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Discussion Starter · #1 ·
The 2400mAh battery is not that good. I get less than 4 hours with it on wifi. I found 4000mAh batteries on ebay for under $20. These are 7.4v 15C batteries.7.4V 4000mAh 15C RC Battery AkkU for SH boat car truck - eBay (item 160426803245 end time Aug-21-10 02:49:08 PDT)I have already taken apart my Zenpad 4 before, I saw how the battery is and how it is connected. My question, is it really that simple? I can easily order one of these batteries, cut the little white connector from the old battery and solder it to the new battery and done! but am I missing something here? the voltages are the same but what about the burst rate? i think the Zenpad 4 has a 5C burst rate. is that a big issue? i dont wanna fry my pad so what precautions do i need take to ensure i have a functioning tablet after? also, what are the dimensions of the current battery? i forgot to measure it and if someone knows, please share. i dont wanna have anything bulging out. I dont mind taking the plunge.
 

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Heat might be another issue. Your best bet is to talk to that one guy who tore apart his 180 in the wi-fi thread and solder on that antennae. 10-1 he'll know all about it. Then come back and tell me so I can go ahead and do the same thing ;)
 

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Discussion Starter · #6 ·
marchino65;40912 said:
ATTENTION the battery installed on pad is type Li-on (same as phone) those of your links are Li-po and are charge differently !!Sorry for my bad EnglishMarco
They are the same types of batteries. Lithium-ion or lithium-ion polymer batteries are the same [email protected] that is a lil thinner, 10mm thick but still too much. I am worried that damn thing wont close. I mean if the batter is to lay on the motherboard, I dont think it will be a problem in terms of space. We are trying to get it to sit in place of the old battery, but if we place it in there and 2mm is sticking out, its just gonna touch the motherboard. That shouldnt be too much of a problem unless heat is a major concern. I must say though, with the update to the latest firmware, 818, battery life seemed a lot better.
 

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[quote name='ayman07;40967]They are the same types of batteries. Lithium-ion or lithium-ion polymer batteries are the same [email protected] that is a lil thinner' date=' 10mm thick but still too much. I am worried that damn thing wont close. I mean if the batter is to lay on the motherboard, I dont think it will be a problem in terms of space. We are trying to get it to sit in place of the old battery, but if we place it in there and 2mm is sticking out, its just gonna touch the motherboard. That shouldnt be too much of a problem unless heat is a major concern. I must say though, with the update to the latest firmware, 818, battery life seemed a lot better.[/QUOTE'] Please read carefullyhttp: / / en. wikipedia.org / wiki / Lithium-ion_polymer_batterymarco
 

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I could easily be wrong as we are all guessing here... But I do believe that these are cheapest Li-ion Polymer batteries as they are are a soft pack in the form factor and dimensions I mentioned in another thread(183x63x5mm)... Yes I understand that they do Not have the balancing circuit that the batteries at 10mm above do... as reccommended by the wiki definition...Prolonging life in multiple cells through cell balancingMain article: Battery (electricity)Analog front ends that balance cells and eliminate mismatches of cells in series or parallel significantly improve battery efficiency and increase the overall pack capacity. As the number of cells and load currents increase, the potential for mismatch also increases. There are two kinds of mismatch in the pack: state-of-charge (SOC) and capacity/energy (C/E) mismatch. Though the SOC mismatch is more common, each problem limits the pack capacity (mA?h) to the capacity of the weakest cell. But either way, I think these are just OEM cheap 2400mAh 7.4v typical battery packs... the ones mentioned in this thread are really close BUT won't fit as even the outside dimensions of these tables is a bit under 10mm (thickness of the battery noted...) I think we could use something up to 183x63x6.5mm but nothing thicker will fit inside the case...
 

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Discussion Starter · #9 ·
I know someone who is an electrical engineer. I will ask them if we can use this battery or not. I'll ask them about heat as well.Sent from my Nexus One using Tapatalk
 

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Discussion Starter · #11 ·
jackhill;43583 said:
Hey ayman07Did you ever speak to your electrical engineer friend?Thanks
Hopefully I will get a response tonight. If he says its okay, then ill probably just get the battery and try it out myself.Sent from my p7901a using Tapatalk
 

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[quote name='ayman07;44293]Hopefully I will get a response tonight. If he says its okay' date=' then ill probably just get the battery and try it out myself.Sent from my p7901a using Tapatalk[/QUOTE'] Thanks. Would be interested to see what battery life you get after upgrading
 

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Discussion Starter · #13 ·
ok well i did ask him and unfortunately he didnt know too much about it. i did some more research and found that the batteries are very similar its just that the lithium polymer deal with overcharging a bit differently. heres a pieces from a site i found.
The cells are sealed in a plastic aluminium laminate, so if the battery sees an overcharge condition, the seal ruptures and vents any gases due to electrolyte oxidation and the cell shuts down rather than having steel or aluminium casings fragment, as in the case of lithium ion batteries that may result in metal shards.
the only thing that might be needed is some sort of ventilation but i wouldnt know how to do it without making the tablet look ugly. does anyone else know a lil more about this sort of stuff???
 

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Here again I wish I was back in the U.S. I would drop by my local Batteries Plus and have them whip me up a battery to my design specifications. I haven't found a place in Japan yet but there has to be some place here too that will make a custom battery.
 

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Hello, (sorry for my bad English) Il have buyed this item : 2 X 7.4V 4000mAh 20C Li-Po Li-poly RC Battery Pack - eBay (item 190424107055 end time Sep-25-10 10:24:13 PDT)Received yesterday, and mount on the tablet case immediately, and .................. that work correctly ! Charge is correct, and fonctionnally great ! Just one problem because the size is a little bigger than the original pack it's necessary to make three holes on the side of tablet to install three screws, for lock correctly the two sides of tablet !Actually on test to see how that improve the autonomy ?
 

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I assume by autonomy you mean battery life. Do these tests:1. Watch a movie with wifi turned on. Calculate how long before the battery reaches 1/2 then when full drained2. Watch a movie with the wife turned OFF. Calculate how long before the battery reaches 1/2 then when full drained.3. How long does the ZT180 take to charge from fully empty to fully charged.Right now the times are:1. 3.5hrs2. 4.5hrs3. ???
 

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didier cornet;50924]Hello said:
2 X 7.4V 4000mAh 20C Li-Po Li-poly RC Battery Pack - eBay (item 190424107055 end time Sep-25-10 10:24:13 PDT)[/url]Received yesterday, and mount on the tablet case immediately, and .................. that work correctly ! Charge is correct, and fonctionnally great ! Just one problem because the size is a little bigger than the original pack it's necessary to make three holes on the side of tablet to install three screws, for lock correctly the two sides of tablet !Actually on test to see how that improve the autonomy ?
Warnings for Using BatteriesPlease tell us or show us how you are able to charge these batteries properly and "SAFELY" without the three pin connector, for the "Balanced Charge circuit", being used?????? These tablets do not support that circuit.....You've got a ticking time bomb there if you don't handle Li-Ion/poly batteries properly. If you charge these just by using the two pin "DC output" connector, there is no way to control the input current to the battery during the charge cycle, NOT GOOD...... Plus, without any control of the "current drain" from the battery, it could overheat and explode like the cheap cellphone and laptop batteries did a few years back. These are not batteries you want too treat poorly, they need a lot of care and respect when working with them or you will get hurt. I will be doing a battery up-grade on my tablet when the batteries I ordered get in and for me to do this mod safely, I ordered a "Protection Circuit Board" to go between them. It controls the battery discharge rate,over-charge,over-discharge and the balance between the two cell when charging though a two pin circuit. I'll post pictures if they fit.
 

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To add a little more info to my previous post. Here are some pictures of what is needed to charge the type of batteries some of you are ordering off ebay. These are battery packs made for R/C vehicles,electric cars, boats, planes and Helicopters. They need to be charged by a charger made specifically for these battery packs. Now the pack in my pictures is a 3 cell 11.1volt pack but the 2 cell 7.4volt pack is only lacking one cell and one pin from the balance charge connector but gets set-up the same. The pictures may be out of order so read the title.
 

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Here is what I will be using. I ordered two cells, 3.7v @4700ma/hr, 85mm x 62 mm x 7mm and a battery protection board for a total of around $45.00. I think I got a great price for batteries that are "UL listed", not something unknown from ebay. I've got many years experience buying cheap battery packs from China, only to have them swell, leak or just die after a few charges. Like the old saying goes, "Cheapcomes out expensive in the end"....... I plan to do this mod once and I will not do it if I have to grow the unit's girth. That's not the goal for me, my goal is to have it look the same as when i got it, otherwise what's the point...... Stay tuned.....
 
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