This thread has gone all frazzled. Each person here has different intentions on how they would employ such a power supply.
I've never bad mouthed the cheapowatt. The thing burst a nut providing 538 watts when it was rated for 350. I think it is admirable it lasted that long. I knew the buzzing I heard was a sign. I pushed it anyway just to see how far it could go. Now we know. Sorry if this information offends the desire to have cheap chinese products work flawlessly and justify one's "frugality"
Not understanding the desire for constant current in the bulk Phase or the logic behind this desire? Can't help you there. Plenty of threads about converters not going into 'boost' and unhappy converter owners out there. Wahhhh m y PD 9260 only does 50 amps for 20 minutes or my Wfco never goes into boost. Seems the only happy converter owners are the ones who never test specific gravity, or who never use the generator to charge, or just travel from pedestal to pedestal.
Yes I want constant current within the device's capabilities until my set Absorption voltage, I don't want to have to fiddle with a voltage pot 12 times during the bulk phases, nor half a dozen times afterward absv is reached to hold constant voltage. This is what the cheapowatt required. Constant human intervention to keep it from smoking itself on a thirsty battery
If plugging in this cheapowatt to a depleted battery, dialed in the voltage pot to just below buzzing level and never touched the trim pot again, the voltage probably would have stopped rising in the low 13's and amps tapering to very little very quickly. I did not get a chance to test this because I moved onto the stress test which smoked it. I can say that the trim pot was still below half, initially, to keep the buzzing at bay.
The stress test was setting the desired end voltage before hooking it to the battery, and letting it go. With no self protection, the cheapowatt burst at the 17 minute mark exceeding its rating by a huge amount. Instead of a thanks for exploring the limits of this unit, a get derided for expecting too much. Kiss me where I poo.
Now the other power supplies available, still made in Asia By the way, which are more expensive do incorporate some type of self protection in overload. The hiccup mode supposedly shuts off the unit until the overload is removed. Niner has said something about documentation that describes this hiccup mode about the Megawatt, yet hiccup mode is not what the website claims occurs at overload. They say the 30 amp supply will do 33 amps for 30 minutes, roll back to 30 amps to cool down for 3 minutes then ramp back upto 33 amps.
Niner's one report about starting in cold temps at 40 amps and quickly tapering to 20 amps does not really follow Megawatt's claims as to function. Niner has offered to allow me to test/datalog his unit in my system, but we are too distant. I'd like to thank him publicly for the offer.
The behavior he described sounds more like roll back current limiting which to me is more desirable than a true Hiccup mode which just shuts down the power supply.
But the Third option is the current limiting mode on overload that Mean Well claims to employ on some of their models. This would seemingly do what I want a power supply to do, in my usage. I want to set an absorption voltage, set a timer and walk away. The battery can obviously accept more amperage than the unit can safely provide, so I want the unit to employ a safe maximum for itself. I'd like this maximum be 30+ amps as my AGM responds to this very well.
I'll Spend what I have to spend to get this, and If I could have 6 cheapowatts delivered for that price, So be it.
Whoa whoa whoaaa hoooo Nellie.
No need to insult my Screwy 31 with claims of worn out and sulfated. :)
It is being working hard nightly and performing well on my current solar alternator schumacher recharge regimen.
Thanks Niner, good to know I can retask my 10 turn trim pot on a Mega watt if that is what I wind up with.
Mena, confirmation can't hurt but don't go through any (more) hassle for me.
So Niner, you want me to acquire the 400 watt Megawatt?..... How bout draining that T-1275 to 75 amps hours from full, Set the MW to 15.0v, hook it to the battery and let that megawatt loose on it, max it out. See if it does the 33 amps for 30 minutes then 30 amps for 3 minutes then 33 amps again for 30 minutes like the claims on the homepage. If it does, I'll click place order on confirmation.
If it drops to 20 amps in a warm climate, No thanks.
I smoked the cheapowatt charging the screwy 31, not the AGM. The AGM was charged the night before and I moved the trim pot about 12 times in 70 minutes to keep the amps above 32amps and under 36.2 amps, and then kept lowering it slightly afterward to keep battery voltage from going past 14.7v.
On the screwy 31, I set it to 14.7v, hooked it to the battery, and blue smoked it at the 17 minute mark.
Ahh, got power an internet back I see. How was Hurricane Ordeal in your location?
I think a depleted group 31 AGM could still max out two paralleled cheapowatts.
Any overload circuitry which allows me to dial in a 14.70ABSV, hook up the battery and not worry about magic smoke release, is worth the money to me. I want 36 amps until battery reaches at least 14.7v. I don't want to have to increase the voltage pot as the battery charges in a feeble attempt to keep constant current, or fight the taper. That was a PITA.
I'll add heatsinks internally/externally, fine tune the mating of heatsink to case, install a better fan, I'll add a 10 turn trim pot, but whatever I get needs to be able to do constant current at 30+ amps for 2 hours. MY cheapowatt, may it rest in peace, needed too much tweaking to hold 36 amps.
Human overload protection is not acceptable, to me.
To no one's great surprise, just replacing the two transistors did not fix the Cheapowatt.
Something went POP soon as I flipped on the 120vAC. Think it was a new Transistor, but no visual damage. No output voltage.
The cheapowatt, is Dead.
New Fairchild transistors felt heavier than the failed ones. Attributed it to the longer leads, but after removal with short legs, still felt heavier.
I used up the rest of my Solder wick, trying to pull some components clear of the circuit board without damage to either. Practice. I am not very good with it. Kind of frustrating getting the wick in the exact right spot when solder liquefies. I think the suction gun would be better, or stiffer solder wick.
Those Capacitors are pretty light in weight.
Anyway, not sure if I am going Megawatt or MeanWell. I'm going to research these hiccupp/current limiting modes, and perhaps send off an e mail to both companies. See if I get an answer different than what is published online already.
I really want to know the behavior of both in a true extended overload situation before dipping my big toe into the power supply pool again. I want a 30 amp plus manual bulk charger, an extended absorption charger, and a finish charger too.
One question I have to Mena, Niner and green, is can you read any numbers on the voltage trim pot? I'd assume They would be 1000 ohms like my cheapowatt but It's be nice to know for sure.
Ahh, hadn't considered the temperatures.
You left your Megawatt outside?
How dare you!! I thought you'd put it on the nightstand.
Wonder when electricity and internet will be returned to seenyore Mex. Forced Digital Detox. I could probably use a detox.
I knew it was a smart phone 'Migrate'
My 31, was about 55 to 60%SOC, amp hour wise if it were still new, yet it was able to gobble 38 amps for those 17 minutes before the magic blue smoke release.
I have about 3 feet of 10awg to about 11 feet fo 2 awg to my 31. I've got some 8 awg on the way. but even when i put my clamp onmeter rght over the battery cable by the battery I was reading 36 amps when meters closer were reading that too.
The dropping to 20 amps in your phone dictation say your battery was much closer to 85%+ when you applied the megawatt, or the megawatt is Limiting current by 1/3, or your battery is not as healthy as you believe.
if it was at 60% when the MW was applied, the MW unless limiting itself it should have done 30+ amps for an hour or more,likely more. Have you another method to check your ammeter for accuracy?
I watched some U tube videos on the less expensive meters on Ebay and amazon, and even calibrated to the limits of the calibration pots, were way off still.
Niner, did the Megawatt actually come with documentation?
I might very well purchase one, the 400 watt model, but first I want to see if I can fix the cheapowatt. New transistors and sil pads Supposed to be here Monday.
Even if I can fix it, I'll likely get a PSU which will not smoke itself or needs to be monitored so it does not.
I've not ruled out a Meanwell either.
Interesting mention of the 'hiccup mode'
On MeanWellsFAQ page,
MEAN WELL has ESC, SC, PA, PB series for battery charger purpose (120~360W). If these series does not meet customers' demands and they like to choose a power supply as a charger, we advice to pick up one which over load protection (OLP) mode is constant current limiting. The models in this mode provide constant current even when the protection circuit is triggered.
The second choice is fold-back current limiting or constant wattage model. In this model, when a battery is running low, the output current of the power supply will gently increase. The level of increase depends on battery's capacity and degree of exhaustion.
Hiccup or shut down model are not recommended because it will stop to generate current when OLP happens.
Love the chingrish.
I want to know what happens when a megawatt is taxed to the max, not what the website claims it will do.
to migrate surpriseat 25 degrees the mean well was showing 40 amp output at startup
the rate quickly fell at about 1 amp per second such that at about 20 seconds I was showing 20 amps input where it stayed and held.
This statement does not fill me with confidence in the Megawatt. But perhaps it says more about your battery.
What size wire and how long a run?
Have you seen it hold 30 plus amps for 30 minutes?
My Schumacher will do 27 amps, rated for 25. When I held the cheapowatts amps at 36 via adjustments to voltage pot every 7 to 10 minutes for that first hour or soon the AGM battery, the difference in voltage the next discharge was even more impressive, along with the ability to crank my engine violently fast. The shcumacher's 25 is superior to my solar's 12/3 amps in these regards too.
If the megawatt 400 watt model, is not going to do at least 36 amps, I'd rather monitor the cheapowatt, at least on the AGM.
One of Niner's reports is that his megawatt started at 33 amps and dropped to 20. I don't know if this was due to battery state of charge, or that the overload function kicked in reducing output to 2/3 of max for self protection.
I of course want it to limit itself right below absolute maximum, and not 2/3 of maxiimum, though this desire might be unreasonable.
Also one thing to keep in mind is these units are capable X amount of watts, the amps in relation to watts will change with battery voltage and PSU terminal voltage, and in this regard my cheapowatt was doing 14.12 at the terminals at 38 amps which is 538 watts!!!
Even more impressive being nearly 200 watts over the -350 sticker on the side
Correct on all accounts as far as I know. Those spec sheets seem to be written in Chingrish, I would be interested in actual overload functionality. Not sure how overvoltage protection would come into use, unless the voltage pot is reduced below battery voltage.
When I did that on my cheapowatt, it whined in a high pitched note in protest and I would disconnect it from the battery, let battery voltage drop, then plug the cheapowatt back in and then dial it to float voltage.
I saw, but cannot refind, that one of those Ammeters on RJ's link, had a hall effect sensor for the Ammeter instead of a Shunt.
Looked big enough that 4awg wire could be fed through it.
I have a Turnigy, well GT power meter, that gets really warm passing 30+ amps. But it can count amp hours and some other features which make it much more useful to me than just a standard Ammeter.
I'd love to get some fatter wire attached to the two sandwiched circuit boards, but the negative board is inaccessible unless the boards can be separated, and accomplishing that would require better tools and skills than I possess.
I don't think, without close user interaction, the cheapowatt would be good for anything but top charging on a bank that can't accept more than the cheapowatt can handle, and the absolute max appears to be 36 amps.
My first 2 tests I was moving the trim pot a lot. I'd estimate that when first started, the trim pot was less than half way up when output exceeded 36 amps and the buzzing began. I kept it just below the buzzing, and as the battery voltage rose, amps tapered, and I'd adjust the trim pot higher to keep it just below 36.2 amps. Eventually the trim pot was maxed out, the battery was taking less than 36 amps, and eventually the battery voltage rose above my desired 14.7v at which point it required dialing back the trim pot.
This close user interaction is obviously unacceptable every single recharge. I am not sure that having a pair of them with a diode separating them would really solve the issue either, as initially hungry batteries could likely still max out both units. I know my depleted AGM could easily accept 72 amps. I've seen my flooded 31 take 75 alternator amps. But of course the amps accepted at this level would be of shorter duration, perhaps short enough duration that the cheapowatt will not release the magic blue smoke.
Now the Megawatt or some Meanwells which incorporate current limiting could be another story. If a battery can accept way more the MW can produce, but the MW limits current protecting itself, then one could in theory set the desired ABSV, turn it on and walk away, and it will feed the maximum amps it safely can right at the current limiting overload protection mode. A timer and some estimation and one might come back and find a battery that is very close to full charge, and future recharges can be dialed in a bit closer with a self wound timer.
I want to fix my cheapowatt. I've grown to respect the little SOB, but I know even if the new transistors do allow it to function again, my relatively small depleted batteries would still allow it to smoke itself again no matter how much heatsinking or ventilation I can add to it, as it incorporates no current limiting but will just give itself a heart attack producing 125%+ of its rating. it should also be noted that my wiring between cheapowatt and battery is heating up a lot. Proper size wiring would likely make the overloading issue even worse.
So it will allow me to do a fast bulk charge, if I am willing to sit there and baby sit it. I guess since when I do have grid power available I generally do not have a time limit, I could set it to float voltage then hook it to the battery, and initially it will max out, but probably taper to below max amps relatively quickly before it smokes itself, and the battery will charge much much slower. But it could be a set it and forget it, but perhaps it would need days to get the SG to the max and on an unloaded battery.
If I do get it operational again next Monday, I'll have to test the above paragraph.
but Ideally I'd have a current limiting MW I could just set to my desired ABSV, attach to battery and let it go.
And one other thing I am curious about, concerning my screwy 31 that needs 14.9 Absv and a 15.3v finish when on 200 watts of solar, what this battery needs when recharged at a higher cheapowatt rate. I checked SG the day after a cheapowatt charge and the SG was maxed out, and before, it usually required 16v for a while after holding 15.3v for a while to accomplish this max SG. LendinG credence to the faster charge rate being more effective than low and slow that is always espoused as being best for a battery, if one has all the time needed to reach full charge.
I really like the small physical size of these power supplies. Since i have relatively small capacity i can make one of these units work for me, but those with larger capacity banks still need a bulkier bulk charger and employ one of these power supplies after the other charging source decapitates Absorption voltage and duration, if/when a 100% recharge is desired.
Perhaps with the right diode incorporation, these power supplies can add to the bulk amps of the other decapitating bulk charger and just take over automatically when the decapitator, decapitates.
Again there is nothing automatic with these, no set it and forget it, and this eliminates them from contention for usage by all but those willing to monitor them to some degree or another.
Yeah, I guess I was listing an ideal automatic charger with user chosen setpoints.
Since they do not really exist, well that is why i said Eff it, I'm getting a powersupply with adjustable voltage pot, and will monitor it.
the cheapo watt just needed more monitoring than i though acceptable, requiring me to keep raising the voltage pot as the battery charged to keep the amps up high.
Setting the voltage then hooking it to the battery is what smoked the cheapowatt. the megawatts claim overload protection and so do Some Meanwells.
I'd not be happy if i got one or the other and they could not sit at at least 90% their rating for the whole bulk stage. The cheapowatt went to 125% the rating and stayed there until the spark show 17 minutes later. perhaps better heatsinking would have delayed the fireworks, but I doubt they would have stopped them
So what you would like is basically a full charging solution with user definable or adjustable set points w/timer? The charger would need to be capable of sustaining a 40 amp draw?
Well my ideal charger would have a dial for maximum amperage allowed, up to 40 amps, but perhaps higher too
It would have a dial for setting absorption voltage at 77f and a battery temp sensor and automatically compensate for temps not 77f.
it would have a float trigger. When amps required to hold ABSV fall below X, revert to finish. which could be anywhere upto 15.5v
A timer to hold finish charge,
Then revert to a user selectable float voltage for 77f ideal, temo compensated.
but I'll be happy enough with a overload protected constant current 40 amp supply with a 10 turn voltage pot, attached to my GTpower which has 6awg leads replacing the provided 12agw leads.
Seeing what the power supply is providing is important to me, counting amp hours returned is desirable.
I should have said I want the timer to be user selectable as to the amount of time too. An Automatic timer would be too close to the automatic underchargers which fueled the desire for a top charger in the first place.
I just want one AC powered charging source, but If i am able to fix the cheapowatt, I might use two depending. One charging one battery, the other floating the other battery which has all my regular loads on it.
I still think about feeding my solar controller with a 20 amp source, let the solar controller go through the hold absv for x amount of time or when amps required to hold absv fall below X amps, revert to float voltage set at X volts.
So cheapowatt as a solar panel
Well I want at least 30 amps to bulk charge my Northstar AGM, it is still doing tarzan yells from the 36 amps the cheapowatt fed it until 14.7ABSV. A portion of that 36 amps upto about ~6.2 amps at times, was feeding loads on the system.
But my Flooded battery has a 'recommended' rate of 13 amps, but as evidenced by my smoked cheapowatt, can easily accept 38 amps.
generally if i have plugged in , i have no time limit, but the AGM needs a high rate, and seemingly the higher the better, like lifeline says on their Agm's.
Ideally, I'd like a user selectable 15 or 40 amp max charge rate, fully adjustable voltage up to 16v, and a built in timer that triggers a user selectable float of 13.1 or 13.6v.
The MeanWell se-400-15 shuts down on overload. I want one which does constant current on overload.
In a dream world, I'd have this unit,and it would go down to 13 volts.
but the 400 watt mega watt would meet my desires for less $$.
Good report green.
I really like the constant current limiting of some or their models the sp-200 being one of them. That MWell model claims 14.3 to 16.5 and you say it can do 13.3 to 17.5?
I'm kind of itching for available 400 watts as I want to use one to bulk charge, and my AGM responded very favorable to the cheapowatts 36 bulk amps from ~50%, and I might purchase a second of the same brand when my flooded screwy 31 bites the dust.
I'd love constant current overload protection and a 13 to 16v range and 400 watts.
I think Mex is without power and internet. Hurricane Odile really Hammered Baja. Reports filtering out of there are not good. Amazing that the storm center stayed directly over the narrow peninsula for 500+ miles, still able to feed somewhat on the warm water on both sides of it.
I bet the main highway has been severed in many places and will be impassable for days.
It appears that Mean well have 12v nominal versions with 10 -13.5v ranges
and that they have 15v nominal models with 13.5 to 16.5 or 13.5 to 18v ranges
Some shut down on overload, some are constant current on overload.
13.5v is too high for floating flooded batteries but should be fine for the AGM crowd.
16 volts can do a flooded EQ charge, and 18, not sure what anybody would 18v for. Perhaps it would power a computer designed for 19vdc
Meanwell even has some PFC'd models if efficiency is a concern.
Personally I'm holding off on any additional purchase for now.
Was just perusing the possibilities.
I've run my megawatt at 15.1 volts for over an hour no problems. it has Sat at 33 amps for over 10 minutes no problems. YMMV
Well technically my cheapowatt made over 38 amps for 10 minutes no problem. It was minute 17 that there was a problem.
The night before I had kept it at 36 amps for over an hour. It barely got warm when making anything under 15 amps.
Got a shipping notification from Mouser already for the new transistors. Hope replacing them works.
It appears that megawatt does have overload protection saying/claiming the 400 model will do 36 amps for 30 minutes then backing off to 30 amps for 3 minutes to cool off before ramping back up to 36 amps
MeanWells have some models which shut off at overload, and some others which hold constant current at overload, but these are pricier.
Meanwell offers lots and lots of different models