Dual battery

Submitted: Friday, Apr 14, 2006 at 14:43
ThreadID: 32891 Views:2295 Replies:6 FollowUps:37
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Is a dual battery in a landcruiser sufficient to run a caravan for the odd overnight stay at a camping ground.

How much does it cost to install a second battery.

Thanks

Travellingblooms
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Reply By: browndog01 - Friday, Apr 14, 2006 at 16:12

Friday, Apr 14, 2006 at 16:12
Travellingblooms,
I was waiting for someone to reply to that, but I guess I will,the answer is yes depending on what you want to run while on your over night stay,one DEEP CYCLE battery will run all your 12 volts lighting and a 12 volt fridge for the night.If you plan to use a microwave, TV and all the mod-cons you will certainly flatten the battery in no time at all and be eating in the dark.
Installation costs will vary a lot, a decent Deep Cycle battery will cost you around $200-300. depending upon your needs.
There are many electronic systems on the market for managing the charge of the 2nd battery, some which costs hundreds of dollars, but to me, nothing is more simple and realiable that installing a simple starter solenoid( a silver looking can) and a few wires.Get the sparky to wire the solendoid to the ignition system so when you shut the car down it cuts power supply between the 2 batteries.I have installed this into serveral friends cars and have never had a problem.With the solenoid and wiring, plugs and stuff it should be around $100.00 plus labour.

AnswerID: 167021

Follow Up By: ACDC - Friday, Apr 14, 2006 at 17:15

Friday, Apr 14, 2006 at 17:15
The local auto elec used solenoids for his cheapy dual battery systems until he did a landcruiser and destroyed 2 alternators,toyota would not replace under warranty because the solenoid caused the failures,now he uses Redarc solenoids, he would,nt listen like most auto elec's.
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Follow Up By: Member - Crazy Dog (QLD) - Friday, Apr 14, 2006 at 17:20

Friday, Apr 14, 2006 at 17:20
How so? I can't see how another solenoid can stuff an alternator...

Grrr!!!
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Follow Up By: ACDC - Friday, Apr 14, 2006 at 17:32

Friday, Apr 14, 2006 at 17:32
Well there's a couple of reasons you can overload the alternator and also the voltage spikes from the solenoid destroys the electronics.
Redarcs and most good quality battery isolators have spike protection and also charge the starter battery first before the second battery which gives the alternator a chance to warm up before the big load.

Would you drive your 4by flat out with a cold engine?
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Follow Up By: The Tinker - Friday, Apr 14, 2006 at 17:37

Friday, Apr 14, 2006 at 17:37
Using straight solenoids is a risk on modern vehicles. Personally would not be silly enough to use a straight solenoid on a modern vehicle. A Redarc solenoid provides the necessary spike protection for modern vehicle, and delay to charge the main battery first.
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Follow Up By: Marn - Friday, Apr 14, 2006 at 18:10

Friday, Apr 14, 2006 at 18:10
What exactly in an alternator needs to be warmed up?
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FollowupID: 422043

Follow Up By: ACDC - Friday, Apr 14, 2006 at 18:29

Friday, Apr 14, 2006 at 18:29
Everything!
It's good practice to warm anything up before you put a load on it.

Yes that too..^_^..
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Follow Up By: Marn - Friday, Apr 14, 2006 at 18:38

Friday, Apr 14, 2006 at 18:38
They always taught me at tech that electrical components run better cold i.e. less resistance in the windings ect. I would have thaught that the only thing that would benefit from being warm would be the bearings, but then again. I have been wrong before;)
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Follow Up By: hotdfa - Friday, Apr 14, 2006 at 22:38

Friday, Apr 14, 2006 at 22:38
I have never heard of having to "warm up" electrical devices ever before! Maybe ACDC has special voltage needs... voltage and current are either flowing or not flowing, warming up makes no difference at all!!!!! Do you warm up your TV before using it ???? Any electronic dual battery system with spike protection will work fine in moden cars.
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Follow Up By: ACDC - Friday, Apr 14, 2006 at 23:19

Friday, Apr 14, 2006 at 23:19
hotfa,
It's a mechanical device as well is it not.
never mind most people understand.
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Follow Up By: Member - Crazy Dog (QLD) - Saturday, Apr 15, 2006 at 00:22

Saturday, Apr 15, 2006 at 00:22
"and destroyed 2 alternators" was the original statement!

Here we go again - all the bloody experts...... I can believe the spiking bit ( being an electronics tech) but really - warming up - what about if you live in the tropics like some of us eh?

Going to bed - had enough of the 3 wise men! and it's only Easter....

Grrr!!!
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Follow Up By: Member - Davoe (Widgiemooltha) - Saturday, Apr 15, 2006 at 02:26

Saturday, Apr 15, 2006 at 02:26
of course you need to warm your tv up before you use it!. No tv just turns on unless it is on standby which keeps it warm. Besides that I have been let down by solonoids a few times. They mask a stuffed battery because they conect both batterys for starting. The stuffed one theives the charge from the good one and next thing you know you have 1 stuffed battery and one flat battery - just better hope you arnt in the middle of no where
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Follow Up By: ACDC - Saturday, Apr 15, 2006 at 13:01

Saturday, Apr 15, 2006 at 13:01
Thanks Davoe,
I'm glad some of us understand.

My tunescope takes 15 minutes to warm up.
My sons Marshall amp takes three minutes to warm up.
Even the wifes Iron takes a few minutes.
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Follow Up By: Geoff M (Newcastle, NSW) - Sunday, Apr 16, 2006 at 00:07

Sunday, Apr 16, 2006 at 00:07
"never mind most people understand." You've lost me!

"My tunescope takes 15 minutes to warm up.
My sons Marshall amp takes three minutes to warm up.
Even the wifes Iron takes a few minutes."

Two of which are devices that contain heated cathodes to emit a stream of electrons used as either an amplifier or a display. The third is again a heating element. None of these examples are valid in rotating AC or DC machines.

Interesting concept this warming up a vehicle alternator, me thinks someone is smoking what they should be mowing.
If this where valid we'd all be driving the first 5k's on a freezing cold, wet winters night without lights, wipers or demisters until the alternator consented to drag itself from its slumbers.
In a reverse idea of the same concept, you'd need to go out and warm your speer point or pool pumps or washing machine before kicking them in the guts. (Same basic machine, different rotor. Yes, I do know the home pumps and motors mentioned are generally single phase and vehicle alternators are usually multi phase, still the same basic AC machine principles, also valid for DC machines)

Power stations spin em up, synchronise to the grid and press the titty. It's the driving force that's warmed up not the generating machine.

Geoff.
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Follow Up By: Member - Davoe (Widgiemooltha) - Sunday, Apr 16, 2006 at 00:18

Sunday, Apr 16, 2006 at 00:18
I actualy understand little except that my tv needs warming up, as for the rest I dont Know and actually care little I actually use a Cole Hersy isolator and havnt blown an alternator - thats all i need to know
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Follow Up By: Geoff M (Newcastle, NSW) - Sunday, Apr 16, 2006 at 08:07

Sunday, Apr 16, 2006 at 08:07
Davoe mate, you're 100% correct, if your setup works for you run with it.
And tele's need warming up for the same basic reason irons take time to warm up neither reason are valid in rotating or solid state AC or DC machines.

Unfortunately sometimes there is some information on the subject of electricity thrown around this forum that can at the kindest be described as unfounded and misleading.

Geoff.
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Reply By: The Tinker - Friday, Apr 14, 2006 at 17:29

Friday, Apr 14, 2006 at 17:29
A better method is to put a sealed battery in the caravan and a small solar panel and 3 stage battery solar regulator $40. This negates all the need for wiring to the vehicle and in reality the battery in the caravan will never get properly or correctly charged. With a solar panel and 3 stage regulator if you use the battery within the capacity of the solar panel you can expect 2 or even 3 times the battery life of attempting to charge it from the vehicle. By the time you mount the battery in the Landcruiser, wire the Landcruiser up with all the gear and large wiring, new Anderson plug and wiring to caravan, a solar panel will work out the same price and a far superior system.
If you only want to power 2 x 12w fluoro lights for a couple of hours you could get away with a 20w solar panel for $200 and a quality deep cycle battery 30Ah battery $130. if you want to power 2 x 12w fluoro, car radio and/or small up to 12" LCD TV a 40w solar panel for $360 and 70Ah battery for $200. If you want to power more then you can go to a 60w solar panel $530 70Ah battery $200 or an 80w solar panel $595 and 100Ah battery for $270. Consider a caravan park costs you $25 a night that is 4 nights for a $100 or 40 nights for a $1000. Your solar system would soon pay for itself and you have the freedom and enjoyment of camping out with others in comfort and silence
AnswerID: 167028

Follow Up By: Dilligaf - Saturday, Apr 15, 2006 at 09:59

Saturday, Apr 15, 2006 at 09:59
this system is the best and wish we had gone that way first
we spent a fortune on dual battery systems and the battery in the van was never charged properly and overall was a failure
now we have the solar panel and battery in the van and have power when we need it and no problems
do not waste your money on a dual battery system in the motor vehicle to the caravan
once you unhook the vehicle you are without power you lose your lights all the stations and time in your radio and clocks
the solar panel and battery in the van first would have saved a lot of money
wish I had listened to one poster who told me this first like the Tinker has instead of listening to all the others without experience
besides getting some good advice here there are some posters who give very bad and wrong information
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Follow Up By: Willo61 - Saturday, Apr 15, 2006 at 10:22

Saturday, Apr 15, 2006 at 10:22
Tinker
I did what you have done but additionally use a small inverter connected to my vehicle battery with a 12 Amp Battery Charger. The charger is connected to the Aux battery over night because charging can take a while. The inverter switches off when the vehicle battery gets low. In fact with this setup the solar panel switched on by day is almost not required
Willo
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Follow Up By: ACDC - Saturday, Apr 15, 2006 at 13:05

Saturday, Apr 15, 2006 at 13:05
Dilligaf,
Obviously you went to the wrong place for your dual battery system,if they used a DC to DC converter no problems.
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Follow Up By: drivesafe - Sunday, Apr 16, 2006 at 03:01

Sunday, Apr 16, 2006 at 03:01
Hi Dilligaf, ACDC got it partly right, you went to the wrong place.

The are tens of thousands of caravans out there that have no problems getting their batteries, ALL their batteries properly charged by the vehicle’s alternator and you do not need a DC to DC converter to achieve a fully charged battery in your van. In fact these DC to DC converters can actually take longer to fully charge the rear battery than if the battery was simply connected directly to the alternator.

What you do need is decent size cable. Having adequately size cable solves 99% of problem relating to poorly charged batteries in caravans and camper trailers.

As for alternators requiring to be warmed up.

Sorry but most alternators on modern vehicle are designed to give the maximum voltage output when they are cold and as their temperature rises, the voltage drops.

The higher the voltage difference between the vehicle’s charge voltage and the batteries charge state voltage, the greater the current the battery can take.

This high starting voltage has a number of effects. First off it is intended to replace the amps, used the start the vehicle, as quickly as possible.
Next it also means that most dual battery controllers will cut-in within a few seconds of the vehicle starting.

The very latest vehicles are now being supplied with charging systems that charge between 13.5 volts and 15.7 volts and 15.7 volts is heap high enough to charge any battery located anywhere in a vehicle or tow vehicle.
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Follow Up By: Wok - Sunday, Apr 16, 2006 at 04:15

Sunday, Apr 16, 2006 at 04:15
Morning Drivesafe.........did your beer runout as well? :)

? Why would a dc-dc converter be slower @ charging then direct alternator connection if the voltage were the same?

eng
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Follow Up By: drivesafe - Sunday, Apr 16, 2006 at 09:37

Sunday, Apr 16, 2006 at 09:37
Hi Wok, first off, a DC to DC converter needs to have a good supply current for them to work properly and to get a good supply current to them, you need to have heavy cables running from the battery / alternator to the converter. If you have these heavy cables to get the high current needed to run the converter then you already have the ability to supply the correct voltage needed to charge ANY battery to full charge WITHOUT A CONVERTER.

Next, the initial current that a low battery will pull will depend on both the supply voltage and the available supply current. If you have a battery of up to around 60 to 70 amp / hours, a 20 converter, providing it has suitable supply cables, will be working at it’s maximum and in this case will be of some advantage to the time taken to get the battery to a fully charge state.

If you have a 100 amp / hour battery or larger, the converter will now restrict the amount of charge current going to the battery further more, for a lot less than the cost of a converter, you could install heavy cable ( which you need to buy for the converter anyway ) and a much larger battery or simply add an additional battery and not only will you charge this additional capacity faster by connecting directly to the vehicle’s charging system but no matter how supposedly good these converter are advertised as, at the end of the day any battery capacity of 100 a/h or high will give you more stored capacity in a shorter charge time for a much lower out lay or putting it another way, for a lot less money you can have a larger set up that will last longer between charges.

There are some, but very few, cases where a converter will be of benefit but it relates to not having the space to put a bigger battery in, in the first place.

All of the above has some many variables that have to be considered but in the vast majority of set ups, if done correctly, it works out much cheaper and with better results, to just increase the the amount of storage capacity ( larger and / or more batteries )
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Follow Up By: Wok - Sunday, Apr 16, 2006 at 21:57

Sunday, Apr 16, 2006 at 21:57
Thks Drivesafe
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Follow Up By: drivesafe - Monday, Apr 17, 2006 at 03:00

Monday, Apr 17, 2006 at 03:00
My pleasure Wok and hope the info was of some use to you.
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Reply By: Derek from Affordable Batteries & Radiators - Friday, Apr 14, 2006 at 18:54

Friday, Apr 14, 2006 at 18:54
Hi TB,

You should be just about totally confused by now !

1) What is in the car that may need the dual battery ?
2) What is in the van that must be run off 12 volts ?
3) Which Cruiser do you have ?

Give me a list and I will work it out for you.

Regards Derek.
AnswerID: 167040

Follow Up By: travellingblooms - Friday, Apr 14, 2006 at 21:05

Friday, Apr 14, 2006 at 21:05
Thanks Derek,

1 nothing
2 lights, fridge and TV
3 99 100 series

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Follow Up By: Derek from Affordable Batteries & Radiators - Friday, Apr 14, 2006 at 23:13

Friday, Apr 14, 2006 at 23:13
Is the fridge 3 way or compressor type and is the TV 12 volt or 240 volt ?
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FollowupID: 422083

Reply By: Bonz (Vic) - Saturday, Apr 15, 2006 at 08:50

Saturday, Apr 15, 2006 at 08:50
Are you talking about the dual battery setup in the 80 series? If so then I would be wary as they arent a true dual battery arrangement in that they are two smaller batteries joined together to make one decent batt.
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AnswerID: 167102

Follow Up By: drivesafe - Sunday, Apr 16, 2006 at 17:44

Sunday, Apr 16, 2006 at 17:44
Hi Bonz, your correct about the two battery system found in some Toyota 4x4s but as this two battery system is intended to over come starting problems in cold climate countries, here in Australia, they can be separated and a dual battery controller put between the two batteries.

A quick and simple set up.
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FollowupID: 422347

Reply By: Kiwi Kia - Saturday, Apr 15, 2006 at 19:21

Saturday, Apr 15, 2006 at 19:21
I am an electrical tech and can't make head or tail of ACDC's reasoning regarding;
1. The brand recomendation.
2. The 'warming up' comment.

Many people have spent a lot of money on duel battery charging systems only to have a 'melt down' which the system was meant to prevent so it is obvious that some brands don't stand up to normal usage or their advertised claims.

I do agree that the only sure way of avoiding the common problems is to use a completely seperate system from the vehicles starting and charging system.
AnswerID: 167158

Follow Up By: drivesafe - Sunday, Apr 16, 2006 at 17:53

Sunday, Apr 16, 2006 at 17:53
Hi Kiwi Kia, I’m not sure what you mean by a “ Melt Down “.

I’ve been working with Dual Battery Controller Systems for around 20 years and when quality devices are fitted properly, there is rarely a problem and for having a completely separate system. Why not use the best device available for charging automotive batteries, the alternator.

Contrary to all the hype about the different fancy ways of charging a battery, the alternator has been around the longest, is the most reliable and by far, the most economical way to charge an automotive battery, or two, or three so why not use it.
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Follow Up By: Kiwi Kia - Sunday, Apr 16, 2006 at 18:26

Sunday, Apr 16, 2006 at 18:26
Hi 'drivesafe', I used the term 'melt down' to cover all the possibilities that could befall dual battery charging systems. The technology is fairly well proven but there are some rather shoddy builders using cheap circuits (less components etc.) and selling for a cheap price. Check the archives and see how many people ask the same questions on this and other forums about their battery charging woes. It is probably the most common problem campers have.

I whole heartly agree that the alternator is the best possible charging system (if you can start the engine).

IF you have the room a second alternator and battery system for the aux. pwr is the safest way to go, this is what I meant by a stand alone system. I was speaking to a friend just yesterday who saved a lone traveller stranded in the bush with two flat batteries. This guy had hf, epirb, etc. etc. but could not use the hf (or any appliances) with out battery pwr. It would have cost close to a thousand dollars to get a person to get to his vehicle for a jump start if my mate had not decided to camp at this very remote site.
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Follow Up By: ACDC - Sunday, Apr 16, 2006 at 20:18

Sunday, Apr 16, 2006 at 20:18
Kiwi Kia,
So your saying Redarc is crap?

Let me ask you this when you use a drill do you turn the drill on before you start drilling or when using a power saw do you put the teeth of the saw in contact with the wood before switching the saw on,NO you get the device up to speed before applying the load.

Also i have fitted approx 400 Redarc's over the years how many have you fitted.
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Follow Up By: drivesafe - Sunday, Apr 16, 2006 at 20:35

Sunday, Apr 16, 2006 at 20:35
For a starter ACDC, I agree with what Kiwi Kia was saying and if you have been following the number of threads on this site and on others, talking about problems with cheapo dual battery controllers, as mentioned by Kiwi Kia, to my knowledge, Redarc has not been mentioned, here or elsewhere and further to your last post, what the hell has a drill or a power saw got to do with the subject at hand.
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FollowupID: 422377

Follow Up By: Geoff M (Newcastle, NSW) - Sunday, Apr 16, 2006 at 20:59

Sunday, Apr 16, 2006 at 20:59
"Kiwi Kia,
So your saying Redarc is crap?"
Funny thing, you are the only one who mentioned a specific product and the only one who used these words!!

"Let me ask you this when you use a drill do you turn the drill on before you start drilling or when using a power saw do you put the teeth of the saw in contact with the wood before switching the saw on,NO you get the device up to speed before applying the load."
All totally useless analogies, what has any of this to do with charging vehicle batteries. Actually what has this to do with charging any battery? What has this to do with anything in this thread?

"Also i have fitted approx 400 Redarc's over the years how many have you fitted. "
None, and I'll bet Redarc are cringing about now. They'd appreciate people representing them who actually have something resembling electrical knowledge and customer relation skills.

Geoff.
Geoff,
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Follow Up By: ACDC - Sunday, Apr 16, 2006 at 22:41

Sunday, Apr 16, 2006 at 22:41
Kiwi stated he could not make head or tail of my brand recommendation and the only brand i mentioned was Redarc.

If you can't work out the rest it's no wonder you have grey hair.
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FollowupID: 422401

Follow Up By: drivesafe - Monday, Apr 17, 2006 at 02:58

Monday, Apr 17, 2006 at 02:58
And we are still waiting for a reason as to what drills and power saws have anything to do with this thread.
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FollowupID: 422432

Follow Up By: Wok - Monday, Apr 17, 2006 at 06:47

Monday, Apr 17, 2006 at 06:47
I thought that Tinker was referring to this response from ACDC in his first question-
Quote:

"Dilligaf,
Obviously you went to the wrong place for your dual battery system,if they used a DC to DC converter no problems. "

Unquote:

As far as drills & electric saws goes, it was an unfortunate choice of analogies to support his case for warming up the alternator
Quote:

"Redarcs and most good quality battery isolators have spike protection and also charge the starter battery first before the second battery which gives the alternator a chance to warm up before the big load."

Unquote:

Oh well...........

eng
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FollowupID: 422435

Follow Up By: Kiwi Kia - Monday, Apr 17, 2006 at 07:57

Monday, Apr 17, 2006 at 07:57
The underlieing problem here is that by making the statements that he has ACDC has no creditability with any other statements about electronic equipment !

Reminds me of an industrial machine that I once had to service many years ago. The small data entry screen occasionaly displayed the word "GIGO", this was not mentioned in the handbook. It stood for "Garbage In - Garbage Out" !

I feel for forum members who ask a question genuinely seeking information and get in return a meaningless and factually wrong responce from someone who has no idea what they are talking about.

As I have previously stated, multi battery charging has several potential problems. There is NO excuse for manufactures of electronic seperation modules to skimp on design and construction of their devices. I do not particularly like using the term when refering to chargeing setups but a 'softstart' mechanism must be used.

Many fleet operators insist that in a multi battery setup the batteries must all be renewed at the same time and must be same make / model. Because of the cost factor most 4w4 owners do not usually do this.

The care and feeding of multi battery systems (and jump starting) is actually very technical and and can lead to a disaster if not done properly. Ask an automobile club road side service tech what they get taught about the precautions taken before doing a jump start and you will start to understand what an electronic switching device has to do in a muti battery 4x4 (or camper) every time the vehicle engine is started and 'see's' a large difference in charge among the system batteries. Spikes and sudden change of load within the system needs to absorbed or 'cushioned' and most 'rough science' electronic devices just do not get it right. Sometimes you get away with it and sometimes you do not!
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FollowupID: 422439

Follow Up By: ACDC - Monday, Apr 17, 2006 at 12:00

Monday, Apr 17, 2006 at 12:00
Kiwi,
You bag me then talk about the exact same thing (soft start).
Obviously some electrical devices load starts can't be avoided but when they can it must be benificial.
Your a joke!
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FollowupID: 422472

Reply By: drivesafe - Monday, Apr 17, 2006 at 18:16

Monday, Apr 17, 2006 at 18:16
You are all missing the point and I might add, most are showing what very little knowledge they have of car electric's.

Soft starts, drills and hole saws and spikes destroying electronics.

The whole lot of it is just make believe.

For a starter, the STARTER motor causes the biggest possible spike you are ever likely to come across and that occurs when you you turn the ignition key to the start position and then release it.

As you release the key, the starter solenoid is de-energised so it gives off one hell of a spike. So tell me how many vehicles have had the computers stuffed because someone started their vehicle and there is no spike protection built into the starter solenoid.

Next, any decent quality dual battery controller has spike protection built in more so to protect it’s own electronics as much as protecting the vehicles electronics.

As I have already pointed out, modern alternators are deliberately designed for a hard start so the the battery can get as much charge put back in to it as quickly as possible to replace the amps used to start the vehicle. This is done to cater for short start stop operations that most vehicles are used for these days.

Last but not least, this thread is so far off subject now as to be next to useless.

Cheers
AnswerID: 167387

Follow Up By: Geoff M (Newcastle, NSW) - Monday, Apr 17, 2006 at 18:35

Monday, Apr 17, 2006 at 18:35
I trust this is the last and final word as it is incredibly concise and accurate. It is actually for once based on known electrical physics.

Geoff.
Geoff,
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