How to wire the 1A micro usb charger with dna 40

[mberlinger3]

Hey guys,

I just got one of these boards (link below) and I don't have any idea how to wire this with a dna 40. It has b+ and b- which I thought would just connect to the dna board but there are out + and out - and I cant figure out what these pinouts are for. Also, I have no idea what gauge wire to use and if I need to fuse the charging board...

http://www.ebay.com/itm/400665520672?_trksid=p2060778.m2749.l2649&ssPageName=STRK:MEBIDX:IT

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[moresalt]

I used the out+ and out- I didn't use a fuse on mine. i don't believe it's required. I used 20 gauge wire when I first did it, although 24 gauge should be fine. In Evolv's spec sheet for the DNA40 & DNA30 they specify a max of 20 gauge and reccommend 24 gauge although they are assuming a 500ma charger.

If you figure that they reccommend 20 gauge (in the DNA30) for the battery (max 12 amps) then 24 should be well within range for a 1 amp charger.

 

[moresalt]

Ok, I thought about the fuse some more...a fuse protects the source...i.e., the charger. At $1.19 why bother. You bought like 5 or 10 didn't you? Also, the input to the charger is 5V @ 1A, 5W. there probably won't be much excitement with that. You fuse the batteries because a shorted battery can get real exciting in a real short amount of time, 4V @ 12-35A, 48-140W. That's alot of energy.

 

[mberlinger3]

Ok, I thought about the fuse some more...a fuse protects the source...i.e., the charger. At $1.19 why bother. You bought like 5 or 10 didn't you? Also, the input to the charger is 5V @ 1A, 5W. there probably won't be much excitement with that. You fuse the batteries because a shorted battery can get real exciting in a real short amount of time, 4V @ 12-35A, 48-140W. That's alot of energy.

I actually only bought 1 lol bad planning. Jury is still out how to fuse my 6400mah lipo. I do not think its really necessary with the dna 40 reverse battery protection. I cant really insert one of the batteries forward and the other one backwards... unless I rip the lipo I guess.

Does the dna reverse batt protection protect the current from all going to the charger and blowing that? I know the charger and batt pinouts are right next to each other but im not sure if theyre internally connected.

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[moresalt]

Uh, i wouldn't want a lipo without some fuse protection. It's not just for reversed batts...if something in the DNA or wiring shorts out you'd lose a face or parts thereof.

I don't know for sure, but I've heard of a couple of cases where the batteries were reversed and no mention of the charger being blown up. Doesn't the lipo have a keyed plug on it?

 

[mberlinger3]

Uh, i wouldn't want a lipo without some fuse protection. It's not just for reversed batts...if something in the DNA or wiring shorts out you'd lose a face or parts thereof.

I don't know for sure, but I've heard of a couple of cases where the batteries were reversed and no mention of the charger being blown up. Doesn't the lipo have a keyed plug on it?

Im waiting to hear back from mamu I asked directly what fuses to use and how to wire it. But now could the dna itself short out?


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[moresalt]

Although I've never heard of it, it is possible...it's an electronic device. Without knowing the exact internals I'm not smart enough to say exactly what the failure mode(s) might be. But why would you ever want to take a chance like that? The down side is magnitudes worse than the cost of fusing a battery. So, for the want of a couple of bucks you'd risk your face?

 

[mberlinger3]

Although I've never heard of it, it is possible...it's an electronic device. Without knowing the exact internals I'm not smart enough to say exactly what the failure mode(s) might be. But why would you ever want to take a chance like that? The down side is magnitudes worse than the cost of fusing a battery. So, for the want of a couple of bucks you'd risk your face?

I guess I could get a pair of 8A fuses but I really don't have a lot of room in my box... can anyone comment on fusing in small spaces. I think the fuses are .12" x .5" x .83" in dimension but id need two...

EDIT: I just found this new fuse will this work? Its a strap type fuse...

http://www.digikey.com/product-detail/en/MF-LR900/20-0/MF-LR900/20-0-ND/3741784

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[moresalt]

Interesting find. yea, max current for a DNA40 is 16A, so you'd probably still need 2, as the tip rating is awfully close to that. Rmin/max is good and a 5 Second trip wouldn't be too bad.

 

[mberlinger3]

Interesting find. yea, max current for a DNA40 is 16A, so you'd probably still need 2, as the tip rating is awfully close to that. Rmin/max is good and a 5 Second trip wouldn't be too bad.

Yeah i ordered 3 from digikey (one is a spare which I'll probably need) . 18A protection seems okay according to mamus post earlier. They are super low profile so I should have plenty of space and I'm going to use double sided tape to stick them on my lipos. Here's and interesting thought, since they have good surface area contact to the lipo, shouldn't it also trip if the battery gets too hot?

 

[mberlinger3]

So guys I came up with a hypothetical situation. Lets say I fuse the battery (a pair of 9A fuses with a 5s trip time) and wire everything up. If I inset the battery backwards, wouldn't all of the current rush from the positive end of the battery through the charger to the + charger input of the dna board through the batt + pinout and to the negative end of the battery before the fuse could trip? Would putting a 1 A fuse with a low trip time (.3s) in line with the charger prevent the charger from frying if this happens?

 

[squagwallow]

I used the out+ and out-

I'm about to do the same thing. Just wanted to confirm you connected the out +/- to the dna not the battery sled, right? Also, did the LED lights function automatically when you wired it this way? It hasn't blown up or anything right?

 

[rolf]

just thinking ....your input is the micro usb 5 volts..your output is out pos and neg. my charger boards id not have a separate alternative in put . you can connect the charger output to the dna or also to the battery ( after the fuses )
I done it both ways on a couple of dna 20 boards . and assume the dna 40 will be the same set up .
both worked just fine . jes don't leave out the fuses !!

 

[mberlinger3]

Is there any reason to use out+/- instead of Batt +/- on the charger? The only difference between the two is that there is a fet switch to prevent overdiscarge of the battery from a load while charging.

 

[mberlinger3]

Bump /10charizards

 

[dimo]

You need to use the bat +/- to get the required 4.2V charge voltage.

The out +/- is a 5vdc output. This board is normally used for stuff like portable battery powered phone chargers.


If your battery up to the out pins you'll fry something.

 

[TheRac25]

You need to use the bat +/- to get the required 4.2V charge voltage.

The out +/- is a 5vdc output. This board is normally used for stuff like portable battery powered phone chargers.


If your battery up to the out pins you'll fry something.

actually, if you look at the picture, the out+ and b+ terminals are connected and b- appears to have a fet switch, wich apears to be some type of protection, while the out- does not