Starter battery is charging, but domestics stopped charging?

[Scotty D]

Have two Leisure deep cycle batteries, 1 starter. Charged through what I think is a split diode charger (not sure, new to this). A solar panel also charges the domestics.

 

Suddenly, the domestics are not charging off the engine any more, and the little display panel (which shows me how much charge is in the battery, and how mcuh is coming from the panel, and how much is being used) has a sad face and is flashing E07 at me.

 

Someone said to me it would be a realy switch, all I can find is something similar to pictures of a split charge diode which has one cable in labelled engine, and 2 out labelled Battery 1 (which goes to engine) and Battery 2 (which goes to domestics).

 

1) How do I figure out what is wrong

2) What are the usual culprits in something like this.

3) I want ot post pictures of the suspected diode but don't know how to here.

 

Help!

[Guest]

Are you sure then egine battery is still charging? You need to get a dc voltmeter across both banks, and measure with and without engine running. If the engine battery is still charging, I would be initially checking for poor connections on the domestic bank. You can measure the output at the diodes and again at the battery bank. You could of course find a good connection on the positive side, but a poor one on the negative connections, which presumably link from your starter battery.

[David Schweizer]

This may seem over simple, but have you checked that there is power passing through the diode into the Domestic battery circuit? with the engine running connect a multi meter between the domestic output contact on the diode and earth. if there is no reading, the diode has gone open circuit.

 

Although some people may insist that this is unlikely to happen, let me asure that it can and does happen (with boring regularity!!). I had two charge splitting diodes go open circuit on the domestic side within three months, which is why I now use a relay for charge splitting.

[chris w]

This may seem over simple, but have you checked that there is power passing through the diode into the Domestic battery circuit? with the engine running connect a multi meter between the domestic output contact on the diode and earth. if there is no reading, the diode has gone open circuit.

That's not correct.

 

If the diode has gone open-circuit and you do this measurement, you will still get a reading from the battery itself (rather than the charging voltage). Thus if, with the engine running, you do this measurement and get around 12v instead of around 14v then the diode has gone open circuit (or there is a bad connection).

[Ricardo]

Suddenly, the domestics are not charging off the engine any more, and the little display panel (which shows me how much charge is in the battery, and how mcuh is coming from the panel, and how much is being used) has a sad face and is flashing E07 at me.

 

If your charge controller is like mine then that code means the solar panel isn't connected to the batteries, if you're not getting a charge off the engine either than I'd start by checking the battery terminals.

 

Ric.

[David Schweizer]

That's not correct.

 

If the diode has gone open-circuit and you do this measurement, you will still get a reading from the battery itself (rather than the charging voltage). Thus if, with the engine running, you do this measurement and get around 12v instead of around 14v then the diode has gone open circuit (or there is a bad connection).

 

Or alternatively you could completely disconnect the diode (or batteries) and run a continuity check between the common terminal on the diode, and the distribution terminals, remembering that a diode will only pass the current in one direction.

Edited March 30, 2009 by David Schweizer

[chris w]

Or alternatively you could completely disconnect the diode (or batteries) and run a continuity check between the common terminal on the diode, and the distribution terminals, remembering that a diode will only pass the current in one direction.

To be pedantic, a continuity check is also not a foolproof measurement, as the diode could have gone short-circuit (which will though cause a different issue to the one above).

 

You need to use the "diode" setting on your multimeter to measure the forward voltage drop.

[David Schweizer]

To be pedantic, a continuity check is also not a foolproof measurement, as the diode could have gone short-circuit (which will though cause a different issue to the one above).

 

You need to use the "diode" setting on your multimeter to measure the forward voltage drop.

 

I acknowledge that there would be different issues if the diode had gone short circiut, one of which would presumably be the possibility of the starter attemting to pull current from the domestic batteries via the diode and through possibly undersized cables.

 

But as far as charging is concerned, surely if the diode has gone short circuit both batteries will charge, which is not the problem which Scotty is experiencing.

Edited March 30, 2009 by David Schweizer

[chris w]

But as far as charging is concerned, surely if the diode has gone short circuit both batteries will charge, which is not the problem which Scotty is experiencing.

I said that above. I was pointing out that a continuity check (in general) is not a good way of testing whether a diode is OK. A forward voltage drop check and reverse impedance check is the only sure way.

[David Schweizer]

I said that above. I was pointing out that a continuity check (in general) is not a good way of testing whether a diode is OK. A forward voltage drop check and reverse impedance check is the only sure way.

So why even raise the matter of short circuiting if it is not relevant to the identified problem, and will manifest itself with a completely different set of outcomes?

[chris w]

So why even raise the matter of short circuiting if it is not relevant to the identified problem, and will manifest itself with a completely different set of outcomes?

Because YOU raised the issue by stating that one could test the operation of the diode by checking it's continuity. I don't want some people to be confused or convinced that that is a valid check without my additional comments above. Using your method they could still pass a possible failed (s/c) diode as good.

 

"Or alternatively you could completely disconnect the diode (or batteries) and run a continuity check between the common terminal on the diode, and the distribution terminals, remembering that a diode will only pass the current in one direction."

[David Schweizer]

Because YOU raised the issue by stating that one could test the operation of the diode by checking it's continuity. I don't want some people to be confused or convinced that that is a valid check without my additional comments above. Using your method they could still pass a possible failed (s/c) diode as good.

Not if it will pass a current in both directions, remember i did say ".....remembering that a diode will only pass the current in one direction."

 

Of course "some people" whoever they are, may not understand simple English and be confused. They must be really grateful that you are around to help them out.

[chris w]

Of course "some people" whoever they are, may not understand simple English and be confused. They must be really grateful that you are around to help them out.

I'm so glad that at last you recognise that fact. Not many will think of you as an electrical "jockey" being a civil servant and all that.

[David Schweizer]

I'm so glad that at last you recognise that fact. Not many will think of you as an electrical "jockey" being a civil servant and all that.

You really need to pay more attention Chris, you get so much about me wrong.

I am not and never have been a Civil Servant, and because I spent my final 20 or so years in a Trained Profession, does not mean that I have no practical skills or knowledge. I could certainly challenge your revered self opinion in a number practical areas.

Edited March 30, 2009 by David Schweizer

[chris w]

You really need to pay more attention Chris, you get so much about me wrong.

I am not and never have been a Civil Servant, and because I spent my final 20 or so years in a Trained Profession, does not mean that I have no practical skills or knowledge. I could certainly challenge your revered self opinion in a number practical areas.

Obviously not in grammar though

[David Schweizer]

Obviously not in grammar though

When your only response is to criticise the absence of one comma, it is time to admit you have lost the plot.

[Smelly]

Scotty, listen to Ricardo, as far as telling us what your solar controller is at least.

 

I'd be prone to checking diodes as well though if you know how to, otherwise, unfortunately it's chequebook time.

[chris w]

When your only response is to criticise the absence of one comma, it is time to admit you have lost the plot.

Ah I wasn't referring to the comma

[David Schweizer]

Ah I wasn't referring to the comma

My God, Chris. They may have taught you, at your old fashioned boys prep school, that one should not end a sentence with a verb, but it is no longer considered incorrect, except by people who are anal about such things.

 

If you are going to correct other people, you should make sure that your punctuation is correct, or didn't you get that far in English language lessons?

 

"People who live in glass houses....."

Edited March 31, 2009 by David Schweizer

[chris w]

My God, Chris. They may have taught you, at your old fashioned boys prep school, that one should not end a sentence with a verb, but it is no longer considered incorrect, except by people who are anal about such things.

 

If you are going to correct other people, you should make sure that your punctuation is correct, or didn't you get that far in English language lessons?

 

"People who live in glass houses....."

Are all civil servants as boring as you?

[David Schweizer]

Are all civil servants as boring as you?

You clearly believe that calling me a Civil Servant will, somehow, cause offence. However, it merely reinforces my view that you should pay more attention.

 

Read my lips - I am not, and never have been, a Civil Servant, If you had been paying attention in the past, you would remember what my professional occupation was.

[chris w]

If you had been paying attention in the past, you would remember what my professional occupation was.

You have obviously mistaken me for someone who gives a sh*t.......

[David Schweizer]

You have obviously mistaken me for someone who gives a sh*t.......

That's the old Chris we have all come to know so well. When you know you have lost the debate, hurl insults.

 

If you really do not give a sh*t, why do you continue to reply?

[chris w]

If you really do not give a sh*t, why do you continue to reply?

ironic humour?

[David Schweizer]

ironic humour?

Each to his own.

 

I'm bored with this now. Byeee