charging batteries in parallel

[NicksVap3]

can you charge multiple cells in parallel? ive googled, and theres not much but opinion i think.

i think the only problem, would be cell equalization, and using diodes to kind of seclude each cell could fix this i think.
sorry for the bad pic, drawings not my strong point
could split the + line from the charger, and run one to each cell also, might seclude the cells better. or would it be better to forget secluding them and forget the diodes? or would this be a bad idea?
the single cell battery packs are what id like to use, but they get rather long with higher mah, i thought maybe use two 1000 mah in parallel

 

[Java_Az]

If you use protected batteries i am pretty sure it wont blow up on you and there wouldn't be a need for diodes.

 

[Rocketman]

Some parallel box mods have the cells permanently connected.
If you use a diode the voltage drop will limit max voltage of the cells.

This works for me

http://www.e-cigarette-forum.com/forum/battery-mods/205833-parallel-18650-box-mod-rocket.html

 

[CraigHB]

If you use protected batteries i am pretty sure it wont blow up on you and there wouldn't be a need for diodes.

You can even do it with unprotected cells if you just make sure they measure out at the exact same voltage before connecting them. You only need to avoid big equalization currents initially. There's no need to do anything special with additional circuitry after that. Once connected and balanced, they'll stay that way without big currents between them, regardless of what they're doing, charge or discharge. When using parallel cells, it's always best to leave them connected all the time and built-in charging makes that easy to do.

Of course, when using parallel cells you always want to match the set and use batteries that are exactly the same with the same amount of wear. Mismatched batteries can cause high equalization currents under certain conditions. You also want to match the cells for series applications, but that's only to keep voltage balanced between the cells on discharge.

 

[NicksVap3]

im thinking dual ps3 remote batteries, or similar. internal charging of course. scrapping the 9v mod idea and swapping out a booster in it. hope this next ones worthy and not another fail. im real pleased how my box came out. after about 20 polishings, i got that aluminium cover looking like a mirror

thanks for all the input.. you guys are great

 

[CraigHB]

I've made stuff with 6061 T6 aluminum and it polishes very nicely. You can get a chrome mirror finish out of it. Of course, it scratches quite easily, but easy to fix with a trip to the buffing wheel.

Those PS3 batts should work nicely for you. I think they are 2C or can output 2 times the charge. So for a couple 1350mAh batts in parallel, you should be able to output 5.4A which is perfect for the 12W TI boost converter.

 

[NicksVap3]

exactly the setup im thinking. the 9v was a fail.... :?

it did polish up nice, the camera dont show it. there are some defects. i tried the bushed look and didnt like it, and i dont have a buffer, so taking a lot of hand polishing to get it where i am. my dad has a buffer so maybe ill bring it there to finish it off

 

[NicksVap3]

2x RC 3.7V 650mAh 20C Li-poly Lipo Battery Akku Walkera - eBay (item 220776916818 end time Jul-29-11 02:30:04 PDT)
went with those, for price and size. i figure my rcr123a's are 750mah, last me all day, 1300mah boosted should too, i hope. the ps3 batteries would fit IF i cut out the standoffs for the lid, which i may do eventually, and make it magnetically hold. these 2 would stack right in, maybe a 3rd will too for 1950mah
now waiting on china for batts and pots... dang china

 

[NicksVap3]

anyone know where to get a budget usb charging module, similar to this? would prefer micro usb, but mini would be OK. new cell is micro so wanna switch over, convenience of one cord for all...
the usb 510 charger i took apart has a board of 20x30mm, the one at sparkfun is 30x11mm and looks like i can cut it down some after i remove the jst connector.
i just think i can get one less than $10+s&h, and i dont want to have to solder a micro usb, dont look easy

 

[CraigHB]

I'm also waiting on a China order for my next mod, driving me nuts.

Yea, that SparkFun module is a bit long. It can be tricky cutting circuit boards. If they have internal layers, they can short easily. If it's just on a two-sided board, you could probably cut it and solder wires to the traces/pins as needed.

Can you make your own circuit board and do the soldering? The charger chips are easy to wire up and you could make it pretty small.

 

[NicksVap3]

i cant. the sparkfun one LOOKS like the bottom quarter or so is just to mount the connector, and wouldnt need any reworking besides that, but would hate to blow that much to find out im wrong...

 

[NicksVap3]

wrong thread, but its my thread and dont want to open a new one for this...

can someone sorta explain caps uf rating in layman terms? how important is it to use the exact uf (say 100uf) cap? can you over shoot, or under shoot at all?

 

[bstedh]

wrong thread, but its my thread and dont want to open a new one for this...

can someone sorta explain caps uf rating in layman terms? how important is it to use the exact uf (say 100uf) cap? can you over shoot, or under shoot at all?

It's basically how much energy it can store. The voltage rating is the most important rating. If you go too far over the uf rating your atty could keep fireing for ashort period after it is turned off.

Sent from my HERO200 using Tapatalk

 

[NicksVap3]

thats what i thought but wasnt totally sure... over shooting the voltage rating, how about that? say you have 7.4 in, and use a 50v cap?
using what i salvaged, and wanna make sure before i solder it all together

 

[bstedh]

the higher the voltage ratting the better...

 

[NicksVap3]

ok thanks alot

 

[CraigHB]

bstedh already commented on the voltage rating so I'll offer some comments on the capacitance value.

You've got a lot of leway on the value. You don't want to go too low, depending on what you're trying to do, it can render the capacitor ineffective. If it doesn't store much energy, it can't do much work. Going the other way on value, it's more about size. Most of the time, the the bigger the capacitance value, the better.

A bigger capacitor takes longer to charge and discharge, but even for big capacitors, the times are generally short, small fractions of a second. A large capacitor with any sort of load will discharge faster than you would be able to notice. The main problem with big capacitance is the large surge currents that occur when the device is turned on. When power is first applied, they're like a short circuit, sucking up current as fast as they can until they gain some charge. The bigger the cap, the bigger and longer the surge required to charge it. That can be a problem for solid state electronics. For example, you wouldn't want to charge 470uF cap through a FET rated only for a couple hundred milliamps. The surge currents would burn out the FET over time.

If you've ever plugged something it and heard a spark as the contacts mate, that's the surge currents charging the capacitors. Happens a lot with wall warts because they have high-value filter capacitors.

 

[NicksVap3]

thanks. i knew little about caps before. enough to install a large cap in car audio to power an amp. knew the basic function of them is to store energy, just wasnt all sure exactly how the ratings go. thanks alot. ill try to stick to spec, but good to know theres some leway, since its way cheaper to use caps out of a broken dvd player than to buy some

side note... been back in the xda scene... new phone means new roms, kernels, radios, etc.... and if i were to ask what a kernel was or how to root, id get flamed. its a helpful forum here. lots of great people... thanks again

 

[bstedh]

thanks. i knew little about caps before. enough to install a large cap in car audio to power an amp. knew the basic function of them is to store energy, just wasnt all sure exactly how the ratings go. thanks alot. ill try to stick to spec, but good to know theres some leway, since its way cheaper to use caps out of a broken dvd player than to buy some

side note... been back in the xda scene... new phone means new roms, kernels, radios, etc.... and if i were to ask what a kernel was or how to root, id get flamed. its a helpful forum here. lots of great people... thanks again

cm7

working on putting on my Nook color....

Oh,.... good luck with your capacitors and you didn't hear anything about rom's from me....

 

[NicksVap3]

got the sidekick 4g. no cm for me upgrade from the g1. need a good hardware keyboard or its not a smartphone in my opinion. very limited on roms for the sk. shoulda went g2 when i could, but they killed it