solar regulator

#21
I use a dcdc in my Pajero because of the smart alternator and 2 x 130 amp agms in the rear tub. I have another in the camper...both fed from the one cable via fuses. Been excellent for 3 years now. Ford Ranger also say in the handbook that a dcdc charger is the best method to use for an aux battery set up. (According to a post on a forum from a bloke who owned a new ranger and asked for a please explain. ). Redarc now produce a 50amp dcdc charger and I,d expect others will have more powerful ones to come.
 
#22
Nick use this site to get an idea mate http://www.voltagedropcalculator.com.au/

if you work on 10amp @ 14v over 4mtr and compare say 4mm cable (1.81) you lose 0.75v, if you up it to say 8B&S (7.91) you lose just 0.17v.

Handy for working out your cable runs.
Thanks for the calculator that will be very handy cheers !
so i think the cable is apox 6mm ,as i have it in conduit i can't see the size , i presume there's no right or wrong in this case I.E minimum size cable .
so i'm probably losing 0.26 V. Using the calculator if i drop the volts back to 13. V as i dont have the smartcharge turn off, the voltage drop does not change just the watts go from 140w to 130 w .
 
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cam04

Well-Known Member
#23
Given a single AGM can easily take 30A on it's own once you start trying to charge a couple+ behind a 25-40a DCDC things get rather slow, that is why a VSR will always charge a aux battery to 80% way faster then a DCDC but a DCDC will get the last 20% faster. It is a myth that a VSR can't fully charge a battery.
.
Which is the precise reason things like SmartPass where invented to work with DC chargers. Why wouldn't you want the best of both worlds with a fast bulk phase and a proper 3 stage charge per the battery manufacturer's recommendation? I agree Lead Acid Flooded cell deep cycle batteries can fully charge off a constant 14.4v alternator feed but I am yet to find a Deep cycle AGM battery manufacturer which doesn't strongly recommend a 3 stage charge, and they all agree that an alternator can't fully charge them.

Just google 'charge deep cycle AGM battery' for pages of manufacturer's specs.
 
#24
Which is the precise reason things like SmartPass where invented to work with DC chargers. Why wouldn't you want the best of both worlds with a fast bulk phase and a proper 3 stage charge per the battery manufacturer's recommendation? I agree Lead Acid Flooded cell deep cycle batteries can fully charge off a constant 14.4v alternator feed but I am yet to find a Deep cycle AGM battery manufacturer which doesn't strongly recommend a 3 stage charge, and they all agree that an alternator can't fully charge them.
At some stage you have to ask how much is too much to spend on charging a battery when you know that the vehicle plus solar will fully charge your battery for camping etc ..... maybe different for you , but for me $ 600 +$ 300 + is money i could spend on more pressing items . cheers
 
#25
At some stage you have to ask how much is too much to spend on charging a battery when you know that the vehicle plus solar will fully charge your battery for camping etc ..... maybe different for you , but for me $ 600 +$ 300 + is money i could spend on more pressing items . cheers

Just depends on how much is too much Nick.. I,ve had winches on every vehicle I,ve owned or worked from for the last 25 years. My own vehicle now doesnt have one. Cant see the point in spending $1000+ just to pull someone else out of trouble. My choice. My electrical set up on the car and camper would easily be$3000 worth. I could just as easily bought cheap shit and done it for half the price. Working as a comms tech taught me the value of quality equipment and overdone is better than under done. Been camping before and had stuff all sun for over 4 days...solar not keeping up. Shit....I even carry a 240v 25amp Projecta charger and a 1kw yammie generator....
 

cam04

Well-Known Member
#26
Looking after your gear and not taking shortcuts pays you back every time. At any given time on a touring trip I would have similar money invested in the foodstuffs, meat and grog in my two fridges as I do in the elecs. Maybe buy a flooded cell deep cycle and keep it well charged with a VSR? Cheaper all round. There's plenty of ways to skin a 12v cat. Solar is an excellent way to top off an AGM - if you can keep the load off them long enough to achieve it.
 
#27
Which is the precise reason things like SmartPass where invented to work with DC chargers. Why wouldn't you want the best of both worlds with a fast bulk phase and a proper 3 stage charge per the battery manufacturer's recommendation? I agree Lead Acid Flooded cell deep cycle batteries can fully charge off a constant 14.4v alternator feed but I am yet to find a Deep cycle AGM battery manufacturer which doesn't strongly recommend a 3 stage charge, and they all agree that an alternator can't fully charge them.

Just google 'charge deep cycle AGM battery' for pages of manufacturer's specs.
Cam I think it's easy to confuse things, in our 12v vehicle setups it's important to understand we are NOT charging batteries we are maintaining them and that is what a car alternator is designed to do. If you are discharging your battery to a point where you do need a charge it with a charger you need to rethink your loads and the requirement.

To quote some Manufacturers like Optima / Fullriver / Century;

alternators have no problem recharging an OPTIMA if it has an at rest voltage of 10.5 or greater.
constant current charger can also be used... See FIGURE 2 below for the recommended constant current charge profile.
Constant Voltage Charging This method charges a battery at a maximum voltage, typically from 13.8V to 15V and a maximum current depending on the charger specification.
I am yet to find a single Manufacturer that states an alternator cannot fully charge a battery, and you won't as its a nonsense as an alternator works in the absorption profile range which is what charges the battery to near full and then float keeps it topped up to prevent overcharging. In a vehicle where there is ALWAYS a load you don't need float as the load is sufficient to prevent overcharging.

Battery manufacturers recommend 3-7 stage chargers because people don't understand whats happening and its good for warranty purposes. If you discharge a battery fully it needs to go on a charger no doubt, if you are maintaining a battery it doesn't as even on your 3 stage charger it will immediately goto the maintenance cycle which is the exact same absorption profile of your alternator so you are not even using the 3 stages.

For you dropping $500-1000 on a DCDC might seem like a good investment and more power to you but I would rather use that money on good high quality solar panels etc and use a VSR.

My batteries will last every bit as long as yours and I won't ever have power issues I can promise you that.
 
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Tink

Well-Known Member
#28
In regards to cable size from VSR to the 2nd deep cycle battery , its apox 3/3.5 meters in length .
what size should i have or what would be the minimum size ? NO dcdc charger
cheers
Two important things to know.
You need to measure the distance between your batteries AND THEN DOUBLE THAT DISTANCE to calculate your optimum cable size. For a 12 volt system, you measure both the positive distance and the return distance.
Cable sizing is all over the place. There is both normal 6mm cable which is true 6mm squared and then there is 6mm AUTO which is only 4.59mm2 because they measure the insulation as well as the copper. Just be cautious.
Tink
 
#29
Two important things to know.
You need to measure the distance between your batteries AND THEN DOUBLE THAT DISTANCE to calculate your optimum cable size. For a 12 volt system, you measure both the positive distance and the return distance.
Cable sizing is all over the place. There is both normal 6mm cable which is true 6mm squared and then there is 6mm AUTO which is only 4.59mm2 because they measure the insulation as well as the copper. Just be cautious.
Tink
Heah
He doesn't have to return the negative back to the battery he could always earth it at the vsr right....????

Like my fridge,earthed @ the tub....
 

Tink

Well-Known Member
#30
Heah
He doesn't have to return the negative back to the battery he could always earth it at the vsr right....????

Like my fridge,earthed @ the tub....
Doesn’t matter where it is earthed, still need to double the distance between batteries, to calculate voltage drop and determine correct cable size.
Tink
 
#31
Just depends on how much is too much Nick.. I,ve had winches on every vehicle I,ve owned or worked from for the last 25 years. My own vehicle now doesnt have one. Cant see the point in spending $1000+ just to pull someone else out of trouble. My choice. My electrical set up on the car and camper would easily be$3000 worth. I could just as easily bought cheap shit and done it for half the price. Working as a comms tech taught me the value of quality equipment and overdone is better than under done. Been camping before and had stuff all sun for over 4 days...solar not keeping up. Shit....I even carry a 240v 25amp Projecta charger and a 1kw yammie generator....
Bigfish not sure what you are leading to :confused: ?? Quote ~ had stuff all sun for over 4 days...solar not keeping up ~ ?
~ I use a dcdc in my Pajero because of the smart alternator and 2 x 130 amp agms in the rear tub. I have another in the camper ~
~..I even carry a 240v 25amp Projecta charger and a 1kw yammie generator ~ end Quote .
It would sound that you are a slave to your power requirements ..... lol :D:D
myself i would prefer the KISS method...
No argument with buying quality equipment here ;) I guess it comes down to how much your prepared pay & justify to yourself .
cheers
 
#32
Two important things to know.
You need to measure the distance between your batteries AND THEN DOUBLE THAT DISTANCE to calculate your optimum cable size. For a 12 volt system, you measure both the positive distance and the return distance.
Cable sizing is all over the place. There is both normal 6mm cable which is true 6mm squared and then there is 6mm AUTO which is only 4.59mm2 because they measure the insulation as well as the copper. Just be cautious.
Tink
So what would be optimum size wire/cable for 7 meters length charging 2nd battery ( 100ah ) via a VSR isolator switch ? currently using 4.58mm2 re picture , A present I don't have any issues with charging D/C battery but would change the size if you think i'm losing out w; cable size & have planes on turning off smartcharge at some stage ( px 2012 ranger )
thanks would appreciate to know what your thoughts are .
cheers nick
 

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#33
Nick..
Bigfish not sure what you are leading to :confused: ?? Quote ~ had stuff all sun for over 4 days...solar not keeping up ~ ?
~ I use a dcdc in my Pajero because of the smart alternator and 2 x 130 amp agms in the rear tub. I have another in the camper ~
~..I even carry a 240v 25amp Projecta charger and a 1kw yammie generator ~ end Quote .
It would sound that you are a slave to your power requirements ..... lol :D:D
myself i would prefer the KISS method...
No argument with buying quality equipment here ;) I guess it comes down to how much your prepared pay & justify to yourself .
cheers

You were questioning how much is too much money to spend on a system. Like I said, that is up to the individual. Like buying a 4wd. I cant see the point in buying the latest 2 litre wizz bang for $80,000. My system is simple Nick..might not sound like it to you but having installed solar systems for communication towers around the country I have a small system for camping that allows me fexibility, power when ever I need it and complete peace of mind when camping remote that I have backup if needed. I also believe in the KISS principle...what is simple for me may be complicated for you and visar-versa.
Cheers
 

Tink

Well-Known Member
#35
So what would be optimum size wire/cable for 7 meters length charging 2nd battery ( 100ah ) via a VSR isolator switch ? currently using 4.58mm2 re picture , A present I don't have any issues with charging D/C battery but would change the size if you think i'm losing out w; cable size & have planes on turning off smartcharge at some stage ( px 2012 ranger )
thanks would appreciate to know what your thoughts are .
cheers nick
If just using a VSR, which is nothing more than a smart switch, it doesn’t charge anything or boost anything, but is all I have ever used, then have a look at this link for your calculations
http://www.voltagedropcalculator.co...t=&fldvoltage=12&fldcrosssection=&reset=Reset

7 metres at 12 volts and 20 amps using 8 B&S you lose 0.62 volts
7 metres at 12 volts and 20 amps using 6 B&S you lose 0.35 volts
7 metres at 12 volts and 40 amps using 8 B&S you lose 1.23 volts
7 metres at 12 volts and 40 amps using 6 B&S you lose 0.71 volts

Depending on how low your battery is, and how much spare capacity your alternator has, will determine how many amps are being pumped into your battery. The battery will only take what it needs and may only take high amps for a short period.

My choice would be 6B&S.

Tink
 
#36
Nick my vote would be to use 6B&S as well, it's what I use in all my rigs and I have never had any drama's with voltage drop and I also charge a battery in my camper trailer from the ute on the road. At the very least don't go below 8B&S.
 

cam04

Well-Known Member
#40
Cam I think it's easy to confuse things, in our 12v vehicle setups it's important to understand we are NOT charging batteries we are maintaining them and that is what a car alternator is designed to do. If you are discharging your battery to a point where you do need a charge it with a charger you need to rethink your loads and the requirement.

To quote some Manufacturers like Optima / Fullriver / Century;





I am yet to find a single Manufacturer that states an alternator cannot fully charge a battery, and you won't as its a nonsense as an alternator works in the absorption profile range which is what charges the battery to near full and then float keeps it topped up to prevent overcharging. In a vehicle where there is ALWAYS a load you don't need float as the load is sufficient to prevent overcharging.

Battery manufacturers recommend 3-7 stage chargers because people don't understand whats happening and its good for warranty purposes. If you discharge a battery fully it needs to go on a charger no doubt, if you are maintaining a battery it doesn't as even on your 3 stage charger it will immediately goto the maintenance cycle which is the exact same absorption profile of your alternator so you are not even using the 3 stages.

For you dropping $500-1000 on a DCDC might seem like a good investment and more power to you but I would rather use that money on good high quality solar panels etc and use a VSR.

My batteries will last every bit as long as yours and I won't ever have power issues I can promise you that.
In a perfect world they might. If you never discharge past 70%, if you religiously drive 7 hrs straight away to recharge to 100%, then maybe you might keep pace for a while. In the real world I have a ute with a fridge that never gets turned off, my camping consists of a lot of stop start driving, short day trips, wet weather and regular short charging and all that ends up in sulphation which is completely normal. I have mentioned in another post just how the walkdown sulfation charging quickly hurt one of my Optimas and how I had to religiously cycle it on a mains charger to keep it in good condition because the alternator couldn't. The why bit is that constant 14.4v (I also have a ranger) is perfectly fine for an initially perfect battery which is returned religiously and immediately to 100% SOC. All of which is a complete fairy tale in the real camping world. Our batteries are short charged all the time and they sulphate because of it. I see your solar panels are punching in enough voltage to help out with sulphation, but the fact remains that 14.4v is NEVER going to approach anything like an equalisation phase (15.2-16v) which AGM batteries need to combat sulphation caused by short charging in the real world, and every single 14.4v short charge will continue to return less and less AH capacity. The smartpass/DC charger is also faster to 100% SOC (the last 5% is the important bit for sulphation) than an alternator only, and it conditions it to boot, thus prolonging battery life again.
I am happy with mine, you are happy with yours. I have spent a lot of years with yours as well and there isn't a snowflake's chance in hell it will keep an AGM alive as long "in the real world" in the absence of panels and mains chargers to make up for the shortcomings of minimum voltage charging. This isn't a bench test.
For my money I also get automatic conditioning and charging of the upstream start battery off the panels, automatic jump starting if needed, downstream users separated from the charge profiles, battery protection cutout circuit, mppt charging, combined solar/alternator charging and various other toys so it isn't remotely a fair $ for $ comparison either.
I'm not selling them, they certainly aren't the ONLY way of doing anything, and I have no skin in the game, but I am a fan after having made the change and not having to artificially supplement my charge requirements anymore due to my heavy use of AGM's.
 
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