I have an electrical problem that has recently appeared. My vans power consists of 2x 110A batteries 2x 80watt solar panels. At night time whilst running power from 12volt for van, all power suddenly drops out and about 5-10 mins later all power is restored. Then 5-10 mins later it all happens again. This continues throughout the night. I watched the voltage drop from 13.8 to 12.2. When the power does come back the voltage has returned to 13.4 and slowly drops back again until the power goes out. In frustration I thought that I would start the generator to see if we could get some power to light the van but that wouldn't work either. Any solutions or comment would be appreciated.
Tony Bev said
11:21 PM Jun 16, 2018
Hi Codhunter, and welcome to the forum
I am not a techy, but this sort of problem happened to me once
12 volt TV and some lights would go off
Switch off all the lights, and the TV would come on again. switch more light on, and the TV would go off
My problem was that the single 100 AH GEL battery I had, had failed to hold charge any more, and I was trying to use more power than the battery could give out
From a laymans point of view, the techies will need more information about your system, otherwise they can only guess what is wrong
Exactly what items have you got running from your 12 volt batteries, when the power fails
160 watts of power, does not seem enough to keep 220 Amp Hours of battery topped up, unless you are running a few LED lights only
But... I am only guessing
Warren-Pat_01 said
10:17 AM Jun 17, 2018
Hello Codhunter & welcome to the forum.
One good tool on this forum is the "Search" button.
Like Tony, I think the batteries may be either not being charged enough (& that can kill an AGM battery) or may be beyond their useable life.
Do you have a "high" current load that you can hook up to the battery? I use a H4 headlight bulb - either the 50w (4A), the 55w (5A).
Do this during the day - disconnect the solar charge to let your batteries stabilise (10-15 minutes), then add the load to one battery (if possible), repeating for the second battery after.
Measure the battery voltage constantly after letting the battery discharge for an hour - monitor the voltage while you do it. It should not go lower than 12.2 to 12.3v (refer to www.energymatters.com.au/components/battery-voltage-discharge/). If the voltage drops off too fast, cease the discharge. You should see a voltage drop but then the battery should stabilise.
Do you have a separate 240v smart charger that you can connect to the battery (one at a time)? 8 to 15A should be adequate - leave it on until the battery is fully charged. Then repeat for the other one. Restore the caravan load to the battery & see what happens.
Jaahn said
10:46 AM Jun 17, 2018
CODHUNTER wrote:
Hello all,
I have an electrical problem that has recently appeared. My vans power consists of 2x 110A batteries 2x 80watt solar panels. At night time whilst running power from 12volt for van, all power suddenly drops out and about 5-10 mins later all power is restored. Then 5-10 mins later it all happens again. This continues throughout the night. I watched the voltage drop from 13.8 to 12.2. When the power does come back the voltage has returned to 13.4 and slowly drops back again until the power goes out. In frustration I thought that I would start the generator to see if we could get some power to light the van but that wouldn't work either. Any solutions or comment would be appreciated.
Hi Codhunter
Sounds to me that your system has a "controller" that cuts the power off when the voltage drops below a certain voltage when it is being used and then after it cuts the power the batteries recover a bit and it switches the power back on again. This just repeats while you are using power. No problems with that system.
However the problem is that your batteries are not storing enough power. As already suggested there could be several reasons for this; the batteries are not being charged enough(likely with those small panels), there is a poor connection in the wiring loosing power, the batteries are stuffed, either one or both. Charge them up as suggested, off the 240V power, and see if things improve. But do something soon or the batteries will die.
More panel power is required though for 2x110Ahr batteries. Double or triple needed for winter depending on where you are camping. Not sure what the generator is wired up to do ?? The 240V should work OK but does it have a charger wired in to charge the batteries or what ?? Check that out.
good luck Jaahn
T1 Terry said
03:38 PM Jun 17, 2018
If the power restore lasts for 5 mins to 10 mins and drops out at 12.2v, then takes about the same time to recover to 13.4v, the batteries are sulphated to the extent discharging is restricted and equally recharging would be restricted. Some of the better quality chargers have a battery reconditioning cycle that pulses the charge into the battery trying to shift the sulphation off/out of the lead plates. This takes quite a long time if the sulphation is actually in the plate material rather than just on the surface and from your description it sounds like that is what is happening here.
You could persevere and try multiple recondition charging cycles and very long float charging periods to try and get the sulphation out of the plates, or you could just buy new batteries.
No matter which way you go you need to address the under charging problem or the same thing will happen again.
T1 Terry
CODHUNTER said
07:12 PM Jun 17, 2018
I have noticed that the 15 amp fuses on each battery although still working are melting the plastic part. I have replaced the one that supplies power to the van with a quality fuse of 20 amps and moved it away from the batteries to inside the van where the other fuses are. I hope this fixes the problem.
Warren-Pat_01 said
12:10 AM Jun 18, 2018
Hans, I would have thought that battery fuses would be in the range of 30-50A, kept relatively close to the batteries & they would again feed your other circuits protected by smaller fuses.
The act that they are meting the plastic means they are getting hot either due to a high resistance joint in the fuse holder or the load is approaching or is greater than 15A (depending on the fuse type, they may blow at 15A or higher). If it's due to the load, then your first query means you need more solar (fixed or portable) to keep the batteries in prime condition.
As TI Terry says you can condition damaged batteries, it just takes time & you may need a 240v smart charger & solar as well as a load to discharge them to (refer to the website above).
Best of luck.
Aus-Kiwi said
02:02 PM Jun 18, 2018
Breakers would be my choice .
oldtrack123 said
02:44 PM Jun 18, 2018
CODHUNTER wrote:
I have noticed that the 15 amp fuses on each battery although still working are melting the plastic part. I have replaced the one that supplies power to the van with a quality fuse of 20 amps and moved it away from the batteries to inside the van where the other fuses are. I hope this fixes the problem.
Hi
The fuse holders plastic melting is a sure indication of all your problems
Either undersized for load & running very close to blowing point or High resistance joints, poor connections ,due to corrosion or not being a tight fit in the fuse holders
Either means voltage drop across the fuse holder =,battery not being fully charged , low voltage cutout,if fitted, tripping!
Quality fuses & holders of the correct rating are required.
The correct current rated Fuses should ALWAYs be fitted as close to the current source as practical & possible
Their primary purpose is to protect the full length of cables from overheating from load currents or if a short circuit occurs.
Since cable protection is the primary requirement, the fuse current rating can be the same as the cable current rating but no higher
Note: Any overheating connection can lead to a major fire
All connections , fuses etc , should get no more than a little warm to touch!!
Aus-Kiwi said
03:19 PM Jun 18, 2018
Larger cable / breaker at battery . ( 35mm sq) Then fuse each circuit or appliance inside van ., Having a system JUST good enough . Is not going to work long term . Double the solar, make sure battery reg is of good quality !! After all battery's are not cheap ! Yes my guess a low voltage cut out is tripping ?? VSR etc
T1 Terry said
04:44 PM Jun 18, 2018
Blade fuses even at 15 amps should have survived, so the fuse holder quality and possible the cheap and nasty Chinese blade fuses could have added to the problem. 15 amps x 12v is 180w, that is the maximum resistance heating you could have had so fuse over load is not the issue, just poor fuse design allowing a poor contact area combined with heat releasing the minimal contact there was in the first place. We only use blade fuses for the 5 amp protection on the cell logger cables, all other fuses are midi or mega fuses because the bolt down design ensures a good contact area with plenty of clamping force. We even stopped using mini and standard ANL fuses because the muck metal fuse holders would melt and reduce the contact clamping pressure creating a feed back loop that ended in failure.
T1 Terry
oldtrack123 said
07:25 PM Jun 18, 2018
T1 Terry wrote:
Blade fuses even at 15 amps should have survived, so the fuse holder quality and possible the cheap and nasty Chinese blade fuses could have added to the problem. 15 amps x 12v is 180w, that is the maximum resistance heating you could have had so fuse over load is not the issue, just poor fuse design allowing a poor contact area combined with heat releasing the minimal contact there was in the first place. We only use blade fuses for the 5 amp protection on the cell logger cables, all other fuses are midi or mega fuses because the bolt down design ensures a good contact area with plenty of clamping force. We even stopped using mini and standard ANL fuses because the muck metal fuse holders would melt and reduce the contact clamping pressure creating a feed back loop that ended in failure.
T1 Terry
Terry
Obviously , not being an electrician, you have no experience with fuses running sufficiently overloaded to heat up , but not actually blow
It does not matter what the voltage is ,or if it is AC or the funny DC stuff, [ that only someone specially trained in EXTRA low voltage DC understands]
.Fuses ,just like circuit breakers ,do have a time lag factor,readily understood by any well qualified electrician.
That is why there are many different types of fuses available
Such as:
Slow blow
Fast Blow
HRC
Motor start
Etc
But even by your own reasoning ,concentrating even 10W of heat in such a small mass will generate a considerable heat rise. in that mass
But having said that the problems can be worse with poor quality fuses
Problems such as high contact resistance, due to insufficient contact pressure , poor contact material, poor contact area, oxidation of contact areas over time or due to localized hot spots.
-- Edited by oldtrack123 on Monday 18th of June 2018 07:30:02 PM
T1 Terry said
02:37 PM Jun 19, 2018
No point in arguing with you Peter, but just maybe me being an Automotive Mechanical Engineer with well over 40yrs experience in a field where blade fuses are commonly used I might have just a tad more hands on experience?
I guess you know all about the problem the VL Commodore (1986) had with blade fuses and what caused the problem?
T1 Terry
Jaahn said
03:59 PM Jun 19, 2018
Hi
Please do not start arguing again you two. It is off the point and not helping the OP.
Up till now the discussion has been useful.
jaahn
Ron-D said
04:00 PM Jun 19, 2018
Mechanical engineer is nothing like an electrical engineer or am I missing something...
T1 Terry said
05:31 PM Jun 19, 2018
Ron-D wrote:
Mechanical engineer is nothing like an electrical engineer or am I missing something...
Mechanical automotive engineer actually does the work so has the hands on experience as well as the technical knowledge because they must both design or diagnose the problem and root cause as well as rectify the problem. A Mechanical Automotive Engineer works generally with voltages between 0.1v and 70v both AC and DC.
An electrical engineer does it all on paper usually low voltage starting around 120v and upwards and an electrical fitter actually does the hands on work. The licence part is a grey area, not all electricians have a licence, just depends on what they are working on and there is a difference between an electrician's licence and an electrical contractors licence
T1 Terry said
05:36 PM Jun 19, 2018
Jaahn wrote:
Hi
Please do not start arguing again you two. It is off the point and not helping the OP.
Up till now the discussion has been useful.
jaahn
No intension of arguing with him Jaahn, it's non productive and he prefers to attack rather than explain. His post was more of a phishing expedition looking to start another round and I really have better things to do at the moment
T1 Terry
T1 Terry
oldtrack123 said
08:29 PM Jun 19, 2018
Ron-D wrote:
Mechanical engineer is nothing like an electrical engineer or am I missing something...
Hi Ron
No ,you are not missing anything
T1 constantly infers I have no practical experience
So Just to clarify I started my electrical apprentice ship ,when it was a 5year course ,2 sessions @ tafe per week ,totalling 7hrs.per week
The co was a large Heavy Engineering Co & Engineering & electrical equipment supplier
Selling equipment such as lathes , all types of welding machines,[ Emf Australia ,Miller America ,Hobart Instrumentation & Control Equipment,,Electrical & Electronic control Systems & Switchgear, much of it under license from major overseas Cos such as Brown & Boveri [Switzerland] Cambridge Instrumentation [England] Wallace & Tierman Instrumentation & Controls[England], ,Westinghouse Roseberry [Australia] Switchgear ,rectifiers , commercial Automatic battery chargers right down to little home battery chargers, . Klockner Muller Switch gear ,icluding being the first to market RCDs in Qld,PLUS
As A 3rd year apprentice I was given the job of being the sole service man on 24hr a day call out for all serving & repairs to such equipment ,No technical back up from any one in the Co ., During that time I easily obtained an "Advanced Diploma in INDUSTRIAL Electronics"
I stayed in that job & built it up until I needed 2 more electrician to meet the demand , both of whom I had to train.
There where two classes of Electrical tradesmans licenses in Qld @ that time In fact no such thing as an "Electrician"
They were :
Electrical Lines man [very limited]
Electrical Fitter, could not do wiring work
Electrical Mechanic, could not do electrical equipment repair work, I have all three
To be a contractors licence holder you have to have the electrical mechanic cert
I was the Co's nominated licence holder until I retired ,[ after 44years]bearing ultimate responsibility for all electrical work carried out by the many electricians employed in the Cos workshops.
Aound the Mid 60s I was offered a job as head electrician @ the then being built GMH Acacia Ridge factory
That starting a bidding war between GMH & my employer, My employer enticed me to stay
From then it was steadily upwards ,ncluding around 6 years in the co's newly established "Technical Investigations & Inspection Dept"
So how someone can get the idea that I have little practical Experience????
This one of T1's is a real pearl
"15 amps x 12v is 180w, that is the maximum resistance heating you could have had so fuse over load is not the issue, ""
I imagine what he is trying to say is that 180W of heat concentrated in a very small mass should not be a problem !!!
We all know how hot even a 15W incandescent light bulb can get!! or try a180W soldering iron
but really the whole remark has little relevance & is just a further indication that some one does not understand the basics
Simple question: At what current does a 15A fuse actually open the circuit.?
-- Edited by oldtrack123 on Tuesday 19th of June 2018 08:54:52 PM
CODHUNTER said
08:46 PM Jun 20, 2018
What's happening here?
Aus-Kiwi said
09:52 AM Jun 21, 2018
No matter the the theory . If an electrical part is over heating ? There is an issue !! Better quality fuses or breakers . Thereâs a hell difference in price . Donât need to be a rocket scientist to see the cheap is too cheep !!
oldtrack123 said
03:57 PM Jun 21, 2018
CODHUNTER wrote:
What's happening here?
Hi
What is happening is someone who has NO electrical qualifications loves to make looong posts trying to show knowledge of the subjects. & continually tries to put down highly qualified fully licensed person, [has a diploma in Advanced Industrial Electronics]
2.5 years of a 4year Electrical engineering course which had to give up for personal /family reasons
Qualified ELectrical Fitter, Electrical Mechanic, Licensed Electrical contractor [until retired]Not just covering Domestic work,but , industrial , commercial & engineering & worked in those fields for over45years with a very large company[now known as Downer EDI}
Granted a nice bundle of shares as bonus during that time on the recommendation of the Co's electrical engineer & director
That poster ,bylots of experimenting, has come up with a sound knowledge of how to set up solar& Lithium batterres but that,as any one with a reasonable level of electrical qualifications would have seen from posts here & elsewhere, should not get involved in the real electrical world
Just a foot note for those who do not understand electrics
There are long established Proven Principles covering the physics,involved despite the poster who seems to believe that Extra low voltage Dc up to [120V ] operates differently & those basic principles do not apply
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:09:23 PM
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:13:22 PM
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:15:03 PM
oldtrack123 said
04:20 PM Jun 21, 2018
Aus-Kiwi wrote:
No matter the the theory . If an electrical part is over heating ? There is an issue !! Better quality fuses or breakers . Thereâs a hell difference in price . Donât need to be a rocket scientist to see the cheap is too cheep !!
A Big ditto to that!!!
But sometimes other factors can be present
Even the best quality fuses can have/ develop problems
You have no doubt had to replace quality service fuses that have over heated??
Possibly some ,from continuous overload,but not sufficient to actually blow immediately
That being the point of my early post on this thread
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:24:50 PM
Aus-Kiwi said
08:35 PM Jun 21, 2018
Why I prefer breakers . Good ole DC load .
T1 Terry said
02:44 PM Jun 22, 2018
CODHUNTER wrote:
What's happening here?
Peter is trying put up a smoke cloud of experience without actually pointing to where he worked with 12vdc powered from batteries and recharged from solar.
No matter what, it has been pointed out by a number of posters the fuse holder to fuse connection was creating a high resistance joint. For every 1v drop and 1 amp load the fuse connections became a 1w heater, 15 amps x 1v = 15w. Still not a lot of heating energy but concentrated in such a small area with poor ventilation which is made even worse by the rubber boot type inline blade fuses, the heat build up will eventually be enough to melt the plastic fuse body.
As far as fuses and circuit breakers go, the hotter they get the lower the failure/trip point is. Circuit breakers with inadequate contact area initially take up to 50% over load before the bi metal strip gets heated to the point of breaking contact. In an auto resetting type circuit breaker this heat gets trapped inside the small body resulting in the bi metal strip being preheated when it again closes the contacts. Now it requires less than the rated current to trip and this gets worse the more often it trips until the load carry ability is down by 50% or more from the advertised capacity.
Good quality fuses that use large area contact points and crimped lugs to attach the to the fuses each end is the best way to minimise resistance in that area.
T1 Terry
oldtrack123 said
06:03 PM Jun 22, 2018
T1 Terry wrote:
CODHUNTER wrote:
What's happening here?
Peter is trying put up a smoke cloud of experience without actually pointing to where he worked with 12vdc powered from batteries and recharged from solar.
No matter what, it has been pointed out by a number of posters the fuse holder to fuse connection was creating a high resistance joint. For every 1v drop and 1 amp load the fuse connections became a 1w heater, 15 amps x 1v = 15w. Still not a lot of heating energy but concentrated in such a small area with poor ventilation which is made even worse by the rubber boot type inline blade fuses, the heat build up will eventually be enough to melt the plastic fuse body.
As far as fuses and circuit breakers go, the hotter they get the lower the failure/trip point is. Circuit breakers with inadequate contact area initially take up to 50% over load before the bi metal strip gets heated to the point of breaking contact. In an auto resetting type circuit breaker this heat gets trapped inside the small body resulting in the bi metal strip being preheated when it again closes the contacts. Now it requires less than the rated current to trip and this gets worse the more often it trips until the load carry ability is down by 50% or more from the advertised capacity.
Good quality fuses that use large area contact points and crimped lugs to attach the to the fuses each end is the best way to minimise resistance in that area.
T1 Terry
Aaah, again that mysterious 12V battery power & solar
Strange stuff , all the electrical knowledge gain many many years ago with EXTRA low voltage DC long before AC became the normal power supply is no longer seems valid ,if it comes from solar
Again Terry, you obviously have no real experience with fuses having prolonged [long term[ over heating , where the overload has not been enough to cause them to actually open the circuit but s have had sufficient heat generated within them [holder &/contacts etc] to permanently damage them
That being why in my first post I suggested it would be wise to check the actual max load current[Simply because the actual load could be in excess of the fuse rating
No thermal tripping device is instantaneous tripping with minor to medium overloads but they can run very hot with the fuse wire close to melting[which in some cases is when they actually open the circuit] & that prolonged over heating will damage the fuse holder/carrier
That is the reason that many situations require thermal/magnetic overloads trip units, the magnetic section will trip at it's designed /set point, virtually instantly & & not just with AC ,such are & have been used in DC systems for donkeys years .
So perhaps ,you could try to answer the question I asked earlier
At what amps will a 15A fuse blow open ???/
Aus-Kiwi said
11:38 PM Jun 22, 2018
Like oils . They are not all equal . The time before it blows too . I my field AC fuses are encapsulated in sand with silver coating to prevent flash & fire . My old Fuso bus had lead strip 15 X 30 mm. as fuse on main feed starter etc . Easy cheap, fast, side of the road fix being a Jap bus . KISS system .
oldtrack123 said
11:55 AM Jun 23, 2018
Aus-Kiwi wrote:
Like oils . They are not all equal . The time before it blows too . I my field AC fuses are encapsulated in sand with silver coating to prevent flash & fire . My old Fuso bus had lead strip 15 X 30 mm. as fuse on main feed starter etc . Easy cheap, fast, side of the road fix being a Jap bus . KISS system .
Hi Kiwi
Yes , All fuses are not the same
Different characteristics can be built in for all voltages & supply types & loads [high > extra low voltage AC & DC
HRC fuses are always mineral filled for arc quenching ability
-- Edited by oldtrack123 on Saturday 23rd of June 2018 12:03:45 PM
Aus-Kiwi said
01:09 PM Jun 23, 2018
Cod hunter . Iâm sure weâve kept you entertained. Seems weâve found the solution? Cover fuses with sand !! Ahaha
Jaahn said
09:24 PM Jun 23, 2018
CODHUNTER wrote:
What's happening here?
Hi
Simple really ! A couple of big egos going on with a lot of useless BS off the point and not helping any one IMHO.
Move on, nothing to see here anymore. Start another question and hope the big egos can keep quiet !!
Hello all,
I have an electrical problem that has recently appeared. My vans power consists of 2x 110A batteries 2x 80watt solar panels. At night time whilst running power from 12volt for van, all power suddenly drops out and about 5-10 mins later all power is restored. Then 5-10 mins later it all happens again. This continues throughout the night. I watched the voltage drop from 13.8 to 12.2. When the power does come back the voltage has returned to 13.4 and slowly drops back again until the power goes out. In frustration I thought that I would start the generator to see if we could get some power to light the van but that wouldn't work either. Any solutions or comment would be appreciated.
Hi Codhunter, and welcome to the forum
I am not a techy, but this sort of problem happened to me once
12 volt TV and some lights would go off
Switch off all the lights, and the TV would come on again. switch more light on, and the TV would go off
My problem was that the single 100 AH GEL battery I had, had failed to hold charge any more, and I was trying to use more power than the battery could give out
From a laymans point of view, the techies will need more information about your system, otherwise they can only guess what is wrong
Exactly what items have you got running from your 12 volt batteries, when the power fails
160 watts of power, does not seem enough to keep 220 Amp Hours of battery topped up, unless you are running a few LED lights only
But... I am only guessing
One good tool on this forum is the "Search" button.
Like Tony, I think the batteries may be either not being charged enough (& that can kill an AGM battery) or may be beyond their useable life.
Do you have a "high" current load that you can hook up to the battery? I use a H4 headlight bulb - either the 50w (4A), the 55w (5A).
Do this during the day - disconnect the solar charge to let your batteries stabilise (10-15 minutes), then add the load to one battery (if possible), repeating for the second battery after.
Measure the battery voltage constantly after letting the battery discharge for an hour - monitor the voltage while you do it. It should not go lower than 12.2 to 12.3v (refer to www.energymatters.com.au/components/battery-voltage-discharge/). If the voltage drops off too fast, cease the discharge. You should see a voltage drop but then the battery should stabilise.
Do you have a separate 240v smart charger that you can connect to the battery (one at a time)? 8 to 15A should be adequate - leave it on until the battery is fully charged. Then repeat for the other one. Restore the caravan load to the battery & see what happens.
Hi Codhunter
Sounds to me that your system has a "controller" that cuts the power off when the voltage drops below a certain voltage when it is being used and then after it cuts the power the batteries recover a bit and it switches the power back on again. This just repeats while you are using power. No problems with that system.
However the problem is that your batteries are not storing enough power. As already suggested there could be several reasons for this; the batteries are not being charged enough(likely with those small panels), there is a poor connection in the wiring loosing power, the batteries are stuffed, either one or both. Charge them up as suggested, off the 240V power, and see if things improve. But do something soon or the batteries will die.
More panel power is required though for 2x110Ahr batteries. Double or triple needed for winter depending on where you are camping. Not sure what the generator is wired up to do ?? The 240V should work OK but does it have a charger wired in to charge the batteries or what ?? Check that out.
good luck Jaahn
You could persevere and try multiple recondition charging cycles and very long float charging periods to try and get the sulphation out of the plates, or you could just buy new batteries.
No matter which way you go you need to address the under charging problem or the same thing will happen again.
T1 Terry
I have noticed that the 15 amp fuses on each battery although still working are melting the plastic part. I have replaced the one that supplies power to the van with a quality fuse of 20 amps and moved it away from the batteries to inside the van where the other fuses are. I hope this fixes the problem.
The act that they are meting the plastic means they are getting hot either due to a high resistance joint in the fuse holder or the load is approaching or is greater than 15A (depending on the fuse type, they may blow at 15A or higher). If it's due to the load, then your first query means you need more solar (fixed or portable) to keep the batteries in prime condition.
As TI Terry says you can condition damaged batteries, it just takes time & you may need a 240v smart charger & solar as well as a load to discharge them to (refer to the website above).
Best of luck.
Hi
The fuse holders plastic melting is a sure indication of all your problems
Either undersized for load & running very close to blowing point or High resistance joints, poor connections ,due to corrosion or not being a tight fit in the fuse holders
Either means voltage drop across the fuse holder =,battery not being fully charged , low voltage cutout,if fitted, tripping!
Quality fuses & holders of the correct rating are required.
The correct current rated Fuses should ALWAYs be fitted as close to the current source as practical & possible
Their primary purpose is to protect the full length of cables from overheating from load currents or if a short circuit occurs.
Since cable protection is the primary requirement, the fuse current rating can be the same as the cable current rating but no higher
Note: Any overheating connection can lead to a major fire
All connections , fuses etc , should get no more than a little warm to touch!!
T1 Terry
Terry
Obviously , not being an electrician, you have no experience with fuses running sufficiently overloaded to heat up , but not actually blow
It does not matter what the voltage is ,or if it is AC or the funny DC stuff, [ that only someone specially trained in EXTRA low voltage DC understands
]
.Fuses ,just like circuit breakers ,do have a time lag factor,readily understood by any well qualified electrician.
That is why there are many different types of fuses available
Such as:
Slow blow
Fast Blow
HRC
Motor start
Etc
But even by your own reasoning ,concentrating even 10W of heat in such a small mass will generate a considerable heat rise. in that mass
But having said that the problems can be worse with poor quality fuses
Problems such as high contact resistance, due to insufficient contact pressure , poor contact material, poor contact area, oxidation of contact areas over time or due to localized hot spots.
-- Edited by oldtrack123 on Monday 18th of June 2018 07:30:02 PM
No point in arguing with you Peter, but just maybe me being an Automotive Mechanical Engineer with well over 40yrs experience in a field where blade fuses are commonly used I might have just a tad more hands on experience?
I guess you know all about the problem the VL Commodore (1986) had with blade fuses and what caused the problem?
T1 Terry
Hi
Please do not start arguing again you two. It is off the point and not helping the OP.
Up till now the discussion has been useful.
jaahn
Mechanical engineer is nothing like an electrical engineer or am I missing something...
Mechanical automotive engineer actually does the work so has the hands on experience as well as the technical knowledge because they must both design or diagnose the problem and root cause as well as rectify the problem. A Mechanical Automotive Engineer works generally with voltages between 0.1v and 70v both AC and DC.
An electrical engineer does it all on paper usually low voltage starting around 120v and upwards and an electrical fitter actually does the hands on work. The licence part is a grey area, not all electricians have a licence, just depends on what they are working on and there is a difference between an electrician's licence and an electrical contractors licence
No intension of arguing with him Jaahn, it's non productive and he prefers to attack rather than explain. His post was more of a phishing expedition looking to start another round and I really have better things to do at the moment
T1 Terry
T1 Terry
Hi Ron
No ,you are not missing anything
T1 constantly infers I have no practical experience
So Just to clarify I started my electrical apprentice ship ,when it was a 5year course ,2 sessions @ tafe per week ,totalling 7hrs.per week
The co was a large Heavy Engineering Co & Engineering & electrical equipment supplier
Selling equipment such as lathes , all types of welding machines,[ Emf Australia ,Miller America ,Hobart Instrumentation & Control Equipment,,Electrical & Electronic control Systems & Switchgear, much of it under license from major overseas Cos such as Brown & Boveri [Switzerland] Cambridge Instrumentation [England] Wallace & Tierman Instrumentation & Controls[England], ,Westinghouse Roseberry [Australia] Switchgear ,rectifiers , commercial Automatic battery chargers right down to little home battery chargers, . Klockner Muller Switch gear ,icluding being the first to market RCDs in Qld,PLUS
As A 3rd year apprentice I was given the job of being the sole service man on 24hr a day call out for all serving & repairs to such equipment ,No technical back up from any one in the Co ., During that time I easily obtained an "Advanced Diploma in INDUSTRIAL Electronics"
I stayed in that job & built it up until I needed 2 more electrician to meet the demand , both of whom I had to train.
There where two classes of Electrical tradesmans licenses in Qld @ that time In fact no such thing as an "Electrician"
They were :
Electrical Lines man [very limited]
Electrical Fitter, could not do wiring work
Electrical Mechanic, could not do electrical equipment repair work, I have all three
To be a contractors licence holder you have to have the electrical mechanic cert
I was the Co's nominated licence holder until I retired ,[ after 44years]bearing ultimate responsibility for all electrical work carried out by the many electricians employed in the Cos workshops.
Aound the Mid 60s I was offered a job as head electrician @ the then being built GMH Acacia Ridge factory
That starting a bidding war between GMH & my employer, My employer enticed me to stay
From then it was steadily upwards ,ncluding around 6 years in the co's newly established "Technical Investigations & Inspection Dept"
So how someone can get the idea that I have little practical Experience????
This one of T1's is a real pearl
" 15 amps x 12v is 180w, that is the maximum resistance heating you could have had so fuse over load is not the issue, ""
I imagine what he is trying to say is that 180W of heat concentrated in a very small mass should not be a problem !!!
We all know how hot even a 15W incandescent light bulb can get!! or try a180W soldering iron
but really the whole remark has little relevance & is just a further indication that some one does not understand the basics
Simple question: At what current does a 15A fuse actually open the circuit.?
-- Edited by oldtrack123 on Tuesday 19th of June 2018 08:54:52 PM
Hi
What is happening is someone who has NO electrical qualifications loves to make looong posts trying to show knowledge of the subjects. & continually tries to put down highly qualified fully licensed person, [has a diploma in Advanced Industrial Electronics]
2.5 years of a 4year Electrical engineering course which had to give up for personal /family reasons
Qualified ELectrical Fitter, Electrical Mechanic, Licensed Electrical contractor [until retired]Not just covering Domestic work,but , industrial , commercial & engineering & worked in those fields for over45years with a very large company[now known as Downer EDI}
Granted a nice bundle of shares as bonus during that time on the recommendation of the Co's electrical engineer & director
That poster ,bylots of experimenting, has come up with a sound knowledge of how to set up solar& Lithium batterres but that,as any one with a reasonable level of electrical qualifications would have seen from posts here & elsewhere, should not get involved in the real electrical world
Just a foot note for those who do not understand electrics
There are long established Proven Principles covering the physics,involved despite the poster who seems to believe that Extra low voltage Dc up to [120V ] operates differently & those basic principles do not apply
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:09:23 PM
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:13:22 PM
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:15:03 PM
A Big ditto to that!!!
But sometimes other factors can be present
Even the best quality fuses can have/ develop problems
You have no doubt had to replace quality service fuses that have over heated??
Possibly some ,from continuous overload,but not sufficient to actually blow immediately
That being the point of my early post on this thread
-- Edited by oldtrack123 on Thursday 21st of June 2018 04:24:50 PM
Peter is trying put up a smoke cloud of experience without actually pointing to where he worked with 12vdc powered from batteries and recharged from solar.
No matter what, it has been pointed out by a number of posters the fuse holder to fuse connection was creating a high resistance joint. For every 1v drop and 1 amp load the fuse connections became a 1w heater, 15 amps x 1v = 15w. Still not a lot of heating energy but concentrated in such a small area with poor ventilation which is made even worse by the rubber boot type inline blade fuses, the heat build up will eventually be enough to melt the plastic fuse body.
As far as fuses and circuit breakers go, the hotter they get the lower the failure/trip point is. Circuit breakers with inadequate contact area initially take up to 50% over load before the bi metal strip gets heated to the point of breaking contact. In an auto resetting type circuit breaker this heat gets trapped inside the small body resulting in the bi metal strip being preheated when it again closes the contacts. Now it requires less than the rated current to trip and this gets worse the more often it trips until the load carry ability is down by 50% or more from the advertised capacity.
Good quality fuses that use large area contact points and crimped lugs to attach the to the fuses each end is the best way to minimise resistance in that area.
T1 Terry
Aaah, again that mysterious 12V battery power & solar
Strange stuff , all the electrical knowledge gain many many years ago with EXTRA low voltage DC long before AC became the normal power supply is no longer seems valid ,if it comes from solar
Again Terry, you obviously have no real experience with fuses having prolonged [long term[ over heating , where the overload has not been enough to cause them to actually open the circuit but s have had sufficient heat generated within them [holder &/contacts etc] to permanently damage them
That being why in my first post I suggested it would be wise to check the actual max load current[Simply because the actual load could be in excess of the fuse rating
No thermal tripping device is instantaneous tripping with minor to medium overloads but they can run very hot with the fuse wire close to melting[which in some cases is when they actually open the circuit] & that prolonged over heating will damage the fuse holder/carrier
That is the reason that many situations require thermal/magnetic overloads trip units, the magnetic section will trip at it's designed /set point, virtually instantly & & not just with AC ,such are & have been used in DC systems for donkeys years .
So perhaps ,you could try to answer the question I asked earlier
At what amps will a 15A fuse blow open ???/
Hi Kiwi
Yes , All fuses are not the same
Different characteristics can be built in for all voltages & supply types & loads [high > extra low voltage AC & DC
HRC fuses are always mineral filled for arc quenching ability
-- Edited by oldtrack123 on Saturday 23rd of June 2018 12:03:45 PM
Hi
Simple really ! A couple of big egos going on with a lot of useless BS off the point and not helping any one IMHO.
Move on, nothing to see here anymore. Start another question and hope the big egos can keep quiet !!
Jaahn