Iota chargers and equalization

[witzgall]

Hi all;

Based on the recommendations of some folks here, I bought an Iota DLS-45 chadger with the smart controller. Their website states that if the charger is hooked up for seven days, it will automatically go into a equalization stage.

I wrote to them asking how I could force it to equalize, like if we were cruising and stopped at a marina for a night. Good to charge the batteries and equalize, right?

The answer leaves me baffled:

The internal IQ4 is all automatic. There is no way to manually switch from one stage to another.
The equalization stage is simply 14.2v for eight hours. If your battery is below 12.8v when you plug the DLS-45 into shore power, the IQ4 will switch the voltage to 14.2v and hold it there for eight hours. The only way to make it switch to the higher voltage is either wait the seven days or have your battery below 12.8v.

what is confusing me is that when I lookup tables showing state of charge, 12.6 is listed as 100%. So if this is the case, the battery would be equalized every time the battery was hooked up to the charger, when the battery was already at full charge. That would require alot of watering and I woud think shorten the battery's lifespan.

So what do I have wrong here?

Chris

[Rick]

First, the state of charge of any lead-acid battery cannot accurately be determined by voltage. More importantly, the state of capacity can in no way be determined by voltage readings.

The Iota voltage control at 14.2 Volts is not only below a value appropriate to recover capacity with a deeply discharged battery (acceptance level should be 14.4 V minimum @ 20 deg C) it is below the cutoff voltage for a true equalization cycle which may terminate at levels above 16Volts. A true equalizaion cycle is done with constant current FROM a so-called "full" state. The value of the current may be between 3% and as much as 7% (but not likely for your battery) of the supposed Amp-hour capacity number.

Don't know why Iota has such a "wrong" value for their so-called equalization model.

[btrayfors]

On the surface of things, the voltage values seem strange, as Rick opines.

However, you have to understand that the Iota with DLS option is a smart charger which uses PWM (pulse width modulation) charging. It is not like most other chargers.

There is no setting for AGM, flooded, or gel. There is no need for such a setting. There is no provision for temperature sensing, nor is there any need for this. The PWM method ensures that a battery cannot overheat, and that it will receive a full charge, and that it will have a minimum of sulfation.

Rick's right that 14.2 volts for "equalization" is far below the usual 15.5V or more for a 12V battery. However, the voltage spikes in PWM charging are said to be much higher than that, and the 14.2 "equalization" charge voltage and the normal float voltage of 13.6 are just approximations.

I have two Iotas: a 55A model on my boat dedicated to two T-105s for the windlass, and a 45A model in my home ham shack dedicated to two T-105s which power my radios. These are left on all the time. I also have a very high end charger/inverter (the Victron MultiPlus) for the house bank (six T-105s) which has a float level of 13.2.

After several years of use, I can tell you that the batteries on the Iota are in much better condition -- without additional equalization -- than are the house batteries maintained by the Victron. The Victron does not have an equalization setting, unfortunately.

Bottom line: the Iota chargers are wonderful devices which will keep your batteries in good shape. I wouldn't worry about trying to interrupt their normal cycle. When you tie up, the charger will do its thing no matter what type of battery bank you have or the state of charge of those batteries.

Bill

[witzgall]

THanks guys. From what I am reading, the Iota might work just fine for my application, which is all I want. If I find that it does not, I'll report back.

Chris

[ssullivan]

My experience with the Iota DLS 90 chargers has been the same as Bill's above. They kept my T-105's in extremely healthy condition with no evidence of any wear, either from sulphation or from out-gassing.

The PWM is supposedly a very different way of charging. The Iota is also programmed to "take care of it all" for you without any input needed. Just let it do its thing and it will take care of your battery bank.

Sorry this isn't a technical post... just wanted to quickly share my success with these chargers.

[Ram]

i HAVE THE 75 MODLE AND AFTER 2 YEARS VERY HAPPY WITH IT, i AM CHANGING TO amg batterys this month and am a bit concerned it will not charge at a high enough rate, - mine by the way charges many times at 14.4
Does anyone have experence with these charges with the AMG batterys?

[Beausoleil]

Originally Posted by btrayfors

On the surface of things, the voltage values seem strange, as Rick opines.

However, you have to understand that the Iota with DLS option is a smart charger which uses PWM (pulse width modulation) charging. It is not like most other chargers.

I talked with an Iota engineer prior to ordering two DLS-75's for my electrical replacement project. He never mentioned (that I recall, anyway) that their chargers with the IQ4 smart-charging option were PWM. I was concerned when I was considering purchasing them that there was no wet/gel/AGM setting, and he indicated that I could manually change default voltage level via a pot on the unit.

What I don't understand is that if these units are PWM, then why does Iota quote ripple in their outputs? Are they pulsed from 0 volts, or from some base value above 12V? While I can understand what advantages PWM brings to the table when battery charging, it seems counter-intuitive that it's used in a charger that doubles as a clean, low-ripple DC power supply...

That being said, I can't find anywhere on their website where they mention PWM being the basis for their smart-charging design. Did you find this out from one of their engineers?

[btrayfors]

Sorry for late response; been working on my son's boat for a few days.

Yes, I learned about their use of PWM technology both from an engineer/sales rep -- a very passionate guy with a lot of experience -- and directly from an engineer at Iota via a telephone conversation over a year ago.

You're very right to be posing these questions, and there are things which do seem contradictory.

Iota is very secretive about their designs; they publish almost nothing other than the "specifications". And, I've never had opportunity to put a scope on one of their chargers to verify the output.

The idea of adjusting output voltage with a pot seems not right to me: first, there's no evident pot (you'd have to open up the unit). Second, there's absolutely no mention of that in their literature, and how could they sell a charger for flooded, AGM, and gelled batteries without telling you about voltage adjustment? What I was told is that the pulsing is well above 15V, but it's momentary and as such never raises the temperature enough to worry about nor does it hurt any kind of battery. The engineer/sales rep went into great detail, but I was distracted by local events and didn't take in the whole spiel....he went on for almost an hour. By contrast, the engineer at Iota was very hard to get any info out of: he just said, "yes, I can confirm that we use PWM technology".

What I CAN tell you is that they work like gangbusters, are very RFI quiet, very reliable, and maintain my batteries better than any other charger I've used. My radios seem happy with them (I have a hamshack FULL of HF radios which all run off of a T-105 battery bank maintained full-time by a DLS-45 with IQ-4 charger. The batteries are now almost 4 years old and check like new, using a sophisticated battery testing device which measures internal resistance of the batteries. Ditto for the T-105 bank on my boat which is dedicated to the windlass, and is maintained full-time by a DLS-55/IQ-4 charger.

By contrast, my house batteries on the boat (6-T-105s) don't test as well, even though they're maintained full-time using a high-end Victron MultiPlus charger/inverter. They need periodic equalization, while those on the Iota chargers appear not to.

One of these days when I find the time I'll stick a spectrum analyzer on the Iotas and see what they're really made of :-)

Bill

[knottybuoyz]

Iota stands behind their products as well. I bought a DLS 55 w/IQ4 from a member here and it quit a month later. Iota replaced with with a brand new unit no questions asked even though it was bought second hand. Now there's a company that really stands behind what they make! I wouldn't hesitate to recommend or buy again.

[Tiara_Patriot]

We have dual Iota DLS-75's with an IQ4 Parallel controller charging two paralleled 375ah Rolls batteries. We have found these chargers to operate flawlessly and they recharge the house bank very quickly without overheating the batteries.

I also spoke with Rolls about these chargers and they were very happy to have Iota chargers charging their batteries.

[ssullivan]

Reading all these posts is bringing up an old worry... I wonder if my Xantrex Freedom Inverter/Charger and the Xantrex Solar Charge controller are taking as good care of my new Trojan bank as the Iotas did... ??

Hard to tell so far, but the Iotas were phenomenal.

[Beausoleil]

Originally Posted by btrayfors

Sorry for late response; been working on my son's boat for a few days.

Yes, I learned about their use of PWM technology both from an engineer/sales rep -- a very passionate guy with a lot of experience -- and directly from an engineer at Iota via a telephone conversation over a year ago.

You're very right to be posing these questions, and there are things which do seem contradictory.

Iota is very secretive about their designs; they publish almost nothing other than the "specifications". And, I've never had opportunity to put a scope on one of their chargers to verify the output.

The idea of adjusting output voltage with a pot seems not right to me: first, there's no evident pot (you'd have to open up the unit). Second, there's absolutely no mention of that in their literature, and how could they sell a charger for flooded, AGM, and gelled batteries without telling you about voltage adjustment? What I was told is that the pulsing is well above 15V, but it's momentary and as such never raises the temperature enough to worry about nor does it hurt any kind of battery. The engineer/sales rep went into great detail, but I was distracted by local events and didn't take in the whole spiel....he went on for almost an hour. By contrast, the engineer at Iota was very hard to get any info out of: he just said, "yes, I can confirm that we use PWM technology".

If that's true, then it follows that the PWM is not high-frequency pulses but must be very low frequency - or else you'd have at a minimum a fair amount of RFI at all sorts of odd harmonics caused by the square wave pulse train. I'd guess that it's not hard pulsing, but rather a fairly low frequency ramp up and hold, then decay. Not long enough to heat up the batteries, but slow enough to not be in the radio spectrum. I'll ask around here at work (we've got a few avionics power guys floating aroung) and see if their familar with such a system.

BTW - right now I'm at the dock and haven't been letting the DLS-75's run for the last couple of weeks - been running off the Magnum inverter. I think I'll let the Iota's run for a couple of days before heading out to Newport, RI for a week-long shakedown cruise.