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David I believe you meant to say:-

The main current draw is on acceleration and it is mitigated by acceleration ramps and individual?axis travel. Both these features have historically been in my?Geminis and I can remember when the individual?channel starts were?implemented.

An accurate lock on the servo allows the slower start and then acceleration continues until the servo approaches lock and slows down to?synchro lock.

A note on Lithium batteries Vs Deep Cycle Absorbent Glass Mat.?My 32AH AGM is trickle charged to 13.4 volts at all times, like the Lithium, It can be charged at?higher voltages from Solar panels, bur the advantage of the AGM, I have an?Anderson Plug connection with truck duty jumper leads and it doubles as my ride on mower battery.

Why have I made a distinction, well if you empty or reverse charge the individual holes in a lithium it never recovers the lost capacity so they need exceptionally good battery?management

Apologies if I am mistaken, but I always have a full battery from the float charge even at the end of my nights imaging.

Regards

Len

On 29 Jun 2023, at 11:37 pm, David C. Partridge <david.partridge@...> wrote:

I think you meant to say:

The main CURRENT draw is when slewing.

?

David

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From:?[email protected]?<[email protected]>?On Behalf Of?Brian Valente
Sent:?29 June 2023 16:03
To:?[email protected]
Subject:?Re: Voltage; was: Re: [Gemini-II_io] L6 Pic Programming Kit Arrived - Long Island NY

?

Edit: (typo and additional thoughts)

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As Paul has mentioned, the voltage range (12-18v) and recommendation to use higher voltage has always been the case since the Gemini was introduced in early 2000s. There is nothing new about the power requirements and recommendations.?

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That being said, many users happily use 12v. Someone else mentioned one of the things to look for in a 12v supply is that it can dip lower than 12v, especially if you are powering multiple devices from the one power source (dew heaters come to mind as power hungry). Batteries typically start at a higher voltage around 13.5v and reduce their voltage output as the night progresses. Lithium batteries do a better job at maintaining the higher voltage output over time, but when they are approaching drain, it can drop quickly. Something to watch for.?

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The main voltage draw is when slewing. You can further reduce your power requirements by reducing the slew speed (consider this more of a hack, such as if your battery is low and you don’t have other options)

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When the mount is just tracking (which is most of the time) power consumption is minimal

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Do not use anything outside of the 12-18v spec.?

?

?

Thanks

?

Brian

?

Brian Valente

Losmandy Astronomical

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Tutorials and vids at?

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From:?[email protected]?[mailto:[email protected]]?On Behalf Of?Brian Valente
Sent:?Thursday, June 29, 2023 7:38 AM
To:?[email protected]
Subject:?Re: Voltage; was: Re: [Gemini-II_io] L6 Pic Programming Kit Arrived - Long Island NY

?

As Paul has mentioned, the voltage range (12-18v) and recommendation to use higher voltage has always been the case since the Gemini was introduced in early 2000. There is nothing new about the power requirements and recommendations.?

?

The main voltage draw is when slewing. You can further reduce your power requirements by reducing the slew speed (consider this more of a hack, such as if your battery is low and you don’t have other options)

?

Tracking is minimal power consumption

?

Do not use anything outside of the 12-18v spec.?

?

?

Thanks

?

Brian

?

Brian Valente

Losmandy Astronomical

?

Tutorials and vids at?

?

From:?[email protected]?[mailto:[email protected]]?On Behalf Of?Paul Kanevsky
Sent:?Thursday, June 29, 2023 4:13 AM
To:?[email protected]
Subject:?Re: Voltage; was: Re: [Gemini-II_io] L6 Pic Programming Kit Arrived - Long Island NY

?

On Wed, Jun 28, 2023 at 11:59 PM, Michael A. Covington wrote:

Let's keep an eye on this.? Does the new firmware somehow make the mount more sensitive to lower voltage?? I can supply any voltage needed when at home (currently using 13.5 V), but when I go portable, the battery puts out 12.0 to 12.6 V.? I have not tried the L6 firmware upgrade yet.

From the very first versions, Gemini was always documented as supporting 12-18v voltage range, but preferring higher voltage for increased servo torque. The reason higher voltage may be needed in some applications is that Gemini servos can't get more power once they reach 100% duty cycle. The only way to increase power to the servos at 100% is to increase voltage. 18v is the maximum, don't try to feed it any more than that. 16v has been my sweet spot with multiple Gemini mounts.

Regards,

? ?-Paul?