Is my Battery Master working properly

Emmenay

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I recently fitted a vanbitz battery master to work in conjunction with my solar panel set-up.

The van has been parked now for about four weeks in brilliant sunshine with nothing but the alarm to use any power.

Today I did a bit of tinkering and soon noticed the engine battery was sitting at 12.2v while the hab batteries had a floating charge of about 13.4v.

Should the engine battery have more voltage than that? Curiosity got the better of me so I thought I would try to turn the green light on the B/M to red by putting a heavy load on the battery.

So without starting the engine I put the ignition on and turned on everything possible which brought the engine battery down to 11.5v, which I kept at for 5 minutes. During this time the B/M light remained green. I thought it would have picked up on the low voltage and turned red, am I missing something?
 

Techno

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In my experience the engine battery is generally only 0.7 volts behind the hab battery when working correctly.

If you have wired correctly my next step would be to check with a voltmeter at your actual points of connection. If the readings are the same as you already suggested then it is not working.
 
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Emmenay

Emmenay

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Yes as well as checking they are the right way I have also re-done the connections just in case. One thing I did note was when I disconnected the brown wire that goes to the engine battery it is reading 12.7v from the B/M.
I thought it would be virtually zero until the B/M kicked in? As soon as I reconnect it, the battery resumes reading at 12.2v......that doesn't sound right to me!
 
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Emmenay

Emmenay

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Thanks Andy (y)

EEEDDDDDDDDIIIIIIIIIEEEEE :D
 

movan

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If it's any consolation, which it probably isn't, my battery master is always doing funny readings like that in similar circumstances. I was told it is fine. Make a note of the readings again, a couple of days later, and then again a couple of days on .... I was told this fluctuation is ok.. (I took the van back to where I had bought it from to be told this.)

This may sound silly, but also, previously on the diagram showing where to connect the wires the correct way round, my diagram is upside down (not obviously) and so at one point someone had connected the wires the wrong way round as the leisure baattery on diagram looked as if it was the engine battery.
 
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Techno

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Mine are reading 13.2 and 12.6 right now which is as I'd expect.

My solar battery bank sends surplus to my leisure batteries via a CBE CSB2 up to 4amps
My leisure batteries then support my starter battery via a battery master at up to 1.1amps.

Just checked the solar batteries after boiling the kettle and they're at 13.7 and climbing whilst also charging the leisure batteries
 
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Emmenay

Emmenay

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Ok, since yesterday afternoon when I re-done all of the connections the voltage at the engine battery has climed from a worrying 12.2v to a slightly more satisfying 12.5v. My gut feeling is that the earth connection via the split charge relay is a tad inferior so I wonder if a heavier earth connection would be of benefit. Also I have now removed the radio facia just in case. Still no sign of a red 'charging' light on the B/M though, it seems to be on constant green permanently giving out 12.7v so in theory my battery should reach that voltage (eventually) and just sit there?
I will keep an eye on for a few more days before bothering Eddie with it.
Now wheres that thanks button......
 
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