Electronics • Led Lights Wattage convert to Milliamps

Sounders, Shark Shields, and other electronics

Led Lights Wattage convert to Milliamps

Postby Stealthfisha » Wed May 28, 2014 9:22 pm

Hi chaps....
I have used my lithpoly battery 4000MA for ages now..(see my build thread)
A bonus so far my kayak has not blown up and or caught fire :twisted:

im about to puchase a fold down 24" led blueline all round light...its a DC needed supply...which I like...it draws 1 watt.....id like to match it to a 1500mwh lithipoly at only 148grams......awesome.

without giving me the formula...can someone tell me in english, watt (what) milli amps does this equal?...yes ive read the formula but im not that smart and thats why im a denture fairy and not a professor of mathematics. ....eg: 1xwatt hour is 50ma an hour...I know my sounder uses around 350-400mah....matched to my 4000mah lithipoly at 374grams is awesome and lasts a few trips and can be charged of the front of my 4x4 in 40 mins....

sorry for being a dumb shit but I want a nice small compact lithipoly battery tucked into my rear day hatch sealed, out of the way....
Stealthfisha
Elite Member
 
Posts: 1579
Joined: Tue Jul 21, 2009 8:18 pm
Kayak: yak


Re: Led Lights Wattage convert to Milliamps

Postby Fishane » Wed May 28, 2014 9:50 pm

I assume its a 12 volt LED. In which case the current for 1w is 1/12 amps or 83 mAh (P=IV)?
Fishane
Regular Member
 
Posts: 81
Joined: Mon May 12, 2014 8:57 am
Kayak: yak

Re: Led Lights Wattage convert to Milliamps

Postby Stealthfisha » Wed May 28, 2014 10:37 pm

Yes mate 12v thanks!!!!!!!
Sooooooo this lights should run for around a year! Hahahahab
thanks again
Stealthfisha
Elite Member
 
Posts: 1579
Joined: Tue Jul 21, 2009 8:18 pm
Kayak: yak

Re: Led Lights Wattage convert to Milliamps

Postby Bradv » Wed Jun 04, 2014 9:20 pm

Content removed to prevent monetization of that given freely and solely for community benefit - sorry :-(
Last edited by Bradv on Fri Aug 22, 2014 7:15 pm, edited 1 time in total.
RIP AKFF - Sold on 21-Aug-2014
Bradv
Regular Member
 
Posts: 38
Joined: Mon Jan 14, 2013 12:41 pm
Kayak: Virtualscope killed this forum

Re: Led Lights Wattage convert to Milliamps

Postby Stealthfisha » Thu Jun 05, 2014 12:13 am

Brad that an awesome response. ....very astute. .....
thanks mate :D
yes I have 4s batteries
all are 35c discharge rate
all are balanced
via an imax6 balanced charger
very shortly ive got a flam retardent charge bag and piezo alarm and led warning modules should each battery drop below 3.3v per cell during use

Do you reckon im on the right track?.....also all my lipo batts are mah....so in reality we are talking nav lights both stern and bow will run for ages right?

Bradv wrote:First verify the measurement units for your battery - is it in mWh, or mAh ? Most battery capacities are listed as mAh, but I see you've mentioned mWh for the battery you'd like to use.


If your battery is 1500 mWh as you've listed, this means it can output 1.5 Watts of power for 1 hour before its voltage drops notably.
So for a LED system that requires 1 Watt of power, you can run it for only about 1.5 hours (assuming the voltage is OK).


However, if your battery capacity is 1500 mAh, that means it'll supply 1.5 Amps of current for 1 hour before its voltage drops notably. For LiPo's, the voltage will be a multiple of 3.7v. Common ones are 3S packs (3 x 3.7 = 11.1v) or 4S packs (4 x 3.7 = 14.8v). Your battery should say the "S" value, or the output voltage. Most likely for a simple LED light the 3S will do the job, but for a shorter time as it's less than the 12v expected.
  • So if you have an 11.1v 1500 mAh LiPo, the equivalent Watts (P=VI) is 11.1 x 1.5 = 16.65W. So for a LED system that requires 1 Watt of power, you can run it for a little less than 16 hours due to the slightly lower voltage.
  • But if you have a a 14.8v 1500mAh LiPo, the same formula gives you a running time of about 22 hours assuming the LED system can handle the slightly higher input voltage.
Either way, it's ages if it's a 1500 mAh LiPo :)



Make sure you do NOT short a LiPo battery; if it gets very hot and puffs up substantially, things will get very nasty very quickly thereafter. LiPo's are awesome for high-performance devices, but make sure you take care of them well (balancing chargers etc).
Stealthfisha
Elite Member
 
Posts: 1579
Joined: Tue Jul 21, 2009 8:18 pm
Kayak: yak

Re: Led Lights Wattage convert to Milliamps

Postby Bradv » Thu Jun 05, 2014 10:47 am

Content removed to prevent monetization of that given freely and solely for community benefit - sorry :-(
Last edited by Bradv on Fri Aug 22, 2014 7:16 pm, edited 1 time in total.
RIP AKFF - Sold on 21-Aug-2014
Bradv
Regular Member
 
Posts: 38
Joined: Mon Jan 14, 2013 12:41 pm
Kayak: Virtualscope killed this forum

Re: Led Lights Wattage convert to Milliamps

Postby Stealthfisha » Thu Jun 05, 2014 11:13 am

Bradv wrote:Good to see someone with all the right gear to deal properly with LiPo's! I like the IMAX chargers too 8)

4s batteries are 4 x 3.7 = 14.8v output, which will easily run your 12v LED system assuming it'll handle the slightly higher voltage (very likely it will).

The 35c discharge rate for a 1500 mAh battery means you can draw a maximum of 35 x 1500/1000 = 52.5 Amps at peak (burst) current. You really only have to note that "c" rating if you're using a high-power device, like in a fast electric model boat 8) Your 1W LED system will draw about 1/14.8 = 0.07 Amps, so you don't need to worry about that!

To prolong the life of your LiPo's, they shouldn't be discharged to less than about 20% of capacity (i.e. you can use about 80% of the battery), hence the warning modules you have - their 3.3v cutoff, depending on the battery, is probably closer to 90% though which is still OK.

So for a 1W LED light running on your 1500mAh 4S pack, your warning module will kick in around approximately 14.8 x 1.5 x 0.9 = 20 hours. So you'r definitely on the right track for a couple of very long nights of fishing!

thanks brad
yep I got it wrong my batts are all 25c discharge rate.....changes things a little....Emufingers was the chap and a couple of others that helped on this project...
the alarm system boards on these batteries are connected via the balance cable and allow you to constantly keep in touch with whats going on should they drop to 3.3v...as you already stated....

Im about to flush mount a waterproof 4 switch gang wit backlights to run a fold down stern light, sounder, illuminated plastismo compass, bow nav lights and finally fish hatch led strip lights.....all for dedicated channel / offshore night fishing....this will allow me to be seen with a simple flick of the switchs between the legs.....yep...im gunna make a nice hole heheheh...we are about to start overnight fishing trips on the coast camping on small out of the way beaches so that another reason for all this....great camp lights hahaha.....so Ill do some searching and ask you some questions of what draw I will end up so I can balance my battery storage etc....gunna be some awesome pimping of the yak...ive decided to keep it....so pimping to the next level in a given now...regards mate keep safe
Stealthfisha
Elite Member
 
Posts: 1579
Joined: Tue Jul 21, 2009 8:18 pm
Kayak: yak

Re: Led Lights Wattage convert to Milliamps

Postby Bradv » Thu Jun 05, 2014 11:42 am

Content removed to prevent monetization of that given freely and solely for community benefit - sorry :-(
Last edited by Bradv on Fri Aug 22, 2014 7:17 pm, edited 1 time in total.
RIP AKFF - Sold on 21-Aug-2014
Bradv
Regular Member
 
Posts: 38
Joined: Mon Jan 14, 2013 12:41 pm
Kayak: Virtualscope killed this forum

Re: Led Lights Wattage convert to Milliamps

Postby Stealthfisha » Thu Jun 05, 2014 1:09 pm

gunna place switches in the same place the sounder is in the photo ....
had to make sure the switches were water proof not resistant....also the nav lights etc....when this happens I will need to turn the yak upside down and sikaflex all this inplace with fasterners and seal with plastic boxing ...so its up out of the way on the inside under the bucket seat etc...compass will be flush mounted to fish hatch
Attachments
84523_lg.jpg
84523_lg.jpg (10.78 KiB) Viewed 1580 times
29035_lg.jpg
29035_lg.jpg (10.4 KiB) Viewed 1580 times
54151_lg.jpg
54151_lg.jpg (4.63 KiB) Viewed 1580 times
sounder2.jpg
sounder2.jpg (119.06 KiB) Viewed 1580 times
Stealthfisha
Elite Member
 
Posts: 1579
Joined: Tue Jul 21, 2009 8:18 pm
Kayak: yak

Re: Led Lights Wattage convert to Milliamps

Postby mangoinorange » Mon Jun 30, 2014 5:28 pm

watts are the product of amps times volts, thus a 1 watt light supplied by 12 volts needs 1/12 of an amp to drive it (0.083amps).
watthours is the measure of watts(milliwatts,microwatts, or wattever) for the time of one hour.
dunno if this helps or hinders but electricity(particularly dc)is not that complicated or magic.
regards,mangoinorange.
mangoinorange
New Member
 
Posts: 11
Joined: Sat May 17, 2014 7:59 am
Kayak: prowler elite

Re: Led Lights Wattage convert to Milliamps

Postby Stealthfisha » Mon Jun 30, 2014 6:34 pm

cheers for all the comments as I needed to ask....I hope some noobs will stumble across this in future to help out with battery choices etc....regards
baggs
Stealthfisha
Elite Member
 
Posts: 1579
Joined: Tue Jul 21, 2009 8:18 pm
Kayak: yak


Return to Electronics

Who is online

Users browsing this forum: No registered users and 2 guests

cron