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Who uses a Duracell Powerpack 600 to power your mounts

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#1 Ballyhoo

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Posted 22 January 2019 - 08:11 PM

I have one and it is beeping really early on in the night. I am wondering whether there is anything i might do to resurrect it?



#2 photoracer18

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Posted 22 January 2019 - 08:25 PM

If its rechargeable then you need to do it. Batteries lose capacity in cold weather. That is why the cold cranking amps of a car battery are less than the regular capacity of the battery. I use a big car battery jump box to power my astro gear and at least in summer I can get 2 days out of it before recharge.



#3 dr.who

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Posted 22 January 2019 - 11:52 PM

If you discharged the battery below 50% you may have baked (ruined) it. The battery is user replaceable. I have done so with mine. I put a 20 aH deep cycle battery in it. No problem with the battery or discharging it. The how to is on line and found with a google search. If you are remotely mechanically inclined it is easy. Batteries can also be found on line.

#4 WadeH237

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Posted 23 January 2019 - 09:33 AM

What all do you have plugged into it?

 

According to the specs I could find, it's a 28 amp hour AGM battery.  If we assume that your mount pulls about .5 amps continuous, it should be good for about 28 hours at whatever temperature it's rated (probably somewhere above 70 degrees).

 

As has been said, if you regularly take this battery below 50% of its capacity, you will shorten its life.  If you run it completely flat, you will dramatically shorten its life.

 

Also note that I mentioned above, the capacity is rated at a particular temperature.  At lower temperatures, the capacity will decrease, as will the voltage it supplies.

 

I could not find a data sheet for the battery that you are using.  I usually buy Universal Power Group batteries because they supply full specs for their batteries.  Here is a data sheet for one of their 26 amp hour AGM batteries.  It should be similar to what you are using.

 

You can see a few things of interest.

 

First, note that it's claimed 28 amp hour capacity assumes a 1.3 amp draw at 77 degrees F.  The current draw is generally specified as some portion of the capacity per hour.  For example, at 1.3 amps, you would be drawing .05 (5%) of the battery's rated capacity per hour (ie. 1.3 divided by 26 is .05).  Many of the charts show the characteristics based on this number.

 

The next thing to note is that at 32 degrees F, the battery capacity drops to about 85% of its rated capacity.

 

Also, note that the current draw affects the capacity.  If you are trying to run a full imaging setup, you will get quite a bit less than the rated capacity.  My imaging rig runs at about 5 amps continuous.  This would be about 0.2C (ie. 5 amps divided by 26 amp hours is just a bit less than .2).

 

At 32 degrees F, its capacity drops to around 85% of it's rated capacity.  If you are running more than just the mount, you will draw more current.  My full imaging setup draws about 5 amps.  That would be about 0.2C.  At the rated temperature, the battery would deliver about 80% of it's rated capacity.  So figure that it's got about 20 amp hours running a full setup.  When the temperature drops to freezing, that drops to around 65%, or 16.9 amp hours.

 

This means that running a full imaging setup, you can use about 8.5 amp hours before discharging below 50% of capacity.  That's about an hour and 45 minutes of imaging time at 32 degrees F.

 

This is why I run two 75 amp hour batteries for my imaging rig in parallel.  Not everyone agrees with my strategy, but you can look at the data sheets for yourself.  I replace my AGM batteries every 8 to 10 years and I never worry about my power consumption.




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