Bob Marley
lvl.4
United States
Offline
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So finally, after three months of researching and deciding to get the I1, then reading a zillion pages of feedback/bs, I ordered my Inspire1, A version, (and it finally showed up today). I have learned sooooo much about this bird, (without ever having touched one), and have been DYING to get my hands on this thing! So I unpacked a bunch of stuff tonight, tablets, laptop, cinimizers, truth meter/connectors, new strings for my guitars, ooops - and the I1 of course -
OK, multiple choice question ......... After opening the I1 and checking that I had everything, having read a zillion pages ........
What was the 1st thing I did ???
a) - download the Pilot app
b) - fully charge the batteries
c) - read the manual
d) - turn on both radio and I1 and see if they link
e) - locate info concealing wire and cut it
The correct answer of course is e. I could not wait to find that thing, then chop it in two!
After reading about 100m charge times, and being told NOT to charge both Radio and lipo pack at the same time, I just had to get at the truth right away!
Here is a pic of the fabled beast, (I'm sure you will all recognize it).
And now ...... "Take that!" POS, hider of info, Now I cut you, one left side, one right side!.................................... "Hey dude, you just VOIDED your warrantee" - eye roll lol
I know most of you can cut/paste, this is the same thing, it's easy, cut/solder "Don't be Scared Homie" (notice the truth meter upper left)
OK, now that everyone is ready, there will no longer be any secrets about what is going on between the left half, and the right half.
The truth meter will now reveal magical info - (I'm getting goose bumps) -
Now before we get too ahead of ourselves, let's get some things straightened out.
Many peeps on these forums have either the WRONG IDEA or NO IDEA how this stuff actually works, so here's a real quickie to get you pointed correctly.
1st, most importantly .....HEAT is the enemy of ALL components - it's simple, if something gets hot, something isn't right - period, end of story, make some adjustments.
On a typical basic electric model plane we want to get as much power (watts) at the prop as we can, without getting anything hot.
Prop.............................. Motor ......................................... ESC ...................................................... Lipo Pack
if only the ESC is getting hot, the Prop/Motor is pulling too much power from the lipo pack thru the esc - Change the ESC
if only the motor is getting hot, the prop is too long/pitch - Change the prop
if only the lipo pack is getting hot, it is NOT supplying enough current- change the pack.
The "sweep spot" is when all components are equally "warm" when your flight is over.
(not cold/underperformance .... or hot/edge of failure.
Same thing when we charge Lipo packs, (except the charger never gets hot).
Power Supply ..........................Charger .............................. Lipo Pack
The Charger is always the boss here, It determines at how many watts the pack gets charged at (volts x amps = watts).
(the charger/circuit board is mounted on top of the lipo pack, people wrongly call the black power supply and cable the "charger" .. stop that please.)
The Power Supply should be like a big lake, with more than plenty of power for anything the Charger asks of it.
If the charger wants to charge a big lipo pack at 400 watts, having a 800 watt supply would be really nice, it would not even break a sweat giving constant 400w to the charger. Power Supplies DO NOT push/or force power to anything. They just sit there, and offer any power asked of them, (up to their rating). Having a giant Power Supply will NOT blow up a lipo pack. It will simply only supply the amount of power the Charger is asking of it.
Having an adequate Power Supply is the most important component in the charging system. "Scottie, we need more power"
K, let's start making some connections.....
First off, here are both the 47 & 48 coming in to the RIGHT side of the truth meter. These packs were only about 60% charged when shipped and display their current voltage before charging. Notice the other values read 0 because the battery is neither charging nor discharging, there is no current flow.
Now you will see the Power Supply's voltage as it's connected to the LEFT side of the truth meter.
You will note the other values are 0 because the Charger is not yet asking it for anything, so there is no current flow.
(also pic of the specs of the Power Supply 26.3v x 3.83a = 100.729 watts).
OK, now it's time to connect the Right & Left sides together and FINALLY see Watts Up (pun intended).
1st - we hook up one of the controllers.
As you can see that the Charging circuit inside the radio is asking the Power Supply for only 23watts and drawing less than 1amp.
"I can easily charge 3 of these of these controllers without even getting warm" the Power Supply exclaimed, (and rightly so).
Now lets unplug the radio and just connect one lipo pack, the smaller tb47. Let's see how much power it's Charger will ask of the Power Supply.
OMG, do you see that! The Charging circuit on the tb47 is beating the tar out of that silly little power supply.
The tb47 want's MORE power than the Supply can offer. If this were a 400w Supply it would be able to easily give the charging circuit anything it asked, without breaking a sweat, but guess what. This supply is MAXED OUT and it is getting HOT !!!
Now we will also connect the radio as well. One might think things will get worse, but it Cannot.
Why?, the Supply is already Maxed out by the lipo pack, so it cannot get any hotter. I could solder 10 pigtails on and charge 10 packs at the same time (parallel charging) and the Supply will not work any Harder, (just longer). As you can see there is no difference with the radio also charging.
So when the question came up in the forums "Can we charge both at the same time" the wrong answer was given on several different occasions.
"No, the Power Supply will get too hot charging Both"
Well, we now know, that's NOT true. The Supply is getting hot from the Lipo pack alone, (and does NOT get hotter/produce more current with a radio also hooked up).
If you look at the Truth Meter the Lipo Pack voltage stops increasing at 25.99v and goes no higher. Divide that number by 6 and you will find a perfectly balanced pack and what voltage the Charging boards charge each cell to.
.
CONCLUSION -
These Power Supplies are NOT "adequate" for these lipo packs, and I am very uncomfortable with the high temps it reaches.
It is no wonder why it takes these packs so darn long to charge. So if we had a gigantic 800w Power Supply, I wonder how many watts the onboard chargers would ask from an more than adequate supply? I'll have the answer by tomorrow.
There are several ways to accomplish this ...
Splice 2 or more of these dji supplies in parallel and give the lipos what they ask for.
Get a different more powerful supply (I have one on order).
Take two 12v deep cycle marine batteries, connect them in series for 24v. (recharge up to 20 packs in the field with no ac power).
So there you go.
After all of this researching and waiting, the first thing I did was insert a truth meter to monitor the most important thing and perhaps the weakest link in all electric airships, the lipo pack. Someone had to do it, I just can't believe I was the first that I have read about.
I can assure you the recent battery glitch thing going from 26% down to 3% in 5 seconds is a Firmware problem, and not a lipo pack problem.
This is very disconcerting because regardless of the "actual" state of the pack, when the software see the incorrect value below 10%, it's going to "auto land", whether its in a Lake, a forest, a mountainside, or an ocean, your I1 is gonna auto land and you're going to lose it -
I guess tomorrow I will read the manual, then take her for the maiden flight. I hope you all learned something and wish me luck tomorrow -
Bob
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