bigmd74

Hey guys haven't been on in a while , ironically It was for a lipo charging problem the last time I was here .Anyway I have a 965 that I charge a zippy 4000mah 25c two cell battery. Now I'm using with a Lrp brushed esc and have a low voltage alarm. This combo worked great for the past few weeks until today. I charged the battery which charged for the normal hr or so. Took the rc10 out and after about ten minutes the low voltage alarm went off. So I thought maybe the charger wasnt plugged in . I charged her up again and the same thing happened. I did notice that the upper right corner was reading 0.00 voltage. The third time i charged today it started reading in the 3.00s and then went to 0.00. Not sure what's going on need help.

John@MRC

@bigmd74
Have you tried checking the battery voltage with a volt meter? I'm curious what the actual voltage of the battery is, not what the 965 is currently reading. Also, are you using any home made adapters with your battery? If so, you may want to check the connector for cold solder joints. You may e-mail me at [email protected] should you wish to converse privately about this matter.

John @ MRC

bigmd74

Hey John thanks for responding, I have not checked voltage. Need to get a voltmeter. From what I can gather from different forums looks like it may be a dead cell? I've been busy with work so haven't had a chance to look at it. Probably go to harbor freight tomorrow for voltmeter and I'll check back in with you. 5 or 6 years ago I had same problem with a lipo battery and MRC charger and I spoke with Tim who gave great customer service . He even let me drop charger off because you guys are near me. Thanks

bigmd74

Also no adapters, just deans plugs

John@MRC

Yup, that's exactly what I was thinking. Confirm the total battery voltage with the meter and we'll know for sure. The total voltage should not read any lower than 6 volts. That's 3 volts per cell. Sadly, they cannot be revived. Did you solder the deans plug directly to the charger? You may want to test the connection from your deans plug to the 965 with continuity after you test the battery voltage. Do you have any other batteries to try on your 965? You can bring the 965 over for inspection if the battery ends up testing ok. We'll talk more about that if you need to bring it over.

bigmd74

Ok gonna test later, plug is soldered directly to charger.

John@MRC

Sounds great. Let me know how the testing turns out.

bigmd74

John I was reading over the manual and it states the charger will indicate the voltage of each cell . Of the few times I've used this charger and battery it has never done that. If I set to charge at 3.00 the display shows that in the upper right corner with an "A" next to it ,but the number also fluctuates.

John@MRC

It is normal for the charge amps to fluctuate a little bit, that isn't an issue. Make sure that the balancer plug on your lipo is connected to the 965. Line up the black wire from the balance plug to the negative symbol on the face of the 965 (the far right). Were you able to check the battery voltage with the volt meter? Based on what you have told me, perhaps the battery voltage is too low for the 965 to properly detect the battery. Let me know what the results are from the voltage test.

bigmd74

John the charger came with an adapter for all different balance plugs. All the wires are red but there is only one way to plug in. Didn't check voltage because I didn't get voltmeter . Had a hard time spending more on that than I paid for the battery. The charger is supposed to read each cells voltage and display?

John@MRC

Yes, the 965 should read each individual cell voltage. But if the voltage of the battery is lower than what it should normally be then the 965 may not be able to "read" it properly. This is why I wanted you to check the voltage with the volt meter. Are you getting a voltage reading on the 965 display at all? I know you said that the amps would read 3.00 but then drop to 0.00. The Super Brain 965 never shipped with any adapter for balancing. Could you email me a photo of the charger with the adapter so that I may see what you have? My email address is [email protected]. I can understand not wanting to spend more money but if I could make a suggestion, buying a volt meter would benefit you in this hobby. You'll not only have the ability to check the voltages of your batteries but you can also use the continuity tester to check for any bad connections. Do you have any other batteries that you can try? Perhaps some NiMH cells?

bigmd74

Yes it's reading about 8.2 but only showing one cell. Ill get the voltmeter jus been busy working ,no time. Maybe tomorrow.i took a pic of it I'll send it.

bigmd74

John I figured it out, I soldered the connections backwards on the esc and charger,therefore had the battery connections backwards. I fixed that and now it's reading both cells. 3.92 and 4.20 .its balance charging now.all seems ok. Thanks I'll check back wit u

bigmd74

Hey John I thought everything was good . The charger balanced charged the battery for a long time. Amps were at 0.00 for a while until other cell caught up.cell 1 was at 4.13 and 2 was at 4.20. I plugged in to esc and it ran for two mins and low voltage alarm went off. How could this be? Maybe the low v alarm is faulty?

John@MRC

Sorry for the late reply. I was out of the office on Friday. I see the plug now. My apologies, I was thinking of another charger we have that also includes a balance board but wasn't included in the first run. Have you noticed how much capacity was built up in the battery by the end of the charge? While it's possible that there could be a problem with the low voltage detection, unfortunately I don't know much about esc's but I would check the setting on there. Maybe the low voltage cut off is set too high. That would explain the early shut down.

bigmd74

Capacity as far as volts? I'm thinkin maybe it's the volt alarm. I got off eBay and it's not adjustable. I'm running a brushed esc and motor with lipo so it's a separate unit. So if the charger is reading both cells good the battery should be ok right?

John@MRC

Capacity in mAh's at the end of the charge. Voltage is important as well but the capacity is how long the battery will last. Sorry for the confusion. You mentioned that the battery is rated at 4000 mAh's. That means by the end of the charge, assuming that your battery is dead when you go to recharge, you should have 4000 mAh's in the battery. There is an indicator on the 965 that displays how much capacity has been added to the battery. Voltage wise, you should see around 8.4 volts for a fully charged 2 cell lipo.

You are correct. If the voltages are reading correctly then the battery should be alright. Here is a simple test that you can perform on your battery. Put the battery on charge tonight and when the 965 indicates a full charge, write down the voltage, and then disconnect the battery from the 965. Return to the battery tomorrow and check the voltage on the 965 but do not start charging. You should see the same voltage as the night before, which means your battery is ok.

You don't have any way of adjusting the settings on the ESC? Do you know if it has a NiMH mode and a LiPo mode? This is very important because even though a 6 cell NiMH battery is the same voltage as a 2 cell LiPo, the cut off setting for a NiMH is drastically different than that of a LiPo. If you really believe this to be the problem then I would suggest trying your battery on a friends RC car with an ESC that they know is working properly. This way you can eliminate any doubts about the condition of your ESC.

bigmd74

Thanks for help John, I'm using an LRP V1 esc and a reedy brushed motor,the esc does not have a cutoff so I'm using a separate unit that plugs into balance plug. It worked good for a few weeks. I'll do the battery test
tonite.

John@MRC

If you are going to run LiPo I would suggest replacing the ESC with one that has a voltage cut off. LiPo's cannot be revived and they're not cheap to replace on a constant basis. Although it's still not good for their long term health if the voltage keeps going to low but you can revive a NiMH. I will await the results of your battery test.

bigmd74

John I got the new voltage alarm . Everything seems ok,it's reading both cells. This one is adjustable, what do you recommend I set the voltage for for the alarm?

John@MRC

That's great news! If it's a per cell voltage then enter in 3.00. But if it's for the voltage of the whole battery then multiply the number of cells by 3. So 2 cells would be 6 volts and 3 cells would be 9 volts, etc... I'm glad to hear that everything is working out for you now.