Dual battery

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.

How so? I can't see how another solenoid can stuff an alternator...

Grrr!!!

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?

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.

What exactly in an alternator needs to be warmed up?

Everything!
It's good practice to warm anything up before you put a load on it.

Yes that too..^_^..

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;)

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.

hotfa,
It's a mechanical device as well is it not.
never mind most people understand.

"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!!!

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

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.

"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.

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

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.

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

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

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

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.

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

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 )

Thks Drivesafe

My pleasure Wok and hope the info was of some use to you.

Thanks Derek,

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

Is the fridge 3 way or compressor type and is the TV 12 volt or 240 volt ?

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.

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.

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.

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.

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.

"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.

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.

And we are still waiting for a reason as to what drills and power saws have anything to do with this thread.

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

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!

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!

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.