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Pack Troubleshooting - 4S4P
#11
I seen those buck converters stress tested on youtube, none could do the rated amp output, and at lower amperage they got too hot. I also use those small buck converter but only to power small 12 volt fans/lights that are less then 1 amp.

Your idea of building a 3s pack is a good one, I been using a 3s16p 31 ah battery to power my 200 watt inverter for years, even when I drain the battery all the way down the bms will shutoff before the inverter does. My 3s li-ion will run everything my 4s lifepo4 does.
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#12
25w is more than 1A. Thats like 25/14 = 1,78A on the output. Then add losses and you are way above 2A.
You can meassure current with your voltmetera as long as you stay below 10A (I think you have it on that multimeter?)
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#13
Whenever dealing with dirt cheap Chinese devices, best to assume:
"Max/peak" performance values -> pure fantasy
"Rated" values -> may overheat and burn out if used too long at that rate
30%~70% of "rated" values -> actually safely usable

It's not like US/Jap/German made brand name devices that often over-deliver on what they promise.
China _can_ and do produce quality devices too, but they're not that cheap.
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#14
(05-21-2020, 05:50 AM)daromer Wrote: 25w is more than 1A. Thats like 25/14 = 1,78W on the output. Then add losses and you are way above 2A.
You can meassure current with  your voltmetera as long as you stay below 10A (I think you have it on that multimeter?)
Thank you!

(05-21-2020, 03:24 AM)jonyjoe505 Wrote: I seen those buck converters stress tested on youtube, none could do the rated amp output, and at lower amperage they got too hot. I also use those small buck converter but only to power small 12 volt fans/lights that are less then 1 amp.

Your idea of building a 3s pack is a good one, I been using a 3s16p 31 ah battery to power my 200 watt inverter for years, even when I drain the battery all the way down the bms will shutoff before the inverter does. My 3s li-ion will run everything my 4s lifepo4 does.

Thanks for the input. 

I suppose it's all about what the intended use case is for the pack. This was my first pack using 18650's and I used the ***** caps instead of soldering so I can re-configure as needed. 
If an AC inverter is the targeted use case, then selecting the cell chemistry to end up with a working voltage range that suits the inverter is key. I'm glad to hear you are having good success with your pack!
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