Battery draw

evilteddy · Post by **evilteddy** » Thu Nov 06, 2008 4:31 am

Just a quick question about my new battery which I bought the other day for 80AUD down from 120AUD. It is a camera battery, 7.2V with 4400mAh and it charges perfectly with my family's camera battery charger however when I swapped it into my portable I found that it doesn't put out enough power to run the screen well. I keep getting wavy lines. This could be due to either the batteries not being able to cope with the current draw (possible), the voltage being to low (improbable considering when it is charged it is about 8.4V) or the DE regulators (which step down to 7.2V but I have tried 8.4V like before) carking out because there is not enough of a voltage differential. I think that last option is most probable but seeing as my regulator is rated for more than what I need it leaves me wondering.

So before I go and rearrange the wiring of my portable so that batteries do not have to go through a regulator to step down to 7.2V I was wondering if anyone else who has used camera batteries has had similar problems, can shed some light on my problem or what setups you use that work.

bacteria · Post by **bacteria** » Thu Nov 06, 2008 4:48 am

hailrazer mentioned recently about hazy lines - interference between the boards; needing shielding. There is no reason after all that your batteries aren't up to the job.

hailrazer · Post by **hailrazer** » Thu Nov 06, 2008 7:17 am

No the lines I mentioned are the straight lines that don't move.

Sounds more to me like it is a grounding problem.

If you're using a Psone screen is the screen getting a good ground to the screens motherboard?

And is the N64 motherboard grounded to the screen also ?

evilteddy · Post by **evilteddy** » Fri Nov 07, 2008 12:00 am

I should have mentioned that it's all working fine with a 12V 1A plugpack and an 11.1V 20C lipo battery. I think it must be the regulators that aren't up to the job. I'll just put them in line with the plugpack when I get home so the batteries don't go through the regulator.

timmeh87 · Post by **timmeh87** » Fri Nov 07, 2008 5:58 pm

Are you using switching regulators? They make high frequency noise.

Possible solution: choke inductor on the output... There are some old threads on this where we were talking about the TI dc-dc converters.

evilteddy · Post by **evilteddy** » Sat Nov 08, 2008 5:52 pm

timmeh87 wrote:Are you using switching regulators? They make high frequency noise.

Possible solution: choke inductor on the output... There are some old threads on this where we were talking about the TI dc-dc converters.

I am using switching regulators as a matter of fact. If rearranging the wiring doesn't work I'll try the choke inductor.

evilteddy · Post by **evilteddy** » Tue Nov 11, 2008 12:09 am

Just thought I'd say that the problem is fixed.

It was that the voltage regulators couldn't handle the load even working in paralell. To fix it I ended up putting the regulators on the DC in line which has the unfortunate side effect of making the whole setup less efficient on wall power but it is more efficient on battery power because there are no regulators dropping the battery voltage down to 8.4V.

Thanks for all the input of everyone who posted.

Evilteddy