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Careful!
The 80% Rule for charging LiPos and TIPS on care and maintenance
LINK TO MY BLOG entry on some "Chargers I have known".
Recharging LiPo batteries - the 80% rule applies to the storage capacity or AMPERAGE of the BATTERY, NOT THE VOLTAGE of a battery. For a 1500mAh battery that means it should not be discharged more than 1200mAh (0.8x1500 = 1200, or 80% of 1500mAh). You won't know that until you recharge the battery with a charger capable of showing you that, or you have a meter capable of reading those values before charging. A good charger will tell you how many mAh it took to completely recharge the battery back to 4.2 volts per cell. It should then be at the full capacity of 1500mAh. HERE is a link to my BLOG entry "Parallel-Charging-batteries-101" that may help. TIP 1: DON'T GO BELOW Low Voltage Cutoff (LVC). LVC is not necessarily at 80% of your LiPo's capacity, but it is a good standby most of the time. A good rule of thumb to use for how far to discharge a battery, is the nominal voltages associated with each cell, i.e. 3.7 volts per cell. If you don't go below 3.7 volts per cell, you probably won't go below (80% capacity) and damage your LiPo battery. Go below the LVC and you will most likely be putting back more than the 80% amp carrying capacity of your battery - NOT GOOD! TIP 2: GET A GOOD COMPUTERIZED BALANCE CHARGER. If you think you will be staying with this hobby, I recommend buying a quality BALANCE charger and stop using the cheap stock chargers that come with most RTR, RTF, ARF & BNF combos. They are OK in a pinch or on a trip where you don't want to carry a full blown charging setup. I won't recommend a charger or brand. New ones come out all the time but a good place to start is searching RCGs, or go to sites such as John Salt's for suggestions. http://www.rchelicopterfun.com/rc-battery-chargers.html or see paragraph 1 above. TIP 3: TAKE IT EASY OF A LIPO's FIRST FEW FLIGHTS. I have found that new batteries will last much longer ON THEIR FIRST FLIGHTS than it is wise to do. Once they have a few flights on them at 5 or 6 mins (2 or 3mins for EDFs), you can decide if longer is a good choice or not. I used to push them to LVC when first starting out. Now I set my Tx TIMER to 5 or 6 mins and stay there for the first 4 or 5 flights. After measuring how they have done in my battery log, I decide how long flights will go. TIP 4: KEEP A BATTERY LOG. Yes, it's a good idea to keep a battery log so you will see where you overdid a flight, or when your battery is starting to die. And it gives you something to help you decide which brand is working, and which are not. TIP 5: DON'T CHARGE MORE THAN A FEW HOURS BEFORE FLYING. Something else to help extend your battery's life is to NOT charge it unless you intend to fly within 24 hours. Even less is better. I also used to charge my batteries immediately after a flight. It's not good for them and you will be surprised how much better flight times will be if you keep them at a storage level (3.85V) until just before using them. TIP 6: USE THE INTERNAL RESISTANCE MEASUREMENTS. If your charger has the capability to measure internal resistance (IR), use it and record it so you can see a trend. The lower the IR is, the better. Measure at the same temp since temps have a major impact on the IRs. OTHER NOTES: You can use telemetry on the pack voltage to find out when you get to LVC. That is not the same as Receiver (Rx) voltages. More Rxs and Txs have Rx voltage as a readout for telemetry than they do for pack voltages. But it is the main power or pack voltage that is most important for flight times. You can use the small voltage testers with alarms too that will alarm to the voltage/cell you set. Those voltages read under load. A plane flying will usually be at 3.8V/cell under load. A setting of 3.4V/cell works for me to decide I'm close to LVC and land. |
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Last edited by hifinsword; Mar 11, 2019 at 09:53 AM.
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Thanks for the advice!!!!
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Fake IMAX B6AC charger
You're welcomed. I recently purchased an iMAX B6AC dual power charger, i.e. AC or DC. It turns out it was a copy, not an original. If you buy one, do some research on the web to know the difference between fakes and originals.
The fake iMAX B6AC was overcharging my batteries by about 0.05 volts. It was charging to 4.25V per cell instead of 4.2 volts per cell. I tried to do the calibration on it but screwed it up. And you only get one try. There are some ways to reset it so you can do it again but it requires some DIY gizmos or things beyond my paygrade. So to fix the problem (not the charger) I changed the battery chemistry on the charger to Lithium Ion (Lion) instead of Lithium Polymer (LiPo). Lion charges to 0.1 volts less than LiPo. So theoretically it is supposed to charge to 4.1V per cell, but is actually charging at 4.15 volts per cell. That's better for the batteries than 4.2V/cell because it gives it longer life. And I don't have to worry about overcharging now. But I can also use it to precharge my LiPos and top them off on my other ThunderPower TP610AC balance charger. HV LiPos charge to 4.35V/cell. I thought I would be able to use the LiPo setting if I was charging HV LiPos but I ended up giving this charger to my g/son with the warnings on how to use it safely. Don ImagesView all Images in thread
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Last edited by hifinsword; Mar 11, 2019 at 09:23 AM.
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Venom Chargers??
After seeing how oilflys Venom charger caught fire, I'd have to look hard at some other models if I were to buy a new charger today, In fact I did just buy the Charsoon 300W AC/DC 20A model at BG for $79.99 after using the discount CODE "12air". HK is also having a sale on their Reaktor line of chargers.
From what I am reading about the new chargers, the iCharger, Charsoon and the new Reaktor all seem to be clones of each other with differences in the loaded software. |
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Last edited by hifinsword; Jan 09, 2018 at 09:43 AM.
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Venom Charger burned down ? Not a good feeling
Today I had what could of been a horrible mishap with 3s lipos Floureon 1500 mah and a Venom dual Charger , I Charged 4 of them up at 2.6 amp to go out for a couple quick flights, Something came up,,plans changed , and as always I set the charger to store my 4 lipos ,,,as I don't like to keep them up on a full charge if I'm not gonna fly them.. The first 2 stored fine , plugged in the next 2 and to be clear these lipos only have about 6 Cycles each at most no crashes no lose wires,, I'm anal on my connectors ,,, 30 minutes into the Storage mode I began to smell Smoke in the house ,, In my hangar Room the charger was on a top shelf and with planes hanging on the ceiling 30 seconds more I believe I would not of been able to control the fire !! Still so uncertain on what it could of been , I've bought that Charger and new when they first came out and used it numerous times but if you study the pictures of the Charger it appears it started from within the Charger itself IDK !!
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Sorry about the fire oilfly! Glad you and the rest of the house are safe. From the pictures, it does look like the fire started inside the charger. You should save the charger and send a copy of the pictures to Venom Products. I am curious how they will respond.
Don |
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Last edited by hifinsword; Jan 09, 2018 at 09:48 AM.
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I am not familiar with the Venom chargers. Does it limit the discharge amperage on the discharge cycle? I read that others dislike the limits some brands put on theirs but others like it for safety reasons.
Don |
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Last edited by hifinsword; Jan 09, 2018 at 09:47 AM.
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