Ultra duo 30 chargers need to fix blew up two of them

[treehog]

Hopefully the exist guru in this section that knows how to fix broken chargers and figure a way to stop blowing my chargers

here is the story of the first charger which blew and no replys in batteries section

http://www.rcgroups.com/forums/showthread.php?t=898865&highlight=30

The two chargers have one common thread

They were both charging the two receiver packs on the same plane

This plane has a twin battery pack which has a electronic method to switch in packs from berry one to battery two if the primary battery fails

I suspect now that there is something to do with this twin battery pack that switch that blows the charger but not sure

I originally suspected that it was the fact that there was two two leads of thin wire as one has with receiver charging units with fast charge rates of 1 amp plus that caused the issue with to much back pressure on the charger

But blew the second charger yesterday and the charge rates were small only .5 amps for each battery pack
I had connected the battery one 1700 mha to the reciever charge point to the right hand side of the ultra duo 30

I then was connecting the second receiver pack which was the 2500 nimh
The positve lead was in place and the negitive was not in place so I could program the primary outlet on the left side to do NiMh 0.5 amps manual mode and then tried to connect the negitive lead to start the charging

As the negitive lead approached there was a spark and as I inserted the lead there was a bang and puff of smoke and the charger was non funcional

I shows on the screen always wrong polarity when polarity is correct go figure

I have supplied a circuit best i can do and fail to see how the swich which is before the aircraft onboard electronicpack selector can effect the charger???

first chharger blown with combo packs of
Battery pack one is 4cells 4000 mha nimh
Battery two is 4cells 2500 AA packs

second charger blown with
Battery pack one is 4cells 1700 mha nicads
Battery two is 4 cells 2500 mha AA packs nimh

I have supplied a piture of the first charger blown power amp
If I knew where to get a replacement op amp I would get one but no writting on the components as to its part number

any ideas guys

Hopefully the second blown charger when I open it will have only one power amp blown
So hopefully I can strip of one of the working power amps from that unit and make one working unit

I would prefer to fix both of them to help me

I am a bit non plused at the rate I eat chargers
I have eaten since 2000
a vario 28 cell
then a ultramat 12

and now two ultra duo 30
and my new third ultra mat 30 after a few month wont let me charge receiver packs on the second socket??? so if I wasn't stuck for a charger I would have sent it back for repairs

any body know plans for a charger that can do 10 amps with 6 lipos preferably 10 as I don't think manufactuered types they last more than year of real field use

Ralf

[darkith]

You're trying to charge too packs with a common negative. I suspect the charger's outputs aren't designed to share a negative...on my chargers (single outputs), the negative isn't connected to either the power supply ground or the metal cases.
I wouldn't be surprised if the charger floats the negative side and drives it with a FET while charging. :P
Isolating the packs entirely, or charging them one at a time might be best.

I've been really happy with my TP 1010C charger, does 10 amps into 10S, though I haven't needed that capability (yet). Pity it doesn't have the balancer built in though...the external balancer adds a bit of tangle.

D.

[Rodney]

I think darkith is correct. You must have both batteries completely isolated from each other while charging them or have them connected in series while charging and charge them as if they were one battery at their combined voltage. This is true for most of the chargers that will charge more than one battery at a time.

[Ron W3FJW]

Also, both packs should have the same rating in mah.

[darkith]

I don't think they should be connected in series for charging, same rating or not. The electronic switching unit is going to discharge one pack before switching to the second pack, so they're going to be at massively different charge levels and false peak.
I think separate charging would be best.

D.

[Ron W3FJW]

It's common practice anymore to charge multiple packs. Two 2S as a single 4S. two 3S as a single 6S etc. All multiple packs are treated as one single pack. The only time a switching unit (voltage) comes into play is when the Charging voltage is higher than the supply voltage. All cells are monitored by individual sections within the charger. Only those cells with a higher voltage will be discharged while the other cells are still being charged. When all the cells are balanced at the terminal or recommended (set) voltage, charging is terminated.
Since all cells are charged in series, only packs with the same current rating should be charged in series.

[Acetronics]

Hi, treeHog

A common charging rule : NEVER charge two batteries with some common leads on the same charger ... Always UNLINK one batt. to the Other.

Unless you have read an authorizing advice on the notice, or you really know about the circuitry.

Alain

[darkith]

It's common practice anymore to charge multiple packs. Two 2S as a single 4S. two 3S as a single 6S etc. All multiple packs are treated as one single pack. The only time a switching unit (voltage) comes into play is when the Charging voltage is higher than the supply voltage. All cells are monitored by individual sections within the charger. Only those cells with a higher voltage will be discharged while the other cells are still being charged. When all the cells are balanced at the terminal or recommended (set) voltage, charging is terminated.
Since all cells are charged in series, only packs with the same current rating should be charged in series.

Maybe with lipos. But he's using Nicads and Nimhs (sometimes mixed)...no balance taps, so it's full series charging without individual cell monitoring. Even *if* he was using matched chemistry and capacity, they'd be at different states of discharge (pack1 would be discharged, pack two partially discharged), so the charger would false peak on the 8 cell pack of varying charges.
The only way you could charge them in series would be to use a 1/10C forming charge....but then what's the point of hooking them to a peak charger.

D.

[Ron W3FJW]

Yes, I was speaking about lipos. But I have charged Nimh in series parallel with success, but not Nicads (haven't tried it but I believe it should be ok), at .5 to 1C rates but only with same rated cells. No way should nicads and nimh be mixed and/or charged together. In parallel I've found it to be ok regardless of the state of charge between packs as long as the packs were of the same chemistry, same current rating and same voltage..

[treehog]

THanks for the feed back

seems to be confusion

The Ultra duo 30 is a charger that can charge two packs at the same time

However the second pack must be NiCad or NiMh as it works from delta peak

The first part of the charger charge lipo Lead acid NiMh NiCad 4 to 30 cells or 10S at 7 amp for low cell count and les for higher cell counts
No balancer features for Lipos so requires seperate balancer

The second charger section is limited to 7 cells of 1.2volt types

Ralf

[8pointroll]

IMHO
As already explained, you are charging two packs with a common ground and your charger appears to be incapable of charging in this mode. My advice would be isolate your packs before charging them.

I wonder why you use an `on board electronic voltage divider` ?

I used to fly with two seperate Rx packs connected to two sockets in the receiver via two seperate slide switches, thus offering power redundency without introducing a device which could fail in flight. The power slide switches used in all (AFAIK) radios are two pole changeover which are paralled up to reduce possible failure. So long as you test each battery individually before each flight you should never have a power failure in flight, and you will benefit from the combined capacity of your packs.

When switched off, both packs are isolated from each other.

Mike

[flunki]

Ralf,

Do you still need the components to be identified ? (Could open up my charger an try to check).

In case you need to charge 2 NiXX batteries which are interconnected either via plus or minus you must use 2 charges and 2 different power supplies.

Tried once to boost the current to charge a car battery by connecting 2 chargers in parallel from a single power supply. = dead charger. It works if you use 2 power supplies . . .

So with Ultramat chargers there is no "common minus", it seems to be switched/regulated.

Cheers
Frank

[treehog]

IMHO
As already explained, you are charging two packs with a common ground and your charger appears to be incapable of charging in this mode. My advice would be isolate your packs before charging them.

I wonder why you use an `on board electronic voltage divider` ?

I used to fly with two seperate Rx packs connected to two sockets in the receiver via two seperate slide switches, thus offering power redundency without introducing a device which could fail in flight. The power slide switches used in all (AFAIK) radios are two pole changeover which are paralled up to reduce possible failure. So long as you test each battery individually before each flight you should never have a power failure in flight, and you will benefit from the combined capacity of your packs.

When switched off, both packs are isolated from each other.

Mike


I decided to use the split voltage divider a it has a beep sound warning and flashing led when either battery goes low

I figured if one pack shorted out it could drain the second pack and with the simplex parrellel solution I would have no in flight info there was a problem

Got lucky at a bring and buy got non lipo charger Vario 28 for E35 euro ~$50 and this can replace one of the broken chargers for non lipo work

I will stick to just charging one pack at a time

Ralf

[treehog]

Ralf,

Do you still need the components to be identified ? (Could open up my charger an try to check).

In case you need to charge 2 NiXX batteries which are interconnected either via plus or minus you must use 2 charges and 2 different power supplies.

Tried once to boost the current to charge a car battery by connecting 2 chargers in parallel from a single power supply. = dead charger. It works if you use 2 power supplies . . .

So with Ultramat chargers there is no "common minus", it seems to be switched/regulated.

Cheers
Frank

Thanks for the useful info on parrel charging for lead acid

saves me that experment

If you open your unit you will see there is is no info identifing the components for the power amp

even I undid all the heat sink plates there was no printed info

I am stumped how to figure out what components the power amps are

I could look to replace all of them with another type if I knew that would work

Some evening I will strip one power amp of the other charger and fit it to the other and see if I can get one charger to work

Ralf

[flunki]

Because you sound desperate and said please, I couldn't restist to open mine up as well (need to change the digiadjuster anyhow). Here is what I could (hardly) read:

- from left to right

(sorry, at your own risk, not all very well readable):

FET6 = IRF3205
FET11 = IRFZ44
FET9 = IRFZ44
D27 = MBR30100
FET5 = 3205
D25 = MBR30100C
FET4 = IRF4905
FET1 = IRF3205
FET10 = IRF4905
D52 = MBR30100CT
FET2 = IRF3205
D4 = MBR30100CT
FET7 = IRFZ44R
FET8 = IRFZ44R
FET3 = IRF 3205

Hope that helps

Cheers
Frank

[treehog]

Because you sound desperate and said please, I couldn't restist to open mine up as well (need to change the digiadjuster anyhow). Here is what I could (hardly) read:

- from left to right

(sorry, at your own risk, not all very well readable):

FET6 = IRF3205
FET11 = IRFZ44
FET9 = IRFZ44
D27 = MBR30100
FET5 = 3205
D25 = MBR30100C
FET4 = IRF4905
FET1 = IRF3205
FET10 = IRF4905
D52 = MBR30100CT
FET2 = IRF3205
D4 = MBR30100CT
FET7 = IRFZ44R
FET8 = IRFZ44R
FET3 = IRF 3205

Hope that helps

Cheers
Frank



Amazing

Thanks

I looked real close for a few minutes and eventualy my older eyes found these faint marking on the back of the fets

Later today I will get a magnify glass to see all the numbers

From best I can see the 8 big Fets (on the back row only) don't know where other Fets are probably all the same nummber

from left to right
no 1 =IRFZ44R
no 2 =IRFZ44R
no 3 =IRFZ44R
no 4 =IRFZ44R
no 5 =IRFZ44R
no 6 =to faint to see now will try later
no 7 =IRFZ44R
no 8 =not known and burnt out

I shall assume that all those fets are IRFZ44R and will try to source another one or another group of 8 fets of similar abilties

Thanks speeded things up a lot

out of curiousity what benifits can you get from adjusting the digiajuster and where is that component ???

Also as I am at it can I replace those IRFZ44R with bigger stronger types?? That could allow more amps charging say like ~14 amps even if the digital shows ~7 amps and is really charging at ~14 amps , that would be easy, I would just have to remember to divide by two for the charger real reading ???

diagram is supplied below

Ralf

PS some links about the part irfz44r

http://www.digchip.com/datasheets/download_datasheet.php?id=438757&part-number=IRFZ44R

http://www.diyaudio.com/forums/showthread/t-125907.html

[flunki]

Ralf,

I'm terrible sorry: I checked the UDP 50, not the UDP30. so you can't use my description. The UDP30 doesn't have a digiadjuster.

Sorry for the confusion! Will now dive into both UDP30 and write again soon.

Cheers Frank

[treehog]

UDP 50 nice toy you got Frank :D
my funds don't go there in this time

anyway you put me on the right track

the PDF for IRFZ44R
http://www.digchip.com/datasheets/download_datasheet.php?id=438757&part-number=IRFZ44R


Advanced Process Technology

Ultra Low On-Resistance

Dynamic dv/dt Rating

175°C Operating Temperature

Fast Switching

Fully Avalanche Rated

Drop in Replacement of the IRFZ44
description
Advanced HEXFET® Power MOSFETs from International
Rectifier utilize advanced processing techniques to achieve
extremely low on-resistance per silicon area. This benefit,
combined with the fast switching speed and ruggedized device
design that HEXFET power MOSFETs are well known for,
provides the designer with an extremely efficient and reliable
device for use in a wide variety of applications.
The TO-220 package is universally preferred for all commercial industrial
applications at power dissipation levels to
approximately 50 watts. The low thermal resistance and low
package cost of the TO-220 contribute to its wide acceptance
throughout the industry.



I think it looks like if I made another heat sink and attached 8 extra fets in parralel with the normal eight I could double my amps

any ideas from any sources shoot

Ralf

[treehog]

I found www.conrad.com which seems to go to http://www.conrad-int.com probably a international version of the well known german www.conrad.de or it french sister company www.conrad.fr

they supply the part IRFZ 44 R for ~E1.10 euro per mosfet

I will probably just order 4 of them

one to fix this charger machine and a spare to fix the other which has probaly blown the same component and a few spares in case my soldering is bad

Tyhe fets have some sort of white powder ( could be a dried out gel )to attach to the heat sink

any idea what is this powder or gel or suitable replacement so I can order it also


Must open up the other charger to see what part blew in that charger

If I got the two charger going again I could look to modify one of them to do more amps at a later date


the direct link for the part IRFZ44R or do search / zucken/ cherche

http://www.conrad-int.com/websale7/MOSFET.htm?Ctx={ver%2f7%2fver}{st%2f3eb%2fst}{cmd% 2f0%2fcmd}{m%2fwebsale%2fm}{s%2fconrad-int%2fs}{l%2fint%2fl}{mi%2fSHOP_AREA_17339_5204027 %2fmi}{pi%2f162750%2fpi}{po%2f1%2fpo}{sf%2f%3Cs1%3 EIRFZ44R%3C%2fs1%3E%3Cs2%3E%24%241%3C%2fs2%3E%3Cs5 %3E1%3C%2fs5%3E%2fsf}{p1%2fb9b9d23d816fdc6b0c5012b 013f5f541%2fp1}{md5%2fe40cf92cfb7e6e500b27065dfda3 c2bd%2fmd5}



Ralf

[treehog]

opened the other ultra duo 30

not good

the fets seem ok but there looks to be a very small micro chip which is broken

diagram shows position

This is one hell of a small micro chip and will be very difficult to extract and replace as the size of it is barely bigger than a small baby fly or marginaly bigger than big flea about ~3mm * ~2mm

I will probably not try to fix this one in this time in case I need the parts for the other charger which looks to be fixable or maybe even extract the mosfet for the other charger

looks best I can tell presently the mosfet are all the same IRFZ44R type

keep you posted

Ralf

[flunki]

Hi Ralf,
just back from my two UDP30.

Have identified the following parts (from left to right):

FET7 IRFZ44R
FET5 IRFZ44R
FET6 IRFZ44R
FET8 IRFZ44R
FET9 IRFZ44R
D1 16CTQ080
FET4 IRF48V
FET2 IRF44N

Using a small blue LED pen was able to read the number in both devices. So you got the following parts IRFZ44R, IRFZ44N, IRFZ48V and 15CTQ080.

The rightmost is definitly a IRFZ44N.

The "small chip" is the FET for the output 2 and is called IRF7805. I wasnt able to find any shop selling this item. The datasheet can be found at: www.irf.com/product-info/datasheets/data/irf7805.pdf

If I would need to replace it I would use just a similar one, comparing the datasheets. Its not so difficult to replace because on one side 4 pins are connected to the same signal, on the other side just 3 pins same plus a single. The tricky part is to get the pins to fit the pcb:)

The white "things" is heat conducting paste. If you are going to order from conrad the product ID is 189069-I5. You need to clean all parts (alkohol) and apply a very thin layer after that prior to mounting the FETs. Dont forget the insulation plate in between .

Conrad seems to be a bit expensive. I tend to use Reichelt but dont know if they ship outside Germany.

Hope that helps

Cheers
Frank

[JohnMuchow]

I suspect that the white powder/gel is a thermal grease (that's dried out) used to increase the conduction of heat between the MOSFETs and their mounting plate. It's absolutely necessary to use it! It could also have been a phase-change thermal compound which is a wax at room temperature and a liquid when it heats up.

You can use just about any thermal grease for your MOSFETs. Just apply a thin layer to the entire rear surface of each MOSFET. Too much of the stuff is almost as bad as too little. Just have enough to squeeze out a little bit all around the MOSFET as you tighten down into place. Don't overtighten them! If you do, the metal tab can warp and the body of the MOSFET will lift off the heat sink a little bit...just enough to prevent good heat transfer and let the MOSFET burn out. :)

As for other MOSFETs to use, check out what other chargers might use with a search in the DIY section. I like the IRF1405. Much lower on-resistance and lower thermal resistance too (more efficient at moving heat out). But, it's a bit slower turning on/off and has a higher gate charge (both of which can cause temperature to rise in switching applications) so I'm not sure where all that balances out. Perhaps someone else will have a recommendation.

I don't know if you can add another set of MOSFETs to increase the current rating. There is a circuit that drives (turns on/off) the MOSFETs and adding more of them slows down the circuit. The slower the circuit works, the hotter the MOSFETs get when the charger is being used. Unfortunately, only experimenting will tell you. :(

John

[flunki]

Ralf,
you can't expect an increased charge/discharge rate by changing the type of MOSFET or adding more. The maximum power (Watts) is set by the boosting circuit and limited via software. The limits for the UDP30 are:

Output 1:
7A / 54 Volts, max total Watt = 150 for charging, 5A / 54 Volt max total Watt = 50 for discharge

Output 2:
500mA and input voltage for charge, no discharge.

Hope that helps
Cheers
Frank

[JohnMuchow]

Ahhh...thanks for the info flunki. So the best Ralf could do would be to, possibly, reduce the operating temperature of the MOSFETs by selecting another one. Either by reducing the thermal resistance or the on-state resistance. Probably not worth doing though as it would take alot of experimenting and if those FETs are using an insulating pad, a lot fo the benefits of a MOSFET with lower thermal resistance would be lost due to the very high resistance of the pad. Best to stick with the IRFZ44R.

John

[flunki]

Hi John,

you are right. Unfortunately by design the UDP30 gets very hot when operated at the designed limits. In case Ralf doesn't want to "re-design" the UDP the best thing would be its operated at not to hot environmetal conditions. Such would help the components to last longer. Adding something like an external fan helps a lot.

And thanks for the hint not to overtighten the metal tab fixing the FETS. Just checked mine an did have to adjust them.

Cheers
Frank

[treehog]

I suspect that the white powder/gel is a thermal grease (that's dried out) used to increase the conduction of heat between the MOSFETs and their mounting plate. ....< snip>...

....John




Thanks for the info will go to local electrics shop and source suitable paste

Hopefully Will have the FET from same shop or extracted from one circuit board and placed onto the good board next week

Going on the info from "flunki" seems to be no benifit to change to another Mosfet so cant see that happening

I was hoping that similar to where ESC can simply double power amps with adding extra rails of Mosfet in parrelel the charger could do similar

Seems not to be the case

keep you posted

Ralf