Another battery question/charging

Only used when camping.
My issue is they just sit there for long periods not being use.
Thanks Ross

Hi Brian
Yep no what you mean P>I>T>A taking them out.
Bigger P>I>T>A buying new ones.
Have to catch up
Ross

Hi Mainey
Yes you are right they do look nice but they are hidden in behind pannels and can't be see :(

My main reason asking the question is I am worried that with daily use of the car usually at least 40min twice a day is that I will shorten their life.

When I am not using the car for a few days I have been puting the charger onto them.

I have a 50lt fridge in the back as well but usually leave it off until needed. Would I be better to leave the fridge on.?

Thanks Ross

Ross,
I leave my AGM batteries connected 24/7 with the fridge disconnected.

Connect the fridge a day or so b4 you need to use it, or put it on 240v the day before you leave to get it down to temperature.

There will be no damage to AGM's when left connected and also being charged when *not* running the fridge, you won't need to use an external charger on the AGM's.

Look at the "megapulse . com . au" website for some good information to eliminate sulphation :-)

Mainey . . .

Careful,
Because different battery 'types' require different charging regimes, there is no battery charging voltage that is best for ALL batteries.

Mainey . . .

Mainey,

Agree 100% which is way I chose a unit that is fully programmable to match the characteristics of the auxilliary battery. That is exactly why I am wary of just allowing the alternator output to charge the battery.

Matt.

Hi Matt, have you got any more info on this '3 stage booster'?Ta . doc

Ranox

From the RANOX website;
""To fully charge a lead acid battery, the charge voltage needs to be around 14.8 Volt. This figure IS *DEPENDANT* on a few factors, including battery type and actual battery temperature. However as the alternator output from most modern engines is around 13.8 to 14.1 Volt, a direct connection will never fully charge the second (remote) battery. Some vehicles even reduce this voltage further, if the ECU thinks its cranking battery is charged""

I agree, SOME battery *types* may need the larger battery voltage, example is wetcell C/C Deep Cycle batteries, but in general we are reading advertising blurb as not ALL batteries NEED this high voltage...

AGM Deep Cycle batteries definitely do NOT require the larger voltage mentioned, because they are a much lower internal resistance battery and will charge fully with a much lower voltage.

I spent $35 and increased my Alternator regulator output from 13.9v to 14.4v - it works for me.

Mainey . . .

OK Mainey, again I am not an expert in the field, but will try to explain my thinking.

Basically, a 240/12v charge (from mains or a generator), a solar panel and (with respect to battery charging) an alternator all have basically the same function. That is to provide a 12v nominal charge to your battery. Only the source of that 12v charge varies.

So if I was to ask what sort of 240/12v charger I should get, then the answer would generally be, 'get a good quality three stage charger'.

If I was to ask about a solar regulator, then the answer would be something like 'get a good quality three stage regulator'.

BUT, if I was to ask about charging from the alternator, then the answer would be 'don't worry about it, just accept what the alternator gives you'?

So why is it so important for a solar or 240/12v input to be matched to the battery's optimal charge profile, but not so important if the charging source is an alternator?

You yourself note, "As the Auxiliary AGM battery system I use gets closer to fully charged, the Steca SÖLAR regulator permits less charge to go the Auxiliary battery, hence there may be 12 Amps available at the SÖLAR panel, but only a few of those Amps is available to the Auxiliary battery system

Generally "elcheapo" solar regulators work on an ‘on’ & ‘off’ principal, this type of regulator will NOT give the same high results as constant charge SÖLAR regulators

*When using SÖLAR power, the Auxiliary battery remains fully charged at the “float” Voltage ~13.6 Volts for wetcel batteries

*If the SÖLAR regulator is a quality engineered product and has “Float” - “Boost” and “Equalize” Voltage programs, just like an expensive 3 x stage battery charger, the Auxiliary battery will be constantly maintained in a fully charged condition".

The way I see it, a three stage charger such as the Ranox do precisely what you are saying should be the case for a solar regulator. So why the difference in thinking just because the charging source is an alternator not a solar panel?

Not saying I am right, just what makes sense from my research into the issue.

Cheers,

Matt.

Right on Matt.

Everyone seems to be tied in to the idea that you need to spend mega-bucks on multi stage chargers when the vehicle alternator does the job all by itself. Just get a modest price (name brand)battery with a good warranty and throw it away every three years. The reason I say get a name brand battery is that the warranty should be good anywhere in the country and not at only on shop in your home town.

I totally dsagree a car alt will not fully charge any battery connected to it this includes the starter battery,as the regulator drops the volts going into the battery, same as the ranox add says, have had this discussion here before, and there are some people that disagree. Col

Theoretically speaking Col you are right but who cares if the battery is 100%, 98% or 95% charged as long as the battery does what you want it to do ? One of the best tests for a battery is to see how well it starts your vehicle under extreme conditions. With the battery and engine temperature at about 3 degrees and the big diesel starts easy then who cares if the battery was only 98% charged ? That's how almost every vehicle in this world gets by with the owner never using brand xyz quad bypass battery charger every month to get that 100% top up. And if you really want to give your battery a test on a cold day then try starting your vehicle with the headlights turned on.

Kiwi Kia,

Fair enough, but we are not talking about cranking batteries here, the issue is auxillliary batteries and many people DO care how fully you can charge them because it CAN make a difference.

Matt.

Kiwi kia, i care how much power is in my batteries as when i go camping in remote areas by myself and run fridges and lights i need as much power in the batteries as i can get, and i dont get that with the standard alt set up. I do get that from my christy generator, and from what the ranox unit is capable of its exactly what im looking for to give me more power. Col

Matt,
I don't believe your wrong :-)
you post ""BUT, if I was to ask about charging from the alternator, then the answer would be 'don't worry about it, just accept what the alternator gives you'?
So why is it so important for a solar or 240/12v input to be matched to the battery's optimal charge profile, but not so important if the charging source is an alternator""

My answer to that question is simple;
You do have to make a choice, you buy what you believe is the best product (you can afford) to do the job of correctly charging the Auxiliary battery system.

With (some) Alternators you can modify or change the regulator output to achieve the same result.

I've changed my Alternator output from 13.9v up to 14.4v

I also choose to use a Steca *3 stage* Solar regulator with PWM instead of an elcheapo reg with just simple on/off regulation.
Because I use the expensive ($200) Steca Regulator I don't need an even more expensive Ranox or similar brand voltage maximiser system to maintain my AGM's fully charged @ 12.8 Volts.

ps: check the rested wetcel battery voltage
@ 12.6v it's charged & no charging problem

Mainey . . .

Mainey,

At the risk of dragging this one out. I agree that the decision to purchase an expensive three stage booster is an individual one and is a matter of priorities, perceived return on investment, etc. I also assume that your solar set up is a permanent (and primary) source of power for you (I also use a Steca regulator to charge the camper trailer batteries). But for many, the vehicle's alternator is the primary source and (to me at least) it would make sense to ensure that the alternator output provides the optimal charging profile for your batteries.

That said, if we take the money issue out of it for the moment, a three stage booster between the alternator and auxiliary battery would still provide a better (fuller) charge and potentially extend the life of your battery, I believe.

I still get a bit confused when you say that a constant 14.4v from the alternator will "achieve the same result". If I apply the same thinking to a solar input, then a solar regulator the puts out a constant 14.4v will achieve the same result. A 240/12v charger that puts out a constant 14.4v will achieve the same result. Yet most seem keen to use three stage chargers on anything but the alternator.

Back to the money question, maybe if your alternator is your primary charging source then the money would be better focused on a decent three stage booster. In your case this is not so, so focusing on the solar set up is the right decision. For someone who predominantly uses powered sites or has a generator, then the decent three stage 240/12v charger is the way to go.

For me, the alternator is primary with a solar panel (and three stage regulator) providing the secondary source.

Cheers,

Matt.

Matt,

As I have previously stated, and also Derek Bester of Affordable Batteries & Radiators ‘ABR’ states (as an EO sponsor) an Alternator will *FULLY RECOVER* a discharged 12v battery !!

LINK->Battery charging ""When a battery recharges, the charge is not consistent - as a guide it will bulk charge until about 60 - 80% full and then slow down and the BALLANCE of the charge may take as long as the first 80%. In the example above, the 60 amp hours used will take roughly 2 hours to *FULLY RECOVER* on a 100 amp alternator, lets say 45 amps in the first hour and 15 amps in the next.””

My 14.4 Volts from the regulator is not a "constant" but a tapered charge from the Alternator to the Auxiliary AGM batteries, but the AGM's will *fully charge* because they are receiving more charge than they contain.

Mainey . . .

Mainey, i still will have to disagree that the alt will not fully charge your batterys. You keep referring to to only one source for your information ie Dereck Bester. As i have mentioned before i to can state names, but i do more research from many sources and my findings dispute what Derek is saying, and the ranox information adds to more than 4 sources i have used for my information. Solar is not an option for me as i usually camp in large shady areas with heaps of trees. Col

Col,
so come right out and say it....
you believe you are correct and myself and also Derek Bester (ABR) are giving WRONG information :-((

Remembering the Ranox system only works through the Alternator, so the vehicles engine MUST be running, either @ fast 'idle' at the camp site or actually driving, neither are ideal battery charging methods for people who want to camp in the one place for some time for very obvious reasons.
The Ranox website says it puts extra charge into the Aux battery system, that is not in dispute here, just because I don't need it because I get 14.4 Volts @ the Aux battery system does not mean there may be some people who may need it for any number of various reasons, all relevant to poor performance of the charging system, including cables and connections or just simply because they are charging HIGH resistance wetcell batteries, not AGM's.

When the Aux battery system is discharged (each night for lights and daily for the fridge) the Ranox system must AGAIN *replace* the lost power, so the engine has to be started and run at a quick idle to replace this power as it's used.

Solar power is more suitable to camping for long periods of time in one place because it's silent, has no ongoing costs, no need for checking if it has run out of fuel and will not overcharge the battery system when left 'on' continuously, but Solar will maintain the battery system fully charged - even when the fridge is running.
The only downside is they are initially expensive to purchase, but they have a 20 year PERFORMANCE warranty :-)


I don't believe any person or even company would actually recommend using the vehicle engine to charge the Aux batteries over solar power or even a generator when camped for reasonable periods, so Col, if you do I would like to see the recommendation "Link" placed here to end the "disputed information" you believe exists.

Mainey . . .

Hi Bruce
I understand what you are saying but the batteries are not being used so the charge is up there all the time, my main worry is being AGM batts and charging constantly off the car.
Thanks Ross

P.s say hi to rodger for us......hehehe

As said below Ross, if the batts are fully charged then they won't need charging off the car ( or charger )

I have 6 AGM's in my CT and they will stay fully charged for a couple of months before needing a top up..

Most important ( and a car setup is easier ) is to not have anything connected across the battery after charging ( including a charger ) and then depending on type of AGM it will only self discharge ( which may take months )

Gronk
Nothing is hooked up to the two batteries except a volt guage via a toggle switch.
So by me pulling the anderson plug that feeds these batts will that be enough or do you recommend pulling the batt terminals.
thanks ross

No, that will be fine........on a CT it can be hard to know what is actually connected to the batts, but as long as you are sure there's nothing connected !!

She be right Trevor. I thought we blew all the cobwebs out coming home from out west......hahahaha

Ross

What "stories"?

Hi Matt M, for a starter, your statement of “That is exactly why I am wary of just allowing the alternator output to charge the battery”

This statement is based on what?

Do you know of people who are having problems with their batteries not being charged properly when using nothing more than their vehicle’s alternator as the charging source?

If you do then there is a good chance the problem is more about an incorrect installation or use and not an inability of an alternator to do the job.

I know of thousands of dual battery users who have nothing more than their alternator as the charging source for both the cranking battery and their auxiliary battery(s) and have had many years of of use from the dual battery set ups with out any problems.

This crap that an alternator won’t fully charge automotive batteries is a myth based on half truths that have absolutely nothing to do with an alternator’s ability to fully charge a battery.

Drivesafe,

The statement was based on my not understanding why a 'three-stage' charging profile seems to be so important for solar input or input from a 240/12v charger and not so from an alternator.

I don't doubt the ability of an alternator to ADEQUATELY charge an auxilliary battery, but am yet to be convinced that a three stage booster won't provide a better result. Now I accept Mainey's contention that the additional cost of a three stage booster may not be justified in terms of increased performance, but that is a personal decision I guess. At no stage did I suggest that using direct input from the alternator would give problems, just that it MIGHT not be the most efficient or effective way of doing it.

So let me ask you a question. You say that, "This crap that an alternator won’t fully charge automotive batteries is a myth based on half truths that have absolutely nothing to do with an alternator’s ability to fully charge a battery."

This statement is based on what?

Cheers,

matt.

Hi again Matt M, you still have not answered why you THINK an alternator may not be the best way to fully charge a battery.

Next, repeated there are statements made, including in this thread that infer an alternator can not fully charge a battery.

Most of the time the statements are made by people who don’t really have an idea of what they are talking about and are just repeating what they have read elsewhere or they have manipulated info for their on gains.

A perfect example of this is a statement that appears on a regular basis that goes “an alternator can not charge a battery to more that about 70%”.

This statement has a basis of truth in that there are large numbers of vehicles with batteries that are lucky to have as much as a 70% charge, but this has nothing to do with the an alternator’s ability to fully charge a battery, the fact is that the alternator in these vehicles has not been given the chance to fully charge the battery because the vehicle has not been driven long enough after each start, to get the battery fully charged.

This has nothing to do with an alternators ability to fully charge a battery and adding fancy charging devices will make little if any improvements to the state of charge in these vehicles but it’s this kind of info that is exploited to make the case that the alternator is the problem.

Again, as posted above, there are statements that generators, solar panels and what ever will do a better job. In some cases this may be the case but again, it comes back to how long the vehicle is driven for and in this specific thread Ross H asked a question, based on his needs and vehicle usage and as such, his alternator will do as good, if not a better job than half the replies would suggest.

This is what I base my reply on, a lot of suggestions posted that actually have little to do with how Ross intends to use his set up.

Cheers.

Drivesafe,

The reason I THINK that an alternator MAY not be as good is based on the generally accepted assumption that a three stage charger (decent solar regulator, etc) provides a controlled bulk charging cycle, an absorption cycle and then a float cycle, and that this is the way to go if you want to go close to fully charging your battery.

That is why I question whether an alternator, which does not provide what might be considered to be an optimum charging profile, may not be the most efficient way to charge your batteries. I can't put in any simpler than that.

My suggestion to Ross was in direct response to the question he had asked. That is, how best to maintain batteries permanently connected to the vehicle's charging system. Right or wrong, the suggestion was aimed squarely at the situation Ross outlined.

I did not introduce solar or generators as an option for him, just questioned why they seem to be treated differently in terms of how the charge is regulated, than an alternator derived charging source. And I still haven't seen any explanation of why this is the case other than a blanket suggestion that a direct feed from the alternator is just as good with little logic to back that statement up.

Cheers,

Matt.

Hi Matt, I didn’t say you introduced the other devices, I posted that they had been introduced in this thread.

Next, if you have a set of batteries connected to an alternator in a vehicle that is driven on a regular basis for a good amount of time each time it is started, so the batteries, all the batteries are going to be kept in a well maintained condition, why would need to connect a battery charger to this set up at any time as the vehicle’s use in itself, will keep the batteries fully charged and the only way a battery charger could keep the batteries in a similar state would be to connect it up every time you turn the motor off.

That just doesn’t make sense, no matter how many different charge cycles a battery charger may have, the batteries are already fully charged.

If Ross was leaving the auxiliary batteries at home and only using them when he needed them or only drove for a few minutes at a time each time he drove his vehicle, than there would a reason for periodically connecting the charger up, but again, to infer that connecting a charger to fully charged batteries is going to improve the state of charge of fully charged batteries just does not make sense.

OK, look I'll retreat to my corner after this one. But, your argument rests on the assumption that the batteries ARE actually being fully charged by the alternator alone, as opposed to just a decent charge which for most applications is probably good enough.

70%, 80%, 90%, I honestly don't know and as you point out, it probably depends on a lot of other factors. Again, I am no expert but I read on the topic a lot (not just on this site either), and the other common observation is that resting voltage alone is not necessarily an accurate guide to SOC.

Anyhow, I'll bow out now, although I am still a bit confused with regards to my original question as to why a solar regulator with constant output or a 240/12v charger with constant output is not every bit as good as the more expensive three stage ones.

Thanks,

Matt.

Matt,
It's not an "assumption" it's fact, the batteries will be fully charged!

I will go way out on a limb here an now, when Ross measures the rested voltage of his battery system tomorrow I believe he will post it is 12.6+ volts, that's 100% charged.

Matt, your reference above to a "solar regulator with constant output" is no where near accurate either, the current of any quality 'regulator' definitely is not "constant" but tapers off as the battery is charged (as I mentioned to you higher up this thread also) as happens with all better quality Voltage regulators.
(ok, elcheapo regs don't work this way, but your not paying for a quality reg and you don't get the same result either)

Mainey . . .

Matt first off, you don’t have to retreat into your corner, I’m not trying to win some one-upmanship or what ever. If you think the info that I, or anybody else, is posting is incorrect, then say so and it’s up to me or who ever to give good reason why what is posted, is so.

Next, some crossed wires here, I did not say that a battery charger or what ever will not fully charge a battery, what I am saying is that in Ross’s situation, not only will his alternator fully charge his auxiliary batteries and keep them that way, for this reason, there is no need for any other intervention.

Ross is not going to get any additional befit from doing anything more than what he is already doing.

Ross,
sorry to mess up your thoughts but what your "testing" is only the surface voltage, wait a few hours and re-check them again, as a fully charged AGM battery will only be ~12.8v (not 13.4v)

As I've said above, "if left there when connected and not being used to power a fridge etc; they would continue to be charged by the ute's alternator" and as DS has now added "this crap that an alternator won’t fully charge automotive batteries is a myth based on half truths . . . etc etc"

When you re-measure the voltage you will also be convinced an Alternator *WILL* fully charge an AGM Auxiliary battery system with-out further expensive outside assistance.

Mainey . . .

Thanks Mainey it was only about half an hour so will wait and test in the morning.

Regards Ross

Ok guys,
Tested the batteries this morning and had a reading of 13.2volts.
The batteries are 2x 120amp amptecs (AGM's) they are charged off the duel battery system (pirana). They are joined with 100amp 8mm cable.

Thanks to everyone for you advice

Regards Ross