PL 8 - Q and A section - How to Set up - Use etc,

[Burgerman]

Never tried either. I just set volume low and low number of beeps. Some sign of something happening is useful. It may silence it, it may stop the fans getting loud and reduce power accordingly... Test and report!

[steves1977uk]

It doesn't quieten the fans unless charging at low amps. It does mute the sounds completely though.

Steve

[Burgerman]

I thought it may limit amps if it gets warm so that the fans run slower. Maybe not that clever!

[Gnomatic]

Never tried either. I just set volume low and low number of beeps. Some sign of something happening is useful. It may silence it, it may stop the fans getting loud and reduce power accordingly... Test and report!

Will do.

Last night I just set the # of beeps on that screen when done charging to to None. And it it not beep when finished. The fans did spin up and get noisy a couple times and woke me up. Wasn't too bad and I'm sure I could get used to it If I had too. But If I can keep them quiet, I'd like to.

Next time I charge I will try the Quiet Charging option and see if that keeps the fans from spinning up.

[Gnomatic]

It doesn't quieten the fans unless charging at low amps. It does mute the sounds completely though.

Steve

About how low do the charge amps need to be set to keep the fans quiet?

[Burgerman]

IT RATHER DEPends on your definition of quiet. Its also temperature and voltage dependent. So nobody can tell you!

[steves1977uk]

It doesn't quieten the fans unless charging at low amps. It does mute the sounds completely though.

Steve

About how low do the charge amps need to be set to keep the fans quiet?

Well the less amps you charge at the cooler the PL8 runs! Or buy a 24v portable fridge and put the PL8 in it! (Joking! )

Steve

[Gnomatic]

I keep my place at 72F. Last night I charged at 15A. Fans spun up a couple times, but not for very long, though. I'll try at around 10A next time.

[steves1977uk]

My room temp is about 21c (70f) during the day and the fans spin up about every 30 mins for about 1 min when charging at 15A. At 7.5A for overnight charging the fans never kick in since temp gets cooler then.

Steve

[Gnomatic]

Good to know thank you. I'll play with it some and see what works best. I'll start with 10A.

[Burgerman]

It works on heat. So depends on efficiency. Best efficiency varies with input/output voltage relationship. Also efficiency varies between the pulse width charger frequency. Theres 3 to choose from. The lower the amps you charge at, the lower the frequency can be. That improves efficiency. So choose charge amps, then lower the frequency to the lowest one it will allow you to use. High frequencies are lower efficiency, waste more heat, and allow big currents with small components. And the opposite is true too.

You can choose 125khz, 62khz, or 31khz.
31 is most efficient. Only for low Amps.
125 is least efficient (more fans) but allows higher currents if you want.

62 is somewhere in between obviously.

I think the limits are 10A, 20Aand 40A.

So a high power preset for up to 40A may need 125khz or 62 so it can cover the full range from a few mA to 40A. But its louder...

[Gnomatic]

I checked my 15A preset I've been using, and Conv. Frequency is set to 62.5khz. So would I need to lower my charge amps to 10A to use the 31.25khz frequency setting?

[Burgerman]

Try it. If it doesn't like it you will see an error in a tab, and it will ask you to change something.
I can do a preset that allows a maximum of 20A to be set. That should allow you to use 31khz. I think...

Send me your preset (add.zip) here and I will change the max Amp setting possible to 20 and then it will..

[Gnomatic]

Here's the preset I've been using.

[Burgerman]

I changed MAX POSS Amp setting to 20A.
And changed the actual charge rate to 20A. And it now wont let you choose more.
And the frequency to 31k so it should be slightly less hot, and fans may not come on as early. And it will go from 85 to 92+% efficiency according to the blurb on the PL8 site. And everyone thinks you just plug in a charger...

[Burgerman]

7% approx efficiency gain doesn't sound much. But its 7% of the total heat. If charging at 20A, and at 28.80v, thats a total of 576 watts.
7percent is about 37 watts of wasted heat... About a third of the total heat wasted in the charger. Hence the fans come on sooner/faster/longer.

[Gnomatic]

Thanks. I'll try this @20A. If the fans get too loud at night, I'll try 15A, then 10A if necessary etc.

[Burgerman]

A typical mosfet/inverter/inductor frequency chart...

http://m.eet.com/media/1049975/C0144-Figure2.gif

[Burgerman]

I tend to charge at full power, lead or lithium. Yes the fans go. But they shut up faster! Soon done. And I no longer hear them. You get used to them.

Bound to make a bit of noise, you are charging not at 8A like a mobility charger but 40A! Thats five times more powerful. Or in your case 20A so nearly 2.5x more power...

28.80V charge, x 40A is 1152 watts.

[Gnomatic]

About a third of the total heat wasted in the charger.

That's not an insignificant amount.

[Gnomatic]

Tried this 20A preset last night. Got a bit noisy once that I heard. Will try 15A tonight.

After going further than any set of lead bricks would ever take me. Wow.

[snaker]

I see this GT1200 supports 8s charging, has the same features as PL8 but costs a half of PL8. I understand it would be less powerful than PL8 and lack some advanced features. But all my needs are just 20A charging. And I do not charge anything other than one lifepo4 pack through the "one button charging" feature. Should I choose GT1200 for saving money? Does it have any hidden drawback?
http://www.store.revolectrix.com/Produc ... GT1200_127

[Burgerman]

Most important! No PC software. Its not configurable in the same way. You cant set up all the parameters we need, or use my pre-configured presets, or anything. And I can do settings that are not technically possible here! That we require. And its got weaker balance circuits. Dont waste your money. If money is tight get a refurb PL8 as Shirley did. Its not about power.

[shirley_hkg]

Watch out for promotion of 15% discount too, , with purchase over $100 .

[snaker]

Watch out for promotion of 15% discount too, , with purchase over $100 .

How can I get that promotion? Is there a link?

[Gnomatic]

After playing around with it, I don't notice the PL8 at all if charging @12A. I know, slow, but fine for me.

What do I need to do to configure a preset for one-button charging?

[shirley_hkg]

What do I need to do to configure a preset for one-button charging?

It doesn't exist , does it ?

[Burgerman]

I dont know. Depends what you mean. I always use my laptop. You should be able to set everything you want in a preset on the PC and lock it. Then just press go a couple of times.

[shirley_hkg]

Press ENTER 5 times , may be 6 .

[Burgerman]

Also just looked at the GT1200S user manual. Its not even got a way to set up the correct voltage for AGM or Gel batteries. Theres 2 options. 14.4 for sealed. 14.7 for wet non sealed... Its seriously dumbed down like most hobby chargers.