bought a sx350 chip for my own mod. got some questions.

[chewcudda]

yes i searched the group for answer but could not find the answers to these.

1. batteries- what amps am i shooting for. i know purple efest and vtc5 is the answer i see over and over again. but there are diff amps/Mah for the purple efests. they now have a 20a/3100mah battery i am interested in using but the chip does .2 ohm and need closer to 30a to push that.

2. upgrading. tried to upgrade my chip and it froze at 0.0 for like 30 minutes. will try on another machine as it was a laptop on batt power. anybody else seen this.

3. is there a maximum number of cells it will support. sick of swapping battries every 3 hours in my CANA 30.

 

[Ryedan]

I found specs here. Looks like it's 12.5A max input, they do however say to use high drain cells like the VTC5 at 30A.

Can't help you with the upgrade.

The input volt spec does not allow a second cell in series, but I see no reason you can't use as many as you want in parallel which is what you want for more run time anyway. You will however not be able to use the usb charger that comes with it or you will eventually have one battery over charged and the other under charged. The over charged one will eventually become dangerous.

 

[chewcudda]

was shooting for parallel but never heard od the one sell going overcharged with these
will need to do more research.

 

[2coils]

I found specs here. Looks like it's 12.5A max input, they do however say to use high drain cells like the VTC5 at 30A.

Can't help you with the upgrade.

The input volt spec does not allow a second cell in series, but I see no reason you can't use as many as you want in parallel which is what you want for more run time anyway. You will however not be able to use the usb charger that comes with it or you will eventually have one battery over charged and the other under charged. The over charged one will eventually become dangerous.

This is the first time I have heard this? Very interesting. I would have thought being wired in parallel it would not matter. Are you sure? I am a noob at modding. I am asking strictly for purposes of learning, as I would not want to put myself in an undesirable situation with batteries. Thanks for the heads up!

 

[dice57]

yeah, want to use at least a 30 amp batt. All those mah's are wasted if it ain't got enough power to run it at max. I'm building on box that will use 2 18650 batts, so have the combined mah's.

 

[Ryedan]

This is the first time I have heard this? Very interesting. I would have thought being wired in parallel it would not matter. Are you sure? I am a noob at modding. I am asking strictly for purposes of learning, as I would not want to put myself in an undesirable situation with batteries. Thanks for the heads up!

No I'm not sure 2coils. It may be only for cells in series. I know I have to use a balancing system for my model airplane lipo packs.

Thanks for bringing this up. Now we can both learn more about it

Might also be good to have a look at the Modding Forum.

 

[rurwin]

You could always use a "reserve tank" system. Have a switch to select which battery you're using. It'd have to take the full 12.5A of course, but wouldn't have to switch it, so there wouldn't be any arcing.

 

[peraspera]

...3. is there a maximum number of cells it will support. sick of swapping battries every 3 hours in my CANA 30.

There seems to be more SX350 technical discussion in this supplier thread, The YiHi SX350 35W Chip at Varitube, than in the modders forum. Searching that thread for "parallel" will turn up some posts about using parallel lipos. The supplier seems to be in very close contact with YiHi so you might want to ask him for any further clarification you might need. He has been very gracious with people who have purchased chips elsewhere.

 

[chewcudda]

ok guys spoke with a guy who comes into my shop that works at a R\C store.
advised how to minimize unbalancing in parallel cells.
he explained that you need to feed power to both ends of the battery stack for both pos and neg when charging.
said if you limit it to two cells in parallel then the balance should stay almost perfect.

 

[p7willm]

When batteries are in series, the positive of one connected to the negative of the next, you add the voltage and charging is a lot more difficult. When you put them in parallel, all the positives connected and all the negatives connected, you add the amps and charging is the same as a single battery, just takes longer with the same charger.

You can stick pretty much as many batteries in parallel as you want. A hundred 18650s would probably last you for a month but it would be a pain to carry it around.