batteries

12roam · Veteran Member

batteries

Tony Bev · Guru

Hello 12roam

Disclaimer
I am not a techie

A normal AGM battery, with normal battery terminals, (same as your car battery terminals) is known in layman talk as a hybrid battery which is designed to start your car
As AGM also has deep cycling properties, then it can also be used as a deep cycle battery, it will normally have some description indicating that it is a starting battery

A designated AGM deep cycle battery usually has flat posts, where you screw a bolt into the battery terminal to keep the leads on.
This battery is a better deep cycle battery than the hybrid type battery.
You can if you wish purchase upright post that will screw into a flat post battery, and use it for starting purposes, but it is not as good as a designed starting battery
AGM Hybrid.jpg AGM Deep Cycle.jpg
You can see the difference in the pics

The battery which is designed as a starting battery (black one), although it has screw on posts, says in the description of its ebay page that it has CCA (Cold Cranking Amp) capabilities

The battery which is designed as a deep cycle only battery (red one), does not mention CCA, but mentions AH (Amp Hours)

Hope that this info helps you out, but I am sure that the techies will come along and explain it all in a precise manner

Joe50 · Guru

Like Tony, I am not a techie but from what I've researched and gleaned from the experts on this forum, a deep cycle battery is what you need for your intended usage. Deep cycle batteries are designed to supply power at a (relative) steady rate over a long period, and from my observations most use AGM (Absorbent Glass Mat) technology. It seems to me that the term "AGM battery" is just another way of describing a deep cycle battery, and a "deep cycle battery with AGM technology" is just marketing spin. If its capacity is described in Amp/Hours then it's safe to assume it's a deep cycle battery.

Cheers
Joe

12roam · Veteran Member

Thanks for that guys What I gleaned off the web later in the day confirms what you guys are saying. A standard AGM is good for constant draw and recharge but at a shallow rate. ie a starter battery. as you guys say. A deep cycle AGM battery can draw down further charge faster and last longer unlike a standard deep cycle battery. I found that there are actually 3 types of deep cycle. Appreciate you guys taking the time to answer my query, The different articles I was reading earlier in the day were conflicting each other. Now I will just have to get the correct battery box for leads in from my solar, and a shop can do that after some more digging.
Thanks again guys.

John

macka17 · Guru

I've got2 x NZ70z Battery's in back of ute
for Waeco. int lights etc.

Have a 40a Charger wired in for mains. and dual controller from front.
80w panel on roof.

Never had a problem, and those 2 x battery's are both second hand starter battery's from boat and Spare out of Patrol

I've been using battery's of differing types and panels the same for a lot of yrs.
Marine.Home and caravan.

I've come to the conclusion that.
AS long as you don't box youself into the state that your battery's HAVE to be in enclosed spaces INSIDE van.

Just the std wet cells. coupled to the panels are fine
I've had Deep cycle. AGM etc. costing a lot more than std.

funnily though. My std battery's coupled to panels in both yachts and cars as backups.
give me an average of 6 to 7 yrs of life.
and generally longer than deep cycle on boats.
Why spend extra when these do the same job for a good period of time.

I reckon it's all a con. When NOT sealed INSIDE.
they are a wasted expense.
Something on the lines of "I gotta bigger car than you".

I have one 100a AGM inside van. All the rest are wet cells.

12roam · Veteran Member

Thanks Macka17 That is sure food for thought. Setting up for free camping could be costly reading all the bumf they hand out and what they say you have to have.

iana · Guru

One of the differences between an AGM (absorbed glass mat) battery and others, is that the plates are wrapped with glass matting, to with stand vibration and harsh treatment. The cells are then sealed, but have a pressure relief valve set into the case. This means no gas , or electrolyte is leaked out unless it is violently charged or discharged, and therefore no electrolyte loss. The battery can be mounted anyway up or on its side.
The cheaper ones, the relief valve is set down to a pressure of about 10 psi, the case only able to take this pressure. The ones with the round cells, are up at about 40 psi and can handle the rougher and more violent charge or discharge, I believe were developed for the military in times past. The case design of course reflects the price.

12roam · Veteran Member

So If I go that way an AGM deep cycle is more robust plenty of info you guys have given me. Setting up for free camping is not all that free, when you tot up the cost to realistically do it. I've just priced solar of all types and shapes to get the lowdown and some of them are expensive but they work. Now I'm getting a little bit of knowledge on the subject of free camping I'll have to jot down a few scenario's on a spread sheet and go from there.
thanks guy's for your info.

PeterD · Guru

Tony Bev wrote:

A normal AGM battery, with normal battery terminals, (same as your car battery terminals) is known in layman talk as a hybrid battery which is designed to start your car
As AGM also has deep cycling properties, then it can also be used as a deep cycle battery, it will normally have some description indicating that it is a starting battery

A designated AGM deep cycle battery usually has flat posts, where you screw a bolt into the battery terminal to keep the leads on.
This battery is a better deep cycle battery than the hybrid type battery.

Not necessarily so. Many deep cycle batteries have battery posts. The only way to find out what duty the battery is designed for is to read the manufacturers literature. Also there are many types of AGM deep cycle batteries. Most good manufacturers make batteries for standby and cyclic use. Always opt for batteries designed for cyclic use, they are more expensive but last a lot longer

Read through this and also this.

12roam · Veteran Member

Thanks Peter could have been caught out with that. there is some good reading in them 2 files. I've copied them into a word document and will read them at my leisure.

Aus-Kiwi · Guru

You can be caught out the other way a swell with batteries . I have a modified car with over 700 HP . I thought fitting a well known battery with all the other so called go fast bits . Well it would turn over . BUT not start ! Even with double the size battery cables and 7.8 compression . Being a deep cycle type battery used for starting there wasn't enough amps for ECU for ignition / injector drivers !! Put normal 650 CCA $130 battery back in . Started first turn . Saving about $300. The old thing about horses for courses applies here . Cost of solar ? Check eBay .i have bought 2 X 120 watt panels for just over $200 with connecrors and wire ..

PeterD · Guru

12roam wrote:
I've copied them into a word document and will read them at my leisure.

A zipped version of all the above current English version battery related Web pages, graphics and spreadsheet on this Web site can be easily down loaded to your computer. Just create a directory for the FAQ and unzip into it. The file size is approximately 1,024 KBytes and was last updated on September 10, 2016.

Battery.Zip

That info is on the home page

12roam · Veteran Member

Your right about horses for courses, I've been looking at solar blankets the one that would have suited my purpose $1500 thank you very much! I trade currency pairs on forex and have been looking at the whole box and dice, for my 40lt Engel lights and so I can trade on my laptop while free camping. think I've been sniffing too much angel dust. laptops eat power, Now I've got a better handle on this it's time to itemize my power usage. with the battery I prefer and see whats possible.

Thanks again
John

T1 Terry · Guru

12roam wrote:
Your right about horses for courses, I've been looking at solar blankets the one that would have suited my purpose $1500 thank you very much! I trade currency pairs on forex and have been looking at the whole box and dice, for my 40lt Engel lights and so I can trade on my laptop while free camping. think I've been sniffing too much angel dust. laptops eat power, Now I've got a better handle on this it's time to itemize my power usage. with the battery I prefer and see whats possible.

Thanks again
John

Just to throw another bit in to get you thinking outside the box, consider a lithium battery, cost might be twice that of a deep cycle AGM battery, but you get twice the useable capacity, much faster recharging and lighter, and takes up less room, and lasts a lot longer. We freedom camp as much as possible, hate being herded into a caravan park, we rely on solar but have alternator back up if absolutely necessary, we have never run out of battery and the house battery is also our start battery.

Think outside the square if you are starting from scratch, lithium is reliable and long lasting enough to actually transfer it to the next rig, so it is a long term investment that will pay dividends over and over even though the original investment may seem high.

T1 Terry

Jaahn · Guru

Hi smile

From my experience. AGM batteries for deep cycle use are better than ordinary LA in two ways. They accept a bigger charge easily with less voltage rise and they give out the power with less voltage drop. Those two things mean you get more out of the same solar panels if you use a MPPT regulator. Bonus power wink Similar to the advantage of Lithium batteries but not as good or not as expensive either. Buy the batteries on Ebay for a good price.

Solar panels ! Been said before but worth saying again. Buy them on ebay. Half the price or even a third of the price at retail stores. They all work OK from my testing of the ones I have bought. Free delivery too usually to your door. Some people say you get what you pay for but that never applies to anything IMHO. Come in sucker does though.

SOLAR BLANKET ?? confuse Just burn a few $100 notes first to get the feel of it, then buy some panels off ebay and spend the rest on wine.

Jaahn

T1 Terry · Guru

Jaahn wrote:
Hi
From my experience. AGM batteries for deep cycle use are better than ordinary LA in two ways. They accept a bigger charge easily with less voltage rise and they give out the power with less voltage drop. Those two things mean you get more out of the same solar panels if you use a MPPT regulator. Bonus power Similar to the advantage of Lithium batteries but not as good or not as expensive either. Buy the batteries on Ebay for a good price.
Solar panels ! Been said before but worth saying again. Buy them on ebay. Half the price or even a third of the price at retail stores. They all work OK from my testing of the ones I have bought. Free delivery too usually to your door. Some people say you get what you pay for but that never applies to anything IMHO. Come in sucker does though.
SOLAR BLANKET ?? Just burn a few $100 notes first to get the feel of it, then buy some panels off ebay and spend the rest on wine.
Jaahn

You have such a way with words Jaahn :lol: As far as the solar panels, look for the Vmp in the specs sheet, lead acid batteries including AGM require a Vmp of 18v or more at the STC rating, this is the most common rating listed and has nothing to do with how the operate in actual full sun. As the panel warms up above the 20*C the STC rating is the Vmp drops, this is the voltage where you get the maximum power (amps), it drops off like a rock after this point but reasonably steady before it, so the Imp (max amps) is what you are looking for, don't expect much more than this figure even with the MPPT smoke and mirros show, it does happen sometimes but that is more due to the sun and cloud reflection than the controller, PWM controllers sometimes see the same thing.

The reason for the higher Vmp requirement, as the panel heats the Vmp drops, a panel in full sun can climb to 70*C or more internally where the actual action is happening, outside atmospheric temp or even surface temp of the panel will be less as there is surface cooling. A lead acid (including AGM) require around 14.4v to be available at the battery terminals, that can't happen if the solar panel is putting out even that voltage as there are losses along the way, cabling, the controller itself, particularly MPPT because they require power to run, so a panel with a Vmp of 16v is not much good for lead acid (including AGM) batteries, but fine for lithium, they don't require more than 13.6v unless you are chasing a return to 100% full and lithium never really need that.

T1 Terry

PeterD · Guru

Terry, can you please explain that gobbledygook?

12roam · Veteran Member

Well guys this is getting more complicated, very glad I asked the question now, instead of just diving in and buying something only to regret it later. Will be doing a bit of study on this before I go any further. How I intend to use it time of year I intend to use it. and how long I intend to keep my present trailer, and what will be the options I prefer for the future. I could go for ever with this but time is precious and you never get it back. The only 2nd battery system I will have in what I have now will be in the back of my Navara next to my Engel. If It was in my trailer. I probably would look at a Lithium, and the idea of putting a lithium in my trailer probably Ok but neither batter would charge well with both drawing on the alternator. I could put a Lithium in the back of my car I will have to research that possibility. The prices for the lithium would probably drive me to buy one on line probably a 100 to 150 ah If I can fit it in between the battery locking clamps. and then buy a battery box to suit locally to make sure it was correct. Now I've got homework to do.

Thanks guys
John

Jaahn · Guru

T1 Terry wrote:
You have such a way with words Jaahn :lol: As far as the solar panels, look for the Vmp in the specs sheet, lead acid batteries including AGM require a Vmp of 18v or more at the STC rating, this is the most common rating listed and has nothing to do with how the operate in actual full sun. As the panel warms up above the 20*C the STC rating is the Vmp drops, this is the voltage where you get the maximum power (amps), it drops off like a rock after this point but reasonably steady before it, so the Imp (max amps) is what you are looking for, don't expect much more than this figure even with the MPPT smoke and mirros show, it does happen sometimes but that is more due to the sun and cloud reflection than the controller, PWM controllers sometimes see the same thing.
The reason for the higher Vmp requirement, as the panel heats the Vmp drops, a panel in full sun can climb to 70*C or more internally where the actual action is happening, outside atmospheric temp or even surface temp of the panel will be less as there is surface cooling. A lead acid (including AGM) require around 14.4v to be available at the battery terminals, that can't happen if the solar panel is putting out even that voltage as there are losses along the way, cabling, the controller itself, particularly MPPT because they require power to run, so a panel with a Vmp of 16v is not much good for lead acid (including AGM) batteries, but fine for lithium, they don't require more than 13.6v unless you are chasing a return to 100% full and lithium never really need that.
T1 Terry

Hi smile

I will leave the rest of Terrys statements, but will comment on MPPT regulators/controllers. MPPT is a tried and proven technology that works and is used in every solar inverter that is grid connected to extract the maximum out of the system. Also used in all good controllers for off grid use too, for both LA and lithium batteries. It just uses some power that is wasted otherwise, particularly when the battery voltage is lower. biggrin

However like most good things, sellers out there can tell porkies about how they work. Recommend silly combinations of panels to battery voltage. They also tell porkies about what they are selling too. So buying a cheap MPPT regulator from ebay or some suppliers will get you a standard PWM regulator with a new fancy description. No smoke and mirrors they just are not MPPT regulators. They do not have the electronic parts inside to work as MPPT.

So people have been disapointed with many cheap MPPT regulators bought from lots of places. Do not buy one unless you get a recommendation that they are genuine quality MPPT units. furious Some retailers also sell the dogey ones too.

MPPT regulators should not use any noticable extra power to work.

Jaahn

-- Edited by Jaahn on Sunday 2nd of October 2016 09:25:28 PM

T1 Terry · Guru

PeterD wrote:
Terry, can you please explain that gobbledygook?

Umm...... I thought by adding what the abbreviations meant it would be easier to follow. Solar panels are tested on a light box at 25*C, I think I posted 20*C before but it actually 25*C. They flash the light on and off again and take the readings, this is so the solar panel will not heat up as the reading drop with an increased panel temperature, hard to sell a panel that in reality only produces 70w not the 100W the panel putout on the quick flash from the light box, so guess which figure they publish wink

Manufactures of better grade panels actually give another measurement, NOCT, Normal Operating Cell Temperature, not quite sure where the outside temp remains at 20*C in full sun in the middle of summer, but that is the test conditions.... and they actually get to pick what cell temperature they advertise these readings, there are no specifications for that. Here is an example so you can see what I mean in this PDF

OK, towards the bottom there is a percentage of loss as the temp increases shown as a percentage per *C, this is what the graph looks like, the lines represent 1v increments so you can see where the output amps start to drop off as the temperature increases, the 40*C used by Kyocera is not actually a realistic cell temperature in Aust, in full summer sun it's more like 70*C plus and Kyocera know they can get up to those temperatures, that is why they show it on their graph.

Kyocera 140w panel with single voltage increments.jpg

T1 Terry · Guru

Jaahn wrote:
T1 Terry wrote:
You have such a way with words Jaahn :lol: As far as the solar panels, look for the Vmp in the specs sheet, lead acid batteries including AGM require a Vmp of 18v or more at the STC rating, this is the most common rating listed and has nothing to do with how the operate in actual full sun. As the panel warms up above the 20*C the STC rating is the Vmp drops, this is the voltage where you get the maximum power (amps), it drops off like a rock after this point but reasonably steady before it, so the Imp (max amps) is what you are looking for, don't expect much more than this figure even with the MPPT smoke and mirros show, it does happen sometimes but that is more due to the sun and cloud reflection than the controller, PWM controllers sometimes see the same thing.
The reason for the higher Vmp requirement, as the panel heats the Vmp drops, a panel in full sun can climb to 70*C or more internally where the actual action is happening, outside atmospheric temp or even surface temp of the panel will be less as there is surface cooling. A lead acid (including AGM) require around 14.4v to be available at the battery terminals, that can't happen if the solar panel is putting out even that voltage as there are losses along the way, cabling, the controller itself, particularly MPPT because they require power to run, so a panel with a Vmp of 16v is not much good for lead acid (including AGM) batteries, but fine for lithium, they don't require more than 13.6v unless you are chasing a return to 100% full and lithium never really need that.
T1 Terry
Hi
I will leave the rest of Terrys statements, but will comment on MPPT regulators/controllers. MPPT is a tried and proven technology that works and is used in every solar inverter that is grid connected to extract the maximum out of the system. Also used in all good controllers for off grid use too, for both LA and lithium batteries. It just uses some power that is wasted otherwise, particularly when the battery voltage is lower.
However like most good things, sellers out there can tell porkies about how they work. Recommend silly combinations of panels to battery voltage. They also tell porkies about what they are selling too. So buying a cheap MPPT regulator from ebay or some suppliers will get you a standard PWM regulator with a new fancy description. No smoke and mirrors they just are not MPPT regulators. They do not have the electronic parts inside to work as MPPT.
So people have been disapointed with many cheap MPPT regulators bought from lots of places. Do not buy one unless you get a recommendation that they are genuine quality MPPT units. Some retailers also sell the dogey ones too.
MPPT regulators should not use any noticable extra power to work.
Jaahn

-- Edited by Jaahn on Sunday 2nd of October 2016 09:25:28 PM

It is deceiving to compare the operation of a grid tie solar controller to a battery charging solar controller, the operation is in no way similar. Grid tie solar MPPT boosts the voltage from the solar to match a set voltage, RV battery charging MPPT step down the voltage to match a varying battery voltage. 2 completely different functions that are in no way comparable, RV MPPT units can not boost voltage, they won't even function unless the solar voltage is much higher than the battery voltage, Victron require a minimum of 5v differential, easy for a dead flat lead acid battery as that only requires a panel voltage of 15v, but a battery up around the 13v mark requires in excess of 18v from the panels and it must be able to maintain that voltage under load, or the unit will drop out. Many reports across multiple forums where MPPT has failed to deliver on less than good solar days until the battery was nearly flat, then it would kick in. not good when there is only limited sun time left in the day. There is no such thing as an electronic device that doesn't waste some power, the more it has to do the more it wastes or actually converts to heat, if that wasn't the case then why do MPPT controllers have such big heat sinks and often fans that PWM controllers of the same capacity don't need so they don't have them?

MPPT may work ok for a 1kW plus system in a very cold climate, but not RV size systems in a very hot climate like Australia, they can not and do not produce more than a comparable quality PWM controller that is at far better price.

Match the panel voltage to battery voltage required and use a good quality PWM controller, spend the $$ left over on more solar, you will be way I front.

T1 Terry

Jaahn · Guru

It is deceiving to compare the operation of a grid tie solar controller to a battery charging solar controller, the operation is in no way similar. Grid tie solar MPPT boosts the voltage from the solar to match a set voltage, RV battery charging MPPT step down the voltage to match a varying battery voltage. 2 completely different functions that are in no way comparable, RV MPPT units can not boost voltage, they won't even function unless the solar voltage is much higher than the battery voltage, Victron require a minimum of 5v differential, easy for a dead flat lead acid battery as that only requires a panel voltage of 15v, but a battery up around the 13v mark requires in excess of 18v from the panels and it must be able to maintain that voltage under load, or the unit will drop out. Many reports across multiple forums where MPPT has failed to deliver on less than good solar days until the battery was nearly flat, then it would kick in. not good when there is only limited sun time left in the day. There is no such thing as an electronic device that doesn't waste some power, the more it has to do the more it wastes or actually converts to heat, if that wasn't the case then why do MPPT controllers have such big heat sinks and often fans that PWM controllers of the same capacity don't need so they don't have them?

MPPT may work ok for a 1kW plus system in a very cold climate, but not RV size systems in a very hot climate like Australia, they can not and do not produce more than a comparable quality PWM controller that is at far better price.
Match the panel voltage to battery voltage required and use a good quality PWM controller, spend the $$ left over on more solar, you will be way I front.
T1 Terry

Hi

MPPT ---- they can not and do not produce more than a comparable quality PWM controller ---
A big statement here that implies all the major manufacturers, including all Aussie ones are on the wrong track !! Hmmmm... hmm

So a couple of observations to make from my experience. A PWM regulator and standard panels are tolerant of poor setup. ie undersize wire and bad connections. The output is sub standard but will work so so under these conditions as the excess panel voltage provides the extra power needed. A bad setup but most people do not notice the problems.
If you put a MPPT regulator on a poor system like that it will not provide any benefit. To get the extra power available you must have proper size wiring and connections both from the panels to the regulator and to the battery to maintain low voltage drops. The MPPT regulator senses the voltages both ways to judge its actions to use the extra voltage differences to get the extra power.

So as Terry said if you have a marginal system then get a PWM regulator and save the money. Or setup a good quality system and go for better power with a proper quality MPPT regulator. I am happy mine is working OK, and my last system did too after I made it work properly. Your choice really. biggrin
Jaahn

12roam · Veteran Member

Thanks Guy's I have a fair handle on my requirements now. just to do a little bit further research on solar wiring and that will handle where to sit the regulator and I'll be ready to buy what I need.

Thanks allot has been very helpful

John

T1 Terry · Guru

12roam wrote:
Thanks Guy's I have a fair handle on my requirements now. just to do a little bit further research on solar wiring and that will handle where to sit the regulator and I'll be ready to buy what I need.

Thanks allot has been very helpful

John

Hi John, no matter what choice of controller type, if it doesn't have separate battery voltage sensing wires it needs to be mounted as close to the battery as possible. To extend the original solar panel cable 6mm auto cable is as good as any, the original cable is 4mmsq conductor and the 6mm auto cable is 4.34mm sq, good for around 150w up to 5 mtrs. A popular connection method is up to 4 separate 6mm auto cable pieces into 50 amp Anderson plug terminals and MC4 connectors on the other end to plug the panels into, then 6 B&S cable for 10 mtrs back to the unit, another Anderson plug mounted on the drawbar and that wired to the regulator. For a bit more security, a stainless steel cable with eyelet loops each end joined to the 6 B&S cable with heatshrink every 500mm or so, an anchor point at the draw bar so a padlock can be fitted, a length of the same sort of stainless cable anchored to each panel and run back to the Anderson plug join, another padlock holds them all to that cable. It won't stop a determined thief, they will unbolt them off the roof if they really want them, but it stops the opportunity thief just walking off with your panels, just too bulky to wander off with so they give the whole idea a miss.

T1 Terry

T1 Terry · Guru

Jaahn wrote:
It is deceiving to compare the operation of a grid tie solar controller to a battery charging solar controller, the operation is in no way similar. Grid tie solar MPPT boosts the voltage from the solar to match a set voltage, RV battery charging MPPT step down the voltage to match a varying battery voltage. 2 completely different functions that are in no way comparable, RV MPPT units can not boost voltage, they won't even function unless the solar voltage is much higher than the battery voltage, Victron require a minimum of 5v differential, easy for a dead flat lead acid battery as that only requires a panel voltage of 15v, but a battery up around the 13v mark requires in excess of 18v from the panels and it must be able to maintain that voltage under load, or the unit will drop out. Many reports across multiple forums where MPPT has failed to deliver on less than good solar days until the battery was nearly flat, then it would kick in. not good when there is only limited sun time left in the day. There is no such thing as an electronic device that doesn't waste some power, the more it has to do the more it wastes or actually converts to heat, if that wasn't the case then why do MPPT controllers have such big heat sinks and often fans that PWM controllers of the same capacity don't need so they don't have them?
MPPT may work ok for a 1kW plus system in a very cold climate, but not RV size systems in a very hot climate like Australia, they can not and do not produce more than a comparable quality PWM controller that is at far better price.
Match the panel voltage to battery voltage required and use a good quality PWM controller, spend the $$ left over on more solar, you will be way I front.
T1 Terry
Hi
MPPT ---- they can not and do not produce more than a comparable quality PWM controller ---
A big statement here that implies all the major manufacturers, including all Aussie ones are on the wrong track !! Hmmmm...
So a couple of observations to make from my experience. A PWM regulator and standard panels are tolerant of poor setup. ie undersize wire and bad connections. The output is sub standard but will work so so under these conditions as the excess panel voltage provides the extra power needed. A bad setup but most people do not notice the problems.
If you put a MPPT regulator on a poor system like that it will not provide any benefit. To get the extra power available you must have proper size wiring and connections both from the panels to the regulator and to the battery to maintain low voltage drops. The MPPT regulator senses the voltages both ways to judge its actions to use the extra voltage differences to get the extra power.
So as Terry said if you have a marginal system then get a PWM regulator and save the money. Or setup a good quality system and go for better power with a proper quality MPPT regulator. I am happy mine is working OK, and my last system did too after I made it work properly. Your choice really.
Jaahn

Been doing this for quite a while now Jaahn, I have actually carried out the testing on a multitude of controllers, yes the likes of Outback and Midnite solar gear (the genuine stuff not the Chinese knock offs) really do work.... if the system is big enough, now look at the physical size and you will quickly realise the more common ones on the market simply don't have the gear required to be able to do what they claim. You just can't fit that much electronics into such a small package and handle that sort of current/voltage without a serious cooling system.... the general stuff on the market does not have a very flash cooling system at all.

There is only one Australian MPPT manufacturer that I know of and after testing the product.... I won't say more, the other Australian solar manufacturer doesn't make MPPT controllers, their product is all PWM as they came to the same results, they just don't work in Australian conditions on RV sized systems.

Don't confuse a manufacturers product that was designed as a DC to DC charger and can also be used as a solar controller, I'm staying well away from that debate yawn

T1 Terry

oldtrack123 · Guru

For T1s benefit[information

RE Quote "It is deceiving to compare the operation of a grid tie solar controller to a battery charging solar controller, the operation is in no way similar. Grid tie solar MPPT boosts the voltage from the solar to match a set voltage, [end quote ]

Grid Tie solar inverters set ups use MMPT regulators with a DC input voltage up to 500V. .!!!

They do not boost the DC ,they convert it to AC 240 /250V, & constantly sample for the PEAK POWER POINT of the array @ that time! biggrin

The output voltage can vary due to a number of factors in the supplied line, so the output voltage is far from constant

The output voltage must always be higher than the mains voltage for feedback to occur

& it is actually pushing back against the MAINS transformer voltage minus line voltage drop with a load that is constantly varying

-- Edited by oldtrack123 on Saturday 8th of October 2016 12:35:38 AM