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p0rtia
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# Posted: 5 Nov 2015 02:14pm
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Hi -- I have a sweet old Honda EX1000 generator. I want to use the 12 volt option to charge a two battery bank (2 6V gold cart batts wired in series). What's the best battery charger for me?
Also, am I risking mayhem if I hook up without a charger as long as I keep an eagle eye out to make sure I don't over charge?
Thanks!
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MtnDon
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# Posted: 5 Nov 2015 03:19pm
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What charger size to use depends on the Amp-Hour capacity of the batteries. If you have two six volt GC-2's in series you have something like 210 to 225 AH. The charger should put out 10 - 15% of that AH capacity, so if we use 215 AH as an example the charger should be in the range of 21 to 32 amps.
If your sole source of recharging is the generator with a battery charger look for a charger that offers three stage charging. Or 4 stage is even better as that adds the ability to do an EQ charge.
Those EU1000's put out so low an amperage it would be difficult to harm a battery. They are also an inefficient use of gasoline because they have such a low output. Something like 6 to 8 amps and you are supposed to run the unit at full throttle. Eco turned off.
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p0rtia
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# Posted: 5 Nov 2015 03:43pm
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Thanks, MtnDon. Yep, GC-2s and the Gen puts out about 8 amps. It's just a back-up to a small (7 amp/100w) solar set up. I use this batt bank to keep the electronics of my propane fridge running. This time of year the sun is behind the trees and of course low, so the batts drain if I don't do something. I leave in a couple of weeks, so it's a short term boost once or twice.
May I ask what three-stage charging encompasses? Also, can I use a charger rated for solar? I have several 10 Amp charge controllers.
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MtnDon
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# Posted: 5 Nov 2015 04:56pm
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Three stages; bulk, absorb, float. bulk pushes in most of the amps up to around maybe 90% full, absorb is a timed finishing charge. Float is the maintenance charge and will not harm a battery.
Like this Samlex. There are others too. Just an example.
Solar charge controllers don't work well or don't work at all if used to try and regulate the output from a generator. Not much sense trying to regulate the 8 amps DC and if you connected the AC to it it would be toasted.
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p0rtia
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# Posted: 5 Nov 2015 05:21pm
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Thanks, MtnDon. Perfect.
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Steve961
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# Posted: 5 Nov 2015 08:04pm - Edited by: Steve961
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You might also consider an Iota DLS-30 battery charger. It's a 30 AMP unit that has successfully been used with Honda eu1000i chargers - not sure if that's equivalent to yours though. If you get the DLS-30 with the IQ4 option, it will provide bulk, absorption, and float charging. I have the DLS-15 integrated into my system and have had very good luck with it so far.
Here's a link to the DLS-30:
Iota DLS-30
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creeky
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# Posted: 6 Nov 2015 09:35am
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Quoting: p0rtia short term boost once or twice
For a once or twice battery boost, I'd probably just head to the local auto store and get a cheap as possible 10 or 15 amp charger with a deep cycle setting. a sports big box with marine chargers would also suit as marine chargers are designed for deep cycle batteries. so what if you spend an extra $2 on gas running a bit longer... run it in the a.m. and then let the sun / murky light finish.
imho charging in supplement to a solar system only requires the bulk charge to get things going on cloudy days. however if you want to go more robust:
I've been happy with my Powermax charger. they have a boondocker model with adjustable bulk charge. you need a charger that will get up to 14.5v for efficient use of your gasoline; give or take .3.
bestconverter sells both the Powermax and the Iota. The iota requires the IQ4 to give you a higher bulk charge. but is a nice affordable unit.
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groingo
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# Posted: 6 Nov 2015 11:18am - Edited by: groingo
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I have been through this exact situation last season and before and tried nearly every charger out their from car chargers, golf cart chargers, boat chargers etc and all promised to charge with high amperages fast ( 15 to 30) while many were programable(Samlex ship to shore) promising they would push high amperages to charge quickly and in the end none delivered or performed any better than my original 10 amp 25 year old Schumacher car battery charger.....why you may ask....I did.
The battery resistance controls the show, when you hook your charger on the battery you will see the highest numbers but an hour later or less they will be a fraction of that amount and after another hour and a half they will spend a majority of the time at 5 amps or below.
In the end, if you run your batteries down to 60 % regardless of the charger it will always take 13 hours to get a full charge.
Also, most 6 volt golf cart batteries have a maximum input of 16 amps, over that and you will damage the batteries.
So what charger do you want, just a basic non digital 10 to 15 amp automotive charger will work best plus it will keep your generator running at its fuel mileage sweet spot which is 250 watts and below so you will get nearly a full charge on 1\2 gallon of gas on Eco mode which will automatically adjust for load.
Just remember, your batteries will by their nature run the show, not the charger.
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MtnDon
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# Posted: 6 Nov 2015 03:33pm - Edited by: MtnDon
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I linked to that particular Samlex charger for good reason. It has true multi stage charging. That is the same method a good solar charge controller uses to charge the batteries from PV panel input. That Samlex can operate as a three stage or a two stage. There are reasons or circumstances for allowing that selection. Everything is explained in the user manual which can be found here. The manual also does a pretty good job of explaining the charger operation.
If we connect it to a partially discharged battery and turn it on it will go into bulk charge. Bulk charge done correctly means it is a constant current charge. The voltage slowly rises as the battery charges and the current remains as high as the rated output, or close to it. The current does not vary in this stage as long as the generator* can supply the needed power. The voltage eventually rises to a set point where the charger switches into a constant voltage type of charge. This is known as an absorb charge, sometimes known as a boost charge or as an acceptance charge. In PV the usual name is absorb.
Being a constant voltage Absorb is the stage where the current is the variable. This is where the battery state of charge sort of self regulates the amperage. I say sort of as if left in absorb too long the battery can be overcharged. It can heat up beyond it's maximum design temperature. The water use will be increased if absorb is prolonged. In many chargers the absorb is a timed event. This Samlex charger has a factory preset low amperage limit. When the amps fall to this setpoint the charger switches into float charge.
Float charge is a constant voltage low amperage charge. Just enough current to compensate for battery self discharge is applied. The charger / battery can remain in float for extended periods without battery damage.
The Iota chargers with the IQ4 come close to this charge cycle. However the IQ4 uses an 8 hour timed absorb stage. That could lead to more water use. However, their voltage is not quite as high as the samlex in that stage so it is probably not harmful.
Many other chargers do not have the controlled constant current bulk charge like this Samlex, no matter if they claim to be 3 stage chargers. They have a maximum which may be reached initially but quickly tapers off as the battery reacts to the incoming charge. There are others, but I don't know what they all are. The data in the Samlex user guide should be read. Once you know what to look for then anyone can research other brands and models.
A good charger will have constant current bulk, constant voltage, variable current absorb and constant voltage low current float. A superior charger will allow the user to vary the bulk stage current from a low range up to the maximum rated amperage. The Samlex does not do that. User programmable bulk current is usually only found in top of the line inverter / charger combination units like Outback, Schneider and some Magnum. There probably are others as well.
* BUT, I re-read the OP and find this recommendation may not be useful. The OP states the user has an EU1000i. I was thinking it was an EU2000i. The Samlex I listed may overdraw the output of the generator when the charge is first initiated. There is a startup surge similar to that of a refrigerator. The Iota chargers have the same "fault" It is inherent to the electronics design. However, I hope the information proves useful.
If one could find a seller with a good return policy then one could try it out and see. But I do believe the Honda would be underpowered for this Samlex.
So a smaller charger like the Samlex SEC-1215UL might be a better choice for the generator. It has the same multi stage charge system but is for a maximum of 15 amps.
As for what charge a golf cart battery can safely receive, the general rule of thumb is 10% to 12 1/2% of the AH capacity. Do the math for the battery you have; 220 AH = 22 to 27.5 amps. Watching the battery temperature is good especially in summer as 125 F or higher should be avoided. A superior quality charger will have a remote temperature sensor. But those are mostly only seen with inverter / charger combination units.
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groingo
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# Posted: 7 Nov 2015 12:54pm
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I did ultimately get a digital charger Stanley BC2509 because it also had a jump start feature but like all the others when plugged into my depleted golf cart batteries it started out pushing 25 amps for about 30 minutes then rapidly dropped to single digits within an hour and like all the others a complete charge still took around 13 hours in the end.
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p0rtia
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# Posted: 7 Nov 2015 02:31pm
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Thanks, Steve, creeky, and groingo. I am now edumacated. FTR it's an EX1000, not an EU1000i.
I love this forum!
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MtnDon
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# Posted: 7 Nov 2015 03:01pm
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The BC2509 is not a constant current charger, so yes the amperage will taper down.
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groingo
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# Posted: 8 Nov 2015 10:43am - Edited by: groingo
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Don:
Every constant current charger I looked at had " battery sense" which automatically reduced charge rate to keep from overcharging batteries so the end result was always the same, otherwise I would think there would be a lot of destroyed batteries and ticked customers.
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MtnDon
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# Posted: 8 Nov 2015 02:40pm - Edited by: MtnDon
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You are helping to make it sound like off grid use has more problems than there really are. Yes, there are issues with being off grid, and many stem from cheap equipment. I don't know just what other ones you tried, but the Stanley you mentioned is definitely not a constant current, multi stage charger. No where in the user manual do they make that claim. The write upon Amazon indicates 3 stage, but I don't believe it. Not for something like $60, when the Samlex is about $200.
The Samlex is a true three stage charger. Page 8 and 9 explains the operation. The microprocessor forces the current to stay high until the voltage rises to the preset "change to absorb" point is reached. I am not just going by the Samlex info but am going by the personal experience of a friend with the same Samlex charger. It works and works well. He charges a couple T-105 Trojans from half full or so in about 4 hours IIRC. It stays in constant high current until the voltage hits 14.4 volts.
That's the same cut off point many folks use on their solar PV charge controller; the bulk to absorb point. At that point the battery has reached about 80% charge, maybe higher. From there on the current tapers, not before. Isn't that more or less how your PV charger works? A good AC powered three stage charger works with more or less the same algorithm. But it takes a proper design to achieve that and that costs more, but works better.
Yes, if cheap chargers did not taper off they could damage batteries and tick off people. That is why those are designed to taper off. But they also are bad for the long term health of the battery as many batteries charged with a cheap charger never reach 100% full. That is just a slower death than being overcharged.
Three stage is better. And that costs money, The Samlex has varied from $195 to 212 on Amazon over the past few months. That Stanley was only $60 - 65 or so, IIRC. Like comparing apples to oranges.
Xantrex Truecharge are similar to the Samlex in operation and even more costly; $330. They have EQ ability, though. It has a battery temperature sensor as an option as well.
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groingo
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# Posted: 8 Nov 2015 06:03pm - Edited by: groingo
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Don:
You got side tracked by the Stanley which is indeed a great example of JUNK, but the reason it was bought was two fold, it could be used as a car jump starter, test alternators, cure world hunger and could push 25 amps ( for a very short time), but mainly a car jump starter.
My full time battery charge is the old Sears 10 amp that in the end charges as fast as any other tested and makes no noise because it doesn't have a fan.
I think you know me well enough to know that I am a picky and demanding SOB, so indeed I have tried a mess of stuff, always looking for the one that can deliver and when I find that I look for something better....it never ends.
As far as making off gridding looking problematic, nothing could be farther from that, I am always looking for the best bang for the buck with the least effort, today we call that value.
Not many have a fully sufficient off grid solar system that can meet all my needs for about a thousand bucks and live comfortably....now that's the great American Dream!
As far as the chargers go and my generator, none have been used since last January and will likely not be used this winter either so they are not really a factor any longer.
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rugercpl
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# Posted: 3 Dec 2015 10:11pm
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I'm a solar newbie even though I've been using a solar gen for 2 years seasonally. I too am interested in upgrading my battery charger. I am using a Schumacher 15A to recharge 3 standard 100ah AGM batteries. Will the Samlex do that faster and more efficiently making my batteries happier and lasting longer?
I admit i had a small sigh of relief when the OP wrote that it's around a 13 hour recharge time when batteries are at 65% because that sounds similar to my situation..not quite that much but close. I'm using a eu2000i converted to propane running on eco mode.
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groingo
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# Posted: 3 Dec 2015 10:34pm - Edited by: groingo
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I have to admit that my Stanley BC 2509 I seem to have under rated as it is performing beautifully and pushing 25 amps for hours now then slowly tapering off, in fact it is doing so well that my 13 hour charge times for batteries depleted to 40% has dropped dramatically to only 4 hours while in your case the power draw on your Honda 2000 at this rate will be in the 25% zone which means a tiny fuel use by your generator which should be just a hair over 1/4 gallon or less.
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rugercpl
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# Posted: 4 Dec 2015 12:58am
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Would that do the same for me using the eu2000i to recharge my 3 100ah AGM's from 60% to nearly full?
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MtnDon
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# Posted: 4 Dec 2015 10:15am
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Check the maximum rate of charge suggested by the AGM battery manufacturer first. Then make sure you don't exceed either the voltage or the amperage.
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groingo
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# Posted: 4 Dec 2015 12:11pm
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Just contacted Crown battery to verify what my CR235 flooded battery max charge rate should be which is 35 to 40 amps while the AGM's vary because they come in different dimensional configurations, just give your battery maker a ring and ask the question....takes the guesswork out.
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