12v Spike Questions

[Tea_Bag]

The tech dept of a major brand in marine electronics has suggested that our boat, a Malo, is suffering from spikes on the 12 v supply. This conclusion arose after having one of their headline hand held portable products damaged twice whilst recharging from a 12 v cradle that was professionally installed.

I ask three questions of the forum:

1 our multimeter see no spikes on engine start, or other major inductive loads such as bow thruster. Is there a better way to detect spikes?

2 have other people seen this problem with lithium battery hand held products.?

3 would forumites suggest a DC DC isolated converter as means of creating "clean" 12 v supply no matter if engine is on or off?

Hoping to gain some clarity on this topic.

Tea Bag

 

[Boater Sam]

The tech dept of a major brand in marine electronics has suggested that our boat, a Malo, is suffering from spikes on the 12 v supply. This conclusion arose after having one of their headline hand held portable products damaged twice whilst recharging from a 12 v cradle that was professionally installed.

I ask three questions of the forum:

1 our multimeter see no spikes on engine start, or other major inductive loads such as bow thruster. Is there a better way to detect spikes?

2 have other people seen this problem with lithium battery hand held products.?

3 would forumites suggest a DC DC isolated converter as means of creating "clean" 12 v supply no matter if engine is on or off?

Hoping to gain some clarity on this topic.

Tea Bag

If there is no mains voltages from either shore line or on board inverters I fail to see how you can get "spikes".
You could get interruptions and back emf spikes off inductors on the 12v like an inverter or ignition coil etc. if you have a poor connection somewhere but the equipment should not be damaged by this.

 

[Sandy]

Ask them what size spike would be needed to damage their product, why this has not been engineered out and what solution they would recommend. You can then work out if their response is based on science or not.

 

[Beneteau381]

The tech dept of a major brand in marine electronics has suggested that our boat, a Malo, is suffering from spikes on the 12 v supply. This conclusion arose after having one of their headline hand held portable products damaged twice whilst recharging from a 12 v cradle that was professionally installed.

I ask three questions of the forum:

1 our multimeter see no spikes on engine start, or other major inductive loads such as bow thruster. Is there a better way to detect spikes?

2 have other people seen this problem with lithium battery hand held products.?

3 would forumites suggest a DC DC isolated converter as means of creating "clean" 12 v supply no matter if engine is on or off?

Hoping to gain some clarity on this topic.

Tea Bag

I think there is some smoke blowing going on. The 12v system voltage can vary up to 14.7v depending on the charge state. This can fluctuate pretty rapidly. The manufacturers should know this and the equipment be designed to cope with this. Any back voltages or EMF spikes from collapsing coil fields? Another matter, it depends on where the charger is connected to. As a precaution, I would check or get an independent electrician to check where the charger is connected in the sytem.

 

[andsarkit]

I have used Transient Voltage Suppressor (TVS) diodes on circuits where there is a possibility of voltage spikes. Tranzorb is one make and will cost a few pennies. TVS
I have thought of putting some on the boat but never got round to it and I've never had a problem with boat electronics damaged by voltage spikes.
An isolated DC-DC converter should remove spikes but should not be necessary for properly designed marine equipment.
You would not see a short voltage spike on a digital multimeter. You need an oscilloscope and even then it is easy to miss.
It is more likely that the equipment has a design or component fault which they are blaming on you. You could ask them which component has been damaged and possibly a copy of the relevant part of the circuit. There are experienced people on the forum who could then comment on how it was damaged.

 

[AngusMcDoon]

The spikes may only be milliseconds long so no chance of seeing them on a multi-meter.

The voltage regulator the manufacturer has used in the power supply should be suitable for the intended application. Components are not made specifically for marine use so automotive is the closest, and is suitable. The power supply circuit in your failed device should be designed to cope with a load dump situation. It sounds like it isn't.

Load dump - Wikipedia

Gory details

 

[Tea_Bag]

Thank you all for great comments and advice. Much appreciated. I am glad to read that such equipment failure is an uncommon occurrence.

In the New Year I will be taking the matter up again with the manufacturer, especially the point raised about what size spike would cause the damage that has occurred. I will also seek further detail on the specific component that failed.

In the meantime I will investigate using the TVS diodes suggested above. This may be a great solution.

Again many thanks for the help, and I will report back on outcomes.

Tea Bag

 

[samfieldhouse]

How old is the piece of equipment and did you purchase it in the UK?

If it’s less than 6 years old you may have a claim within your rights as set out in the 2015 consumer rights act.

Your ‘contract’ is with the seller, not the manufacturer. As the manufacturer has told you the product is not suitable for use in an environment where voltage spikes exist, and it is reasonable for on board voltage to fluctuate between 12v and 14v, you could reasonably claim the product is unfit for use.

If the seller refuses to repair or replace it, take them to the small claims court.

“If a defect develops after the first six months, the burden is on you to prove that the product was faulty at the time the goods were delivered to you.

In practice, this may require some form of expert report, opinion or evidence of similar problems or defects across the product range.

The retailer can also make a deduction from any refund for fair use after the first six months of ownership if an attempt at a repair or replacement is unsuccessful.

You have up to six years to take a claim to the small claims court for faulty goods in England, Wales and Northern Ireland, and five years in Scotland.

This doesn't mean that a product has to last six years - just that you have this length of time in which to make a claim if a retailer refuses to repair or replace a faulty product.”

 

[Tea_Bag]

Thank you for the information Samfieldhouse. I am quite happy dealing directly with the manufacturer.

The item is only 18 months old and purchased in the UK. I will hopefully have some kind of resolution early in the New Year.

 

[samfieldhouse]

No problem - the thing is the manufacturer is not under any legal obligation to help you.
The seller however is.

 

[savageseadog]

Engine starters can generate significant spikes. Fitting ferrite suppressors to sensitive equipment can help.

 

[William_H]

The question comes to my mind is related to the charging cradle. Is it sold with a 12v power converter to be charged from 240v mains. If so this converter will give a very accurate 12v to the charging cradle. If the manufacturer /designer agrees that it is ok to use the ships 12v system to feed the charging cradle that would support your argument against manufacturer when you get a failure. However because your "12v" can as said rise to 15v (if you have a smart charge controller) and it can carry back EMF spikes the charging may not be suitable for straight substitute ships 12v for mains charge power converter.
A DC isolated 12v to 12v converter will take whatever voltage (within reason) you give it and produce accurate 12v dc for cradle. This will fix problems of high charge voltage and voltage spikes.
The actual question of voltage spikes is a fraught with uncertainties. The voltage spike could originate from engine start anchor winch or thruster. Generally the battery will absorb the spike. However the length of cable source to battery can allow the spikes to appear near the source. If you take power for charger from near the battery (wire length wise) then you would have more immunity than if power is taken from wiring which is shared by the spike source. However I think you will find from general boating experience (like this forum) that voltage spikes are not a huge problem. (voltage drop however is a problem for some electronics) (on engine start)
See what the manufacturer says about 12v supply but I would suggest if you find yourself alone on this problem that you go for a 12v to 12v converter. ol'will

 

[jdc]

Can you take a photo of the charging cradle's main PCB and post it here? Preferably both sides of the PCB. A certain amount of reverse engineering should be possible from that, in particular to understand if it uses Automotive spec semiconductors, and possibly how it might be modified to include better protection. Or see if it's just a dumb electrical connector.

FWIW in answer to the OP's qu 2. the answer is 'never' (not even from those I've designed myself).

 

[QBhoy]

Hi. I’m aware that some rechargeable gizmos have a max Amp rating perhaps. I have a twin usb charging out let. One port is 2amp and the other is 4 or 5 amp. I once damaged a torch with a lithium battery by charging it off the higher output. Only after reading that the torch shouldn’t have had any more than a couple of Amps to it.
is it perhaps likely that your issue is similar ? And not so much voltage related.

 

[Graham_Wright]

An analogue meter will be better for transients. A digital one has too long an analysis time.

 

[Tea_Bag]

Thank you again to everyone who has considered the issue I raised.

Ol'Will's comments concerning the charging cradle are particularly apposite as the device has both a manufacturer supplied mains transformer and a manufacturer specific 12v supply connector. The latter is in the form of "cigarette lighter" type connector and barrel "CCTV" type plug to attach into the cradle.

I cannot see any PCB or other electronic components in the cradle and there appears to be only a cartridge fuse on the 12v cable which is fitted within the cigarette plug part.

I'll let the forum know the results of my discussions with the manufacturer. I now feel much more equipped to raise this issue with them again, and can only thank you all for such considered comments.

Happy New Year


Tea Bag

 

[Caladh]

Thank you all for great comments and advice. Much appreciated. I am glad to read that such equipment failure is an uncommon occurrence.

In the New Year I will be taking the matter up again with the manufacturer, especially the point raised about what size spike would cause the damage that has occurred. I will also seek further detail on the specific component that failed.

In the meantime I will investigate using the TVS diodes suggested above. This may be a great solution.

Again many thanks for the help, and I will report back on outcomes.

Tea Bag

You may like to join and post on our Malo Owners Facebook page to see if other Malo owners have experienced similar, although I am unaware of any such thing happening.

 

[Tea_Bag]

A resolution - hopefully - with the equipment manufacturer on this issue.

In summary, the device has multiple ways of being charged with one involving a cradle and a direct 12 v DC supply. It is in this mode that we have had issues.

For my specific use, the manufacturer has constructed a modified cradle using a Transient Voltage Suppressor (TVS) diode in the circuit for use with 12 v DC charging.

I am considering a belt, and braces approach by also fitting a 12v :12v DC isolated transformer too.

Thank you to the people who suggested using a TVS and thank you all for your enabling me to better frame the questions I posed to the equipment manufacturer.

 

[jamie N]

Which manufacturer are you dealing with, as it seems that they should be lauded for 'doing the right thing'!

 

[Beneteau381]

A resolution - hopefully - with the equipment manufacturer on this issue.

In summary, the device has multiple ways of being charged with one involving a cradle and a direct 12 v DC supply. It is in this mode that we have had issues.

For my specific use, the manufacturer has constructed a modified cradle using a Transient Voltage Suppressor (TVS) diode in the circuit for use with 12 v DC charging.

I am considering a belt, and braces approach by also fitting a 12v :12v DC isolated transformer too.

Thank you to the people who suggested using a TVS and thank you all for your enabling me to better frame the questions I posed to the equipment manufacturer.

I suspect more so now that as I alluded to at the beginning that its a collapsing field effect thing in the charger?