Split Positive Boost Charger

[SkyWatcher]

Hi bob, thanks for the reply, yes the cen-tech seems to work really well.
I have been watching the other threads for sure and studying your results and others, though i don't have a boost converter yet, nor sufficient batteries yet, so i can't make similar tests yet.
However, i am learning much from the setup i do have at the moment.
This setup is showing very promising results, using the 20 cell nimh battery pack, with cen-tech inverter splitting positive between 12 volt tractor battery, then off one of the 115vac output plugs, a transformer with 24 vac step down, then full wave bridge, with 12 volt-4 watt yard bulb splitting positives to 12 volt charge battery.
This setup seems very efficient and is for sure recovering just about all, if not more, the energy that came from the 20 cell nimh battery in split positive phase.
One thing i notice, the 12 volt charge battery should be discharged enough before the split positive phase, otherwise, the energy is not absorbed well enough, if it is too close to fully charged.
So, i am powering the 12 volt-4 watt yard bulb, essentially for free, for sure.
I also definitely see the need for a decent sized charge battery bank.
I also see the need for good wire connections, thick, low resistance wire preferred.

Hi turion, oh, i have no doubts at all, based on what i am seeing and at some point, i will have what i need to make similar replication.
Thanks for all your efforts to share turion.
peace love light

[SkyWatcher]

Cheap meter caution

Hi folks, i just want to share some observations.
First, don't use el-cheapo meters to read amperage, they give readings all over the map.
Mainly because i was questioning my results and decided to just use a 1 ohm 5 watt resistor to verify amps into inverter from 12 volt battery.
So i can calculate how many watt hours it outputs, that it received from the 20 cell nimh battery in split positive phase charging process.
The meter was reading 1.05 amps and the 1 ohm resistor reads just over 1.6 amps.
The output watt-hours are just about the same as what was used by the 20 cell ni-mh battery pack, in split positive mode.
I'm throwing out these cheap meters and it's a cen-tech, though very cheap, funny though, their inverters work pretty good.
peace love light

[SkyWatcher]

So my question is this, for anyone that can help, are the amp hours that is shown put into battery on my astroflight charger, an accurate account of how of much capacity was actually used by the battery before recharging?
Thanks.
peace love light

[SkyWatcher]

Hi folks, well for now, i see no reason why the astroflight amp hour charge readings should be questioned, so, here are the results from the last test i just made using the inverter splitting positives, with 6 watt led bulb connected to inverter plug.
20 cell ni-mh battery, watt hour usage = 15.6 watt hours
12 volt tractor battery, watt hour output = 12.7 watt hours
Efficiency of this split positive test = 81.5 percent

These next results, are from using the inverter, splitting positives, with transformer off inverter plug, 24 volts ac through full wave bridge, through 12 volt-4 watt yard bulb, then into 12 volt charge battery.

20 cell ni-mh battery, watt hour usage = 18.2 watt hours
12 volt tractor battery, watt hour output = 17.25 watt hours
Efficiency of this split positive test = 94.7 percent

So it appears my previous comments are wrong, using the transformer off the inverter output, actually improved efficiency in the system.
Your comments or questions are welcome, let me know how this sounds to you.
peace love light
Edit: the difference between these 2 tests, is the fact that the bulb load is allowed to again split positives with the 12 volt charge battery.

[BroMikey]

So my question is this, for anyone that can help, are the amp hours that is shown put into battery on my astroflight charger, an accurate account of how of much capacity was actually used by the battery before recharging?
Thanks.
peace love light

I doubt it, I just drained out a LITHIUM battery rated at 1300mah
and it only gave me about 700-800 mah Max. You have to run them
and see just like you are doing.

This sets a standard baseline as I am sure everyone understands.

Aaron told me to run battery C all of the way down and when i did
that I found out the actual amount the batteries can offer.

Charging the death "C" position battery is easy now. To give everyone
a perspective I discharged a single battery into a bulb at 750ma
for 1 hour burning up all of the power to ground.

NEXT:

I put battery "C" in it's rightful position to charge in the split
positive diagram and only 500ma down to 400ma running thru
the light bulb load for 1 hr.

Now it is charged again all the way to 4.19v

Now i will see how much power is in this same battery C
by removing it from the split pos..........system and burning
up all of the power once again to ground.

THIS is what I am doing

Gone see how much I get out this way.

[Aaron]

battery dead voltage

I doubt it, I just drained out a LITHIUM battery rated at 1300mah
and it only gave me about 700-800 mah Max. You have to run them
and see just like you are doing.

This sets a standard baseline as I am sure everyone understands.

Aaron told me to run battery C all of the way down and when i did
that I found out the actual amount the batteries can offer.

What voltage did you run it down to? What are those particular batteries dead voltage considered to be at in order to get the full capacity?

[BroMikey]

What voltage did you run it down to? What are those particular batteries dead voltage considered to be at in order to get the full capacity?

3.2v = DEAD
&
4.2V = FULL

I discharged them and recharged them like this always
because Lithium batteries suffer damage so they say if
you go lower than 3.2v similarly like 12v batteries being
discharged to their safe limits.

For these particular batteries

You got me thinkin I am thinkin keep doing that to see
how much is in batteries A & B plus the load so that should
prove interesting, NO?



.........................................

.

[Aaron]

lithium discharge

3.2v = DEAD
&
4.2V = FULL

I discharged them and recharged them like this always
because Lithium batteries suffer damage so they say if
you go lower than 3.2v similarly like 12v batteries being
discharged to their safe limits.

For these particular batteries

You got me thinkin I am thinkin keep doing that to see
how much is in batteries A & B plus the load so that should
prove interesting, NO?



.........................................

.

Ok - for 1.3Ah rating you got about 0.75Ah or about half of the rated value.

What was the draw for that? I apologize if you already posted that, but I didn't see it.

Maybe recharge to 4.2 volts and do another discharge with a lighter load and see if that makes a difference. It shouldn't with lithiums for the most part, but it would tell a lot.

[BroMikey]

Ok - for 1.3Ah rating you got about 0.75Ah or about half of the rated value.

What was the draw for that? I apologize if you already posted that, but I didn't see it.

Maybe recharge to 4.2 volts and do another discharge with a lighter load and see if that makes a difference. It shouldn't with lithium for the most part, but it would tell a lot.

No apology needed I am the one who should say sorry
cause I did a type-O saying 40ma charging rate when I meant
500ma down to 400ma charging rate THRU the load.

I fixed that type-O blunder.

Thanks for your gentle way of correction, we don't want
everybody freaking out with bad figures like that. I just got in
and man was it hot again, like a sweat box, no air moving 200
percent humidity. I felt like the junkyard dog itchin and scratchin..

I am back to double check all these results. C-U-ALL shortly
when I have another result. I can't wait to see that water
generator breaking all the records. That one you setup with
high energy ignition? Yeah that one, can't wait.

Yeah I am back and actually finishing that first charge that is at
around 4.18 but I think I'll go all the way to 4.2ovolt. When i left
it was below 4.20v. It started up at 500ma and after 1 or 2
minutes slowly dropped. It is running 400ma like before.

4.19volts now.

Yeah right that is what I am doing, I am charged up and gonna
runher down once again

Now it is 10 minutes later and the charge current is 380ma.

Yes this is the way to reuse power, I love it.

There it goes 4.20volts After 1 minute disconnected the battery is
still 4.05volts. I will wait till it stops. 4.03v now. so yeah it is
important to charge up the battery all the way.

It will sit at like 4.01 or 4.00 volts.

One hour later the light ran once again at the 700ma average
staring volts 4.2v and ending was 3.15v. Here is what I have
taken from these 3 batteries so far.

1 hour run time of light directly off battery "C"
1 hour run time of light while charging battery "C"
1 hour run time of light once again straight off "C"

So far three hours of light so remember the the conventional
discharge curve above shows that all three batteries in parallel
gave a 5.5hr run time of light.

So the goal is to see how many times I can charge and discharge
battery "C" running the light and charging in this split pos..........
diagram.

The run voltages of battery A & B while I am on this 4th hour of light
while charging at the same time is A = 3.60v and B =3.66v under a
load. Now I don't know if you understand the significance here but
this is very impressive. I only ran it for a couple of minute to get the
readings and then stopped. We will see next time how many hours
we have left.

Judging from my past measurements I will have to say that we will
get a lot of extra light doing it this way.

[SkyWatcher]

Hi folks, Hi mike, thanks for sharing your tests and results, they are looking good.
Are you rotating positions of lithium cells, like swapping B with C, then A with C, that idea.
Unfortunately, i can't do that with the setup i have right now, though i do have three lithium polymer 3 cell packs, that are 11.1 volts each at 1300mah, i use them for my homebuilt, foam board electric planes.

I made another split positive single cycle test last night.
Using the same configuration, transformer off inverter plug, though this time i used two 12v-4 watt yard bulbs in parallel, for a greater 8 watt load.
The charge battery was climbing much faster, but the inverter alarm started sounding a couple minutes before finishing the 30 minute run.

20 cell ni-mh watt-hour usage = 24.7 watt-hours
12 volt battery watt-hour output = 23.9 watt-hours
Efficiency for this split positive test = 96.7 percent

Again, i'm basing these numbers off the charger lcd readout, showing how many amp-hours were put back into the nimh battery after being recharged after the split positive test.
And when discharging the 12 volt battery, i have chosen a specific voltage point that i observe and when it hits that voltage, i stop the discharge phase and calculate the output watt-hours.
peace love light

[citfta]

Are you rotating positions of lithium cells, like swapping B with C, then A with C, that idea.
Unfortunately, i can't do that with the setup i have right now, though i do have three lithium polymer 3 cell packs, that are 11.1 volts each at 1300mah, i use them for my homebuilt, foam board electric planes.

Hi Skywatcher,

I also fly homebuilt foam board electric planes. I belong to the RCGroups forum. They have a section just for homebuilt foam board planes with lots of plans. My favorite is called the Paint Ball wing. You can find some YouTube videos of our flying group. Just look for Pecan Patch on YouTube.

If you have been flying a while then I guess you probably know about the dangers of the LiPo batteries when not charged with the proper chargers. You don't want to see one of those catch fire if it is inside a building. It is almost impossible to put out and the fumes are dangerous also. I always use a balance charger and the special nomex bag with the battery inside it when charging my batteries. And I never leave them for more than just a few minutes while they are charging.

I did have one of them explode and burn while flying one day. It had previously been in a crash but looked to be fine. It charged ok but as my wing was climbing out it got up about 100 feet when BOOM the battery exploded and blew right out of the plane and landed on the runway and burned for while until there was nothing left but ashes.

Please be very careful if you are thinking of using the LiPo batteries for testing in these circuits.

Respectfully,
Carroll

[SkyWatcher]

Hi citfta, yes i am aware of the dangers and i normally use a balance charger.
I probably will not use them for these tests though, just an idea, as i don't want to ruin them, need them to fly, hehe.
I've built 8 dollar tree foam board planes so far, all from the plans at flite test.
peace love light

[citfta]

I know I am getting farther and farther off topic but I thought you might like to see this:

https://youtu.be/bVh9Vj1HIQg

[Matthew Jones]

I know I am getting farther and farther off topic but I thought you might like to see this:

https://youtu.be/bVh9Vj1HIQg

Darn I thought we were going to get to see one blow up..LOL


Matt

[citfta]

Sorry Matt,

But at least you got to see a midair collision and a couple of crashes.

By the way I wasn't flying then. I was shooting the video.

Take care buddy,
Carroll