silentcropduster

I'm new to rc world, the closest I've came thus far is custom/modified police flash lights. More specifically with 2000 lumens run by 2x 18650 3000mAh batteries.

Anyways...I bought a Traxxas Rustler VXL very gently used from a friend. I'm trying to understand the battery lingo but it's getting the best of me. I'm just trying to figure out how to charge them and also balance them or make sure they are balanced. Pic of charger & batteries are below. I was told to check the cells to make sure they are no more the 0.2 off. The blue battery is off by .1 and .3 in 2 of the 3 cells. Im using the balancing charging as of right now and the cells are almost spot on now.

The specific questions I have: I have 3 different batteries (see pix below) What are the exact specs I am supposed to be charging them at ?

The charger came pre-set from the last owner but i want 2b sure im chargning the batteries right. The top blue battery is a 3 cell 11.1v 5000mAh....I have the options selected for 11.1v charging @ 0.5A (balance charge) - but whats odd is the "end voltage" says it will be 12.6v is that right? Also the "capacity cutoff" is 5200mAh...but the battery is 5000 mAh....is that all normal ?


I know enough to be dangerous which I’m sure doesn’t go hand in hand with Lipo batteries :-)

Also I did read the manual on the charger which barely outlines anyway best.

Thanks in advance.

RustyUs

I would read up a bit on LiPo use...Everything you need to know about LiPo batteries...
That's a great charger you got. 100 watts and charging up to 7 amps...nice.

The old standard of charging LiPo packs safely was at a 1C rate. Battery packs mah capacity divided by a 1000 would get you to the 1C charge rate. Example: A 5000mah pack would be charged @ 5 amps; a 4200mah pack would be charged @ 4.2 amps; a 3600mah pack would be charged at 3.6 amps....etc.

When balance charging LiPo cells, the charger will put energy into each cell until each cell reaches 4.2v...
You are correct:A 3S pack will have an ending combined voltage of 12.6 volts

If there is nothing on the battery case saying how many 'C' you can charge them at (not the discharge "C" rating) I would not charge a battery at more than a 1C or 2C charge rate. (4000mah LiPo pack) 4000/1000 = 4 amps = 1C charge rate. A 2C charge rate would be 8 amps. A 3C charge rate would be 12amps...etc. On your charger you would not be able to charge a 4000mah pack at a 2C rate anyway.

RustyUs

I guessing you are going through some of the charger's safety features. If the charger reaches the 5200mah "capacity cutoff" it will stop charging until you reset the charger.

Twarmbier

Hi. I agree with rustyus. I think ur in the setup menus. A word of warning with venom chargers. I've had three of them -diffrent models in the past couple of years. The second one I bought was defective out of the box. Sent it to Atomic rc to be checked out and they admitted it was defective. All three chargers had the same problem. The charger doesn't know what the battery voltage is so it over charges all the cells except one that it thinks is still at a lower voltage. If ur battery start to puff up and it's taking longer than usual to balance u may want to stop using it. Unfortunately for me the chargers ate $900 worth batteries before i figured out it was the chargers and venom basically told me sorry about ur luck

RustyUs

Twarmbier, that just sucks having that brand of charger happen to you.

Thanks for the word of caution on them chargers. I normally don't recommend them, 'cause I know they are (most of the time) just someone else's chargers wrapped in a different chassis, or with a well known brand sticker(s) on them...so they can ask more money for the product. Meh.

I guess I should have just said that charger ( OP's Venom charger) had nice specs for a four button type of AC/DC charger.

I use two; have three (one spare); no-name; re-branded 80watt; 4 button type; 6 amp max; $18~$25 (my approx. winning bids), AC/DC chargers that I'm happy with. I have no problem telling people what I use, but I tell myself not to recommend the chargers that I personally use, to people. This is because of the RC 'snobs' using high-end; DC only chargers; that will charge packs in 4S LiPo packs in 15 minutes; saying things like, "...you get what you pay for". I don't need the headache . I do generally recommend products with a known brand name for the sole purpose of a warranty, 'cause the RC industry is filled with QC (quality control) issues . Sometimes products are released with little quirks that end up being problems, and need to be returned for repair/refund.

I've raced buggies for years. Having the latest, and greatest $$$ Turbo 30 or whatever Tekin chargers I had in the pits with me....I'm not the "pushing the limits of NiCd/NiMh batteries" guy anymore. These days I just bash/run @ my backyard track with only the need for chargers that have "middle of the road" specs.