Can we get back onto the Blue batteries for a minute

tramcar trev

tramcar trev

all manner of mechanical apparatus...
Ok my steam tram motor has a 4.8Ah blue battery in it. Symptoms are that the motor has no torque.... Its driving a conventional Bachmann tram motor/chassis/wheels via an ESC. I have changed the ESC a few times from different brands I've swapped the wires over ( some esc's only give 80% in reverse) still the thing misbehaves. I am wondering what the go is. The smoke unit which draws an amp works well and with smoke on or off makes no difference, it still makes all the right noises but crawls along until it hits a curve then stalls. Battery voltage is around 12v fully charged....
Power it via a 2 amp bench power supply and I get wheels slipping.... Must be the battery is all I can think of.... I may have to rip the blue battery out and make up a Ni-Mh pack and see if that's the problem....

Thoughts from the floor?
 
Trev never heard of these Blue Batteries. What are they so that I can avoid them if indeed that is the problem. May also be worth checking your Back to Back measurements. I know your lines curves are tight so that if it is a little over the nominal that may be impacting.
JonD
 
Checked the charger, 12.7V 830mA output.... battery charged overnight... Battery Voltage 12V....
 
I've had these Batteries Lose a cell under load, Whats the battery Voltage under Load and what current is being drawn?
 
I'll check and get back to you... sounds the right symptoms for what is happening....
 
Appears that it may be the ESC. Battery voltage 12.5 but on the outlet side of the ESC I'm only getting 10.5V. I have tried 3 different ESC's too HK, Turnigy and this; http://www.ebay.com.au/itm/RC-ESC-10A-Brushed-Motor-Speed-Controller-for-RC-Car-Boat-W-O-Brake-/261210546358?pt=AU_Toys_Hobbies_Radio_Controlled_Vehicles&hash=item3cd15ca0b6&_uhb=1
 
Yes they all have similar specs and now having tested them they all seem to allow a 2 or 3 Lipo cell (11.5) voltage through to the motor....


Unless of course my meter is out... hang 5 till I check it against another... wonder how difficult it would be to convert to brushless motors...
 
3s provides more voltage than the specs I saw say.
If you want success you will need to find a brushless ESC that can handle 3s.
Then, unless the specs say you can, don't try a 4s looking for more speed. For that you will need an ESC that permits 4s.
 
Ok this has just become stupid. With the blue battery at 11.5 v I get 10.5V at the motor. Ok so I connect up a 2 amp power supply and set it at 14V switch on and I get 14V at the motor.... In fact if I fiddle with the voltage on the power supply I get out from the ESC whatever I put in. If I connect the battery direct to the motor it runs as it would at 11.5.... If I use the power supply and sit the tram on the tracks the wheels spin if I prevent progress EVEN IF I DROP the supply to 11V. Using the blue battery this does not happen....
I have bought 4 lion cells that I'm going to make up into a pack and try those. I suspect that there is something going on with the voltage protection circusry in the blue battery LiPo which stops over discharge. The battery also has an over discharge circuit built in and shuts down if the drain is more than 5 amps. Stall current on the tram is .7amps.....Of course I could unwrap the battery and rewire it and use one of these; http://www.ebay.com.au/itm/NEW-7-4V-11-1V-Lipo-Battery-low-voltage-Alarm-Indicator-TR-/310966781489?pt=LH_DefaultDomain_15&hash=item4867108631&_uhb=1
 
Looking at the lable on the "blue battery" it says" super polymer Lithium ion battery" model DC1248A ( DC 12 V 4.8 Ah) .... So the blue batteries are lions not lipos. Now I feel comfortable unwrapping Lions but not LiPos http://www.ebay.com.au/itm/Rechargeable-Li-po-4800mAh-Battery-DC-4-CCTV-Cam-12V-/390716438185?pt=AU_Electronics_Batteries_Chargers&hash=item5af883b6a9&_uhb=1
But as I say I have 4 x double AA Lions ready to wire up...
Ok so maybe the ESC does not like the battery chemistry though how it would know is beyond me. The reason I guess they are preferred is because of their cell voltage, to get 12V in NiMh is going to be a big pack... 10 cells.... and NIMH's self discharge. Lions are reasonably stable but easily destroyed by over discharging them....

Hands Up those who have used these blue batteries with complete success with R/C and let me know what sort of ESC you are using....
 
I agree Trev.
Unless there is a wired contact between the battery pack and the ESC, other than + & -, there is no way the ESC will know what the type the battery is.
Beginning to sound more like crap batteries to me.
 
Ok, I am going to unwrap the battery and see what the onboard electronics do.... If there is an extended delay in getting back to you assume the worst.... No flowers by request..
 
Yes Ross, mate I`m still here... I think from what I discovered there is greater danger from cutting yourself with a scalpel removing the wrapping than anything else... Do calm down Ross you`re being alarmist. I mean had I blown myself up how would I have proceeded to litigation?

Ok from the pictures you can see what happens to an ordinary ant when exposed to an unwrapped LION battery pack...

Each cell is in series; and, they are as we know, charged in series. Each cell has as can be seen a small PCB connected to it. I know for a fact that the PCB prevents over current discharge, short the pack out it shuts down until it is switched off and it resets. It also regulates charge current to around 400mA per cell even though its being series charged, so maybe 1 cell fills and rather than the full charge current... so the cells can`t be balanced which suggests maybe they are balanced to start with. Under load ( and the max I could draw was 3 amps) the cell voltages remained similar ie 3.68V each so I`m not dropping a cell under load. There is also a lot of HD foam packing inside the cardboard outer box and as space is at a premium I shall repack this lot in either some silicone self amalgamating tape or a length of heat shrink. As can also be seen the output and input leads are commoned at the switch, I shall replace that with simply 2 wires  to a single connector that will allow me to disconnect it for charging and turn the battery off at the same time.... The outer plastic foil wrapper is insulated from the innards of the battery

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I could of course make individual connections for each cell and charge with a balance charger but why bother...
 
#!@#@! I've now got a very similar problem. Doing a conversion and am getting an unbelievable voltage drop across whatever sort of Rx & ESC combo I try (I've given one of Tony's, one of Cliff's and a chinese dimmer controller a go). However, the batteries I'm using are NiCd sub Cs, and they all individually OK. The motor demand works out at just over 0.8A starting; input voltage to the esc is 14.2V, max output I'm getting is around 8V (varies between about 7.8 and 8.6). The wires are what I always use so I shouldn't have an issue there, and the individual bits of the circuit all check out. Time to rebuild the whole thing from scratch I think. God I love DC electrics.
 
Spoz said:
#!@#@! I've now got a very similar problem. Doing a conversion and am getting an unbelievable voltage drop across whatever sort of Rx & ESC combo I try (I've given one of Tony's, one of Cliff's and a chinese dimmer controller a go). However, the batteries I'm using are NiCd sub Cs, and they all individually OK. The motor demand works out at just over 0.8A starting; input voltage to the esc is 14.2V, max output I'm getting is around 8V (varies between about 7.8 and 8.6). The wires are what I always use so I shouldn't have an issue there, and the individual bits of the circuit all check out. Time to rebuild the whole thing from scratch I think. God I love DC electrics.
Click to expand...
I have a very low impression of Nicads at the best of times....They always seem to end up with STML while under my care.... 5 Amp Lions are the go; http://www.ebay.com.au/itm/18650-GTL-Li-ion-5300mAh-3-7V-Rechargeable-Battery-for-LED-Torch-Flashlight-CM-/271262704378?pt=AU_Electronics_Batteries_Chargers&hash=item3f288462fa&_u

I reckon what may be happening here is that there is some sort of EMF (electro magical feedback) between the pcbs on each cell and the ESC.
I'm going to try a lion 18650 home build battery pack and see if that does the trick. If not, then as they are high discharge cells, the fault has to be within the ESC and Im going to try a model boat ESC especially designed for 12V operation. What if that fails? I could always go back to a servo moving contacts over a series of resistances.... One other thing that may be causing the problem is the BEC on the ESC from which the Rx draws its power.
Spoz have you tried using an external power source?
Keep in mind I have R/C trams that run perfectly well (if the track and overhead is clean) using identical Rx, ESC and motor.... That leaves only 2 questions and suggests an answer...
 
They look nice Ross... BTW U1 on the pcb also has thermal protection built in...
So I would hypothesise that these batteries are fairly safe being designed with several safegards in place but they do need at least an overnight charge, fast charging them may be dangerous but you cant anyway because the electronics prevent that....
 
Spoz said:
#!@#@! I've now got a very similar problem. Doing a conversion and am getting an unbelievable voltage drop across whatever sort of Rx & ESC combo I try (I've given one of Tony's, one of Cliff's and a chinese dimmer controller a go). However, the batteries I'm using are NiCd sub Cs, and they all individually OK. The motor demand works out at just over 0.8A starting; input voltage to the esc is 14.2V, max output I'm getting is around 8V (varies between about 7.8 and 8.6). The wires are what I always use so I shouldn't have an issue there, and the individual bits of the circuit all check out. Time to rebuild the whole thing from scratch I think. God I love DC electrics.
Click to expand...

Where are you powering your Rx from?
I have had to use a separate BEC for a robot motor controller because the onboard BEC could not supply the Rx current and it was loading down the circuit.
The Hobbyking ESC that I commonly use has jumpers for different battery chemistries as does the robot controller they are for discharge protection of Lipo batteries.

Just thoughts to maybe consider.
 
Reading all this, I'm kind of glad that for the present at least, I'm sticking with track power and DCC...... ;) ;) ;)

Does anyone still use good old-fashioned sealed lead-acid batteries anymore? I know they're heavy and (relatively) bulky, but nosing round the ones in Rapid's retail shop turned up some that could quite easily be fitted into a large square diseasel, like a 2095 for us Euro bods or pretty much anything US-profile.....?

Jon.
 
Zerogee said:
Reading all this, I'm kind of glad that for the present at least, I'm sticking with track power and DCC...... ;) ;) ;)

Does anyone still use good old-fashioned sealed lead-acid batteries anymore? I know they're heavy and (relatively) bulky, but nosing round the ones in Rapid's retail shop turned up some that could quite easily be fitted into a large square diseasel, like a 2095 for us Euro bods or pretty much anything US-profile.....?

Jon.
Click to expand...

yes! I have several in regular use on the railway driving power cars and several standby in the workshop on regular recycle for model scenery power units occasional lighting etc. They were originally alarm type backup batteries and work very well. I used them in a couple of largish model lakes launches and a four foot three prop MTB. I also use several Ni cad battery packs that I made up pre 2000 which are regularly used running locomotives as 7.2v PSUs. Still running strong. I also run four of the latest blue offerings with no problems. I always use marine ESCs with BEC, mainly because I have so many redundant ones removed from model boats. Vipers, Fleet, Electronize (6-24v 12 amp) and others. Never ever had any of the problems described in this thread (well not yet anyway). I also use 27m, 40m and 2.4gig radio gear on various locos and even a couple of 27AM (out of the arc) rigs. Trev got me interested in the blue battery packs which I find fine to use and comparably light weight. i have lately been experimenting with the 18650 type single cell 3.7V Li-ion as free fitted series linked packs. They claim to be 5000mAh which in itself is quite interesting. The supplied twin cell chargers are decent quality so time and experience will no doubt prove the pudding.
 
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