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WHAT EXTERNAL LITHIUM ION BATTERY AMP / HOUR SPECS FOR ETX90

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#1 namor

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Posted 19 October 2019 - 10:01 PM

I have a 2007 ETX90 and was thinking of getting an external Lithium Ion battery . I need to know what a good portable AH rating battery to get. Is 6 AH good enough or should I go double digit AH like 10 AH plus 

 

I dont know the current Amp comsumption for the ETX90 SIDEREAL (tracking ) rate or the larger Amp  needed for the SLEW rate. Does anybody know these 2 Amp parameters please?

 

I know the ETX AC adapter #547 is 12 v at 2.5 A and has a male plug 5.5 mm OUTSIDE DIAMETER and a  2.5 INSIDE DIAMETER. and the RED lead from the battery is plug CENTER PIN with a fuse. Should I put a fuse on the black lead also?. And what size fuse Amp to get and should it be a fast blow fuse or ???

 

Does the battery have to have a steady 12 volts output or is there some voltage variation acceptance . I'm afraid anything under 12 volts going into the scopes circuit board may damage it 

 

Any ideas would be appreciated 

 

thanks

Gus 

Toronto Ontario Canada


Edited by namor, 19 October 2019 - 10:07 PM.


#2 namor

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Posted 19 October 2019 - 10:10 PM

This is the battery I was thinking of getting but its output voltage fluctuates from 9 volts to 12.6 Volts 

 

https://www.aliexpre...8b-4dfbe431d214



#3 junomike

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Posted 20 October 2019 - 03:38 PM

I reading it as the output Voltage is 9V - 12.6V depending on the needed voltage, not limited by the battery.

Cheap enough, that's for sure.



#4 EdIII

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Posted 21 October 2019 - 08:20 AM

I have a 2007 ETX90 and was thinking of getting an external Lithium Ion battery . I need to know what a good portable AH rating battery to get. Is 6 AH good enough or should I go double digit AH like 10 AH plus 

 

I dont know the current Amp comsumption for the ETX90 SIDEREAL (tracking ) rate or the larger Amp  needed for the SLEW rate. Does anybody know these 2 Amp parameters please?

 

I know the ETX AC adapter #547 is 12 v at 2.5 A and has a male plug 5.5 mm OUTSIDE DIAMETER and a  2.5 INSIDE DIAMETER. and the RED lead from the battery is plug CENTER PIN with a fuse. Should I put a fuse on the black lead also?. And what size fuse Amp to get and should it be a fast blow fuse or ???

 

Does the battery have to have a steady 12 volts output or is there some voltage variation acceptance . I'm afraid anything under 12 volts going into the scopes circuit board may damage it 

 

Any ideas would be appreciated 

 

thanks

Gus 

Toronto Ontario Canada

 

 

That battery will work for 4 or 5 hours, maybe more, depending on how much you are slewing. I did not check to see if it had the correct plug, but it appears you did. I don’t know the line voltage where you live, but that wall wart will not work in the US without a 120 volt adapter. 

 

I use a 2 amp standard fuse, but that was just what I had. Mine did not come with a fuse. No, you don’t need a second fuse. I have never bothered to measure the true amp draw.

 

I have seen mine run batteries down until it quit. Low voltage has never damaged my scope.

 

Ed


Edited by EdIII, 21 October 2019 - 08:23 AM.


#5 sg6

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Posted 23 October 2019 - 03:58 PM

A Li-ion battery will drop by about 5% from it's starting voltage and maintain that until it is approximately 80% discharged, then it drops off fairly rapidly.

Power-Tech

 

So if you start at 12v, you have in general terms 11.4v available for 80% of the time, but as your drain rate varies difficult to give a value. Although ETX's do not draw a lot when just tracking.

 

Will say I guess the battery starts higher then 12v, maybe 12.2 or 12.4.

So for the majority of the time voltage should not be a problem - well until that unknown 80% mark.

 

I can only suggest you assume 1 amp per hour, unless you intend to wander all around the sky all night. In which case 1.5 amp per hour.

 

So the battery should manage 0.8*6.8 = 5.5 hours(ish).

They should do a 9600mAh Li, I would suggest one of those. Same size, greater capacity - OK more cost.

One of those should last around 0.8*9.6 = 7.5 hours.

 

Personally I would consider the first OK for 4 hours and the second OK for 5 hours. Likely get a bit more but I tend to use worst case and then some more. You might get 5 hrs and 6 hrs. Just don't bank on it all the time.

 

Search out Talentcell, almost certainly the same internally, look nicer, and I have the option of another encased like Talentcel, half the cost and with a 5v output for phones etc - useful.

 

You will have to make a small converter from the battery lead to the ETX socket - different sizes. As it is center to center and so edge to edge no problem. I had to make one for mine.


Edited by sg6, 23 October 2019 - 04:02 PM.



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