unhappy generator pulsing

[Duchess Omnium]

Hi, Folks. Last year I bought a Honda generator. I have a Sterling pro Combi Q 2500 inverter/battery charger. I debated whether to buy the Honda 20i or the Honda 10i, but after taking advice on this forum and elsewhere, I opted for the 10i (1000 watt). It seemed that 1000 watt would be all I needed (I don't run a washing machine or anything power hungry -- my greediest appliance is a 12 volt fridge).

 

What swung me (besides the price) was someone on this forum pointing out the difference in weight. I need to lift it onto the shore and bwck on the boat each night...

 

Anyway, it has been troubling me for almost a year... It does a weird pulsing cycle while it is charging. When I f irst turn it on, for three minutes or so it charges at 25+ amps, then after that it surges: it goes up to 25+ amps and then cuts out, down to a negative number, then back up again. Eventually it stops doing this, but after a very long time.

 

I've had a couple of engineer friends take a look at it. They both have come to the same conclusion: the charger wants more from it than it can give, so it cuts out. They both think that if I could regulate how much the charger demanded, it would be solved, but neither know of any way to reduce the charger's demand. Then they just look at me and shrug.

 

After that, my engineer friends shake their heads and say this pulsing is NOT GOOD for the generator. Also not efficient, as a good proportion of the time it is running it is not charging at all (becaue it cuts out, then resurges). All very well, but not very helpful, since they can't offer any solutions.

 

Any thoughts? Or have I just got a hopelessly mismatched system, needing smaller battery charger or bigger generator? Is there anything that could be built to reduce the call from the charger so it never charged at more than 25 amps? (about 28 amps seems to be where the generator gives up).

 

I hope this description of the problem makes sense. Any help most appreciated.

[by'eck]

Your Sterling Combi has a 70 amp charger. The start up current from this would give a heavy load to an EU20i never mind the 10i you have especially as low charge batteries will demand the full 70 amps from it. No wonder its complaining.

[Richard10002]

Your Sterling Combi has a 70 amp charger. The start up current from this would give a heavy load to an EU20i never mind the 10i you have especially as low charge batteries will demand the full 70 amps from it. No wonder its complaining.

 

70A x 14.8V = 1000W approx. The 10i isn't rated at a kilowatt, so won't cope. I have a 20i which copes fine with an 80A and a 100A charger, but hunts if it is asked for more than about 1.6Kw, I.e. it's not rated for 2Kw.

[mrsmelly]

Hi, Folks. Last year I bought a Honda generator. I have a Sterling pro Combi Q 2500 inverter/battery charger. I debated whether to buy the Honda 20i or the Honda 10i, but after taking advice on this forum and elsewhere, I opted for the 10i (1000 watt). It seemed that 1000 watt would be all I needed (I don't run a washing machine or anything power hungry -- my greediest appliance is a 12 volt fridge).

 

What swung me (besides the price) was someone on this forum pointing out the difference in weight. I need to lift it onto the shore and bwck on the boat each night...

 

Anyway, it has been troubling me for almost a year... It does a weird pulsing cycle while it is charging. When I f irst turn it on, for three minutes or so it charges at 25+ amps, then after that it surges: it goes up to 25+ amps and then cuts out, down to a negative number, then back up again. Eventually it stops doing this, but after a very long time.

 

I've had a couple of engineer friends take a look at it. They both have come to the same conclusion: the charger wants more from it than it can give, so it cuts out. They both think that if I could regulate how much the charger demanded, it would be solved, but neither know of any way to reduce the charger's demand. Then they just look at me and shrug.

 

After that, my engineer friends shake their heads and say this pulsing is NOT GOOD for the generator. Also not efficient, as a good proportion of the time it is running it is not charging at all (becaue it cuts out, then resurges). All very well, but not very helpful, since they can't offer any solutions.

 

Any thoughts? Or have I just got a hopelessly mismatched system, needing smaller battery charger or bigger generator? Is there anything that could be built to reduce the call from the charger so it never charged at more than 25 amps? (about 28 amps seems to be where the generator gives up).

 

I hope this description of the problem makes sense. Any help most appreciated.

 

Hi

 

The gennie is simply way too small. I have just removed the same stirling combi unit from my boat and when I was using a gennie to charge through the combi mine had 2.2kw continuous rating and the combi made that work hard at times.

 

Tim

[nb Innisfree]

I wish generator manufacturers wouldn't call them 1000 or 2000 or 3000 something or other, it's very misleading. But who among them is going to call their Fireball XL 1000, Fireball XL 800 instead, and give the impression it is smaller than the opposition. A Victron rep once told me they named their inverters to reflect it's peak output (e.g. 12- 2500-120 instead of it's true continuous output of 2kva) because other manufacturers did the same. Very confusing for the uninitiated..

[smileypete]

Any thoughts? Or have I just got a hopelessly mismatched system, needing smaller battery charger or bigger generator? Is there anything that could be built to reduce the call from the charger so it never charged at more than 25 amps? (about 28 amps seems to be where the generator gives up).

 

I hope this description of the problem makes sense. Any help most appreciated.

Probably the charger draws it's input current in a funny way that overloads the inverter genny.

 

Would be interesting to find out what the 'input VA' rating of the charger is, it's likely to be much higher than expected.

 

How many batts do you have out of interest?

 

cheers, Pete.

~smpt~

Edited November 1, 2012 by smileypete

[Proper Job]

I wish generator manufacturers wouldn't call them 1000 or 2000 or 3000 something or other, it's very misleading. But who among them is going to call their Fireball XL 1000, Fireball XL 800 instead, and give the impression it is smaller than the opposition. A Victron rep once told me they named their inverters to reflect it's peak output (e.g. 12- 2500-120 instead of it's true continuous output of 2kva) because other manufacturers did the same. Very confusing for the uninitiated..

Unfortunately they all do that.

 

The EU10 has a max output 1,000W, but it's continious rating is 900W

The EU20 is 2000W peak, but only 1600W continious

 

Peak is fine for short term start up loads (motors)

 

Inverters are often the same. They can give a short term high load, but have a lower continious rating

 

Ignore what it's called and check the continious rating.

 

Also think about the voltage requirement. The rating will often be power/Amps at 12v. Not a lot of good when your output from the charger is , say, 14.6v

[Richard10002]

Hi, Folks. Last year I bought a Honda generator. I have a Sterling pro Combi Q 2500 inverter/battery charger. I debated whether to buy the Honda 20i or the Honda 10i, but after taking advice on this forum and elsewhere, I opted for the 10i (1000 watt)..

 

Whatever you do, don't chuck the charger. The Hondas hold their value well, so you could sell it on here or eBay.

 

The Eu20i is much heavier than the 10i, 21kg I think. I don't think my wife would want to be lifting it, other than in an emergency. The better option might be to buy a smaller charger, say 40A, and only use the Combi for charging on shore power. You'll get a good charger for much less than a new genny, and you will still be able to use a genny you can manage.

[Duchess Omnium]

Thank you, all. Yes, I did work out that the charger was too much for the generator... (though my specs seem to say that the charger is 50 amp). I was wondering if there was a way of stepping down the charger. Sounds like I might have to go for Richard's suggestion and buy a smaller one.

 

edited to add re Pete's question: I have 5 domestic batterries

Edited November 1, 2012 by Duchess Omnium

[Arthur Brown]

I'd guess ( I can't see the items ) the charger needs more power than the generator will supply so the generator overheats and cuts out and restarts after a while, hence the hunting or cycling, which is probably part of a thermal heat/cool cycle.

 

Run a smaller charger, or look in the manual for a low power setting -there may be one.

 

Obviously as the battery charges the cycling stops as the charge rate naturally decays as the batteries charge, then you get the normal charging pattern you expect.

[Duchess Omnium]

Hi, Arthur, yes, I believe that is exactly what is happening (though don't know if it is overheat setting or what, but it is definitely cutting out in response to t oo much call from the charger). There appears to be no low power setting. I guess I was hoping one of you electrical geniuses would know some kind of intermediate regulator that could step down the call the chargerr is making.

[Richard10002]

Thank you, all. Yes, I did work out that the charger was too much for the generator... (though my specs seem to say that the charger is 50 amp). I was wondering if there was a way of stepping down the charger. Sounds like I might have to go for Richard's suggestion and buy a smaller one.

 

edited to add re Pete's question: I have 5 domestic batterries

 

Your charger is a 50A. I have a Pro Combi S 2500W, which is a 70A charger, but the specs show the 2500W Q model is 50A. I assumed the same size inverter charger, Quasi or Pure Sine, would have the same size charger - it doesn't!

 

50A x 15V = 750W, which the Honda Eu10i should be capable of - Back to the drawing board?

[by'eck]

Your charger is a 50A. I have a Pro Combi S 2500W, which is a 70A charger, but the specs show the 2500W Q model is 50A. I assumed the same size inverter charger, Quasi or Pure Sine, would have the same size charger - it doesn't!

 

50A x 15V = 750W, which the Honda Eu10i should be capable of - Back to the drawing board?

 

50 or 70 amp, the start up power requirements will be more than your calculations which take no account of inefficiencies.

 

Why ignore the facts? The generator is not up to it.

[Proper Job]

50 or 70 amp, the start up power requirements will be more than your calculations which take no account of inefficiencies.

 

Why ignore the facts? The generator is not up to it.

The EU10 would probably cope with the start up requiremnts of a 50amp charger as it would soon drop back down to within its continious running rating (<900W)

 

By the sound of it, it was coping with the start up load. It then 'tripped' when it sensed that the load was still in excess of 900W.

 

I've got a 40 amp sterling charger (non combi) that I ran for a short time on a borrowed 1000W genny. It didn't appear to make the genny grunt to much, but I wouldn't have expected it to.

 

When I invested in my own, I got an EU20. It gives me the flexibility to run power tools etc. Additionally, when charging the batteries it's a lot quieter because it's on less than half load (rather than a 1000W unit running near full load)

[Duchess Omnium]

Your charger is a 50A. I have a Pro Combi S 2500W, which is a 70A charger, but the specs show the 2500W Q model is 50A. I assumed the same size inverter charger, Quasi or Pure Sine, would have the same size charger - it doesn't!

 

50A x 15V = 750W, which the Honda Eu10i should be capable of - Back to the drawing board?

 

Yes! That's exactly what is so frustrating. I started a thread last year, stated what I needed my genny for, my power usage, my charger (supposedly 50 amps) and specifically asked whether I should get the 10i or the 20i. The general consensus was the 10i would probably be enough for my needs and as someone pointed out the difference in weight (let alone diff in price) I went for the 10i.

 

Ok, it seems to have a problem (though why it should with a 50 amp charger I am not sure; you guys no better than I). So all I am asking is can anyone find a fix other than buying a 20i (not happening, since I paid a fair bit extra to have the 10i converted to propane*) or buying a smaller spec charger (which seems like the best solution).

 

* before any of you get sidetracked, the pulsing problem has nothing to do with the conversion; that was the first thing I thought of,but it pulses on petrol as well as propane.

 

Sorry! Probably not a very interesting question after all. 1000 watt gemerator just not up to 50 amp charger. But might be useful for others to know.

 

Edited to add I should have repeated that I am really grateful to everyone who has taken the time to think about my problem, and especially to those whe have made suggestions. This is a great resource that I have used for as long as I have thought about having a boat.

Edited November 2, 2012 by Duchess Omnium

[by'eck]

To put things in perspective I have a Kipor IG2600 suitcase inverter generator claimed to give 2300 watts continuous, 2600 watts peak. I also have the larger Sterling Combi with 100 amp charger.

 

Admittedly it has an LPG conversion which probably reduces its power capability, but it struggles when I first turn on the Combi when its charger hits 100 amps. In fact I usually turn on my second 50 amp charger first until its warmed up.

 

Given these facts I don't find it in the least surprising that your generator of less than half capacity suffers from surging, which as has been suggested, will certainly stress connected equipment.

 

Given Honda quality I doubt there is a problem with your genny. Despite all the speculation and maths offered, the unfortunate bottom line is there is no fix other than using a larger generator.

[Arthur Brown]

Assuming that the batteries and generator are fixed in this application the simple answer is to run a smaller charger til the charge rate subsides a little then change to the bigger charger to complete the charge cycle. If your current charger is 50A then maybe a 40 or 35A charger would suffice without too much increase in run time. /321014686104?p 280938099140?p from ebay may offer ideas.

 

Alternatively put a very low ohm power resistor in the charge lead to reduce the current to what the engine will stand, fit a switch to short it out as the correct taper is needed. Realistically I'd play with a 0.02ohm resistor of 200+ watt rating. Maybe just adding a metre of connecting wire would do the job.

[captain death]

my electroquest 45A charger has a button to half the output power from 45A to 22.5A . Handy if you generate hates large startup loads and the like.

 

It seems that it's quite good at taking the available amps from the generator, rather than popping a fuse. However my generator is old and clunky, and not one of these

new inverter type's.

 

Not exactly power control , but it does work well.

 

on shorepower i can get 540 watts ,directly if the battery want that much current. On generator, i can get 300-400 watts of power.

 

not all of that is going to the charger, I'm not quite sure what my Power factor is.