Lucas 33RA relay failure.

[Smelly]

CARGO part number 160343 up to 70A, 160399 to 120A. Both units are for 2 batteries and incorporate a third "compensating" output for the F+ connection.

 

 

How do you compensate for the voltage loss?

 

Sense the voltage downstream of the diodes...

[NB Alnwick]

This really is resurrecting a very old thread! I repaired my Lucas 33RA relay back in 2010 and my soldered repair has lasted more than ten years.

Before I repair it again - I just thought I would check to see if there has been any real progress in the market place with reliable split charge relays?

I recall that Gibbo recommended products made by Albright and Sir Nibble suggested a Cargo product. What else are folks using?

[Tony Brooks]

2 minutes ago, NB Alnwick said:

This really is resurrecting a very old thread! I repaired my Lucas 33RA relay back in 2010 and my soldered repair has lasted more than ten years.

Before I repair it again - I just thought I would check to see if there has been any real progress in the market place with reliable split charge relays?

I recall that Gibbo recommended products made by Albright and Sir Nibble suggested a Cargo product. What else are folks using?

 

Such split charge relays are arguably obsolete, especially with the prevalence of battery chargers or  solar. I would advise a VSR (voltage sensitive relay). They will be an almost direct replacement except they do not need the small positive energise wire so may help the alternate energise at lower revs.

 

All charging source outputs to the DOMESTIC bank. VSR between domestic bank and engine battery and sensing from the domestic bank. Whenever the charging voltage from any source s above about 13.6 to 13.8 both banks will be charged.

 

 

[David Schweizer]

10 hours ago, NB Alnwick said:

This really is resurrecting a very old thread! I repaired my Lucas 33RA relay back in 2010 and my soldered repair has lasted more than ten years.

Before I repair it again - I just thought I would check to see if there has been any real progress in the market place with reliable split charge relays?

I recall that Gibbo recommended products made by Albright and Sir Nibble suggested a Cargo product. What else are folks using?

 

I found that the Lucas relay only seemed to last a few years before failing, and following Gibbo's (remember him?) advice, I fitted an Albright 150amp relay, and never had any more problems, even when I upgraded the Alternator. They are still available here:-    https://www.arc-components.com/albright-su80-series-single-acting-solenoid-contactors.html   A  bit expensive but worth it in my opinion.

 

 

 

Edited May 14, 2021 by David Schweizer

[nicknorman]

7 minutes ago, David Schweizer said:

 

I found that the Lucas relay only seemed to last a few years before failing, and following Gibbo's (remember him?) advice, I fitted an Albright 150amp relay, and never had any more problems, even when I upgraded the Alternator. They are still available here:-    https://www.arc-components.com/albright-su80-series-single-acting-solenoid-contactors.html   A  bit expensive but worth it in my opinion.

 

...and you’d want the continuous type, not the intermittent type.

[David Schweizer]

Just now, nicknorman said:

...and you’d want the continuous type, not the intermittent type.

 

Yes, I no longer have the technical notes for Helvetia, and could not recall the type, but assumed that the supplier could probably advise.

[Tony Brooks]

9 minutes ago, David Schweizer said:

 

I found that the Lucas relay only seemed to last a few years before failing, and following Gibbo's (remember him?) advice, I fitted an Albright 150amp relay, and never had any more problems, even when I upgraded the Alternator. They are still available here:-    https://www.arc-components.com/albright-su80-series-single-acting-solenoid-contactors.html   A  bit expensive but worth it in my opinion.

 

 

 

 

That is almost certainly because the alternator output went to the engine bank rather than the domestic bank. It may also be because your Lucas relay as the lower current (cheaper) one that was intended for caravans.

[David Schweizer]

17 minutes ago, David Schweizer said:

 

Yes, I no longer have the technical notes for Helvetia, and could not recall the type, but assumed that the supplier could probably advise.

 

Surprisingly, I have just found the Owner's Manual for Helvetia and the Relay fitted was the Albright SW180B :-

https://www.arc-components.com/search/for/Albright+SW180B/   I had not noted the version fitted, but assume that the SW180B-2 would be the correct one.

 

Edited May 14, 2021 by David Schweizer

[NB Alnwick]

Well that was like turning the clock back eleven years! Tony and David you both contributed to the original topic in February 2010!

I appreciate that many things have changed with time - but we still have the same old boat with the same old challenges . . .

[NB Alnwick]

The image below shows what I have behind my uncomplicated control panel - I still have a spare Lucas split charge relay (and they are still available at a reasonable price) but I will take the foregoing advice and procure a more reliable replacement. The options are a VSR rated at 100 Amps or the Allbright SW180B - I need to check the dimension to make sure that the replacement will fit the space available. My other current project is the installation of a bilge water warning lamp just in case the automatic switch on the bilge pump fails to activate again. The link to the ARC catalogue provides a useful source of the necessary parts for this too.

 

[frangar]

Blue sea systems VSR every time.....they just work! 

[NB Alnwick]

5 hours ago, frangar said:

Blue sea systems VSR every time.....they just work! 

 

I think I can see why this Lucas relay stopped working!

 

 

 

Edited May 14, 2021 by NB Alnwick
image compacting.

[Tony Brooks]

Do I need to repeat why this sort of thing happens?

 

Probably best to check no batteries are shorting internally. Extra gassing in individual cells, dry cells, hot cells and eventually hydrogen sulphide.

Edited May 14, 2021 by Tony Brooks

[Tracy D'arth]

I have used Durite 180Amp relays for preheater switching and split charge with the engine battery as the first connected, the relay switching in the cabin batteries, for over 30 years and never had one fail in normal use.

I would suspect that the main cause of relay failure is poor connections adding to the heating which is normal in the relay coil.

Perhaps I have been lucky.

 

The only one that ever burnt out was when a numpty fitted a cabin battery with reversed polarity, I think it was entitled to!

[NB Alnwick]

1 hour ago, Tony Brooks said:

Do I need to repeat why this sort of thing happens?

 

Probably best to check no batteries are shorting internally. Extra gassing in individual cells, dry cells, hot cells and eventually hydrogen sulphide.

 

In this case, dry cells caused by my laziness in failing to keep them topped up!

[Tony Brooks]

10 hours ago, NB Alnwick said:

 

In this case, dry cells caused by my laziness in failing to keep them topped up!

 

Dry cells should not increase the current through the relay. In fact just dry cells should reduce the floe because of less plate area in contact with acid. If the dryness caused the plates to shed material and short out then I would agree but the danger of this is happening is minimise if the alternator feeds the domestic bank rather than the engine battery.

[David Schweizer]

4 hours ago, Tony Brooks said:

 

Dry cells should not increase the current through the relay. In fact just dry cells should reduce the floe because of less plate area in contact with acid. If the dryness caused the plates to shed material and short out then I would agree but the danger of this is happening is minimise if the alternator feeds the domestic bank rather than the engine battery.

 

I have just found the wiring diagram for Helvetia, and note that the feed  was  correctly connected to the Domestic batteries. Nevertheless I burnt out two Lucas relays before fitting an Albright relay, after which I had more than twelve years of problem free charge splitting. It was still working correctly when I sold the boat This suggests, to me, that the Lucas relay was inferior to the Albright.

 

 

Edited May 15, 2021 by David Schweizer

[Tony Brooks]

24 minutes ago, David Schweizer said:

 

I have just found the wiring diagram for Helvetia, and note that the feed  was  correctly connected to the Domestic batteries. Nevertheless I burnt out two Lucas relays before fitting an Albright relay, after which I had more than twelve years of problem free charge splitting. It was still working correctly when I sold the boat This suggests, to me, that the Lucas relay was inferior to the Albright.

 

 

 

The red bit is unarguable but I got near 20 years from a Durite 180 amp (I think) relay before I changed it to a VSR so solar charged both banks. I consider Durite on a par with Lucas.

[frangar]

2 minutes ago, Tony Brooks said:

 

The red bit is unarguable but I got near 20 years from a Durite 180 amp (I think) relay before I changed it to a VSR so solar charged both banks. I consider Durite on a par with Lucas.

The trouble both Lucas and durite are just marketing names now for Chinese tat! There’s recently been a thread on a series Land Rover forum about the lack of quality of Lucas branded kit. 

[NB Alnwick]

Obviously, when our boat was fitted-out in the 1990s the arrangement with the Lucas 33RA relay was considered appropriate. The present arrangement gives charge preference from the Lucas/CAV AC5R alternator (24v, 55A) to the starter batteries and only charges the domestic bank when the relay operates. When connected to the mains or our portable generator, the Sterling 20A charger provides what is described as an "intelligent charge" to both sets of batteries.

For my purposes, a simple manual switch would suffice in place of the Lucas relay. The starter batteries would need be recharged as soon as the engine has started but once up to full charge the charge can be switched to the domestic bank where there is likely to be a continuous drain. I still have two spare Lucas relays but my plan is to have a good look at the requirements and change the wiring round to provide the best solution. I have purchased a VSR rated at 100A but at this stage, I am not sure if it will provide the ideal solution.

[Tony Brooks]

15 minutes ago, NB Alnwick said:

Obviously, when our boat was fitted-out in the 1990s the arrangement with the Lucas 33RA relay was considered appropriate. The present arrangement gives charge preference from the Lucas/CAV AC5R alternator (24v, 55A) to the starter batteries and only charges the domestic bank when the relay operates. When connected to the mains or our portable generator, the Sterling 20A charger provides what is described as an "intelligent charge" to both sets of batteries.

For my purposes, a simple manual switch would suffice in place of the Lucas relay. The starter batteries would need be recharged as soon as the engine has started but once up to full charge the charge can be switched to the domestic bank where there is likely to be a continuous drain. I still have two spare Lucas relays but my plan is to have a good look at the requirements and change the wiring round to provide the best solution. I have purchased a VSR rated at 100A but at this stage, I am not sure if it will provide the ideal solution.

 

I don't understand the need to charge the engine battery before the domestic bank. Forest of all the engine battery with an engine in fair condition will only be discharge by  a few Ah per start. yes high amps but only for under 1 minute.

 

When you link batteries the charge gong to each is inversely proportional to their terminal voltage and thus discharge. The larger the difference the more charge will be applied to that battery. So even though a near fully charged start battery will receive less charge than  when direct connected to the charge source it will still get some charge so even if it were only 1 amp over half an hour that will give maybe 20Ah which is more than enough to fully replace the starting discharge.

 

I am convinced that the supposed advantage for charging the engine battery first is a result of non-technical marketeers.

[Tracy D'arth]

32 minutes ago, Tony Brooks said:

 

I don't understand the need to charge the engine battery before the domestic bank. Forest of all the engine battery with an engine in fair condition will only be discharge by  a few Ah per start. yes high amps but only for under 1 minute.

 

When you link batteries the charge gong to each is inversely proportional to their terminal voltage and thus discharge. The larger the difference the more charge will be applied to that battery. So even though a near fully charged start battery will receive less charge than  when direct connected to the charge source it will still get some charge so even if it were only 1 amp over half an hour that will give maybe 20Ah which is more than enough to fully replace the starting discharge.

 

I am convinced that the supposed advantage for charging the engine battery first is a result of non-technical marketeers.

From my experience the reason for the propensity of engine first charging is due to the alternator output B+ being connected to the starter motor battery lead as a matter of convenience instead of a longer heavy cable to the site of the split charge relay.

The alternative of siting the relay on the engine is not a good idea as vibration will damage the relay.

It is easier to pick up both battery positives in the control panel area, site the relay there where the D+ lead is also available to power the relay.

I accept the advantages of cabin battery first charging, it is something I have not until now considered.

[NB Alnwick]

I have attended enough of Tony's lectures to know that he talks sense. I can now see that I may have to look at some re-wiring. This may also include fitting a switch that can combine battery output like the one illustrated below. This would make life easier if/when the starter batteries fail. I have not yet calculated what the starter motor draws during cranking - the switch illustrated is good for 1200A.

 

Blue Sea Systems e-Series Selector Battery Switch

[GUMPY]

19 minutes ago, NB Alnwick said:

I can now see that I may have to look at some re-wiring.

Whilst you are at it,  it might be a good thing to change the uninsulated crimps on the fuse board to insulated ones.

 

Edited May 15, 2021 by Loddon

[David Mack]

4 hours ago, Tony Brooks said:

 

I don't understand the need to charge the engine battery before the domestic bank. Forest of all the engine battery with an engine in fair condition will only be discharge by  a few Ah per start. yes high amps but only for under 1 minute.

.....

I am convinced that the supposed advantage for charging the engine battery first is a result of non-technical marketeers.

Isn't it also just historical? In the early days of electric start engines there was only one battery, which supplied both the starter motor and some limited domestic uses (as in vehicles). But as engines all had hand starts fitted as well, it didn't matter too much if domestic use left the battery too low for starting. Then domestic demands started creeping up, and so an additional auxiliary battery was fitted for domestic use,  with a separate manual, later automatic connecting switch fitted. But the direct alternator (or dynamo) to start battery connection remained to ensure starting ability, particularly as many engines no longer had hand starting. Over time domestic demands increased to the point of needing multiple domestic batteries but still only a single start battery, and it took a long while for the penny to drop that the main function of the alternator was now to charge the domestic batteries.