Development Double the battery life on Pocket Edge

[romanlutsk]

Greetings,
I'm considering connecting a second PE battery in parallel to the original to double the lifespan.

Would anyone know if it's safe to do so (the connector seems to have around 10 pins, so I'm not sure if connecting all the pins from both batteries in parallel could do any damage to the electronics inside the batteries or the PE itself).

Thanks,
Roman

[ivanjt]

Not a good idea as you could easily burn out the charging circuit in your PE.

If you are looking for longer time of battery use then the best idea would be to get a rechargeable 12v battery pack that has a set of plug tips and use that plugged into the power socket.

If you do decide to add an extra internal battery you will need to find out which are the battery monitoring contacts and somehow devise a way that will enable the charging circuit to know the state of both batteries and so determine the charge rate - not an easy task.

Early in this forum there was a discussion about using different chargers and a couple of posts about using an external battery pack that might be worth your searching for them and having a read.

[romanlutsk]

Thanks for the detailed answer. I couldn't find the posts you mentioned - could you post the links?

What about bypassing the charging electronics and connecting the internal battery contacts directly directly to the internal contacts of the second battery.

So, the charging electronics battery would handle two cells, connected in parallel, instead of one.

Would that be ok?

[Gunnerp245]

enTourage Archive.

[romanlutsk]

Thanks, but I couldn't find anything useful. The closest thing I found was:
https://www.mobileread.com/forums/sho...ternal+battery
https://www.mobileread.com/forums/sho...ternal+battery

but it wasn't helpful.

So, what do you think about connecting the internal battery contacts to another PE battery (bypassing the electronics), effectively letting electronics from one battery manage both.

It should just see it as one cell with double capacity, right? The only thing I can think of is if one of the cells starts loosing capacity, it would drag the other along. But since they are exactly the same batteries, it's probably not likely to happen.

[exscentric]

I don't know how the circuitry works. If it senses voltage and acts accordingly hooking the two bats together would work but on the other hand if the circuits sense current flow it could be confused since with two bats it would be seeing double the current.

Unless someone more knowledgeable comes along to assist I think you are on your own to try it or not - depends on the cost of frying something.

I would think there is a fuse of some sort to protect from overloads but whether there is or not or if you could ever find it if it blew is another unknown.

Off the top I'd guess it would not work but I've been wrong many times before :-)

[romanlutsk]

You are saying that since the internal battery resistance will be halved, the charging current will double. Also, it looks like there is a slight chance that the cells will get off-balance.

It sounds like it'll be easier to get a 5v to 12v voltage booster and feed it from a mobile power unit via usb.

Something like this, perhpas:
http://www.ebay.com/itm/1PCS-LM2577-...50852080428%26


http://www.ebay.com/itm/LM2577-LM257...50852080428%26

http://www.ebay.com/itm/DC-DC-Switch...item4abc2a1bad

I'm not sure which one would be best though

[tarvoke]

yeah it really depends on how they designed the charge controller. it could be fine, it could die a slow heat death, it could just asplode. balance would not be my main worry here ;-)

(also aren't these "smart" batteries with their own electronics/management too?)

on something like an apc ups where the specs are known and/or the thing is smart enough to know better (software), I've not had problems adding on extra or bigger batteries. same goes for my solar backup and electric bike projects recently. but on the device we all love and hate...?! hmm... yeah...

[ivanjt]

romanlutsk, there is a slight problem with using any form of adapter from the 5v 0.5A USB socket to supply 12v at over 1A - it just will not work.

As for connecting two batteries on series you have the very real problem of burning out the charging circuit or, if that does not happen, neither of the batteries ever getting a full charge at the rate they are designed for.

One question, you talk of using another PE battery, where did you get it from? If you bought it as a new item pleas let us know where you got it from and the part number for future reference.

As a bit of information, I have and regularly use a 12v 2.5A limited output adapter that plugs into my car lighter socket to charge my EE.

tarvoke, you are talking about two different design ideas when comparing an APC ups to a PE. APC design to a strict specification that allows for upping capacity - we have a rack mounted 2kW unit that now uses a large truck battery and keeps it charged without problems - whereas the PE was designed to a price with a 'this will just do' specification - remember the WSoD caused by pushing the video subsystem too hard.

[romanlutsk]

Originally Posted by tarvoke

yeah it really depends on how they designed the charge controller. it could be fine, it could die a slow heat death, it could just asplode. balance would not be my main worry here ;-)

(also aren't these "smart" batteries with their own electronics/management too?)

I meant bypassing the charging electronics and connecting the internal contacts of one battery directly to the internal contacts of another battery.

So, the charging electronics of one battery would handle two cells, connected in parallel, instead of one.

Originally Posted by tarvoke

on something like an apc ups where the specs are known and/or the thing is smart enough to know better (software), I've not had problems adding on extra or bigger batteries. same goes for my solar backup and electric bike projects recently. but on the device we all love and hate...?! hmm... yeah...

Yes, you might be right. It's a little too risky to burn another device.

[romanlutsk]

Originally Posted by ivanjt

romanlutsk, there is a slight problem with using any form of adapter from the 5v 0.5A USB socket to supply 12v at over 1A - it just will not work.

Actually, USB 2.0 is rated up to 1A. I'm using this:
http://www.goodluckbuy.com/5v-mobile...18650-box.html

Originally Posted by ivanjt

As for connecting two batteries on series you have the very real problem of burning out the charging circuit or, if that does not happen, neither of the batteries ever getting a full charge at the rate they are designed for.

My understanding is that they'll be charging twice as slow (so it's going to take twice as long to charge), but slow charge is supposed to be much better for the batteries (avoids overheating, etc)

Originally Posted by ivanjt

One question, you talk of using another PE battery, where did you get it from? If you bought it as a new item pleas let us know where you got it from and the part number for future reference.

I fried one PE when a no-name Chinese charger broke down. Then I bought another one with WSoD issue, hoping to replace the charging circuit, but it didn't work. Finally, I just got a third working PE, so now I have two non-working PEs.

Originally Posted by ivanjt

As a bit of information, I have and regularly use a 12v 2.5A limited output adapter that plugs into my car lighter socket to charge my EE.

That's nice, but I need something on-the-go, as I can be away from my car for several days.

Originally Posted by ivanjt

tarvoke, you are talking about two different design ideas when comparing an APC ups to a PE. APC design to a strict specification that allows for upping capacity - we have a rack mounted 2kW unit that now uses a large truck battery and keeps it charged without problems - whereas the PE was designed to a price with a 'this will just do' specification - remember the WSoD caused by pushing the video subsystem too hard.

I'm not familiar with this issue (links?) Do you mean that if you make PE run too hard, it consumes more current than the battery can provide?

[ivanjt]

romanlutsk, I will try and answer your points in order.

If you read the USB 2 specifications - all 30 odd documents - you will find there are two current specs. 0.5A for computer USB sockets and 1A for USB charging devices. What you need is the 12v equivalent of your 5v box - one that has a set of plug tips so you can get the right one for your PE.

With two batteries connected together each will try and take as much charge as they can - the only limit being the charging circuit and if the battery with the battery state circuit in nearly discharged the circuit will cut all restrictions as to current and with two batteries drawing as much current as they can something is going to get very hot and burn out. There is also a down side to low rate charging of batteries, it can destroy them by chemical contamination/change. We have had to change several batteries in clients laptops because they kept the battery installed and constantly used them running off the mains power supply.

It is good that you have a source of parts, something very few of have. I would suggest using the one with the WSoD to charge its battery and the battery of the unit with the dead charging circuit, then remove them and store them in a cool dry place. That way they will have a very reasonable life expectancy.

A question. You are looking for ways to power your PE, what is wrong with the mains power supply that came with it, or are you away from mains power for long periods as well?

My comment to tarvoke, was that unlike professional grade equipment the EE and PE were built down to a 'it just works' standard as several people found out when they tried to push the operation of, mainly, the video circuit beyond its capability resulting in the WSoD because sections of the video chip were fried. The only way you will increase battery drain to any extent is to be in a WiFi fringe area - WiFi increases the power output to connect, or try and increase the clock rate of the processor and there you will see increased power drain and heating.

I have to admit I am at a bit of a loss as to why you are thinking to do what you describe because I find it strange in this day and age that anyone would be out of reach of mains power for any length of time.

We have one client that has a house in the mountains that doesn't have mains power connected but he uses all his mobile devices and laptop there without problems - we supplied him with a ups powered by a large car battery he only has to remember to bring the battery down the mountain with him and charge it for the next time he goes up to the house. If you are in that situation matbe somethinf like that would work for you.

[romanlutsk]

Thanks, a lot of good info.

Originally Posted by ivanjt

If you read the USB 2 specifications - all 30 odd documents - you will find there are two current specs. 0.5A for computer USB sockets and 1A for USB charging devices.

Yes, and since I use the mobile USB charger that provides 1A, I should be able to convert it to about 0.4A at 12v (4.8W) with DC-to-DC booster. By my calculations, PE uses about 3.7W (14.8W battery, lasting 4 hours)

Originally Posted by ivanjt

What you need is the 12v equivalent of your 5v box - one that has a set of plug tips so you can get the right one for your PE.

Yes, that'd be nicer, but also probably bigger and more expensive. Besides, I already have the 5v box that I use for most of my other gadgets. I wouldn't want to carry another box, just for PE. I'd use one of the plug tips from:
http://www.ebay.com/itm/90W-Universa...item3cc4fd8934

Originally Posted by ivanjt

With two batteries connected together each will try and take as much charge as they can - the only limit being the charging circuit and if the battery with the battery state circuit in nearly discharged the circuit will cut all restrictions as to current and with two batteries drawing as much current as they can something is going to get very hot and burn out.

The idea is to connect one charging circuit to two cells in the same state, so they charge and discharge at the same rate.

Originally Posted by ivanjt

There is also a down side to low rate charging of batteries, it can destroy them by chemical contamination/change. We have had to change several batteries in clients laptops because they kept the battery installed and constantly used them running off the mains power supply.

You are probably referring to the older Nikel-based batteries (Ni-MH or NiCd). From everything I've read on LiPo batteries, it's perfectly ok to leave (newer) laptops plugged-in all the time. The battery life will be prolonged, as there will be much fewer charge/discharge cycles.

Originally Posted by ivanjt

It is good that you have a source of parts, something very few of have. I would suggest using the one with the WSoD to charge its battery and the battery of the unit with the dead charging circuit, then remove them and store them in a cool dry place. That way they will have a very reasonable life expectancy.

Thanks. I was thinking of selling one or both for parts, as I expect the battery to last for quite some time.

Originally Posted by ivanjt

A question. You are looking for ways to power your PE, what is wrong with the mains power supply that came with it, or are you away from mains power for long periods as well?

Yes. I attend many whole-day conferences and sometimes it's hard to find a good seat near a power outlet.

Originally Posted by ivanjt

My comment to tarvoke, was that unlike professional grade equipment the EE and PE were built down to a 'it just works' standard as several people found out when they tried to push the operation of, mainly, the video circuit beyond its capability resulting in the WSoD because sections of the video chip were fried. The only way you will increase battery drain to any extent is to be in a WiFi fringe area - WiFi increases the power output to connect, or try and increase the clock rate of the processor and there you will see increased power drain and heating.

I see

Originally Posted by ivanjt

I have to admit I am at a bit of a loss as to why you are thinking to do what you describe because I find it strange in this day and age that anyone would be out of reach of mains power for any length of time.

The main advantage is not to be tied to a power outlet (even for 1 hour) when on the move.

Originally Posted by ivanjt

We have one client that has a house in the mountains that doesn't have mains power connected but he uses all his mobile devices and laptop there without problems - we supplied him with a ups powered by a large car battery he only has to remember to bring the battery down the mountain with him and charge it for the next time he goes up to the house. If you are in that situation matbe somethinf like that would work for you.

Good idea, but again, if you attend whole-day conferences, having a tablet that you don't have to worry about recharging every 4 hours (when in constant use) is quite advantageous.

[ivanjt]

OK, I have a better idea of your needs now but I have to ask are you prepared to take the risk of burning out the charging circuit by adding the second battery?

That being said I think your best approach would be to get something like http://www.amazon.com/Rechargeable-3.../dp/B007RQW5WG which is 12v only output only, or if you need 5v as well then there is http://www.amazon.com/3800mA-5600mAh.../dp/B0063EYY5Y or even http://www.ebay.com/itm/Lawmate-Long...-/140656640010

I may sound as if I am preaching to the choir but don't get so stuck on the idea of adding an extra battery to the existing one in your PE and not look at the easier alternatives because if you do there is a very good chance the next problem you will have is how to repair the charging circuitry.

What ever you decide it has to be your decision so, good luck.

[romanlutsk]

Originally Posted by ivanjt

OK, I have a better idea of your needs now but I have to ask are you prepared to take the risk of burning out the charging circuit by adding the second battery?

That being said I think your best approach would be to get something like http://www.amazon.com/Rechargeable-3.../dp/B007RQW5WG which is 12v only output only, or if you need 5v as well then there is http://www.amazon.com/3800mA-5600mAh.../dp/B0063EYY5Y or even http://www.ebay.com/itm/Lawmate-Long...-/140656640010

I may sound as if I am preaching to the choir but don't get so stuck on the idea of adding an extra battery to the existing one in your PE and not look at the easier alternatives because if you do there is a very good chance the next problem you will have is how to repair the charging circuitry.

What ever you decide it has to be your decision so, good luck.

Thanks. I already bought this:
http://www.ebay.com/itm/180957599819...84.m1439.l2649

and will try to hook it to my existing 5v mobile battery. By my calculations, it should provide additional 10-12 hours.