Doc Diy 6.6kW Zero 1hour COMPACT charger !

[grindz145]

hillzof, You're right, the PFC itself is really to improve power factor due to reactive (imaginary) power losses. However, PFC chargers usually have a nice front end that boosts everything to a 300-400V bus and the clean regulation allows for higher efficiency. Plus in general, if they have a nice PFC front end, it doesn't make sense for them to skimp elsewhere since it's not cheap to begin with. It can also bring down peak inductor / capacitor currents which can save very real power losses.

 

[heathyoung]

PFC will always give you an efficiency hit - its another stage (step up, then step down, vs step down). There is no escaping that. It produces more heat etc. than an equivalent non-pfc supply.

A non-PFC supply will have higher efficiency, especially if it is well designed (as the meanwell supplies are) BUT its apparent power will be higher than its output power.

Case in point - my crappy capacitive divider (aka badboy etc etc) charger has a PF of 0.3. That means while you are charging at 700W actual power, you are pulling ~2250W in reactive (KVAR) power - up that to 1Kw, and you are blowing breakers that are rated for 3Kw. Those 2Kw BMSBattery chargers are (IIRC) 0.8 PF, which means you derate to 1.2 X output + efficiency losses.

For those of you in 110V land, this is a big deal - less so for those with higher mains voltages

What it does allow you to do is to get the actual power closer to the apparent power - you can pull more power out and into your batteries without tripping breakers.

It also is a big deal for any industrial uses, where consumers DO pay KVAR and not just KWH.

 

[Doctorbass]

PFC will always give you an efficiency hit - its another stage (step up, then step down, vs step down). There is no escaping that. It produces more heat etc. than an equivalent non-pfc supply.

Are you sure a PFC supply produce more heat?? :? It is more efficient and the meanwell use synchronous mosfet instead of rectifier wich decrease heat again more...

Please explain what you mean by saying that a PFC supply produce more heat... the RSP serie certainly does not!

A non-PFC supply will have higher efficiency, especially if it is well designed (as the meanwell supplies are) BUT its apparent power will be higher than its output power.

heathyoung, i know you are probably better in electronic than me but please can you explain when you say :

A non-PFC supply apparent power will be higher than its output power. .. Well i know NO power supply that have higher output power than the apparent power! :lol: unless you invent free energy :lol: or combine with these "magnet generator"

Those 2Kw BMSBattery chargers are (IIRC) 0.8 PF, which means you derate to 1.2 X output + efficiency losses.

For mine it's more like 0.7 to 0.8.. they dont have any real PFC.. i get about 1500W out for a 2000W in... until the breaker trip... lol.. ( so i readjusted teh current limit)

It also is a big deal for any industrial uses, where consumers DO pay KVAR and not just KWH.

In Canada, Home electrical meter do measure apparent power(KVAR). They assume that the PF of average use is high enough. The suggest that if the power factor is less than 0.9 for medium to low power demand or if it is less than 0.95 for higher power, customers can request teh install of a power factor corrector device at their cost and upon their approval.

Doc

 

[heathyoung]

Are you sure a PFC supply produce more heat?? :? It is more efficient and the meanwell use synchronous mosfet instead of rectifier wich decrease heat again more...

Please explain what you mean by saying that a PFC supply produce more heat... the RSP serie certainly does not!

Its an extra stage, so it will never have 100% efficiency, so you add the losses of both (step-up - PFC, and step-down - PSU) and you end up with a bigger number than you would have had you just had a single stage (step down).

Efficiency (ie. power in vs power out) of a PFC increases as its input voltage increases, but its effectiveness (power factor) drops at the same time. Its bloody complicated, and basically means at 115V you can achieve 0.99, and 277V, 0.89. Due to the current in the inductor, your I2R losses in the inductor and highside/lowside mosfets are higher with a lower voltage and lower with a higher voltage (efficiency).

There is a long, complicated whitepaper explaining why, I read it and it made my head hurt, but it has something to do with being able to extract energy over a longer part of the cycle at lower voltages. Reading the graphs on their PFC supplies you will see this as well.

RSP is pretty efficient, especially if it has a synchronous rectifier on the PFC rather than a shottky diode (so I2R losses rather than VFI losses) - they are a high frequency converter and a full bridge if I remember correctly, so no need for core reset (and the attendent losses there as well).

Those 2Kw BMSBattery chargers are (IIRC) 0.8 PF, which means you derate to 1.2 X output + efficiency losses.

For mine it's more like 0.7 to 0.8.. they dont have any real PFC.. i get about 1500W out for a 2000W in... until the breaker trip... lol.. ( so i readjusted teh current limit)

It also is a big deal for any industrial uses, where consumers DO pay KVAR and not just KWH.

In Canada, Home electrical meter do measure apparent power(KVAR). They assume that the PF of average use is high enough. The suggest that if the power factor is less than 0.9 for medium to low power demand or if it is less than 0.95 for higher power, customers can request teh install of a power factor corrector device at their cost and upon their approval.

Doc

Well I'll be darned - domestic consumers being charged for KVAR? First time I have ever encountered this.

Is it measured or actually charged for? I know the PF of my house is abyssmal - switchmode PSU's and LED's, CFL's, motors - and the only heating elements are in the dishwasher and oven - PF is usually about 0.5-0.65 most days! I always wonder if I end up using more of the solar generation as a result though...

TL;DR - nice job, turned out well, RSP's are very nice supplies for the money, especially if you can get them for the price you did (they are three times the price here!).

 

[countermeasure]

Most impressive Doc.

Are those brackets holding the modules together custom made?
What size and type of wiring do you use for the interconnect?
Do you have a picture showing the interconnection and the AC side of things (show us the stuff under the metal cover)?

Thanks.

 

[Doctorbass]

Most impressive Doc.

Are those brackets holding the modules together custom made?
What size and type of wiring do you use for the interconnect?
Do you have a picture showing the interconnection and the AC side of things (show us the stuff under the metal cover)?

Thanks.

Yes the bracket are custom hand made and are using flat hex M4 screw The goal for the front bracket was to release stress from the wires connections of each power supply so all the wires are attached to that bracket. i also have fixed the 130A DC fuse inside that bracket. The CFM requirement of the psu is still ok with all the connections, fuse etc that are insid ethat bracket. The air exaust is on each side open of the "U" braket. I plan on installing a wattmeter and programmable Ah counter display on it too.

All the 3 L1, L2 input and GND are paralleled together to 3 turnigy wires 10AWG for the AC input. I know that 10 AWH is the max for the 30.5A consumption i have and that it is 8 AWG that is the best but i dont like the size of the Anderson connector that are the PP75. these are too ugly and the PP30 do the job really well with the 10 AWG . These wires stay ice cold.

The 2x 48V 41A psu are wired in parallel and hae also the two current share wires paralleled.

I also have installed some shottky diodes in parallel with these 2 psu.

The output of that dual combo goes in serie with a 24V 80A psu that i also installed a protection diode on it.

These diodes are to portect against reverse current in case that one of the two psu group ( the 48V or the 24V) would enable befor ethe other and would make reverse corrent goes to the other psu not enabled yet... that's to protect the current sense circuit.

btw i also use current sensing on these and the sensing is also directly connected to the 6AWG output Anderson SB50 connector.
The sensing negative sensing of the 48V goes to the negative connector lead. The positive sense of the 48V group goes to the negative output of the 24V psu with the serie junction to the 48+ to 24V neg. The negative sense of the 24V psu goes to the positive output of the 48V psu ( same serie junction to the 48+ to 24V neg) Then The positive sense of the 24V psu goes to the goes to the positive anderson connector lead.

This ensure that the CC-CV stage keep maximized time for the CC. (the internal resistance of the charger keep low and will push max current for longer period instead of fade out slowly.
Doc

 

[hillzofvalp]

Why is the SE-1000 typical output around 1kW but typical input 17.5*115VAC = 2012W?!?!?! It says it's 89% efficient... not 50%.

 

[Doctorbass]

Why is the SE-1000 typical output around 1kW but typical input 17.5*115VAC = 2012W?!?!?! It says it's 89% efficient... not 50%.

It's because of few things: Just like the RSP serie, the SE can give up to 1250W in constant current limiting so that's 25% more output max than the rating so it's 1250W not 1000W

Also the AC specified current is for a specified AC voltage input RANGE. This power supply can take from 90 to 264VAC so the 17.5A is the MAX it can draw and it is at 90V probably due to the PWM that will draw more current when less volt are present at AC input.

INPUT=90V x 17.5A=1575W
Output = 1250W

= 79% efficiency.


But these DONT have the PFC that,s your answer!.. that's why they draw more current! with a not corrected PF that mean more current draw and more KVAR and less real( equivalent resistive) power.

The RSP serie are the best.. period!.. RSP = up to 21.4W per cu inch while the SE serie is only 7W !!

plus it is 92% efficient while the SE is 79%

You get what you pay for, no magic here :wink:

Doc

 

[hillzofvalp]

what is the price difference between SE and RSP? I ask because I figure you know where everything is the cheapest.

also, what did you do to road-proof them? Do they need extra potting in places to resist vibration?

 

[Doctorbass]

what is the price difference between SE and RSP? I ask because I figure you know where everything is the cheapest.

also, what did you do to road-proof them? Do they need extra potting in places to resist vibration?

You will get all these informations on teh TRCelectronics website like i mentionned in many posts :wink:

SE to RSP is like 2 times pricy.

I have added silicone to critial parts in teh RSP to reduce low freq vibrations on some critical parts. but these are air cooled so no potting in teh RSP or SE or ant of these high power meanwell serie.

Doc

 

[hillzofvalp]

Sorry, I don't read everything. Which parts do you consider critical to hit with silicone? pretty much anything tall or unsupported? I'm used to seeing it primarily on caps, pots, and inductors.