Preliminary testing with the DNA30

[mamu]

Been testing this DNA30 off and on for the last few weeks and so far so good. I love the new watts lock feature!

With the range of 7W to 30W, I got 0.1 - 0.2 voltage difference from what the dna display showed to what the watts meter showed with the watts meter displaying the lower value.

With regard to watts, I got from 0.3 - 0.6 watts difference from 7W to 20W with the watts meter reading the higher of the watts, and 1.5 watts difference from >20W with the watts meter reading the lower of the watts.

So all that is pretty good news.

Did some testing with voltage drop under load with 2 of the better 18650 30A batteries - Sony and LG.

LG 18650 30A 2500mAh battery...

 

[mamu]

Sony 18650 30A 1600mAh battery...

 

[Laoboi]

Great test mamu! Are you using the Keystone battery holders in these tests?

 

[mamu]

No, it's not a Keystone battery holder.

This video shows the difference in voltage drop under load without battery contacts...

 

[bapgood]

lol.....your going to make me watch videos to know the results

 

[bapgood]

Ok watched the videos and here is what I got.

LG single in holder - ~0.54v drop
LG dual in holder - ~0.32v drop
Sony single in holder - ~0.46v drop
Sony dual in holder - ~0.28v drop
LG single no holder - ~0.31v drop


So with the vdrop being fairly close the LG's look awesome!!!, since your basically getting 900/1800 more mAh

My LG's are out for delivery!!!.....Can't wait to thaw them out and get them charged

I would say your battery holder is doing ok, when I was testing a FT battery holder it wouldn't even fire the dna at 30w with a single battery.

 

[mamu]

LOL bap - thanks for doing the summary!

 

[bapgood]

Preliminary IR results are in for the LG's

Just a couple of notes....the LG's are FOB and not broke in by any means, so I will be checking them every couple of charges to see how the IR changes over break in.....also I noticed that the Sony batteries give a lot more stable reading, the LG's bounce around a little more....possibly due to the Sony's being broke in??? Also I was kind of surprised that the Sony's went exactly half with two batteries and LG's didn't.

 

[mamu]

Thanks for sharing bap!! Interesting results. Will be curious what IR is after a couple of charges.

And that IR not halving like the Sony with dual LG batts - gremlins I tell ya... gremlins.

 

[bapgood]

This is kind of funny....I got a little impatient before and pulled them off the charger before they were all the way charged. Didn't think it was a big deal because from what I have seen it doesn't make much if any difference of charge, however what I think was the difference is letting them settle after charging. The first time they came right off the charger and tested, this time they had set for about hour after being fully charged.

So now they match the Sony's and read just as stable.

 

[bapgood]

Just as an FYI (maybe this is common knowledge and I'm slow)....but with the new wattage lock feature I was thinking it would be kind of nice and cool to have a third button just for the wattage lock, a button that would essentially press both buttons at the same time. I had thought that since the up/pot didn't share a common ground that it couldn't be done, but I got playing and found that if you take the center up/pot pad to ground that it works!!! So then I wired it and the down + together to one side of the switch and down - to the other side of the switch and bing-bang-boom...press the switch for ~5 seconds (which seems like forever) and now you have a single wattage lock/unlock button

 

[retird]

Thinkin' a double pole switch (button) will work also......

 

[mamu]

A 3rd button? ach lol.

I have no issues with pressing both the up/down watts buttons at the same time to get watts lock.

I'm not keen on having to add more parts if something already does the job.

 

[bapgood]

lol....depends on where the wattage buttons are and etc

Mainly just throwing it out there....but I do I have some little jog switches....so up and down for adjustment and use the center press for lock

 

[gorethugz]

I wanted to ask you quite silly question.

I bought some 650-RGEF400 fuse and a keystone dual battery holder.
Im going to set it to parallel for the battery with sony vtc4 battery.
how many fuse that i need to use for each battery? or is there any other way?
please advise mamu!

 

[Vapant]

Can you lock the wattage with an extra switch if you are using a pot then?

 

[mamu]

I wanted to ask you quite silly question.

I bought some 650-RGEF400 fuse and a keystone dual battery holder.
Im going to set it to parallel for the battery with sony vtc4 battery.
how many fuse that i need to use for each battery? or is there any other way?
please advise mamu!

2 fuses in parallel/battery (you will have a total of 4 fuses - 2 on each batt).

Can you lock the wattage with an extra switch if you are using a pot then?

Since I've not tried this, I'm not sure. Bap's suggestion of the way to do it sounds like a go though.

 

[Skyfntm]

I guess I'm also going to ask a silly question. For the fuses, when wiring them to the batteries in a parallel in an battery holder, do you wire all 4 on the positive wire or split the positive connection on the holder, wire 2 fuses, reconnect, then wire the other 2 fuses off the positive wire going out?

 

[mamu]

Split the positive connection on the holder so each batt will have its own fuse shut down. That way if one batt goes ballistic, the other batt won't see the backlash.

If you don't split the positive connection on the holder, you will have one common fuse - if you happen to put one batt in backwards and the other batt in correctly - you'll have a batt meltdown. That's why each batt needs its own independent fuse to protect that batt in situations of extreme current dump that happens with short circuit or reverse polarity.

Batt1 + > 2x fuses in parallel > common wire
Batt2 + > 2x fuses in parallel > common wire
Common wire > DNA + input

Another alternative since your goal is to simply lower the resistance of the fuse when using parallel fuses, is to use a single fuse on each batt that has the same hold current as the 2x fuses in parallel. With a single fuse on each batt, you will still have parallel fuses when you connect the common wire so the combined resistance of the fuses will be lower.

For example, if you have a fuse with a 5A hold current and you put 2x in parallel, you now have a 10A fuse. Use a single fuse with a 10A hold current on each batt.

Batt1 + > single fuse > common wire
Batt2 + > single fuse > common wire
Common wire > DNA + input

The problem is though the higher the hold current, the larger the fuse is in size - so you may not have space inside the mod for the larger fuse. And you can't find surface mount fuses higher than 4.5A hold current - at least that's what I've found with my search for one.

Another thing is that since current is shared with parallel batts, you can use a lower hold current fuse on each batt and still safely protect each batt and the circuit. However, you don't want the fuse to trip during normal operating mode and you don't want it to trip from simple internal or external heat - so you need to choose a hold/trip current high enough that will prevent inadvertent tripping but not too high that it won't trip to protect the batt and circuit.

Choose whichever method works best for you and the space you have inside the case. Your goal is to protect each batt as well as the circuit.

 

[bapgood]

Just as an FYI (maybe this is common knowledge and I'm slow)....but with the new wattage lock feature I was thinking it would be kind of nice and cool to have a third button just for the wattage lock, a button that would essentially press both buttons at the same time. I had thought that since the up/pot didn't share a common ground that it couldn't be done, but I got playing and found that if you take the center up/pot pad to ground that it works!!! So then I wired it and the down + together to one side of the switch and down - to the other side of the switch and bing-bang-boom...press the switch for ~5 seconds (which seems like forever) and now you have a single wattage lock/unlock button

Disregard this.....I will explain later