Hi Kerry and Bruce,
               I do have a solution you can run a separate charge line directly from your alternator via a 30 amp circuit breaker directly to the house batterys, I have done that with my campervan and have not had any problems, both of my deep cycle house batterys are always fully charged after a few hours driving,.....Hope that helps.....
     Ash

-- Edited by Ash on Thursday 26th of July 2012 10:22:07 AM

Mccanic wrote:

---

The previous circuit is excellent though expensive, just a votage sensing isolator will set you back several hundreds of $ so I have fitted about 50 or more systems like this:

Hope it works.

Just a note, the battery feed to the van should either have a large Diode on the feed cable or at least fuse it at the house battery just incase the cable it gets damaged and dead shorts.

Remeber, always run cabling carefully  where it has little chance of getting damaged and if you suspect it can get damaged then check it regularly, I know a few people who have lost vans and equipment by not checking.

Cheers,

 

Damo

---

 Hi Damo, just a slight error in the pinout of your relay diagram which may cause a bit of confusion. The standard 5 pin auto relay has pin 30 as the common or input side of the switch, pins 87, 87 or 87, 87a or 87, 87b as the switched output side of the switch, and the coil between pins 85 and 86. Relays with two pins marked 87 have two output pins that are physically connected in the relay. The 87a type (aka a changover relay) has one normally open output contact (87) and one normally closed output contact (87a). The 87b type has two separate normally open output contacts which aren't connected to each other.

 

(I hope you don't mind me pinching part of your diagram)

Bob

The 87b type relay is usefull for fitting spotlights or similar higher current devices to reduce erosion of contacts by sharing the load between the two sets of contacts.

-- Edited by 03_troopy on Saturday 28th of July 2012 05:11:49 PM

Mccanic wrote:

---

The previous circuit is excellent though expensive, just a votage sensing isolator will set you back several hundreds of $ so I have fitted about 50 or more systems like this:

Hope it works.

Just a note, the battery feed to the van should either have a large Diode on the feed cable or at least fuse it at the house battery just incase the cable it gets damaged and dead shorts.

Remeber, always run cabling carefully  where it has little chance of getting damaged and if you suspect it can get damaged then check it regularly, I know a few people who have lost vans and equipment by not checking.

Cheers,

 

Damo

---

 I recently purchased avoltage sensing isolator in the form of a Redarc "Smart Relay" http://redarc.com.au/products-and-services/sbi-series-dual-battery-isolator for $125 "show price". I understand the RRP is about $175, hardly "hundreds of dollars". Baintech and other suppliers have these for a similar price. By using this type of isolator there is no need to tap into the existing vehicle wiring to provide a control circuit as the isolator itself will do all the controlling.

I would not advocate the use of a diode in a charging cuircuit as this will cause a voltage drop of approx 0.7 volts due to the forward voltage of the diode. This would seriously limit the circuit's ability to charge a battery. I do endorse the use of a fuse or circuit breaker to protect against any short circuits.

Jim

$175 plus $80 to $160 for fitting for most people ends up at well into the hundreds of $ mark well at least a couple of hundred anyway I would say.

A $7 relay, some cable and terminals plus half a day to the absolute novice or about $80 for an autoelec would be well within the boundries of most people just to charge an inhouse battery.

There is no big deal about breaking into the loom, there are normally plenty of wires you can tap with just a plug in terminal at your main fuse box under the bonnet, that's the first place I normally look and I havn't been wrong yet, you don't need anything big as it's just to switch the relay, as long as it doesn't have anything to do with your body computer is the only thing to worry about so test it to see that it's 12v and not 5v or something silly like that.

As far as Diodes go, I'm not quite sure of what you mean as your red arc system runs at least 4 on it's board so you must have massive drop in charging voltage but if your talking an active current sensing circuit as your so called diode (i.e Red arc) then yes, your talking about an UP TO 0.7 amp drop in current but I may be mistaken on what you mean there so please don't take it personally but I would like to know what you mean.

I've fit at least 50 of these systems and I appologise about the diagrahm, it was right off the top of my head and I should have checked a diagrahm to get it right and specified a NO or NC (normally open/closed) relay and 40a at least which is about the best you can get in the standard automotive relays but you can go up to 100, 200, 250amp relays if you want but your only charging a battery and in most cases it won't try and draw more than 10 to 20amps to charge it anyway.

Red arc is a great system and I'm not saying that this is as good but it does the job a crap load cheaper than fitting a voltage sensing system.

03 Troopy, cheers mate for that, always better to have someone correct a stuff up than stuff up because of what I have told them to do.

And not a prob with using my diagrahm, that's why i posted it.

Cheers Damo

-- Edited by Mccanic on Monday 30th of July 2012 10:13:33 PM

Hi Mccanic, what Jimricho is saying is that if you had a a battery of exactly 12V potential difference between the terminals, and you connected a resistor (load) in series with a diode (forward biased) across the terminals, you would see 11.3V dropped across the resistor and O.7V dropped across the diode.

Edit: As for the redarc or similar voltage sensing relays, the circuit board is only for sensing the voltage of you starting battery, and setting the switching voltages for the solenoid. Once the solenoid is energised the charge path is only via the contacts in the solenoid, not the circuit board. Once the starting battery has reached a charge voltage of 13.2V the circuit board allows the solenoid to be energised, connecting the aux battery so that it can then be charged. If the starting battery voltage drops to 12.7V, the solenoid is deenergised, thus dissconnecting the aux battery from the charging circuit.

Cheers Bob.

-- Edited by 03_troopy on Tuesday 31st of July 2012 08:55:49 PM

03_troopy wrote:

---

Hi Mccanic, what Jimricho is saying is that if you had a a battery of exactly 12V potential difference between the terminals, and you connected a resistor (load) in series with a diode (forward biased) across the terminals, you would see 11.3V dropped across the resistor and O.7V dropped across the diode.

Edit: As for the redarc or similar voltage sensing relays, the circuit board is only for sensing the voltage of you starting battery, and setting the switching voltages for the solenoid. Once the solenoid is energised the charge path is only via the contacts in the solenoid, not the circuit board. Once the starting battery has reached a charge voltage of 13.2V the circuit board allows the solenoid to be energised, connecting the aux battery so that it can then be charged. If the starting battery voltage drops to 12.7V, the solenoid is deenergised, thus dissconnecting the aux battery from the charging circuit.

Cheers Bob.

-- Edited by 03_troopy on Tuesday 31st of July 2012 08:55:49 PM

---

 Thanks, Bob, a good summary.

To ensure effective charging of a van/house/aux battery from the alternator it is necessary to limit any voltage drop in the circuit as much as possible and therefore the use of diodes should be avoided. If wishing to isolate the charging circuit from the 3way fridge supply from the vehicle (and this should be done) methods other than diodes should be adopted. A DC-DC charger is good option for this and other reasons.

As a "by the way" I have a fully solid state (no mechanical contacts as in a relay) dual battery isolator between my main battery and my vehicle's aux battery and it has very little forward voltage (most likely uses a mosfet). It's a "Rotronics" unit and has given over 12 years of reliable service.

Jim

LeighW wrote:

---

Hi all,

It is possible to charge a van battery from a car providing suitable cable is used, it will just take longer to
do so.

Are you referring to a cranking battery or a auxilliary battery.

It should in most cases, be quicker to charge a battery to 95% SOC off an alternator than a DC DC charger.

All batteries and if so please explain in more detail.

The DC DC charger only being quicker for the last 5% and generally a lot slower to 95%.

More info needed.

As for modern vehicles, yes the charge voltage can be lower due to car manufacturers using excessive temperature
compensation to meet engine emission requirements. In this instance there are other lower cost options than
the use of DC DC charge and depending on the battery setup may provide much better results:

One could be to use Optima type batteries that will quickly charge at a lower voltage than a normal battery
and much quicker off an alternator than a DC DC charger.

Please expalin why you preferenced the Optima as Im sure a lot of people would also like to know why.

Another could be to use an Alternator Voltage booster diode, but as manufacture on of one type of these
I have a vested interest in them so will leave the members to do their own research.

If as you first stated you can do it off an alternator with the correct cabling why even use one of the booster diodes.


Cheers
LeighW

---

 

I have listed some battery detail on the thread Deep Cycle Batteries on page 2.
I hope this helps people get a better understanding of the battery type AGM.

The resistance of the battery combined with recombination technology controls what the battery will accept and is at its best when the charging system also has temperature compensation.
Regards
Ian

Peter
Leigh is a male and I believe a technician and from the Melbourne area of Victoria.

There are two supposed makers of the smart fuse and Leigh would have the best product .

I bought a few hundred dollars of his product as I believed the voltage boost would enhanse the use of DC/DC chargers where some to me actively and possibly unknowingly promote underwiring and inneficiency of their own operation by using lowervoltage acceptance and forcing the use of more amps input to produce the stated amps capacity output and in one instance one unit in use pulled a massive increase in amps in to produce amps out that it made the stated 90% efficiency as claimed look rediculous.

I have reservations about the specific voltage produced in some instances by the smart fuse for underbonnet continuous charging use and without the installation of a DC/DC charger controlling the voltage there could be battery damage in underbonnet applications.

If Leigh genuinely has the knowledge reqired he would answer the questions and work to promote the use of his product that compliments it rather than claiming it as the end all to be all which it is definately not.

Its good to see you come on again Leigh and prove that you know nothing about DC/DC chargers and are prepared to deride a product to just push your own barrow.

Small DC/DC chargers do leave a lot to be desired in their capacity in time frame to better a cable only system and especialy one with a voltage booster that has the ability to recognise the potential for over voltage and temperature compensation but to date the voltage booster is a dumbwaiter and cannot perform the functions mentioned and required.

Well designed DC/DC chargers with full bulk absorption and float and with temperature compensation have the capability to work with alternators up to 300A and they come in three types (1) Alternator Smart Regulators, (2) Alternator to Battery Chargers and (3) Battery to Battery Chargers.
All units come with the ability to temperature compensate alternators and batteries.

Due to the drop voltage issues of some alternators the start up threshold of some DC/DC chargers can be compromised and there is two ways to fix this and that is try a booster fuse and or modify the DC.charger to cater for the drop and the later is the better long term option.

I tried your Booster Fuse in a Diesel Landcruiser 100 Series and it took the voltage too high for a safe operation of the batteries under the bonnet so the owner would not use it and removed it .
He rang you and you told him just use the fuse on its own dont use DC/DC char gers they are a waste of money.

Thank you for putting your desire to sell your product above the potential of cooperation and by lambasting a good product you showed your ignorance to what and how a system does truly get the best benefit.

All sealed batteries whether AGM,Sealed Lead Acid and Gel are voltage sensitive and with over voltage can suffer water loss that cannot be replaced and your unit has proven to have the potential to do just that especially under bonnet batteries that are prone to a high ambient environment anyway so high ambient voltage increase on top of voltage fuses may be a recipe for disaster with the only thing saving auxiliary batteries being underwiring giving voltage drop relief to the batteries.

If as you say your not pushing your own barrow why did you come on here in the first place .
I'm on to push my barrow of information but not to the extent that I'm in need of sales as I am a Grey Nomad in reality and my desire is to let people know what can be done and it is up to them to decide what to do for the best by sorting the wheat from the chaff.

-- Edited by powerstream on Monday 6th of August 2012 09:04:25 AM

-- Edited by powerstream on Monday 6th of August 2012 09:06:03 AM

-- Edited by powerstream on Monday 6th of August 2012 09:08:11 AM

LeighW wrote:

---

powerstream wrote:

---

 

Due to the drop voltage issues of some alternators the start up threshold of some DC/DC chargers can be compromised and there is two ways to fix this and that is try a booster fuse and or modify the DC.charger to cater for the drop and the later is the better long term option.

Come on Ian, you knew the DC DC charger you were trying to market wouldn't work properly with the newer charging systems in the Toyotas so instead of doing the right thing and getting the manufacture to correct the issue you tried to use my device as a makes shift cure, doesn't sound like you have your customers best interests at heart to me. 

The product in question was designed and successfully used in the marine market for many years and still is and was too in the RV market before the drop volt alternator and has a start up threshold of 13.35V and ramps up to full power at 13.5V and the alternator was dropping to 13.2V.

New units now being built will cater for the new threshold but in the interim I wanted to help people get the benefit now so I got your units for them to try.

I tried your Booster Fuse in a Diesel Landcruiser 100 Series and it took the voltage too high for a safe operation of the batteries under the bonnet so the owner would not use it and removed it .
He rang you and you told him just use the fuse on its own dont use DC/DC char gers they are a waste of money.

My units have been installed in many 100 series and the output voltage has always remained in the range specified by Toyota as normal for a 100 series, if you have documented proof of overcharging please supply and I'll address the issue. I don't recall having said the above to any of your customers, I do recall a conversation though were one of your customers indicate he had complained to you of a problem with interference to his cars radio after your company installed a charger and one of my devices and you fobbed him of to me saying the booster was the problem. I told him the booster couldn't possibly cause the issue and to prove simply replace the booster with a fuse. We did get around to discussing the installation of my booster with one of your chargers, I said it does seem a waste of time to boost the alternator voltage then add a DC Dc charger, As I never heard from him again I assume the noise issue was with the charger you installed. By the way, if you were installing my booster in conjuction with your charger in an attemp to solve issues with your chargers why was your customer contacting me for support, surely you should have been doing this? 

I doubt that Toyota would condone the use  of product where the installation interferes with the computor and warranty of the vehicle in Question your unit does the Ster ling does not as it is an external fitment Batter y to Battery .

We do not do installation work as such and did not install the vehicles you refer to and it is not our responsibility for the way a product is thus installed.

  

Thank you for putting your desire to sell your product above the potential of cooperation and by lambasting a good product you showed your ignorance to what and how a system does truly get the best benefit.

DC DC chargers have their place in the market but there not the be all end all you try to make them out to be, more cost effective systems are available that work just as well in the majority of cases as the many users will agree with and statements that it is impossible to properly charge a battery of a vehicles charging system is just plain rubbish.

If a mains battery charger is the best  method of charging due to the algorithms used giving them bulk absorption and float and a DC/DC charger can emulate that same charge regime then you may find it hard to convice people that you have a better solution.

All sealed batteries whether AGM,Sealed Lead Acid and Gel are voltage sensitive and with over voltage can suffer water loss that cannot be replaced and your unit has proven to have the potential to do just that especially under bonnet batteries that are prone to a high ambient environment anyway so high ambient voltage increase on top of voltage fuses may be a recipe for disaster with the only thing saving auxiliary batteries being underwiring giving voltage drop relief to the batteries.

 

Hmmm interesting statement as all DC DC will at times in the charge cycles supply a considerably higher output voltage than the alternator ever will and generally at the end of the charging cycle when the battery is its hottest. 

That is why good DC/DC chargers have temperature compensation to protect the batteries the same as mains chargers can and reduce the amps during absorption and then if float occurs reduces both volts and amps.

Alternators are shut down early as they are dumb waitors and do not do that so the early shut back is to protect the batteries and also limits the charging ability.

If as you say your not pushing your own barrow why did you come on here in the first place .
I'm on to push my barrow of information but not to the extent that I'm in need of sales as I am a Grey Nomad in reality and my desire is to let people know what can be done and it is up to them to decide what to do for the best by sorting the wheat from the chaff.

 

I simply was making users aware there are alternatives, your the one who appears has become upset that it may affect your bottom line if members have choices.

 

As your charges are so effective, how about putting up on your website a few graphs showing how much better your chargers will perform at charging say two 100AH

batteries compared to an alternator running at around 14.3V, and battery life? I've had a quick look at your site and haven't been able to find such, actually I had a look at most

of the DC DC chargers manufacturers/ sellers sites and never been able to find such a comparison. Funny thing that.

 I do what I do because I enjoy it not because I have to so if I do nothing it costs nothing as I am not dictated to by sales targets or necessity.

If you did find the charts and details you wouldnt post them as they would prove you are wrong.

Ive taken the initiative to fill the gap with the Sterling and we are working on a DC/DC charger now to lower the input voltage to 12.9V to cater for those that are likely to need it between now and when the new units are available. I do not intend to say how it is to be done but I'm sure a smart salesman could not do it.

<span style="c

-- Edited by powerstream on Tuesday 7th of August 2012 07:58:54 AM

BTW Leigh
Please tell everyone how an alternator being a dumb waiter with an added dumb waiter can produce charging to algorithms for bulk absorption and float and control battery voltage and battery temperature with temperature compensation to protect the batteries to discount the benefits of a good DC /DC Charger.
Ian

Thanks for all the advice folks.

Regarding the original question.
I may have overlooked it but the vehicle type should be checked to see what the alternator is producing on start up and then again after nothing less than a half hours driving to determine if the vehicle has a drop volt alternator
If the vehicle has a drop volt alternator then it may be that the alternator only produces anywhere from 13.6V to 13.2V and if it goes to those figures then a problem will exist with charging a van battery with cable only and even with a booster fuse of 0.5V added to 13.2V only produces 13.7V which is just a float charge for most batteries and will fall well short of fully charging most batteries.
If the alternator is producing 13.6V and you add the booster fuse that would mean that you may get 14 .1V and at that voltage you can charge US Gel and US AGM that are set to accept that voltage charge but those batteries are the expensive batteries.
The 14 .4V to 14.8V range of voltage required for a lot of auxiliary batteries is far short of what can be produced and those figures are based on no allowance for voltage drop due to cable length and cable size.
Calcium if used as an auxiliary needs 15.1V to charge correctly.
The minimum cable size you should use for efficiency in most tow vehicle to caravan application is 6B&S and if less then you are not really charging your batteries correctly if at all.
This sized cable should be used even with DC/DC chargers as the minimum to give the best efficency of what you use.
Ian

-- Edited by powerstream on Tuesday 7th of August 2012 08:35:13 AM