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Electroblock went bang!

Vernon B

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Some years ago, can't find it, a thread ran about Schaudt Electroblocks being knocked out by a spike in electricity. There was no fuse to protect the unit against this surge and it had to be returned to Schaudt for repair. Schaudt then offered a fix which involved purchasing a separate device which you put into the circuit.


What I'd like to know is whether Schaudt are now supplying their units with the fix already installed.


(You will have gathered that I am not an electrical engineer but hopefully you'll get my drift)



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There was a lot of misinformed advice on the Forums a few years ago with some posts incorrectly stating that the Schaudt Elektroblock did not have any inbuilt Spike/Surge protection, when they do.

They actually have VERY good inbuilt Spike Surge protection, exactly the same as all other Motorhome/Caravans.

In the past 6 + years we have repaired thousands of Schaudt Elektroblocks, like the EBL 99, yet we have had less than 10 that have suffered genuine Sikes/Surges.


Almost always the reason an EBL fails is from poor batteries, an overlarge battery bank or both.



What caused confusion was that Schaudt introduced a device called an Over Voltage Protector 01 (OVP 01) that was designed to trap damage from 'rogue' Generators.

The OVP 01 is a relatively slow acting device designed to trap 'slowly' rising voltages, like when a Generator runs erratically on start-up/shutdown. If you look at the spec for the device, Schaudt do not mention ANYTHING about Spikes or Surges, most of which will be trapped by the EBL inbuilt Spike/Surge components.


Hence the device being called an Over Voltage Protector, not a Spike/Surge protector. An OVP will lock out the voltage coming in to the device if it goes outside 190v to 260v.



If your EBL has popped and wasn't being used on a Generator at the time, I would be prepared to bet £5 the batteries are the culprit?

Ask yourself why, if the Motorhome was hit by a mains borne Spike, it only picked on the EBL and not every other 230v connected device, like Fridge, Water Heater, etc?



Of the handful of units hit by a genuine spike, in all cases from a nearby Lightning strike on overhead cables, the 240v devices in the Motorhome were decimated, from TV's on standby to Fridge elements, etc

On one, the OVP was destroyed along with the EBL.


If you are somewhere the 220v infrastructure is of a basic nature without strong voltage regulation, like rural Portugal, Spain, France, etc where Lightning storms can also be more common, then protect EVERYTHING in the Motorhome by disconnecting EHU till the storm passes.



We can supply OVP versions of all the EBL's and also supply an OVP 01, but we would advise you save your money to spend on decent batteries, not an OVP 01.



If you really, really want extra Spike/Surge protection, then just pull the 230v Kettle lead from the front of the EBL and put a PROPER 13a Spike/Surge protector in the power cord to the EBL.

Something like that in the photo costs a fraction of an OVP01. It also allows the EBL charger to be switched 'Off' using one of the switches on the Adapter as well as providing auxillary 230v ports for additional charging units, etc.




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I think what we are talking about here is a Metal Oxide Varistor, These devices are usually in the form of a disc with leads attached to both faces. Normally they have high resistance, but if rated voltage is exceeded the resistance drops sharply.


Varistors are usually connected across the input of a device, inboard of the input fuse. Hopefully the resulting high current then blows the input fuse of the protected device.


If provision has been made on the pcb for fitting a varistor, fitting one should be a relatively simple matter.

I think that tis is an area where Allan of aandacaracanservices may be able to assist.




I see that Allan got there first!

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AlanB, Thank you and EXACTLY right. If you look at the photo below of a standard Schaudt Elektroblock charger PCB from an EBL 99, you will see a nice big fat MOV already in place across the supply rail right after the 230v fuse!!!


As can be seen by everyone, the protection the Forums say isn't there, clearly is.

The same protection, or better, is built into every EBL from the 99 to a 266.



If you trace the origins of the misinformation it goes back to a 'Supplier' who 'highlights' this alleged weakness in the EBL, and then offers for sale the OVP01 as a 'solution'.

I don't think there was deliberate intention to deceive, just they were misinformed.




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You were right Allan the thread was about an OVP01. As it happens I had my own EBL "blown away" at exactly that time. I was using a domestic vacuum cleaner - 1900 watts - and simply turned it off. Would this be equivalent to running a generator?


Schaudt repaired the unit foc and I did fit an OVP01. Never had a problem since - but never used a high powered vc since either. But pretty sure my experience couldn't be put down to the batteries.


Thanks for your comments and suggestions



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The 230v circuits in a Motorhome are no different to that in your house, likewise the appliances.

I can think of no reason whatever why a good fully functional Vacumn cleaner should impact any 230v appliance on the same sound supply?


Not heard of any 'House' Televisions going pop when the Vacumn Cleaner turns off, or the Fridge/Freezer motor stops, or the Central Heating Pump Motor cuts in/out?

All good 230v appliances these days are safe in respect of this.



However, if there was an issue with the EHU cable/connection/sockets causing significant voltage drop under the 1,900watt load, then I could see that impacting the Motorhome, as it might for all electronics.

But that is not an issue that any electronics should be expected to endure and would be classified as an external fault.



We have also seen this behaviour when a big load is run on an Inverter as they are sometimes less than ideal at regulating voltages when load variations are significant. One Inverter we monitored was putting out a static 269v which rose to 289v when the load varied!!


Under these conditions an OVP 01 would protect the EBL, but leave everything else at risk. Better to address the cause?.


I wonder if it would be a good idea for you to fit a 230 voltmeter to monitor just how much variation you see on the mains supply?




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aandncaravan - 2017-08-08 11:08 AM


AlanB, Thank you and EXACTLY right. If you look at the photo below of a standard Schaudt Elektroblock charger PCB from an EBL 99, you will see a nice big fat MOV already in place across the supply rail right after the 230v fuse.






Thanks for the picture. Nice to see a HRC fuse as well. (For those with less electrical knowledge, a High Rupturing Capacity (HRC) fuse can safely interrupt much greater currents than the more usual glass type.)



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One point that I don’t understand.


"If your EBL has popped and wasn't being used on a Generator at the time, I would be prepared to bet £5 the batteries are the culprit? "


It’s been mentioned before that old batteries cam be the cause of an EBL failing and I’m wondering why batteries can total an EBL. I appreciate that say a 20 amp draw on a 16 amp EBL could cause it to burn out. I would have expected though that the EBL would limit the current it's able to supply to within its acceptable range or alternatively, a fuse would blow before the EBL becomes damaged? What am I missing?

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Almost all chargers have current limiting circuitry, so shouldn't output greater current than their limit, so in theory you are correct, they should take care of themselves.


But if that is the theory, why are so many failing, from all manufacturers from around the World, from Italy to Holland?


A poor battery, or even worse more than one battery, will cause the charger to work to it's maximum. While the current may not exceed this maximum, the charger will still work really, really hard.


Not just because the battery draws more current, but it also takes longer to charge.

This causes the charger to run at a higher temperature and for longer.


When the temperature rises, most chargers should back down the charge rate to protect themselves. But even so they still run far hotter and for longer than design.


This results in long term overheating of the components, which subsequently breakdown and fail.


In support of this :


Schaudt recognised this overheating issue and heat breakdown of the components so made two major changes which culminated in the K charger model.

One was the adoption of a ventilated rear panel, this panel is also the heat sink, to try and improve cooling.

Uprated components were also adopted along with a minor revision of the PCB's.


Very strange for Schaudt, the manufacturer of more chargers in more Motorhomes World wide than any other, to make such a change on a charger that our competitors say 'doesn't fail from Battery degradation because it has inbuilt current limiting'?



The change was a move in the right direction (I think around 2012?) but it coincided with a trend to add extra batteries. The result is that while the K series model is undoubtedly a big improvement, the extra load of additional batteries has meant the overall picture has not improved with these units failing as quickly as the pre K series charger.


If anything there is a greater tendency for the newer Motorhomes, with K spec chargers, to be rolled out of the Dealers with multiple batteries and a subsequent increasing failure rate.


One of our competitors makes a marketing statement of fitting 'uprated' components for 'longer life', yet we think the issue is one of overheating/Cooling, not being able to pass more current safely, which in anycase is limited to the exact same current as before by the electronics.

In our opinion, unless the 'uprated' components have a higher temperature tolerance, their customers might be in for a disappointment in the future?


Schaudt addressed the cooling issue with an improved Heat sink. We address the issue at source by trying to communicate the importance of perfect batteries.

I wonder if our key competitor will change their approach in the future?



Some of the awful batteries we have removed from Motorhomes have been almost totally shorted. Such a load will be akin to putting an Iron Bar across an alternators terminals.

If you think a Motorhome Alternator or Leisure battery charger is going to regulate itself quickly enough to survive that, you might be in for a bit of disappointed.



The theory of how a charger works with good batteries, goes completely out the window when batteries age. Especially as they can age and fail in so many different ways with different symptoms.



We have cut open hundreds more failed batteries than anyone we know in an attempt to understand our business.

I think our unique skillset of working both in Motorhomes and repairing chargers allows us to see the Motorhome environment which caused the damage that is subsequently revealed inside the charger.

That, along with our real world battery knowledge makes us unique in Europe, not just the UK.











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Thank you Alan. I find this sort of insight absolutely fascinating.


Is there deemed to be a straightforward way to judge the ‘equivalent age’ of a battery short of cutting it open? By ‘equivalent age’ I don’t mean how many years it’s existed but how youthfully it is still performing.


I’m thinking that none of us wishes to discard good leisure batteries unnecessarily or take risks with batteries which are young enough to be ok but may have been prematurely aged through miss-treated by previous owners.

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I wish there was a magic formula I could pass on but it is down to the battery technology, how deeply the battery is discharged, how much it has been used, how it is 'stored' etc.


The budgets rarely last past 2 years, so that would be my guide there. By that I mean they will be starting to place a higher load than normal on the charging systems, yet may hold their charge and appear 'ok', but can be down to 70% efficient.


An Exide G80 might still be above 90% efficient at 6 years of age.



It is a judgement only you can make on how your battery is behaving.


The best advice I can give, and have been heavily criticised for this in the past, is to replace the battery at 2 times it's warranty period.


By that I mean a 'real' warranty, not the '4 years warranty' of some budgets, that when you look at the 'small print' only allow you to claim against a 'manufacturing fault'.


"Failed after 2 years you say? Can't possibly be a manufacturing fault Sir, that would have shown up in the first 3 months, you must have over discharged it Sir and that isn't covered, sorry?"



So if your Exide has a 2 year warranty replace it by 4 years at the latest.


If you buy a Varta LFD 90 for £90 and it only lasts the 4 years of warranty, that is an outstanding £23 a year running cost.

If you try and run it longer and damage the Alternator with an attached £500 bill, that is not so cost effective.


Only you can gauge it, but binning it earlier rather than later, usually saves money.



The best way, IMO, to assess a battery is to charge it fully.

Then isolate it from any wiring and leave it 24 hours and record the voltage.

Leave it 2 weeks and record the voltage again.


If the voltage has dropped at all, and a good quality battery will hold it's voltage for months, then recycle it.




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  • 4 weeks later...

Update from Natalie -


I have just updated the webpage on the Over Voltage Protector 01 device following months of extensive research/testing on Elektroblock EBL charger failures by Martin our Senior Technician. See : http://www.aandncaravanservices.co.uk/schaudt-ovp01.php


While the OVP 01 device is designed to look for Over Voltage and Under voltage situations, where it will cut the supply to the protected device, it has an 'accidental' benefit in protecting a modern Inverter charger, like the Schaudt Elektroblock, where there are multiple, rapid interruptions to the 230v power.


Where a power supply to an EBL charger is subject to repeat 'breaks and instant reconnects', such as when an EHU cable has a loose wire or fault at a campsite, this may generate waveform distortion inside the charger causing it to fail.


This is not in situations where voltage Spikes occur, the voltage may never rise above 230v, but if the charger waveform is distorted by a break and reconnect in the power supply, the charger can become damaged.

However, we could only inflict damage to the charger in the tests if it was working really hard, like charging a poor battery or an over large battery bank.

So obviously poor batteries will also increase the risk of this type of waveform distortion failure.



The OVP 01 prevents this damage from waveform distortion because it detects the falling voltage from the power interruption, and then disconnects the EBL from the mains for a period of 1.5 seconds, a long enough time to allow the EBL charger to recover from the waveform distortion, so no harm is done.


In real terms the testing we carried out, although lengthy, is small in the real world, further testing will continue, but at a lesser rate.



We have therefore revised our advice in regard to the OVP 01, suggesting that it's contribution to a Schaudt Elektroblock's longevity is significant and therefore a worthy accessory.


However, in relation to trapping Spikes, our testing showed the OVP 01 was too slow to trap the bigger ones, so the previous advice with removing EHU when a thunderstorm is nearby, still stands.



Martin can't explain Vernon's EBL failure 'from the Vacumn cleaner' but suspects it may have been something to do with the high current drawn and less than ideal EHU connectors, or even 16a to 13amp adapters? But does accept that the Vac load was the Catalyst.




This text is my (Natalie's) attempt at putting into words what a very Technical person explained to me, so may not be 'technically precise'.



Please note that we have no intention of stocking or selling the OVP 01 to maintain our impartiality on the products we recommend.

Brownhills regularly advertise them on ebay, so suggest you try there?












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