My newest electrical toy.

Adjustable voltage power supply:



This is not an automatic charger, one can adjust absorption voltages for different batteries, and then once the battery has been held at ABSV for ~ 2 hours or so, turn of the power supply off manually (or use a spring wound timer), or lower the voltage trim potentiometer to float voltages.

Most automatic chargers are automatic underchargers. Most will not go to a high enough absorption voltage, and will not hold the battery at absorption long enough. This is fine for an engine starting battery, it is not fine for a regularly cycled deep cycle battery.

The Meanwell RSP-500-15 is about 120$. It is capable of 40.92 amps. It has Over current, overvoltage, and over temperature protections built in. I had a cheap version of a 350 watt power supply that smoked itself providing 538 watts as it had no protections. It was only 23$ so not a huge loss.

I put my GTpower RC meter in line, after increasing the wiring thickness on it from 12awg aluminum, to 8 awg tinned marine wire. Now it stays cooler and reads the same voltage as the output terminals, upto 17 amps anyway.

Right now I have it set at 13.6 volts, and it is holding the battery full, while powering all 12v loads.

Anyway, I am happy with my new toy. 40 amps bulk charge rate is nothing to laugh at, unless one has a huge battery bank.

Many people need to do equalization charges on their flooded batteries, and have no charger which can get a battery in the mid to upper 15's. This MeanWell power supply can do 19.3V if asked.

If one has the ability and desire to monitor the charging process, this is a very capable tool.

if one just wants something automatic and is not really concerned with getting the most out of their battery, then any of the automatic chargers/converters can fit the bill

I'm going to admit my ignorance, I don't understand what you are using for a charging source? Are you plugged into shore power? Does this replace your solar controller?

I don't have the big picture.
Bob

Yes, this is a shore power/ generator charger, and a highly capable one. Input AC voltage range is 85 to 265 vAC.

Rated at 500 watts output but can exceed this. My GTpower meter measured 589 watts maximum and it held that level for a half hour, until the battery could no longer accept 589 watts.

http://www.meanwell.com/search/RSP-500/RSP-500-spec.pdf

The GTpower meter is no new toy for me but it too is an excellent tool for electrical enlightment, especially for those who have no Idea how much electricity they are consuming, or how much their charging sources are producing.

http://www.amazon.com/gp/product/B0...d_t=201&pf_rd_p=1535523722&pf_rd_i=B0090YW78U

Yesterday I removed the 12awg aluminum GTpower leads and replaced them with 8awg tinned marine wire. This power meter is also very capable and about 90 to 95% accurate on loads above 0.8 amps. It counts upto 64 amp hours flowing in one direction and records and displays voltage minimum and Amperage peak and wattage peak. It displays voltage, amperage, wattage, amp hours (upto 64) , watt hours, amp peak, watt peak.



The weakness is the 12awg aluminum leads which limit sustained current in the 40 amp range( instructions say 50a) so large loads like inverter powering microwave should not be passed through this meter. It also cannot not account for Peukert in which larger loads reduce battery capacity available.

I'm going to order another one, as this one is now dedicated to the Meanwell power supply.

I recommend using 45 amp powerpole connectors for relocating the device to other circuits or flippng it around to measure current flowing on the other direction.
http://www.powerwerx.com/anderson-p...45-amp-red-black-anderson-powerpole-sets.html

These require either a special crimping tool, or that the crimper has skills to choose which dies on their existing crimper can achieve a good mechanical and electrical connection.

I've been swapping all my SAE connectors to the powerpoles as they are superior.

I had originally used these connectors throughout my van but found they heated up and failed in the 25 continuous amp range.
http://www.amazon.com/CES-Gauge-Qui...11847334&sr=1-1&keywords=SAE+10+awg+connector

http://www.amazon.com/Pico-1878pt-2...im_auto_4?ie=UTF8&refRID=0ZPA0RQ5978DEPD1G22D

Bob,

Adjustable voltage power supplies are something you usually see on a technicians bench along with the other usual suspects - oscilliscopes, signal generators, etc.

They run on 120 volt ac, so you would need to have shore power or a generator to use one.

The controls on them let you set a precise voltage - say, exactly 14.9 volts, and it will put that exact amount of voltage out until you manually change it or turn it off.

Stern believes - and I ain't saying he's wrong - that automatic battery chargers and solar controllers cut back way too soon and never bring batteries back to full, 100% charge.

This is only for the conscientious and highly knowledgeable, not for the average van owner. If you aren't careful with something like this, you could overcharge your batteries and damage them.

Regards
John

Yes this is a manual charging source.

The adjustable voltage power supplies on a tech's bench usually has dials for both voltage and current and cost upwards of 300$ and are the size of a small suitcase.

This Meanwell power supply is very compact and one needs a small screwdriver to adjust the voltage. There is no Current adjustment, other than what is afforded by changing the voltage.

This power supply could indeed overcharge a battery if set to a mid 14's absorption voltage and left there for more than a few hours. If set to a float voltage it would eventually fully charge any battery, maintain it at full charge, and power any loads ( upto ~ 40 amps) on the battery at the same time.

I do despise automatic chargers for their "we know what's best for each and every battery" algorithms and marketing claims. I really wish people would not put so much trust in these automatic chargers to do the job they claim. They are designed to Not overcharge a battery merely to get it close, which is fine for a car starting battery, but not a regularly cycled battery.
They are Not designed to fully charge a battery, but their marketing claims say otherwise.

Thanks for ther info on this....
Could the RSP-500-15 be considered as an alternative to solar panels for battery charging? Assuming that it was connected to a 800 watt inverter and set to a float voltage and the van was driven 2 or 3 hours per day?

stealthywon said:

Thanks for ther info on this....
Could the RSP-500-15 be considered as an alternative to solar panels for battery charging? Assuming that it was connected to a 800 watt inverter and set to a float voltage and the van was driven 2 or 3 hours per day?

Click to expand...

I can't see this as working.

1. You're going to convert 12 volt dc to 120 volt ac, THEN convert the 120 volt ac BACK to 12 volt dc. None of this stuff is 100% efficient, I would expect a fair amount of energy loss along the way.

2. More importantly, you mentioned setting it to FLOAT voltage. It takes FOREVER to recharge a deep cycle battery at float voltage. It certainly ain't gonna happen in 2 or 3 hours.

Do a little research on 3 stage battery charging - bulk, absorption, and float. The Lifeline Battery Manual - available as a free PDF download from the Lifeline website - has a good discussion of this. I'm sure there are lots of other sources of info on this.

Regards
John

basic physics, for every conversion of one form energy to another there is a loss. nothing is 100% efficient. the more conversions the less efficient. most of the time you are better off not converting but sometimes you have no choice. highdesertranger

stealthywon, You question has been answered.

The RSP-500-15 is designed to be plugged into the power grid. Can you plug it into an inverter on the engine battery, and use it to charge a different battery? Sure,

But, this is not the best way to accomplish charging a different battery in most instances.

In the case of travel trailers, or any situation where the House battery is very distant, round trip circuit wise, from the alternator, then an inverter hooked to engine battery, powering a battery charger, or in this case the rps-500-15 charging the distant battery over a long 120Vac household extension cord, then it is very possible for more amps to make it into the distant battery than other methods.

Also since the Distant MW Rsp-500-15 voltage can be set up high, then the amperage into the distant battery can be higher too. But the engine battery might not be receiving enough alternator current to not discharge when powering the rsp-500-15 which maxes out at 40 amps, so the engine battery would have to make at least 50 amps to account for inefficiencies in conversion. Robbing Peter to pay Paul as it were.


But when the battery is 12 to 15 feet away from the alternator, like in a full size van with extra battery in back, then 2awg cable through the standard solenoid/ manual switch/ACR method will be more effective at battery charging.

The RSP-500-15 maxes out at 92% efficiency, and that is at 240Vac. An inverter is lucky to exceed 85% efficiency. it is also possible a cheaper MSW inverter will not allow the RSP-500-15 to operate properly or if i can, as efficiently as a clean smooth Pure/true sine wave could.

The RSP-500-15 is ONLY for those who understand the basics of battery charging, and want the manual adjustable voltage controls that it allows, and are actually there and have the tools to measure current into the battery, and can lower the voltage at the appropriate time.

A spring wound timer can be employed when one is familiar with how much the battery can take at a certain level of depletion.


The RSP-500-15 can be employed to equalize batteries at 16v.

16v for an hour or 2, every thirty deep cycles can easily extend battery life 2 times compared to a flooded battery which is never EQ'd.

Very few vehicular/alternator charging systems, at hot engine idle speed can maintain 50 amps into a battery. Many would be hard pressed to produce this at highway cruising rpm when asked to do so. Exceptions exist. no need to prove me wrong if your system can, but those without the tools to prove me wrong should not assume their alternator is coming anywhere close to its rating, at idle or max output. If you cannot measure, you are flying blind. Simple as that

Hey Joe Thanks for the the reply.

I do have a basic understanding of charging a 12v battery bank despite my last post'(been lurking here for quite ahile) the reason I reffered to the float charge was because being a manual power supply it won't shut down when the batterys reach there full soc and the inherent risk of the inevital melt down.

I should have started of with.... assume a 50% state of charge and a 40 amp initial bulk charge to get things going I was hoping to sort of skip the a absorption charge for safety reasins and go right into the float charge. as sternwake said" If set to a float voltage it would eventually fully charge any battery, maintain it at full charge, and power any loads "

Currently I have 2 inverters 800 watts and a 2500 watt. I use the 2500 watt inverter to power a 6000 BTU window ac unit to keep the back of my van cool. It easily runs the the window ac unit that draws draws 960 watts/8 amps at start up and 535 watts/5 amps while cooling.

So the inverter goes from DC to AC and then the power supply would go from AC to DC So both units are designed to make the conversion and I look at the 12v power avaiable to me coming from my alternator as readily available. I have a 2003 chevy express 3500 that still has the original alternator and understanding that this puts a strain on it I have a new one in my van ready to be installed if it should crap out on me.

As far as not being 100% efficient I'm not sure why that would matter but I may not be seeing the big picture as I don't get this stuff right away

I would appreciate anymore suggestions you may have

I mentioned the inefficiencies because I think it probable you will put more energy back into your house batteries by just running a direct dc feed from your alternator.

You mentioned your two inverters, but you didn't mention whether they were pure sine wave or modified sine wave (more honestly called "a square wave generator trying to fake a sine wave").

As I'm sure you know, lots of things will run sort of ok on a MSW, but some stuff just really needs the PSW. I have no idea whether this power supply would run on a MSW or not, and it's possible not even the manufacturer could tell you.

In the end, it may come down to you just having to try this, and then reporting back to the rest of us whether it works or not.

Just remember the old joke about pioneers and arrows, and don't be totally surprised if the magic smoke leaks out of something.

Good luck.

Regards
John

ps: the boating world is a lot more innovative about stuff like this than the rv world is. If you want something sure to work, take a look at battery to battery chargers from someone like Sterling Power.

I have no idea if the Meanwell power supply would work properly on a MSW inverter. I am not going to risk it trying.

YOu could set it to ~13.2v, and it will put out its maximum for as long as the load on the battery it is attached to has that much of a load on it.

While this power supply is capable of 590 watts, it is only rated for 500. If you need more than 500 watts, they make 750 and 1000 watt and even larger models.. They recommend not running it often at maximum output where the overload protections are activated.
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I have done some more modifications to my Toy. I removed the original voltage trim pot and installed a 1k Ohm 10 turn wire wound potentiometer that allows me to precisely dial in any voltage from 13.12v to 19.23 volts. The provided "1000 ohm" trim pot allowed a range of 13.34 to 19.23 volts. When these voltage pots are turned to maximum voltage, fully clockwise, there is no resistance on the pot. When they are set to minimum voltage, the resistance approaches 1000 ohms. My 10 turn pot had like 25 more ohms resistance which allowed the minimum voltage to go from 13.34 to 13.12, which made me happy.

The Meanwells 40MM internal fan is also very loud when it kicks on. There are 2 temperature sensors inside the unit near the transistors that regulate this fan's operation. On or off, no variable speed.

I wound up installing 2 quiet Noctua fans into the power supply's lid, one 60MM blowing inward on an internal heatsink, and one 80MM exhausting. Now, at 70f ambients, when producing 40.94 amps at 14.7v, the loud 40MM fan does not kick on.

But, at 91F ambient temps, the 40 MM fan does still kick on after 12 minutes, when the power supply is kicking out nearly 41 amps.

Here I just have the 10 turn potentiometer taped to the lid. A better mounting system will be fabricated soon for it.



I have a large aluminum finned heatsink just resting on the side of the case in this photo. I have a bunch of these and I am going to attach them to the case exterior adjacent to the 9 transistors which produce a majority of the heat and use the casing as a heat sink.

The cooler the unit is kept the longer it will last, and since I am basically maxing it out for an hour or so every time I plug it in, so much so that the self protections kick in, I want the extra heat dissipated as best as possible.

Here is a graph of the volts and amps when I set the MW to 15.00v and plugged it into my flooded group31 battery which was 44 amp hours from full, if my battery monitor can be believed, and I only think it is 85% to 90% accurate.

The voltage dip at the ~40 minute mark was when the battery touched 14.8 volts, and I dialed down the trim pot to keep it from exceeding 14.7v.

MWTV is voltage measured at the MW's output terminals.
GTPV is the voltage measured by the GTpower meter
IPNV is the battery voltage as read by my IPN pro remote battery monitor
IPNA is the amps flowing into the battery
GTPA is the total amps the Meanwell was producing. I was still running TV, lights, fans and this amperage was not making it into the battery, thus the 2 different tapering lines.

At 2 hours, my battery monitor was reading 2 AH from full, but I suspect it was still a bit lower than this. The GTpower meter said it passed 57.079 amp hours, and I do not think my loads accounted for 15 amps hours worth in that 2 hour span.

I should have taken a specific gravity reading, but it was 3 in the morning and I just spent 2 hours taking recording volts and amps and temoerature every 5 minutes and was done on all levels.

US battery recommends a 10% charging rate, which would be 13 amps on this group 31 battery, and the MW was feeding it 3x that amount until just before ABSV was reached at the battery terminals.



This test was before I added the second noctua fan and the 10 turn trim pot and upgraded from 10awg to 8awg between 45 mp powerpole connector to battery switch and shunt. The 8 awg upgrade reduced the voltage drop, but I was done taking measurements for subsequent tests, so no more graphs, as they are Kind of a PITA to make.

When charging My northstar AGM battery, the MW produces 1 extra amp, which is due the the less internal resistance of AGM batteries.

This graph shows how quickly the amps taper once Absorption voltages are neared and held. If the voltage is lowered earlier, then the amps would be much much less and at the end of 2 hours the battery would be much less charged.

Not a big deal if you have a long time to recharge, but if you only can plug in for an hour or 2, or if you can only run a generator for an hour or two, then getting to ABSV and holding it there gets the batteries much fuller much faster, and most automatic charging sources, would not do as well as this power supply given the same maximum amps and the same amount of time.

dang stern documentation and graphs. I am impressed. highdesertranger

I know!

Well, it took me 10 months, but I finally got the extra finned heatsinks mounted to the casing's exterior with thermal transfer epoxy.

In general this power supply has been used a lot. More than I should be proud of, but the fact is I can basically plug in and not even cycle my batteries as I pretty much have a good home base on which to park.

The original 45 amp anderson powerpoles have hundreds of insertion and removal cycles on them and were showing some wear and tear and were getting warmer than when new. They were among my first installs and could have been done better.

I redid them just recently. Crimped and then soldered, and a bit more strain relief on them as the Meanwell is on my cabinet door and can put a lot of stress on the connector when opened or closed.

The 2 additional fans now have grille's on them, and had all their compacted dust removed in the tune up.

The heatsinks worked well. In very hot ambient temps at maximum output of ~40 amps, the original very loud fan kicked on after a few minutes, but then it shut off at 34 amps, 10 amps higher than without the extra heatsinks.

The 10 turn potentiometer was a 7$ cheapo version and developed a few spots where the resistance would jump around and send the voltage jumping around too.

Some Caig F5 fader lube sprayed inside the potentiometer cleared up that issue.


I am still deciding how I want to mount the 10 turn potentiometer, but held in place by some foam rubber in between the two fans might just last for another 10 months.

It really is quite a Kick burro 40 amp manual adjustable voltage charger. The Wattmeter really allows one to see when the battery is chock full bursting, and it can be dialed in for precision charging any 12v lead acid battery. The unit, even with extra heatsinks and external fans, is a fraction of the size of other 40 amp chargers.

Equalizing a flooded battery, or 'conditioning' an AGM battery is as simple as twisting a dial while watching the watt meter.

Manual voltage control is very empowering, and enlightening. For instance, say I have been floating a battery at 13.2v for a few days while there have been cycling loads on the battery as well.

Was 13.2v high enough to keep the battery from discharging while loads were still on the battery? I can goose the voltage to 14.4v, and if amps do not quickly taper back to the sub one amp range quickly, the answer is no. 13.2v was too low for floating my AGM. 13.5v was not.

Try and determine that with solely with an automatic charger or regular converter. Cannot be done. One is blind and has blind hope that the product is doing the job it claims to do.

With this unit I have returned a few chronically undercharged batteries of my friends and neighbors back to full function and saved them the cost of a new battery. Their bell and whistle laden Automatic chargers had failed them. This Meanwell holding them at 14.8v for 4 hours then ~5 amps applied until 16 volts was reached restored the battery to maximum remaining capacity, and all batteries are still in use, instead of recycled.

My friends were like, you just saved me 100$, and threw some cash my way or had me over for dinner and drinks, or both.
This unit has paid for itself, and kept batteries from going to the recyclers prematurely.

I know a manual charging source is not for everybody, but there are a lot of DIY'ers here who want more control. This could be the solution for them, as it has been for me. I know it is extending my battery life by being able to properly and fully charge them precisely to their individual requirements. The fact that it can float the batteries at the perfect voltage so that I need not even cycle them certainly extends their useful lifespan, for when I do not have grid power available.
And If I only have an hour to plug in, well a 40 amp charge rate is no Joke either and due to the adjustable voltage, I can make sure those 40 amps do not taper as the battery fills, as would other chargers.

Truly inspiring, thanks for this thread.
I love making electrical gadgets , been doing it since I was 10!

Sternwake

As you know I have the MegaWatt 36a variable voltage power supply. With the eyes of Mr Magoo and the hands of a nervous gorilla I decided to forego the ten turn pot modification. Luckily with a offset screwdriver I haven't found the voltage hard to set.

I did put a 50 amp analog meter with a internal shunt on it the other day. Not as nifty as the RC meter but functional.

I bought it for two reasons, the biggest is maintaining the Lifelines here at the house. I use to drag a panel out and hook up a solar system to do that before. The other is while camping and needing to charge up when it's too cloudy for too long OR hitting the batts with everything I have. Use the solar at 40-50a peak, the mega at 36a and even the converters 55a up to 13.6v and I have 140a if needed. Our generator should be able to support two or three MegaWatts if need be.

I haven't used it much for high amp applications except right after the last trip that had a few cloudy days in the end. I had the Mega lightly wired for set up and low amp conditioning charging but when I hooked up that hungry bank, all heck broke loose. After 15 minutes the fan was going nuts, the Mega was hot, the cords to the batteries and to the outlet were both hot. I shut it down and ran 10 gauge (all I had) and everything cooled right back down.

I have to say that the MeanWell looks like it met the borg and was assimilated. LOL

Be careful Sternwake, it might have been assimilated into the Locust Hive Mind!

You might be next! We all know resistance is futile!
Bob

Jim, good to hear you got an Ammeter on the output.  Can it maintain 36 amps or does it roll back to 30 once it heats up as Niner reports?

I really like this MeanWell as it will hold 40 amps as long as the battery can accept it.  it does not roll back output to protect itself, and with my extra ventilation and heatsinking, this does not beat it up as much, as it is heat which kills electronics.



The 60MM fan provided with these power supplies are just sleeve bearing junk.  Sleeve bearing fans do not do well in a horizontal mounting position.  The 40mm fan on my Meanwell is insanely powerful, for a 40mm fan.  It is quite loud and much of my efforts  in heatsinking/ventilation were to keep this fan cycling on and off under lighter loads when the unit is basically powering my Van overnight.

Replacing the fan is very simple.  On my original 23$ Cheapowatt power supply I replaced the 60Mm fan and did some other tweaks to the heat dissipation that were effective.  The cheapowatt just had no self protections, and I allowed it to burst its guts out providing 536 watts when it was only rated for 350.  Still it lasted 17 minutes at maximum output before the magic smoke escaped, and I believe my efforts at improved ventilation extended that time until smoke release.

I had cutout the aluminum restriction on the casing's lid and installed a noctua fan on the outside.  Not pretty but effective.

Removing the lid is just 4 or 5 screws, and the fans wiring is easily accessible.  If your fan is already struggling, do not let it kill your Megawatt.  Replace it.

I used this Noctua Fan:
http://www.noctua.at/main.php?show=productview&products_id=48&lng=en

It is now on the Meanwell blowing inward and a Noctua 80Mm next to it pulling out.  Very quiet fans, but not insanely powerful.

Larger fans can move much more air for the same current drawn and make much less noise doing so.  The Noctua NF-f12 draws only 0.05 amps and moves 53cfm.  This fan on the casing blowing inward would make your MegaWatt happy.

As far as the little voltage potentiometer included on the units, they will wear out if one changes the voltage a lot.  They were not intended to be adjusted often.  The one which came on my Meanwell was much easier to dial in a voltage, whereas the one on my Cheapowatt, which is the same as your Megawatt, became more difficult to dial in, and downward pressure on the screwhead started causing large voltage swings, making adjustment quite difficult.

The ten turn potentiometer is not so simple to wire up, and was much more difficult to do so on my Meanwell compared to the Cheapowatt .

But it is so nice to spin a dial to change voltage 0.01 volts so easily.

Locust Zapping precision.

Mine only heated up once and that was from under wiring. Luckily I checked it minutes after I started it to charging up the bank after the trip. Rewiring it changed everything instantly. It ran slightly warm for the rest of the charge up from 12.5v resting to 14.4v and that took quite a while with a 675 Ah bank. If a set of hungry Lifelines don't heat it up....

Speaking of which, someday bypass the RC meter and see if the Meanwell runs cooler. I was in RC for a long time and nothing I remember dealt with that kind of power. I'm talking ten foot scale birds with huge servos. Even charging in the electrics wouldn't pull that many amps for long so I have a hard time believing the RC meters can handle the load like the 50a analog.

I'll have two of the terminals on each side wired with 10 gauge. They will combine at the Amp meter on the positive side with 2 gauge going from the amp to the battery. On the negative side the two 10 gauges will just combine to a 2 gauge to the battery. I'll throw a switch and fuse in there too. The 2 gauge is from the old inverter and I have four 2 ft cables doing nothing, well worth it if it runs cooler. I can put a voltmeter on the third terminals.

the fan only made that noise while I adjusted the voltage with no load on it. Once I reconnected the bank it ran quiet again. Anymore issues and I'll swap it out for peace of mind.