voltage regulation for dna 30

[gunlocators]

Ok have a build and plan to use a 7.4v battery pack to power the DNA 30 what would be best method to reduce voltage to 3.7v any suggestions and part numbers is appreciated

 

[Hobby Kid]

you mean you want to step down the lipos power before it reaches the dna? your battery is likely a 2C so you'd need to take it apart and connect the cells in parallel

 

[gunlocators]

Well let me elaborate more. I am putting this mod in a gutted handheld ham radio enclosure. I want the Mod to look like a ham radio and thought If I use the 7.4 battery pack and regulate the voltage down, then I could use the radios charging base to charge back up the battery. So I would like to keep the lipos intact for this purpose. Matter of fact the up and down mode buttons n the radio will depress tactile switches for up and down on the DNA and the transmit button will have a tactile switch wire to turn on and fire the dna 30.

 

[Zamazam]

here ya go, put the specs in the calc and figure out what type of buck you need:

http://www.ti.com/paramsearch/docs/...S=Other+OT+stepdown-sbd#p32=1;4&p238min=1.5;4

 

[Hobby Kid]

here ya go, put the specs in the calc and figure out what type of buck you need:

http://www.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=751&uiTemplateId=NODE_STRY_PGE_T&DCMP=hpa_pmp_portablepower&HQS=Other OT stepdown-sbd#p32=1;4&p238min=1.5;4

Yes. I was initially going to suggest something like an LM2596 but I hesitated because they do have a tendency to get hot. There's a lot of cloned LM boards out there so I would suggest not buying one from ebay. Go to a trusted components seller

 

[gunlocators]

Here is some pics to give you an idea of what I am trying to accomplish. I tinted the clear radio screen so the DNA screen can show through it.

 

[Zamazam]

Yes. I was initially going to suggest something like an LM2596 but I hesitated because they do have a tendency to get hot. There's a lot of cloned LM boards out there so I would suggest not buying one from ebay. Go to a trusted components seller

Can always put a low profile heatsink on it

 

[gunlocators]

Any issues using a Li-Ion for a Mod

 

[Hobby Kid]

Any issues using a Li-Ion for a Mod

Some. Before using lipo you have to ask why you want to use one. Various mods have lipos in them but nearly all of them are sealed boxes. Lipos can puncture if not hard cased and vent quite badly. They're popular amongst mech modders for their high mah capacity and max amps. But high mah lipos should be charged using a hobby charger to receive the correct charge cycle, and in your case, to be balanced.

I think instead of adding a second board you should get a different chip. It looks like an awesome mod you're going to build. So why go through the pain stacking ordeal of stepping down the current? LM chips don't last very long in my experience and tend to be unpredictable at the best of times. Other than that, why not pop over to hobbyking.com and get a 1C lipo. You can get a 6000mah for $15 (although that might be a bit big for your handset). You'll see the sizes in their descriptions.

 

[Hobby Kid]

I just had another look over the photos you posted. For what you want to achieve I wouldn't use that battery if I were you as it's likely to not be a high drain cell(s). What you could do is keep the casing but remove the battery inside and fit a new lipo in there. If your new battery comes in a hard case you can remove it, thus reducing its size, as that case will be its new home.

 

[Setanta]

There are a few problems with what you intend to do, as has been intimated in the above posts. The major problem is that a battery designed for use in a radio in almost certainly unsuitable for use in a mod in that it won't be able to provide the necessary current safely. The DNA30 can draw up to 12 amps. Your battery is unlikely to be capable of providing more than about 2 amps safely..
Head in the direction of a pair of lipos in parallel,, so a battery pack with that configuration, and forget about the charging stand unless you feel like modding it to suit.

Setanta