Introducing the NEW Cellpro Dual PowerLab 8x2 from Revolectrix

[Gregor99]

Thanks for the feedback!. I used a Harbor Freight aluminum case. http://www.harborfreight.com/18-x-12...ase-69318.html

On sale it was $21 and change so I did not feel back cutting holes in the side if it. Its not a very large case which is one of the reasons I choose it. I wanted show that with the new smaller size of the DPL it can be fit nicely even into a small case.

The power supplies are DSP-1001ABs. These are 48v supplies and support parallel operation. They are rated at 700 watts each on 120v and 1000 watts on 220v. I've had a single unit up to 860 watts and it was fine. That's 1720 watts total, and more than I can safely pull from my generator. Only thing about these supplies is they are heavy, 7lbs each. Doesn't sound like much but it adds up. The case is 24lbs and 14 of that is power supplies.

[GRR45]

Thanks for the info on the case/power supplies. Is there enough room on the deck to use a pair of MPA boards?
Thanks again for all the help/info.

[Gregor99]

You could get two MPAs on the deck but it would be tight and there would not be room for packs.

[ROGER G]

Hi Gegor99
I have a set up very similar to your case and what I found to be very useful is to cover the entire deck with Velcro. Most people have velcro on their batt. and you can put velcro on the connector boards. Then nothing slides around or falls from the deck. And you can place things anyway you want, and they stay put. Just my 2 cents.

[ROGER G]

I just wanted to add, I got these extensions from a local hobby shop. It is much easy'er to plug your balance plug into this than into the adaptor board itself. They make them for all cell counts.

[GimpyGolden]

So what kind of output can we expect with thing using 2 AGM Deep Cycles as the input?
Will it max out on 6/7S or does it need 48V to get there?

[Gregor99]

The input current is 40 amps per channel, or 80 amps combined. So if your 24v sources can deliver the full 80 amps without significant voltage drop, then the total output about 1700 watts, or about 860 per side (24v source).

But 80 amps is a lot to expect from a pair of Pb batteries in series. In fact ,about three times the amount that should be pulled from a Pb battery. AGMs may do a little better. But even then, 80 amps continuous is going to put some serious hurt on those things. Most likely the voltage will be dropping into the 11s, or even the 10s and you won't be able to get the full use of the Pb batteries (as compared to drawing at a lower current).

To max out each channel on 6s you'll need about 28v to 30v input at 80 amps.
To max out each channel on 7s you'll need about 33v to 35v input at 80 amps.

[GimpyGolden]

I am looking for full 40A out on a each channel. Plan was to stagger charge but if I cant get 40A on 6S with 24v in then this doesn't suit my needs.
I'll be better off with a second PL8.

[Gregor99]

The Powerlab8 is still an awesome charger and having a second one only makes it better. But the DPL is a fair bit smaller than two Powerlab8s and you can run it with three Pb batteries in series to max out on 6s. More choices for everyone.

[GimpyGolden]

3Pb's is not an option here.
For one I'm not dropping another $300 on an AGM to match my set and two I don't have space for a third.

[skunkworx]

The funny thing about this charger though is that essentially is a dual PL-6. With a limited input of 40A, that's the same thing as a PL-6 which will output the same 40A as a PL-8, only you had to provide it more voltage in order to meet the same output power.

The only thing this seems to provide over a paired up set of 6's is the ability to do two more cells in series, or am I really missing the mark? How practical is it to try and get 36V out of a power supply when most are only 12V to begin with and are a stretch when putting them in series for 24V.

Not trying to rain on anyone's parade here. It just doesn't seem to have the same magical ability as the PL-8 to make more power on less, or more 'common' voltage.

[Gregor99]

Originally Posted by skunkworx

The only thing this seems to provide over a paired up set of 6's is the ability to do two more cells in series, or am I really missing the mark? How practical is it to try and get 36V out of a power supply when most are only 12V to begin with and are a stretch when putting them in series for 24V.

Its closer to two Powerlab8s in a single case. 8s instead of 6s and 190 watts of discharge vs 100 watts (50 watts per PL6). Also its about $110 cheaper than buying two Powerlab8s and because its smaller fits easier into a case.

The other feature it has over both previous models is the increased voltage limit of 48v. As it turns out the commonly available 24v power sources are not ideal for charging 6s packs with any charger. When the input voltage is close to the output voltage. There is an issue when DC-DC transitions between boost and buck mode. This issue can be addressed by raising or lowering the supply voltage. Unfortunately, the voltage of most server supplies cannot raised high enough to prevent the issue. So you are forced to lower the supply voltage which increases the supply current.

As the power levels continue to climb, raising the input current is not the right approach. My two Powerlab8s have a combined current limit of 130 amps. While you can split this up across the two supplies, its still 65 amps. Higher currents requires larger heavier components. The trend in our hobby to support higher power levels is to increase the supported voltage, not increase the current levels

36v is not too hard to come by. Three supplies can be run in series just like two server supplies are configured today. Additionally, there a few server supplies as well as higher end brands, like Meanwell. These are less common than 12v supplies but are still available. For the beta I used two DSP-1001AB supplies running in parallel off of 120 AC. These are 48v supplies that are have load sharing capabilities. If you shop around you can find deals on these. I was a bit short on time to acquire my supplies and ended up paying $60 for the pair shipped. Two of these pull more than a typical 120v AC breaker or 2000 watt generator. There's also the HP ESP120 3000w 48V 57A, for this with access to 220v


Many in the US will likely choose to run 3 supplies. This is easy to do and will allow you tap off the 24v source to power existing lower voltage chargers.

[GimpyGolden]

If it would push 7S @40A from 24V I'd be sold.
What is the max output on 6S with 24V in?

[theColonel]

by my calculations at 24V it will 816Watts per channel.

[GimpyGolden]

So around 32A, not good enough.

[GimpyGolden]

Unless I did 1/2 12S pack per channel.
Then it ties up the whole deal though and defeats the benefit over PL8.

[theColonel]

Originally Posted by GimpyGolden

Unless I did 1/2 12S pack per channel.
Then it ties up the whole deal though and defeats the benefit over PL8.

I understand where you are coming from, looking at the powerlab range the input voltages aren't really designed around possible power rigs, the 30V to 32V PL6 requirement is flawed in my opinion. I think for some users, the DPL is a step forward, but for you it looks like two PL8s would be a better, if not slightly more expensive option.

I had been thinking about buying a PL8 about a month before the DPL announcement to charge my 6 cell batteries. Given my calculations, I'm going to wait for the DPL, as there are a few PSU options that will allow me to max it out even at 8 cell. I doubt I will be doing that soon, but I want a charger that will last for many years and once you get the voltage above 40V for 8S (or 30V for 6S), it's cheaper than two PL8s per watt.

I've done my calculations on each of the range based on the list prices on the Revolectrix International site and compared the dollars per watt at 12V, max output and 1000W.

Prices for future reference.
PL6 - $165
PL8 - $230
DPL - $360
2xPL8 - $460

Max Watts output @12V
PL8 612W - $0.376 per W
PL6 408W - $0.404 per W
DPL 816W* - $0.441 per W *2x 408W

When maxing out each charger:
DPL - 2688W - $0.135 per W
PL6 - 1000W - $0.165 per W
PL8 - 1344W - $0.171 per W

At 1000W (or 2000W for DPL) so max output for a 6S charge.
PL6 - $0.165 per W (between 30V and 32V)
DPL - $0.18 per W (between 29.4V and 48V)
PL8 - $0.23 per W (between 19.6V input and 32V)

For charging 6S packs the PL6 comes out top, unfortunately the input voltage range 30-32V is not a multiple of 12.

[Gregor99]

Regarding 12v and 24v supplies, just because that's they way we've always done it, doesn't mean its the best option for charging higher cell packs. Like I said above, 36v and 48v supplies are not that hard to come by. Even three Pb batteries would get you there. The Powerlab8 is still suitable for those that cannot do three Pb batteries.

But for anybody charging 6s or they should be looking at supply voltages higher than 24v. Its been a long time coming and I glad that the trend toward higher input voltages is finally here.

[RedOctobyr]

Greg, I think you had a post recently (I can't find it now) mentioning that within the Dual PL8's case are 2 separate processors, etc etc. Essentially that within it live 2 chargers, which can work together.

Given that, I hope that we will soon see a PL8V3, with the ability to run off 48V

[skunkworx]

Originally Posted by Gregor99

. When the input voltage is close to the output voltage. There is an issue when DC-DC transitions between boost and buck mode. This issue can be addressed by raising or lowering the supply voltage. Unfortunately, the voltage of most server supplies cannot raised high enough to prevent the issue. So you are forced to lower the supply voltage which increases the supply current.

What exactly is the issue? I can understand there might be a little bit of a hiccup when switching from boost to buck conversion, but it's all controlled by PWM so it should be fairly seamless. Does it damage the charger or cause them to have a shorter MTBF?