lipo batteries

[pistol_pete_2011]

Hi ive got a losi 8ight 2.0 & ive just changed to lipos ie receiver pack & regulator..i charge & balance the receiver pack together but when i go to track my dx3s flicks to 4.8 R.X ect & warns me of this & as you will know stops on fail safe due to the battery level... This is only after 5-10 minutes tops..
Please help !!!!!Thanks Dave:mad:

[leeleefocus]

Sounds like high Ri cells or one of the cells is bad. You need to load test the cells so you can see what they are doing during use. Could be several other things although the fact it is working for 5-10 minutes points towards poor quality cells or they are going/gone bad.

What pack is it you have so i can get an idea of what the cells are supposedley capable of. Should be able to come up with a way you can load test the cells as long as you have a fairly accurate way of monitoring the voltage.

[pistol_pete_2011]

Hi many thanks...the battery is Turnigy 2200mah 4 cell lipo...as we speak i have put on the charger CORE UAC-40..and it is only picking up 3 cells and it says only to charger if both are identical..but this is 4cell ..?? thanks

[leeleefocus]

First you need to check if the balance lead is broken or one of the cells has gone to low for the charger to detect it.

If you have a multi meter it's just a case of checking the voltage of each cell through the balance lead.

The Turnigy batteries are very good if you have a healthy battery but they can be prone to a bad cell once in a while which normally highlights itself from new.

Does it charge without balancing.

[pistol_pete_2011]

Hi yes it does but only charges for about 20 mins each time at 2 amp and says its full then put in car and then as a result of using steering and throttle its draining battery into RX warning = failsafe.

[damselfly]

Leelee has it spot on.
A cheap and crude way to check cells under load would be to place a low ohm high power resistor in parallel with your voltmeter. Check the resting voltage before doing this (without the resistor) for reference though.
If the cell voltages drop when under load, the internal resistance will be high hence premature low voltages.
You don't need to use a resistor, but it's an ideal load and can be tailored for your use.
Personally, i'm not a big fan of Turnigy cells and have noticed a fair loss in performance from them within about 90 cycles of usage.

[leeleefocus]

What regulator are you using.

Do you own or have access to a multi meter. This is so we can atleast sort out the issue with it not balance charging and then we can move onto giving the cells a health check.

A high power resistor is ideal for testing cells but not many people have access to them but normally Car headlight bulbs or the halogen spotlight house bulbs do a good job of giving a decent load on the cells. I can talk you through how to set it up and all you need to do is post up the results and we can figure out if the cells are good or bad.

[pistol_pete_2011]

Hi Thanks for all your help !!
The regulator & receiver pack are both losi as brought from je spares !!! top shop!!!! but went for the turnigy starter box lipo as the losi 1 from je spares was £75.
No i dont own a multi meter...
Do you have to discharge and charger again from new to show the battery its cycle..
Demselfly is saying not a fan of turnigy but my losi receiver pack is dont the same thing...must be something im doing wrong..DAVE

[leeleefocus]

Ok i'm not sure which pack you are using in which place. So you are using a losi lipo reciever pack (2s 7.4V) that is showing up as low voltage on you telemetry and you are using the turnigy (4s 14.8V) in your starter box. Is this right.

Sounds like you said you have used both as a reciever pack or am i just misunderstanding what your saying.

I had a quick look at JE Spares and found the regulator you are using but still not sure which exact battery packs you have.

Lipo's don't need any cycling so don't discharge them. The charger will charge them at any state of charge they are in.

[pistol_pete_2011]

Ive had a look back & ive changed from receiver pack to starter box battery..my mistake sorry..new to all this..
Yes im using a losi receiver pack 7.4 2s...and losi regulator both jespares & a 14.8v 4s turnigy for the starter box ive not used this as a receiver pack just starter box..

The receiver pack is saying fully charged on charger but when connecting to the car its drawing too much voltage & putting the car into failsafe straight away ?? maybe its shorting out somewhere else on the car...??

But the turnigy battery is only showing on the charger when plugged in 3s found & its a 4s battery so do not want to risk charging it.. Thanks

[leeleefocus]

Probably (I say probably because without having it infront of me to check it then it's difficult to give a definate) just a broken balance lead on the Turnigy lipo. It means the lipo needs to be opened and the balance lead reconnecting.

With the Losi stuff it could be a weak lipo or the regulator may be faulty. Again it's difficult to say for definate without doing a few checks with a multi meter and load testing the lipo.

Are you running bigger servos than would normally be used or anything like that. Maybe the equipment you are powering is asking to much of the Losi gear.

[pistol_pete_2011]

Just using savox 1256 & 1258..
All batteries ie receiver pack, starter box lipo & regulator are brand new 1 week old..may it just be a faulty new 1 ??

Just expensive to keep buying each 1 again till problem is gone !! Ive stripped it all down checking each wire etc but everything looks fine..
Can i still charge the starter box lipo as the charger is only picking up 3 of the 4 cells or is it a fire hazard ??

I wish i stuck with the standard receiver and stick packs !! just brought smd v2 starter box & lipo battery & cut starter box to put deans on it and cut lipo too..now i cant put stick pack bk in it & my lipos dead !!

Also the regulator and lipo receiver pack as i have also cut car wires for deans and cant just pop the standard receiver pack bk in & now cant start car to run my brand new engine & pipe..only got 1 tank of fuel through it and battery started playing up..

Spent about £500 on it and its all a big headache !!!!!:mad::mad::mad::mad:
As you can tell im gutted at the mo as was going to race tomoz.
Sorry to go on but had a bad day... lol:thumbsup:

[leeleefocus]

Not sure how much it would cost to post the Turnigy but as long as the cells are good i will be able to fix that battery for you no problems.

Don't charge the lipo until you know for sure what the problem is. If it is a bad cell and you charge it on the standard 4s setting then your likely to over charge one or more cells which can be bad. If in doubt with lipo then don't do it.

The Losi pack and regulator may need to go back. Give JE Spares a call and tell them what is happening with it. It may be a simple case that the battery was stored for a long time and is just past its best. I can only give an educated guess with that one but seeing as it is brand new i would be inclined to see if they will let you try another battery and/or regulator. Does anyone you know have a lipo pack you can test with the regulator which should tell us if it is the battery at fault or not. It looks like that setup was pretty much made to be used in the car you have so it should be man enough to supply enough current to the Servo's.

[pistol_pete_2011]

Hi, Just to let you know that i found out what the problem was it was the earth on my savox 1258...:blush:so just ordered a new one from JE SPARES.. after all that a... and ive just brought a new starter box lipo.. thanks for all your help m8..