Battery Charging Math

[blu666z]

Am I way off base here?

UA-5 draws 500mah w/ phantom power on.  

Charger rate is 280mah.

So would I charge it almost 2hours(500/280) for every hour I intend to use it or longer?

-Kevin

[caymanreview]

sounds about right, what type battery -sla or rc pack? does your charger have a trickle charge once the battery is full, it then tops it off? you may want to run it a touch longer to insure full charge

280mah charge rate isnt going to cause any damage by overcharging, the extra juice will be let off as some heat correct?

my rc charger charges at 2000mah, then trickles at 50 untill topped off and the packs always get warm before it shuts off, it is an auto shutoff smart charger

[blu666z]

Its a 3000mah batteryspace pack.  Charger is a 5 hour charger from Rat Shack.  

I had been looking at this theard and wasn't sure if the charging to 1.5x  applied to basically dead batteries or if you could apply based on how much power you intended to use.  

http://www.taperssection.com/yabbse/index.php?board=25;action=display;threadid=12035;start=msg147389#msg147389

-Kevin

[caymanreview]

im not sure if the 1.5x applies to non-dead packs or what

i also have the 3000mah packs from batteryspace, and i highly reccomend the charger they have. it charges at 2000mah and trickles at 50mah untill topped off and then has auto shutoff. automatic voltage detection for any of the different rc packs. at 30 bucks, it is a steal

[blu666z]

Cool, I'll go track it down.  +T

-Kevin

[caymanreview]

i originally used the rat shack 5/7 hour charger, but at 280mah, i had to run the charger a few times to fully charge a dead pack

so when i ordered my 2nd and 3rd 3000mah packs i just bought the combo with the smart charger. now each pack is charged in 1.5hrs instead of a whole day!

good for multi day runs or festivals imho

+T right back at ya!

[blu666z]

This the one?

http://www.batteryspace.com/product.asp?3=353

Full charge in 90mins would be great!  Doesn't require as much planning to get enough charge in.

-Kevin

[caymanreview]

yep. its great. and a solid little thing too, i figured from the pictures it would a cheapo little thing, but its not!

with me having 3- 3000mah packs, i could be fully charged and back in action in no time, or at festivals, always have a pack charging on an inverter in the car, and never be without juice!

for 30 bucks it is well worth it! buy it, you wont be dissapointed!

[caymanreview]

and right now if you spend >50 bucks you get a nice little set of binoculors! added bonus!

[blu666z]

The only feature I wish it had was a discharge option.

-Kevin

[caymanreview]

i second that, i looked around and couldnt find any with that option. i just did a cycle or two at home with myy gear, and everything was cool. would be way easier to have a charger that would do it though...

[leegeddy]

Am I way off base here?

UA-5 draws 500mah w/ phantom power on.  

Charger rate is 280mah.

So would I charge it almost 2hours(500/280) for every hour I intend to use it or longer?

-Kevin

kevin;

not quite the way you should see things....

you need to keep things separated:  1. charge calculations and 2. discharge calculations (UA-5 consumption).

first, your UA-5 does not draw 500mAH. mAH is a measure of "capacity".  you probably meant that it draws "500mA" per your manual, etc.

depending on what type of battery, capacity of battery and the environment, your charge curve and discharge curve my well be different.

you can always use ballpark figures, but i would calculate how long it would fully charge your battery based on your charger/battery combo.  then, figure out how long the fully charged battery will power your load source (UA-5). keeping one calculation separated from the other.

equating your charger's output capacity to your UA-5's current draw is totally incorrect.

hope this helps,
marc

[2speedy]

 

[blu666z]

Not trying to argue, just want to understand.  If I know how much power my UA-5 will draw in one hour, why can't I divide that by the rate of charge to the battery to determine how long I need to charge the battery for each hour I intend to use it?

-Kevin

[blu666z]

+Ts all around BTW