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Old 27-03-2011, 18:49   #16
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Re: Questions about replacing battery charger

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Originally Posted by ADMPRTR View Post
That is great information, Bill. Thank you. Also,the Iota chargers are very well priced as you indicate. Yes, I have a diesel engine. Why is that significant?

It sounds like I should consider my future charging requirements then. If I purchased a 75A or even 90A charger, would there be any problem with my existing batteries (i.e. would exceeding 25% damage my existing batteries)?

Andrew
Andrew,

It matters somewhat because the Iota chargers are not "marine approved". They are safe and under normal operation do not produce any sparks, but it's best IMHO not to use them on gasoline boats. BTW, I have had two of them for the past five years, and have installed many of them on my client's boats.

You want the IQ-4 smart charge option. This can be either internal to the charger, or a small box you plug in. It costs about $35 I believe. I have one of each :-)

I would not get the 90A version, because: (1) the Honda generator will not handle it; and (2) a normal 15A 120VAC outlet will not handle it either. If you want a large charger, the model DLS-75/IQ-4 is the way to go.

Note also that these chargers are very robust, are frequency and voltage tolerant, are extremely quiet both to your ears and to radios, and the company has a very excellent record of support. They also will put out full wattage for a considerably longer time than most chargers.

Mine stay on 24/7. The DLS-45/IQ-4 sitting next to me here in the ham shack maintains a bank of two Trojan T-105 golf cart batteries which runs all my radios, and will be seven years old this July.

Bill
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Old 27-03-2011, 19:09   #17
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Re: Questions about replacing battery charger

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stevensuf,

No, you can't compare watts DC with watts AC. A Honda EU2000i can (barely) handle an Iota DLS-75, but cannot handle a DLS-90. And, certainly NOT a charger of over 100 amps.

Also, batteries will only take what they will take. You could hook a 150 amp charger up to a 450AH flooded battery bank, and it would still only take about 90A initially, then would dial back as the charge came up.

The only way to push up the amperage beyond the battery's safe charging rate is to raise the charging voltage higher than about 14.4VDC for a 12V battery. Smart chargers and regulators prevent this from happening.

Bill
Does that mean that I could buy charger that exceeds 25% of my current requirements without fear of damaging my existing batteries, in the expectation of eventually replacing with deep cycle batteries?
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Old 27-03-2011, 19:26   #18
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Re: Questions about replacing battery charger

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Andrew,

It matters somewhat because the Iota chargers are not "marine approved". They are safe and under normal operation do not produce any sparks, but it's best IMHO not to use them on gasoline boats. BTW, I have had two of them for the past five years, and have installed many of them on my client's boats.
Thanks Bill.

Does marine approved only mean they are not sparkless or would they be more prone to failure in a marine environment?

One of the things I was thinking of looking for would be a waterproof marine charger. The one I purchased is not waterproof, however. This is a concern for me because my boat, being old, is not as water tight as I would like (something I hope to resolve). I also have propane on my boat which could be a concern if there was leak that wasn't picked up by the sniffer, I would think.

Andrew
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Old 28-03-2011, 03:46   #19
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Re: Questions about replacing battery charger

Andrew, we recently moved our charger from the cockpit locker to the stern cabin because of concerns about damp. Its not a water proof one either, it makes it easier to see the lights and what is happening.

Those Iota charger prices look good, doesn't say if they have measure the battery temperature with a sensor as many modern chargers do though. Perhaps Bill can confirm.

If you keep you current sealed lead acid batteries for now, you will need to adjust the charging voltage down or risk over charging them. Flooded lead acid batteries will accept a slightly higher charge battery which reduces the charge time. However, when you replace the sealed ones then you could raise the charge voltage back up again. Its normally just a switch or circuit jumpers as used in Sterling chargers.

This may be a useful read. Some folk agree with Charles, some don't, I do.

Sterling Power Products: What is the best battery to use for an auxiliary charging system?

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Old 28-03-2011, 03:49   #20
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Re: Questions about replacing battery charger

btrayfors
1w dc or 1w ac are both 1 watt, ie 1 joule per second, they are exactly the same! you may get a power factor correction in ac with the current being out of phase with the voltage (no offence but i do have a bsc in electrical engineering), i do have a cheapo 1kva max rated genny which is 800kva nom which runs my sterling 50a charger no problem at all. battery chargers are not hugely inductive loads, not like a compressor or motor where the kva output of the genny will have to be much more than the motor.

Batteries will try and draw more amps when greater discharged than when charged, ie the greater the voltage difference between the battery and charge source the more current they will try and draw, till they reach the current limit of the source (ie charger) Hence the notion of 1/4 amp hour max charge rate to stop them overheating, some of the fancier chargers have temp sensors which are bonded to the batteries to monitor battery temp.
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Old 28-03-2011, 04:09   #21
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Re: Questions about replacing battery charger

Andrew, the other fact sheet that is worth reading covers fast charging with higher voltages.

Sterling Power Products: How effective is advanced battery charging on a battery and can it damage the battery?

Although the article is taking about charging from an alternator the bit about batteries holds true.

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Old 28-03-2011, 05:00   #22
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Re: Questions about replacing battery charger

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Originally Posted by ADMPRTR View Post
Does that mean that I could buy charger that exceeds 25% of my current requirements without fear of damaging my existing batteries, in the expectation of eventually replacing with deep cycle batteries?
Yes, providing it's a modern smart charger it will not/cannot damage your batteries.

RE: the propane, strictly speaking, that's a concern....but a remote one.

As another poster noted, it's always best to install a battery charger at a location where it will be dry, out of the engine compartment, and protected from inadvertent damage.

BTW, the "marine accepted" label is only a partial protection against sparking, but it's not absolute. A neighbor of mine on a houseboat was blown into the water some years ago by a "marine charger" when he inadvertently hit the off/on switch while climbing into the engine room! He survived, the boat didn't :-)

Iotas survive just fine in the marine environment. But, like with all electronics, be careful to install them in protected locations.

Bill
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Old 28-03-2011, 05:05   #23
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Re: Questions about replacing battery charger

one thing worth noting is that while fast charging can bung more amp hours into the battery in a shorter time , itis no where near as efficient much more energy is lost in heat.
The desulphating of the batteries is minimal you need short high pulses to desulphate , hundreds of volts for microseconds, running to 14.8 vs 14.4 will make very little difference to sulphation of the plates. a bit of marketing gumbo going on me thinks, also heating a battery will reduce its life span, simple fact, chemistry is chemistry and heat causes more reactions to occur than less heat.

A decent digital battery charger should be 90% efficient and have a power factor very close to 1, eg
say 50 amp at 14.4 volt is 720w charging power, add 10% for charger losses
=800w a 1kva max genny should do 800kva nominal the power factor on these digital
chargers is less than 5 % = 840kva draw on the genny slightly overloaded but only on full charge which is very short lived in most cases.

Bear in mind some older cruder battery charges will present a far greater load to the genny, some older analogue chargers may have a power factor close to 60-70% and have losses of 15-20% , so an old crude charger may use 840 watt to give 50 amp coupled with a power factor of say 70% would represent a load of around 1200kva to the genny,this may be why btrayfors thinks a 2kva genny cannot run more than a 75a charger.

Get a good efficient digital charger with a power factor close to 1 and it will make all the difference in the size of genny you require.
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Old 28-03-2011, 05:16   #24
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Re: Questions about replacing battery charger

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Does that mean that I could buy charger that exceeds 25% of my current requirements without fear of damaging my existing batteries, in the expectation of eventually replacing with deep cycle batteries?
No, unless you can turn down down the charging current, you risk overheating the batteries as the charger will inject too much current during the "bulk " phase.

Some chargers have a regulation on the supply current, ir to reduce the effect on the mains supply, its can be hard to translate that into actual max charge current.

dave
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Old 28-03-2011, 05:26   #25
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Re: Questions about replacing battery charger

Yes, of course. I phrased it badly. What I meant to say is that you have to look at the specs and do the math correctly, BSEE or not.

One hundred watts input power rarely equals 100 watts output power when dealing with power conversions. Here, we're dealing with converting 120VAC to 12-14 VDC. There are always losses involved. The Iotas are pretty good, however, and generally run about 80% efficiency.

An Iota DLS-75 has a maximum AC current draw of 17 amps, and a maximum inrush current of 50 amps (single cycle). The Honda EU2000i has a maximum continuous output rating of 13.3 amps and the maximum intermittent output (30 minutes) is 16.6 amps. This charger, both from published specifications and from the experience of many sailors, will JUST handle the DLS-75.

It will NOT handle the DLS-90 or other chargers of more than 100 amps output, EXCEPT if the batteries are pretty well up and don't need much current.

Bill


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btrayfors
1w dc or 1w ac are both 1 watt, ie 1 joule per second, they are exactly the same! you may get a power factor correction in ac with the current being out of phase with the voltage (no offence but i do have a bsc in electrical engineering), i do have a cheapo 1kva max rated genny which is 800kva nom which runs my sterling 50a charger no problem at all. battery chargers are not hugely inductive loads, not like a compressor or motor where the kva output of the genny will have to be much more than the motor.

Batteries will try and draw more amps when greater discharged than when charged, ie the greater the voltage difference between the battery and charge source the more current they will try and draw, till they reach the current limit of the source (ie charger) Hence the notion of 1/4 amp hour max charge rate to stop them overheating, some of the fancier chargers have temp sensors which are bonded to the batteries to monitor battery temp.
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Old 28-03-2011, 05:48   #26
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Re: Questions about replacing battery charger

Bill yes you are right on that model, its not a very efficient charger is it? it says max output 1000w 80% efficiency so 1250w consumption the power factor must be way off to demand about 1800 kva ie 17a at 110v roughly , power factor of 65 ish% a pretty poor item to run from a generator .

Again if you get a good digital charger with 90%+ efficiency and powerfactor close to 1 it could run it no problem at all.
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Old 28-03-2011, 05:56   #27
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Re: Questions about replacing battery charger

Below discontinued but has the right idea, the 20amp model would run about 260kva you could get 60amp out or a 1kva genny using three of these. 0r 120amp out of the eu2000i using 6 of these chargers

Sterling Power Products: ProBudget
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Old 28-03-2011, 05:57   #28
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Re: Questions about replacing battery charger

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Bill yes you are right on that model, its not a very efficient charger is it? it says max output 1000w 80% efficiency so 1250w consumption the power factor must be way off to demand about 1800 kva ie 17a at 110v roughly , power factor of 65 ish% a pretty poor item to run from a generator .

Again if you get a good digital charger with 90%+ efficiency and powerfactor close to 1 it could run it no problem at all.
Glad we're ALMOST in agreement.

Actually, the Iota is a very good selection to run from little generators, because of it's excellent range of acceptance of input power. And, at 80% or better efficiency, it's middle of the pack. BTW, the Iota often puts out MORE power than it's rating; they just don't tell you that. It also hangs in there longer with high output than many other chargers.

As to "more efficient chargers", I have a high-end Victron Multi-Plus inverter/charger on my boat. It has a power factor of 1. It can be set to accept a wide range of input power, too. However, even with all the "dirty power" settings, it simply does not like the output from my NextGen 3.5KW 120VAC generator. I have to put a resistive load on the generator's output in order to get the Victron to accept and pass thru the generator's output power. A real pain in the butt.

By contrast, the Iota DLS-55/IQ-4 on my boat has no problem accepting the NextGen's output.

I guess not all chargers are created equal...even the high-end ones :-)

Cheers,

Bill
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Old 28-03-2011, 06:14   #29
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Re: Questions about replacing battery charger

Another good one in production is the sterling pro charge ultra pretty much would use 10% more in kva than in watts ie the 60 amp model would tun on a honda eu1000i would push it at full charge but would do it.
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Old 28-03-2011, 06:31   #30
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Re: Questions about replacing battery charger

Sorry bill for not checking the specs on the unit, i just assumed that if they were looking at chargers to run from a generator, that they would be power factor corrected units. My apologies for not looking deeper! My 50amp sterling runs just fine on my 1kw genny but it is pf .975 not quite 1 but i think a bit cheaper
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