Making a Bulk Travel Charger (edit)

I currently have a 9A charger for my motorcycle. J1772 charging stations are popping up everywhere around me, and I would like to take advantage of the two to three times faster charging rate that these 240V stations can provide. Problem is typical 87.6V cutoff, 20-30A chargers are too bulky, heavy, and/or expensive.

I haven't found a perfect solution, but starting to consider two of the new bmsbattery 900w units @ $145 per shipped:
http://www.bmsbattery.com/alloy-shell/457-alloy-shell-900w-lifepo4li-ionlead-acid-battery-ev-charger.html

These are supposed to deliver 10A for 24s lifepo4. So I'm considering putting two in parallel for 20A. If that works, I might add a third for 30A. On my GBS 40AH cells, the recommended charge rate is .3 to .8C (12A to 32A) with .5C (20A) as the ideal charge rate.

Anyone see a problem with paralleling two to three of these chargers together? Are there better solutions for fast opportunity charging off 240V charging stations? Any precautions I should make in paralleling them? I expect to pot many components/connectors to make it a more reliable mobile charger.

I like the fact that you can order these chargers with a specific HVC as I might add two more cells and bring the pack to 26s.

Thanks,

Pretty certain that diodes are required for paralleling charger's and P S U 's. Info from and older tread, but it all made sense at the time.

The diodes steer all power to the batteries and prevent power, going back and forth between charger/P S U 's due to inherent output difference's .

Thanks, I keep going back and forth between buying large/heavy PSUs and just building a cheap but dangerous "bad boy" charger using a 5000W rated electric dryer heating element to limit the current.

Efficiency isn't a concern as it will just be used for opportunity charging on long trips and the charging stations are free to use or charge by the hour. So idea is to rectify 240Vac to 340Vdc, run through heating element of about 10.7 Ohms and then through 80V battery pack. So 260Vdc/10.7Ohms =~24.3A. Maybe use Fechter's charger cutoff circuit to limit pack voltage to 82-83V and a cell-log8m to handle HVC on weakest cell. But with a 6300W blast furnace (think something that looks like a muffler) on my bike, I probably will be nearby during charging.

Also some intresting ideas in the current thread on " Poor mans 15 amp battery charger "

Ahh, what does a jack for this standard cost?

I also found a project to create your own home charging station:

http://www.instructables.com/id/Arduino-EV-J1772-Charging-Station/?ALLSTEPS

From my reading you are negotiating the max charge current. I.E. you could negotiate 16 Amps but only consume two.

Jack or adapter cable for this standard is $120 shipped. Pricey for a connector and cable but worth it if a can make a cheap charger.

Turns out the vehical requirements are extreamly simple a diode and some resistors.

The following link shows a diagram.

http://jackrickard.blogspot.com/2011/01/j1772-2009-charging-for-your-ev.html


The inlet/Jack is whats bloody expensive.

Probally not kosher but the J1772 plug has female recepticals that the pins in your inlet jack mate too. Since you don't need all the pins; maybe manually insert them as some public plug and force them into epoxy puddy to get the spacing.

Just have to find the mating pins.

1.5 mm for connection switch and pilot control lines
2.8 mm for ground line
3.6 mm for main, neutral and ground lines

http://portal.fciconnect.com/res/en/pdffiles/AutomotiveHighPower/FCI_Power+S3+SAE+J1772+Charge+plug+2010+06.pdf

On the poor man's thread there was talk about those stations maybe having their own current limit capabilities. You might want to consider that.

Kin said:

On the poor man's thread there was talk about those stations maybe having their own current limit capabilities. You might want to consider that.

Click to expand...

Actually I think these connections are designed for more power then we could possible use! 70-90 amps at 208+ volts.

So no need to limit to 10amps to keep from blowing the circuit breaker when doing a vampire tap.

fredsparkle said:

Kin said:

On the poor man's thread there was talk about those stations maybe having their own current limit capabilities. You might want to consider that.

Click to expand...

Actually I think these connections are designed for more power then we could possible use! 70-90 amps at 208+ volts.

So no need to limit to 10amps to keep from blowing the circuit breaker when doing a vampire tap.

Click to expand...

Yes! They're definitely designed for more power than we can use. I was suggesting however that I read from someone (ugh, hearsay), that the station might allow you to regulate the current that it will output, through the control interface. You will still have to pay attention to voltage, of course. And, I didn't end up reading whether or not this person's claim was verified. So, uhm, yes. I understand my original statement was not clear that I meant active current limitation, not ultimate power limitation.

In looking at J1772 and charging from a normal outlet.

The typical public charging station only supplies 240v and if you go with a typical high power battery charger like the alloy shell they do not dynamically switch input voltages.

Has anyone debated using multiple laptop chargers?

In this case you would be jumping back and forth between 120 and 240.

Presently I use the Meanwell HRP-600 series. However I've been looking at the Meanwell RSP series for bulk charging off the EV stations. Two HRP-600 in series consume about 1000W. That's fine for local use but for cross country it can take up to 9 hours to recharge my pack; not a reasonable wait for an EV station.

I am careful however that I will still need to charge within 115VAC @ 20A bathroom circuit (unless I had a current-limiting device <hint hint nudge wink>). The RSP units worthy of consideration are listed below with pricing from PowerGate:

• RSP-1000 ~ $255 USD
  RSP-1500 ~$355
  RSP-2000 ~$430

They can be strung in series, and/or up to 4 in parallel for true load-sharing. And can run on either 115/230 VAC.

Be sure to read the specs before purchase; the RSP-2400 and -3000 units DO NOT use 115 VAC. :|

~KF

Kingfish said:

Presently I use the Meanwell HRP-600 series. However I've been looking at the Meanwell RSP series for bulk charging off the EV stations. Two HRP-600 in series consume about 1000W. That's fine for local use but for cross country it can take up to 9 hours to recharge my pack; not a reasonable wait for an EV station.

I am careful however that I will still need to charge within 115VAC @ 20A bathroom circuit (unless I had a current-limiting device <hint hint nudge wink>). The RSP units worthy of consideration are listed below with pricing from PowerGate:

~KF

Click to expand...

Very interesting my thoughts were when using a J1772 station there would be no power limitation on the input side; just what you can force feed your pack. In my case was thinking I could do 48v @ 32amps for the charge rate. Which in this case could be the RSP-1500

However base on other reading here; you would want to limit 120v draw to 10amps for vampire taps of random outlets.

Another consideration is dynamically reconfiguring the pack from 48v to 24v or even 12v which I have the option of doing.



Hmmm, wander into a gas station; somethings wrong can I use your 12v charger? Or heck stand on the side of the road and hold up some jumper cables?

Say mister can you spare 250 watt hours to get me home?

Kingfish said:

• RSP-1000 ~ $255 USD
  RSP-1500 ~$355
  RSP-2000 ~$430

They can be strung in series, and/or up to 4 in parallel for true load-sharing. And can run on either 115/230 VAC.

Click to expand...

I personally have the RSP 1000 and RSP 1500 and i can say they are the most compact stabilized charging solution ever.

The RSP 1000 actually output 1250W Dc and the RSP1500 is outputing 1700W Dc.

The RSP-2000 wich is as compact as the RSP1000 is the most compact of the trio but i dont have one at the moment.

I just can't imagine how powerfull thet are!.. imagine two of the RSP-2000 stacked in serie to get 100V at... 4500W out of the size of a kleenex box!

Doc

Doctorbass said:

I personally have the RSP 1000 and RSP 1500 and i can say they are the most compact stabilized charging solution ever.

The RSP 1000 actually output 1250W Dc and the RSP1500 is outputing 1700W Dc.

The RSP-2000 wich is as compact as the RSP1000 is the most compact of the trio but i dont have one at the moment.

I just can't imagine how powerfull thet are!.. imagine two of the RSP-2000 stacked in serie to get 100V at... 4500W out of the size of a kleenex box!

Doc

Click to expand...

Hi Doc

You get the extra wattage by using the external voltage sense?
This could also be used to turn down the input power it draws?
How do you achive cc/cv?

fredsparkle said:

Doctorbass said:

I personally have the RSP 1000 and RSP 1500 and i can say they are the most compact stabilized charging solution ever.

The RSP 1000 actually output 1250W Dc and the RSP1500 is outputing 1700W Dc.

The RSP-2000 wich is as compact as the RSP1000 is the most compact of the trio but i dont have one at the moment.

I just can't imagine how powerfull thet are!.. imagine two of the RSP-2000 stacked in serie to get 100V at... 4500W out of the size of a kleenex box!

Doc

Click to expand...

Hi Doc

You get the extra wattage by using the external voltage sense?
This could also be used to turn down the input power it draws?
How do you achive cc/cv?

Click to expand...

These Meanwell power supply are CC-CV by defdault, but for exemple, the rsp-1000-48 is rated 21A but the overload protection limiting is limiting the max output current to 25A max so it does the CC at 25A not at 21.

The only way i found to lower the output current is to remove some of the current sense resistor on the back of the PCB. the rsp 1000-48 have 2 resistor so removing one will limit the output current to 12.5A... etc

these are CV too by adjusting the voltage pot.

when i'll have time i'l investigate to locate precisely the voltage divider resistor on teh pcb that regulate the current and will add a pot. these should not be so far from the shunt resistors.

Doc

Doctorbass said:

These Meanwell power supply are CC-CV by defdault, but for exemple, the rsp-1000-48 is rated 21A but the overload protection limiting is limiting the max output current to 25A max so it does the CC at 25A not at 21.

The only way i found to lower the output current is to remove some of the current sense resistor on the back of the PCB. the rsp 1000-48 have 2 resistor so removing one will limit the output current to 12.5A... etc

these are CV too by adjusting the voltage pot.

when i'll have time i'l investigate to locate precisely the voltage divider resistor on teh pcb that regulate the current and will add a pot. these should not be so far from the shunt resistors.

Doc

Click to expand...

Hi Doc

In looking at the diagram for the RSP-1500 there is load share input, is that just a logical level or some voltage level to contribution effort from the slave power supply?

DB,

I just picked up a RSP-1500-48.
Wondering if it is possible to replace one of the resistors with a pot and adjust output current that way???

teslanv said:

DB,

I just picked up a RSP-1500-48.
Wondering if it is possible to replace one of the resistors with a pot and adjust output current that way???

Click to expand...

Dude!

I haven't found a schematic for that online yet, but if you like - we could reverse one from the circuit board and narrow down where it might be possible.
Unless Doctorbass happens to know :wink:

Good on you, KF
PS - just the one, not two?

The EE learning is slow, but I'm starting to understand more.
Looks like we have more projects than just a battery bag to finish :wink: