'99 Pollensa - 30a Fuse melting to Leisure Battery

[STILLETTOPSA]

Hi All,

New to this site and have read some excellent information prior to joining; so I wonder if any of you has shared this experience.

I've a 'T' Reg Peugeot Boxer Pollensa 2.5D (5.95m) that is in very good condition throughout and clearly over the years, prior to our purchase in June 2018, has had electrical updates.

My issue is the overheating, that subsequently leads to melting and blowing of, the 30a fuse between the vehicle battery and the switching relays during leisure battery charging when the vehicle is in motion. This has happened three times and is causing me some concern contemplating the current being drawn to melt a 30a fuse!. Both vehicle and leisure batteries are new. Relays are fortunately located within the vehicle cab, under drivers seat, and so are spared from moisture and weather, however this morning I have removed and cleaned the contacts just to be safe. Wiring looks fine and of adequate size...............any thoughts please?

 

regards

 

Andy

[colin]

What size battery bank have you got?

[Derek Uzzell]

Welcome to the Out&AboutLive forums, Andy.

 

Based on on-line comments about ‘around-Year-2000’ Pollensa-related fuses, I’m guessing that the fuse that is melting is located in the engine compartment (and the 30A rating seems to be correct).

 

A couple of possibilities...

 

1: The fuses you’ve been fitting are poor quality.

 

2: The contacts within the fuse-holder (into which the fuse is inserted) are corroded/bent/damaged, leading to arcing that eventually results in the fuse melting.

 

You might try asking about this on the AUTO-SLEEPER OWNERS FORUM

 

https://www.autosleeper-ownersforum.com/

 

as that’s where knowledge of older Auto-Sleepers models is likely to reside.

 

 

[witzend]

Could the engine battery be pulling power from the leisure batterys when starting poor earth ?

[STILLETTOPSA]

just the one battery: an 85Ah

tks

[STILLETTOPSA]

1: The fuses you’ve been fitting are poor quality.

 

2: The contacts within the fuse-holder (into which the fuse is inserted) are corroded/bent/damaged, leading to arcing that eventually results in the fuse melting.

 

You might try asking about this on the AUTO-SLEEPER OWNERS FORUM

 

Hi Derek, thanks for getting back:

 

1. I am using standard Halford's fuses so am 'assuming' they have reasonable QA, but as you suggest get another brand in.

2. My first port of call was to inspect and clean the holder, but perhaps replacing would be the best option.

 

and will certainly ask in the Auto-Sleeper College of Knowledge.

 

cheers

[STILLETTOPSA]

Hi Witzend,

Could the engine battery be pulling power from the leisure batterys when starting poor earth ?

 

As I understand it, it is the vehicle alternator that actually charges the leisure battery once vehicle battery is fully charged and given that both batteries are less than 1yr old it would be highly unlikely. However, for a 30a fuse to slowly melt could be an intermittency somewhere.....thanks.

[Keithl]

STILLETTOPSA - 2020-11-25 4:46 PM

Could the engine battery be pulling power from the leisure batterys when starting?

What Witzend meant was that if the split charge relay had failed in the closed condition then when you start the engine the power for the starter motor would be drawn from BOTH engine battery and leisure battery. This current would be far in excess of 30 Amps but only for a relatively short length of time and may not immediately blow the fuse, but I personally think an unlikely scenario.

 

STILLETTOPSA - 2020-11-25 4:46 PM

As I understand it, it is the vehicle alternator that actually charges the leisure battery once vehicle battery is fully charged...

Incorrect theory! As both batteries are connected directly in parallel they will both receive exactly the same voltage and hence rate of charge. You would need some fancy electronics to monitor the charge of the starter battery then switch over charging to the leisure battery.

 

Can you measure the voltage of both batteries at rest with the engine off and then again with the engine running please.

 

Keith.

[STILLETTOPSA]

Derek Uzzell - 2020-11-25 2:06 PM

 

2: The contacts within the fuse-holder (into which the fuse is inserted) are corroded/bent/damaged, leading to arcing that eventually results in the fuse melting.

 

You might try asking about this on the AUTO-SLEEPER OWNERS FORUM

Cheers Derek, the ASOF support your suggestion above....many thanks.

 

Andy

[Tracker]

Having had a few A/S vans over the years this is somethibg that we experienced on an older Talisman.

It turned out to be a poor and corroded or hidden damage connection between the fuse holder and it's feeder cable and once a new holder was fitted the problem went away.

I am not an electrical expert but as far as I understand it, when current is too high the fuse blows, as intended, but when it overheats and the plastic melts it is usually because of electrical resistance generating heat and this can happen at any level of current flow.

I would be inclined to chop the old one out and crimp in a new one and at least if the problem persists you will have spent very little discovering what it is not!

[Derek Uzzell]

Andy

 

These links may be of interest

 

https://www.12voltplanet.co.uk/split-charging.html

 

https://www.12voltplanet.co.uk/fuses-guide-uses.html

 

https://www.redarc.com.au/faq-tech-tips/bad-fuses-or-bad-fuse-holders

 

Originally, in 1999, your Pollensa is likely to have ben fitted with the simple split-charging system shown in the 2nd example on the 1st link above - though I note your comment about the motorhome clearly having had "electrical updates” prior to you acquiring it in June 2018.

 

What has been the interval between the 3 occasions when the 30A fuse melted/blew? For example, has it happened about every 10 months, or is it happening more recently (say every 4 months over the last year), or is there no obvious interval pattern? Presumably the fuse blowing/melting phenomenon occurred before the new starter and leisure batteries were installed and has also happened since then?

 

Me, I’d start by changing the fuse-holder, as having had three overheated fuses in it during a 30-month period can’t have done it any good - besides which the fuse-holder must be a prime suspect. (I’ve copied the ASOF advice below)

 

"This is a common problem with that type of installation. The contacts that the fuse fits into relax and and make poor contact to the fuse blade. The current therefore is flowing through a (relatively) high resistance and generates heat. Clean everything and check wire connections below fuse holder. You may have to replace the fuse holder.”

[STILLETTOPSA]

Keithl - 2020-11-25 5:05 PM

 

STILLETTOPSA - 2020-11-25 4:46 PM

Could the engine battery be pulling power from the leisure batterys when starting?

What Witzend meant was that if the split charge relay had failed in the closed condition then when you start the engine the power for the starter motor would be drawn from BOTH engine battery and leisure battery. This current would be far in excess of 30 Amps but only for a relatively short length of time and may not immediately blow the fuse, but I personally think an unlikely scenario.

 

STILLETTOPSA - 2020-11-25 4:46 PM

As I understand it, it is the vehicle alternator that actually charges the leisure battery once vehicle battery is fully charged...

Incorrect theory! As both batteries are connected directly in parallel they will both receive exactly the same voltage and hence rate of charge. You would need some fancy electronics to monitor the charge of the starter battery then switch over charging to the leisure battery.

 

Can you measure the voltage of both batteries at rest with the engine off and then again with the engine running please.

 

Keith.

 

Hi Keith,

thanks for clarity. I tested them both earlier today: vehicle battery - 12.64v engine off/14.35v engine idling, Leisure - 12.79v/13.90v.

In an ideal world during idling I would have liked the two voltages to be a little closer; is it perhaps related to my issue? The fuse in question, 30a adjacent vehicle battery, is only slightly warm after a 10 min. engine idle.

 

thanks.

 

[Keithl]

STILLETTOPSA - 2020-11-25 10:27 PM

I tested them both earlier today: vehicle battery - 12.64v engine off/14.35v engine idling, Leisure - 12.79v/13.90v.

In an ideal world during idling I would have liked the two voltages to be a little closer; is it perhaps related to my issue?

Measure the voltage at any point you can access along the route from vehicle battery through fuse and relay to leisure battery and try to identify the cause of the voltage drop. It may just be that your wiring is undersized for the current but worth measuring.

 

Keith.

[Derek Uzzell]

Andy

 

The late-Allan Evans’s website provides the following advice

 

http://www.aandncaravanservices.co.uk/battery-to-battery-chargers.php

 

http://www.aandncaravanservices.co.uk/add-a-second-battery.php

 

The latter link includes an example where alternator charging voltages of a motorhome’s starter and leisure batteries are quoted.

 

Rather than just discuss this, we our going to document the workings of a real World 'Test case' we worked on to show how effective a typical motorhome actually is at charging the Habitation area battery from the Alternator and how it copes with additional loading.

 

We have selected a 2018 model Rapido with CBE equipment installed. The CBE installation usually performs better than the majority of British charge/controller systems, so a good demonstrator.

 

VEHICLE :

The customer had asked for a second AGM battery to be installed alongside the existing, awful Platinum AGMLB110L.

The vehicle has Solar which was charging the AGM habitation battery at a fixed 13.8v.

No provision for Solar charging of the Starter battery which was sitting at 12.9v.

 

START OF TEST.

With the Fridge off totally, and the battery in need of a charge, we started the engine.

Starter battery charging went up to 14.4v confirming a good working Alternator and charge to the Starter battery.

The habitation battery voltage increased only very slightly to 13.9v not the 14.4v it should be.

 

We then activated the Fridge on 12v to create a 'normal driving' scenario and the load caused by the Fridge/Freezer resulted in the Starter Battery charge voltage dropping 0.2volts down to 14.2volts.

The charge at the habitation battery also dropped slightly to 13.8v.

13.8v is the exact same voltage used by mains chargers to 'trickle' charge a battery so it obviously isn't going to charge a battery very well at all. You can see that by adding a second battery, the load will be even greater, resulting in further voltage drop and even slower charging.

 

The CBE kit was installed ok, but the wiring/connectors were undersized and overlong.

The photo below shows that the Battery cable ran from the Starter battery at the front of the vehicle all the way to the back plus the equivalent of another metre or so further. We moved the battery location further forward (reducing rear axle loading) taking about 4 metres out of the cable run.

 

Autos-Sleepers produced the “Pollensa” model on either a Peugeot Boxer or Ford Transit base and - although I believe a 1999 Boxer-based Pollensa will have its starter-battery in the engine compartment - I’m not certain whether Auto-Sleepers put the leisure-battery there too or installed it beneath the driver’s seat.

 

The cabling for the starter-battery will have been installed when the Boxer chassis was built, so might be expected to be ‘adequate’. The cabling and relays relating to the leisure-battery will have been installed by Auto-Sleepers when the Boxer chassis was converted into a motorhome and (certainly 20 years ago) optimisation often wasn’t at the top of UK converters’ priority list.

 

Presumably you are taking the voltage readings at the battery terminals, not relying on a gauge on the motorhome’s control-panel? It OUGHT to be possible for the alternator’s 14.35V charging output to be available at both batteries, so if you follow Keith’s advice you may be able to identify what’s causing the voltage drop. (I doubt that the difference in voltage readings will have contributed to the fuse melting issue.)

[STILLETTOPSA]

Keithl - 2020-11-25 10:39 PM

 

STILLETTOPSA - 2020-11-25 10:27 PM

I tested them both earlier today: vehicle battery - 12.64v engine off/14.35v engine idling, Leisure - 12.79v/13.90v.

In an ideal world during idling I would have liked the two voltages to be a little closer; is it perhaps related to my issue?

Measure the voltage at any point you can access along the route from vehicle battery through fuse and relay to leisure battery and try to identify the cause of the voltage drop. It may just be that your wiring is undersized for the current but worth measuring.

 

Keith.

will do cheers

[STILLETTOPSA]

Derek Uzzell - 2020-11-26 7:36 AM

 

Andy

 

The late-Allan Evans’s website provides the following advice

 

http://www.aandncaravanservices.co.uk/battery-to-battery-chargers.php

 

http://www.aandncaravanservices.co.uk/add-a-second-battery.php

 

The latter link includes an example where alternator charging voltages of a motorhome’s starter and leisure batteries are quoted.

 

Rather than just discuss this, we our going to document the workings of a real World 'Test case' we worked on to show how effective a typical motorhome actually is at charging the Habitation area battery from the Alternator and how it copes with additional loading.

 

We have selected a 2018 model Rapido with CBE equipment installed. The CBE installation usually performs better than the majority of British charge/controller systems, so a good demonstrator.

 

VEHICLE :

The customer had asked for a second AGM battery to be installed alongside the existing, awful Platinum AGMLB110L.

The vehicle has Solar which was charging the AGM habitation battery at a fixed 13.8v.

No provision for Solar charging of the Starter battery which was sitting at 12.9v.

 

START OF TEST.

With the Fridge off totally, and the battery in need of a charge, we started the engine.

Starter battery charging went up to 14.4v confirming a good working Alternator and charge to the Starter battery.

The habitation battery voltage increased only very slightly to 13.9v not the 14.4v it should be.

 

We then activated the Fridge on 12v to create a 'normal driving' scenario and the load caused by the Fridge/Freezer resulted in the Starter Battery charge voltage dropping 0.2volts down to 14.2volts.

The charge at the habitation battery also dropped slightly to 13.8v.

13.8v is the exact same voltage used by mains chargers to 'trickle' charge a battery so it obviously isn't going to charge a battery very well at all. You can see that by adding a second battery, the load will be even greater, resulting in further voltage drop and even slower charging.

 

The CBE kit was installed ok, but the wiring/connectors were undersized and overlong.

The photo below shows that the Battery cable ran from the Starter battery at the front of the vehicle all the way to the back plus the equivalent of another metre or so further. We moved the battery location further forward (reducing rear axle loading) taking about 4 metres out of the cable run.

 

Autos-Sleepers produced the “Pollensa” model on either a Peugeot Boxer or Ford Transit base and - although I believe a 1999 Boxer-based Pollensa will have its starter-battery in the engine compartment - I’m not certain whether Auto-Sleepers put the leisure-battery there too or installed it beneath the driver’s seat.

 

The cabling for the starter-battery will have been installed when the Boxer chassis was built, so might be expected to be ‘adequate’. The cabling and relays relating to the leisure-battery will have been installed by Auto-Sleepers when the Boxer chassis was converted into a motorhome and (certainly 20 years ago) optimisation often wasn’t at the top of UK converters’ priority list.

 

Presumably you are taking the voltage readings at the battery terminals, not relying on a gauge on the motorhome’s control-panel? It OUGHT to be possible for the alternator’s 14.35V charging output to be available at both batteries, so if you follow Keith’s advice you may be able to identify what’s causing the voltage drop. (I doubt that the difference in voltage readings will have contributed to the fuse melting issue.)

Thanks again Derek; The battery and relays are indeed under the drivers seat so cabling is as short as possible so limited VD with distance. All measurements are taken at battery terminals as there is no digital voltmeter (just analogue) built into the guage.

After many short trips and four x 6 weeks trips since purchasing we know the electrical demands in the habitation space is relatively little and so we are happy with this relatively basic system; but I have considered different charging systems and a second battery but concluded that given the age of the vehicle, and our need, additional technical expenditure is not justifiable. However, as suggested by yourself and other members the cable sizing 'is' worth pursuing and your explanation of conversion to MH from van makes sense. She is due service and MOT next week so will have a chat with garage man.

 

Andy

[STILLETTOPSA]

Tracker - 2020-11-25 5:51 PM

 

Having had a few A/S vans over the years this is somethibg that we experienced on an older Talisman.

It turned out to be a poor and corroded or hidden damage connection between the fuse holder and it's feeder cable and once a new holder was fitted the problem went away.

I am not an electrical expert but as far as I understand it, when current is too high the fuse blows, as intended, but when it overheats and the plastic melts it is usually because of electrical resistance generating heat and this can happen at any level of current flow.

I would be inclined to chop the old one out and crimp in a new one and at least if the problem persists you will have spent very little discovering what it is not!

Great advice; thanks.

Andy

[STILLETTOPSA]

Just a follow-up to all your excellent advice and links for the future.

This morning checked cable sizes - all good to go.

All terminations checked and cleaned.

Replaced 'problem' fuse holder with new from Halford's, checked cable ends for hardening and cleaned internal female spade receptors.

Fired her up and checked voltages on idle: Vehicle battery - 14.40v, Leisure battery - 14.35v (previous reading was 13.85v)

 

I would call that a result.....many thanks.

[Tracker]

STILLETTOPSA - 2020-11-26 8:37 AM

However, as suggested by yourself and other members the cable sizing 'is' worth pursuing and your explanation of conversion to MH from van makes sense. She is due service and MOT next week so will have a chat with garage man.

Andy

 

Again, from a non techy point of view so I might be wrong, if the cabling were insufficient to carry the full current it would get at least warm if not hot when charging at a high rate,

I seem to recall that a common ploy by converters is to use light weight cable as a means of preventing the charge rate going much above 10 amps - theoretically to prevent hydrogen gassing from the batteries in the hab area - but I am far from convinced that theory is of much benefit in the real world?

That the cable does not overheat is, I think, due to it's electrical resistance along it's full length diluting the heat effect at any one point.

If I am wrong I would be delighted to hear what is right please!