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Old 08-27-2016, 03:39 PM   #1 (permalink)
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Post Gt EIGHT, my first impressions

Got the GT8 one day ago, as substitution for my PL6, which became broken after 2.5 years of success usage and I have to send for repair soon. So, GT8 already did yesterday evening charge for all my battery, then today used on the field, now another evening charging for tomorrow. My impressions:
* GT8 is big! bigger than PL6 (see picture). And 800W, not 1000W.
* Very simple to use! I would say - too simple , especially after PL.
* Cooling fan(s) are noisy, not smart, always run on charge start and never stop, even if charge amperage low - they run, mindless absolutely could air exhaust. PL6 starts fans only if necessary, on internal discharge or really high amperage charge.
* In same time the speaker volume are low, even on max settings, I can't hear from cellar, which was easy with PL6 not on max settings. No 90% beep option with GT
* PC software very simple, just to update FW, and save/load user presets, but without ability to see/edit.
* However It does its job, charge my batteries quick and precision enough, no complain ... Except!
I REALLY lose the auto-calculation for parallel charge!
Actually, I never charge only one pack, always at least two in parallel. But GT has no ability or option to define number of packs and calculate amperage, IR, capacity accordingly! That's shame.
Would send this request to Revolectrix and hope such feature will be implemented in next FW. Please!
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Old 08-28-2016, 04:55 AM   #2 (permalink)
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Thank you for your feedback!

We shelved the parallel charge setting due to a lack of screen space in cycle mode. All lines on the screen were taken up but we'll review this again to see if there is another way to do it. This should be after we release the GT1000. Your other suggestions will be taken into consideration as well.
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Old 08-28-2016, 04:13 PM   #3 (permalink)
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RevoFong, thanks for answer!
I think, the "standard PL" dialog - "parallel pack?" on charge/discharge/store/cycle job start will be fine. And additional information about parallel pack processing you can put on first upper, non-scroll line, where I see now: "LIPO CHG 16.00A" you can probably fit the string like: "LIPO 4P CHG 16.00A", then other strings about battery information will be related to one pack only (from 4 in parallel). So, no additional screen space required.

Other impressions after "two evenings at home and two days on field using":
* I really like the automatic supply menu option on start-up, with multiple (up to 6) presets. I actually use now 3, one PSU at home and 2 different supply battery on field.
* I really like how quickly GT8 (compare with PL6) start battery processing and popup battery information.
* I really like display information (especially with auto-scroll), really appreciate that no lines appears with empty info "---" if I work with 6S battery not 8S.
However, still dislike noisy fans and bad speaker/beeper, still wish about the parallel charge settings/options
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Old 08-31-2016, 08:24 AM   #4 (permalink)
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Yes, it may be possible to have the parallel pack screen show on job start although this will be a slight deviation from the UI.

However, the parallel pack information cannot be displayed as you suggested since the first line also has to show "DONE" when finished.
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Old 09-12-2016, 08:12 AM   #5 (permalink)
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Want to buy my first Revolectrix charger and I'm undecided between PL6 and Gt8. As gt8 does not have the option to set the number of packs in parallel charge how would I set it to balance charge let's say 4 6s5000 packs in parallel?

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Old 09-13-2016, 10:09 PM   #6 (permalink)
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If you're planning to charge at 1C or 5A per pack, you can set the charge amps to 20A.
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Old 05-27-2017, 04:06 PM   #7 (permalink)
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The FW 2.29 for GT500 and GT Eight was released 7 Feb 2017, but I catch that only today, accidentally clicking the GT500 icon on my laptop desktop
Well,
1) Fixed display bugs. - don't know what that means?
2) Changed fan operation to temperature controlled - wow! cool! but even if I set it to maximum allowed 50C - the fan behavior remain pretty same as before. Ok, fan start not immediately on charge start now, but after 1 min
3) Added parallel charge/discharge option. WOW!!! Exactly what I want! But... It affect only the "Charge amps" setting - now I can define 5.0A x2 and have 10A charge amps if i charge my 2x 6S 3700mAh = 12S pack. The "Capacity In" and "IR" calculation - still not take into account the parallel packs count!
So... better then nothing - but still not what I expected.

correction about point 2) Ok, the fan now not spin on CV phase, that's good!
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Last edited by 3Daemon; 05-27-2017 at 04:21 PM.. Reason: correction
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Old 05-28-2017, 09:28 PM   #8 (permalink)
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Quote:
Originally Posted by 3Daemon View Post
The FW 2.29 for GT500 and GT Eight was released 7 Feb 2017, but I catch that only today, accidentally clicking the GT500 icon on my laptop desktop
Well,
1) Fixed display bugs. - don't know what that means?
2) Changed fan operation to temperature controlled - wow! cool! but even if I set it to maximum allowed 50C - the fan behavior remain pretty same as before. Ok, fan start not immediately on charge start now, but after 1 min
3) Added parallel charge/discharge option. WOW!!! Exactly what I want! But... It affect only the "Charge amps" setting - now I can define 5.0A x2 and have 10A charge amps if i charge my 2x 6S 3700mAh = 12S pack. The "Capacity In" and "IR" calculation - still not take into account the parallel packs count!
So... better then nothing - but still not what I expected.

correction about point 2) Ok, the fan now not spin on CV phase, that's good!
I have updated my gt500 to 2.29 so does the fan cycle on and off or does it actually use a pic controller to maintain temp at setpoint (40 or 50 c)?
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Old 05-29-2017, 06:08 PM   #9 (permalink)
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Originally Posted by soviet911 View Post
does the fan cycle on and off or does it actually use a pic controller to maintain temp at setpoint (40 or 50 c)?
According to my tests with 2.29 on GT500 and GT Eight - NOT! It seems NOT really sense for temperature (where? which?), just seems use some kind of "time-amperage" behavior. Starts fan "a bit after charge start, stop fan on CV phase "if charging Amps less x.xxx A"...
My sensor (hand) always feel absolutely cold exhaust airflow from fan...

... would like to see any comments from Revolectrix developers. Mostly about "parallel charge/discharge option" implementation. Currently it looks like joke.
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Old 05-29-2017, 09:47 PM   #10 (permalink)
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The GT chargers senses the internal ambient temperature instead of directly on the mosfets or heatsink. If the mosfets start heating up, there would be a delay before the internal ambient rises. For this reason, above a certain power, the fan would always be turned on to start the cooling process or else damage to the mosfets could occur. For GT Eight, this power is 120W. Below this power, the fan operates by cycling on/off with a small hysteresis.

It would be nice to have Capacity and IR displayed for individual packs in parallel but the controller is heavily taxed during charge and discharge. So I would prefer not to tax the controller further by doing this calculation during ops.

1) Fixed display bugs. - don't know what that means?
A user commented the amps fluctuate between zero and a large number after charge has completed. The above fix is meant to address his feedback.
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Old 05-30-2017, 05:19 AM   #11 (permalink)
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Quote:
Originally Posted by RevoFong View Post
For GT Eight, this power is 120W. Below this power, the fan operates by cycling on/off with a small hysteresis.
Ok, this is an answer. My usual usage for GT500 and GT800 is above 200W, so fan always spin (except CV phase end)
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Originally Posted by RevoFong View Post
It would be nice to have Capacity and IR displayed for individual packs in parallel but the controller is heavily taxed during charge and discharge. So I would prefer not to tax the controller further by doing this calculation during ops.
Does it mean that such feature will never be implemented?
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Old 05-30-2017, 08:03 AM   #12 (permalink)
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I'm sorry to disappoint but it is unlikely to be implemented. Unless there is a serious problem that requires a restructuring in the code, I do not see this happening in the near future.
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Old 06-08-2017, 05:32 PM   #13 (permalink)
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Well, just my practical and honest summary about GT series:
- works well, just lack of some features:
* the "temperature controlled fan operation" - fake! Actually no sense for temperature, just always switch fan to full RPM if charging power above XXX watt - that means - always.
* the "parallel charge/discharge option" also fake! No real calculation.
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Old 07-02-2017, 08:54 AM   #14 (permalink)
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is this GT8 worth to buy? or better get the PL6 /8 ?
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Old 07-02-2017, 11:31 AM   #15 (permalink)
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Quote:
Originally Posted by Xfreak3D View Post
is this GT8 worth to buy? or better get the PL6 /8 ?
Probably worth it but if you can afford a PL6/8 why are you even asking?

The only thing that bothers me about the PL8 is the starting time, there are 30 seconds that the charger doesn't do anything. I dont know why does it have to wait and why exactly 30 seconds. My HW charger begins immediately. Charging from ballance plug only other than the 30 seconds the power rises very very slowly, almost two minutes to reach 1A, than proceeds a bit faster...

Other than that the charger is a champ and sustains 40Amps like a beast!
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Old 07-02-2017, 12:08 PM   #16 (permalink)
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as a spare charger... i have 16packs of lipos.. need a few more chargers
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Old 07-02-2017, 04:52 PM   #17 (permalink)
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I'd go Dual PowerLab 8.

They're on sale now too.

Good timing!

Quote:
Originally Posted by Xfreak3D View Post
as a spare charger... i have 16packs of lipos.. need a few more chargers
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Old 07-02-2017, 09:54 PM   #18 (permalink)
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Quote:
Originally Posted by 3D Dave View Post
I'd go Dual PowerLab 8.

They're on sale now too.

Good timing!
i dont see the purpose of having 2 charges stick into 1 unit..

if 1 unit damage.. i have to send whole charger back. better buy split 2 units.. so if i unit damage.. i still got 1 to use ?

GT800 is going for $99, but i read some issues with parellel charging
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Old 07-02-2017, 10:59 PM   #19 (permalink)
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Quote:
Originally Posted by Xfreak3D View Post
i dont see the purpose of having 2 charges stick into 1 unit..

if 1 unit damage.. i have to send whole charger back. better buy split 2 units.. so if i unit damage.. i still got 1 to use ?

GT800 is going for $99, but i read some issues with parellel charging
Been using my Dual PowerLab 8x2 since December 2013 and never had an issue with it. After using a dual port charger I'm not sure I'd purchase another single port charger.
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Old 07-02-2017, 11:51 PM   #20 (permalink)
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do you do parallel charge on the duo? or jus single pack at one side of charger?

GT charger seems a shortcut of the powerlab firmware?

just went to my LHS get the isdt sc-620 500w ( $55)... charged 4packs 5200mah @ 400W.. seems so far so good..
and its half price of the GT Eight

but i stil not really confident on the isdt charger.. so i charge the 4 packs outside my house.. dont dare to do inside..

but i would go for a better charger like the DuoPL in near future.. to be safe
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