tprice
Posts: 7
Joined: Wed Jun 06, 2012 10:53 pm

How many hours on a 5v/10000mAh

Wed Jun 06, 2012 10:59 pm

So im getting my pi in the next few weeks. I have bout this battery of ebay http://www.ebay.com/itm/190679286964#ht_6367wt_1126 How many hours can i get off it with that battery?

Thanks

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nick.mccloud
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Re: How many hours on a 5v/10000mAh

Thu Jun 07, 2012 8:20 am

Figures posted on the boards here suggest 4/500mA. So 10,000 / 500 = 20 hours - assuming the battery remains at full potential after it's first few cycles, which is unlikely.

godFather89
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Location: Timisoara, RO

Re: How many hours on a 5v/10000mAh

Thu Jun 07, 2012 8:55 am

There are some inconsistencies in there.
Capacity:10000mAh/23Wh
Port output:5.0V,0.5-2A
5V * 10Ah would give 50Wh but it's stated at 23Wh (2.3 V cell?) so I guess the 10Ah is just marketing. More like 5000mAh. The Pi draws about 2W of power (I haven't measured it, but I read it on the forum), so the battery will last 23/2 ~= 11 hours. I guess 8-9 hours is more likely.

Let us know how it is.

tprice
Posts: 7
Joined: Wed Jun 06, 2012 10:53 pm

Re: How many hours on a 5v/10000mAh

Thu Jun 07, 2012 8:53 pm

godFather89 wrote:There are some inconsistencies in there.
Capacity:10000mAh/23Wh
Port output:5.0V,0.5-2A
5V * 10Ah would give 50Wh but it's stated at 23Wh (2.3 V cell?) so I guess the 10Ah is just marketing. More like 5000mAh. The Pi draws about 2W of power (I haven't measured it, but I read it on the forum), so the battery will last 23/2 ~= 11 hours. I guess 8-9 hours is more likely.

Let us know how it is.
Oh you make a good point with the "23Wh" so 8-9 hours could be what it might be.
nick.mccloud wrote:Figures posted on the boards here suggest 4/500mA. So 10,000 / 500 = 20 hours - assuming the battery remains at full potential after it's first few cycles, which is unlikely.
"it's first few cycles" do you mean charges? So you think it would only last a few charges before dropping?

trancen
Posts: 8
Joined: Sat Jun 02, 2012 4:17 am

Re: How many hours on a 5v/10000mAh

Thu Jun 07, 2012 11:52 pm

I just did some testing on a Solar Charger/Battery pack I bought for my iPhone. It has a 2600mAh battery and running XBMC on the RPi(no load) it lasted just a little over 3.5 hrs.

http://www.ebay.com/itm/ws/eBayISAPI.dl ... 0764547533

tprice
Posts: 7
Joined: Wed Jun 06, 2012 10:53 pm

Re: How many hours on a 5v/10000mAh

Fri Jun 08, 2012 12:05 am

trancen wrote:I just did some testing on a Solar Charger/Battery pack I bought for my iPhone. It has a 2600mAh battery and running XBMC on the RPi(no load) it lasted just a little over 3.5 hrs.

http://www.ebay.com/itm/ws/eBayISAPI.dl ... 0764547533
Oh that looks cool! how well does the solar charger work?

trancen
Posts: 8
Joined: Sat Jun 02, 2012 4:17 am

Re: How many hours on a 5v/10000mAh

Fri Jun 08, 2012 12:15 am

I haven't had a chance to test out the solar part of it yet. I just got it this week. I'm going to try doing some tests this weekend.
solarphoto (Small).JPG
solarphoto (Small).JPG (52.05 KiB) Viewed 7910 times

tprice
Posts: 7
Joined: Wed Jun 06, 2012 10:53 pm

Re: How many hours on a 5v/10000mAh

Fri Jun 08, 2012 12:52 am

trancen wrote:I haven't had a chance to test out the solar part of it yet. I just got it this week. I'm going to try doing some tests this weekend.
solarphoto (Small).JPG
Oh that iphone looks in bad condition.

Let me know how well it work for $12 you cant beat it!

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mahjongg
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Re: How many hours on a 5v/10000mAh

Fri Jun 08, 2012 12:57 am

Do note that many devices ("5V powered" devices like many smartphones) do not care if the 5V from the battery significantly drops, they will still "work" (charge their own batteries) from voltages as low as 4 Volt, not true for the PI, it needs 4.75 volt, and a maximum of 5.25 Volt, not an easy task for a battery, even if it generates about the right voltage, chances are it will drop below 4.75 Volt while having depleted only a fraction of its capacity, that or when fully loaded it will generate more than 5.25 V, which -might- damage the PI.
The best solution is to use a "SEPIC switcher", but they are difficult to get, and expensive.

You could just try, but "mileage may vary".

trancen
Posts: 8
Joined: Sat Jun 02, 2012 4:17 am

Re: How many hours on a 5v/10000mAh

Fri Jun 08, 2012 1:00 am

My GF's iphone and her screen protector needs replacing for sure :)

tprice wrote:
trancen wrote:I haven't had a chance to test out the solar part of it yet. I just got it this week. I'm going to try doing some tests this weekend.
solarphoto (Small).JPG
Oh that iphone looks in bad condition.

Let me know how well it work for $12 you cant beat it!

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