharged by a load.

From your description the meter would seem to be reversed.

[Xthewater]

3 solutions I can suggest.
Reverse blocking diode in one leg of the ammeter. Replace present ammeter with center balanced analog meter so you can see the rate of charge/discharge or digital meter for same reason.
I'd opt for 2nd as 3rd requires a very small (milliamperes) draw on batteries though easier to read at a glance.

[Xthewater]

Originally Posted by unclemack

DC ammeter:

Engine alternator or charger coming on line should deflect needle to the right.
Switching on a load should deflect it leftward.

Needle right of centre, batteries are being charged.

Needle left of centre batteries are being discharged by a load.

From your description the meter would seem to be reversed.

Perhaps I interpreted wrong. My read needle below scale suggested it was 0-30 as example, not 30-0-30 scale i.e. Center balanced.

[paulajayne]

Originally Posted by KadeyKrogen38

I would contact Blue Seas for info and advice. DC meter should not act this way. It should show the increased voltage being supplied by charger, not the other way.

It is an ammeter and will not show voltage.

As said above it is showing input from the charger - showing a gain instead of a deficit.

[Stu Jackson]

Forget the diodes.

The ammeter shows NET current. The charger is + going in, the - is current being used (or going out).

Not so hard.

All ammeters do this is wired properly. That is their purpose.

Kinda like your checking account: your write a check: (-); you make a deposit: (+).

[unclemack]

Originally Posted by Xthewater

Perhaps I interpreted wrong. My read needle below scale suggested it was 0-30 as example, not 30-0-30 scale i.e. Center balanced.

No, probably me who misinterpreted the OP

Only Blue Sea ammeters I see on evilbay are 50-0-50 and 100-0-100 in 2" or 2.75" sizes.

Just assumed it would be zero-centred because - why would anybody not want that?