diy-pro

Probably going to try my luck tomorrow with ordering lipos from hobbyking. Thinking about 2x 3s 25c 2200mah zippy packs just wondering why they weigh less than the 20c version and they are the same price And as my first lipo charger im going with the hk 30w dc 2-4s anyone have any input? Only going to be used with my cheapo brushed esc and ryobi 700 motor which i think is a mabuchi not sure tho... oh yeah it has double bearings :]]] closest i can get to brushless. Looked up the weight of a 2000 mah nimh onyx bat i have 323 grams! ive been running 3 7.2v packs in serious thats a whole kilo yes my boat is fat... 4 now lol

Goldenduff

If your batteries can be charge at 2c or more your charger won't be able to take advantage of fast charge times (30w/12v is 2.5amps)

siberianhusky

Spend some money on a better charger, that thing won't even charge the packs your buying at 1C, nowhere near enough wattage. That thing is made for charging mico heli batteries that are under 1000mah. Probably take 1 1/2 hours to charge a battery with that charger.
There are a number of HK eco 6-10 200w chargers being used around here under varying vendors labels, pretty good charger for under 40$.

diy-pro

So a 50 watt 5a charger would give me a 30 min charge time?! 40 dollars!!! Pffft im not even trying to spend that much total but i will look into a better charger. Tell me will a slow charger give them a bad charge even if the charger is of good qaulity or you guys just reccomending it so i dont go through the hassle of waiting. I think ill be fine with an hour and a half ive been watching my 5 hour nicd/nimh charge my bats at 7-8 hours a piece 1 1/2 is going to get me wet lol

siberianhusky

Still not enough wattage to drop the charge time that much, you end up about an hour with a 50 watt charger, you'd be able to at least get a 1c charge rate for 3s 2.2 AH batteries.
With more power you can also charge multiple packs at the same time. I wire them up in series and charge as a bigger pack with the same capacity, eg 2 2s 5000mah wired in series to make a 4s 5000mah pack. My charger has the power to be able to charge the "4s pack" in the same time as a single 2s pack.
Not a fan at all of parallel charging, takes longer to put 10 000 mah into a 2s battery than 5000mah into a 4s, and I don't like trying to balance 2 cells at the same time, safer to go series so each cell is being balanced by itself, all you need is a proper balancing adapter to go series.

diy-pro

Ahhh you are a good man thanks for that suggestion and i would never try to parallel charge a lipo just doesnt seem like the right way to take care of one.

Ok this isnt going to shorten my charge time for one bat but i can charge two 3s at once and maybe make it to the creek 3 times a day. Still cant believe how light these lipos are O_O
http://www.hobbyking.com/hobbyking/s...cessories.html

Def not spending more than that im saving for a trip to amsterdam and plus my wife chokes me enough...

NobodyFamous

This is the charger I got from HK, I charge my 5.8 2s packs in less then an hour from dead (80%)

NobodyFamous

This one is probably just as good, but less power and moneyhttp://www.hobbyking.com/hobbyking/s...792&aff=194830

diy-pro

i think im going to stick with the cheap one for now theres no way id ever spend 180 on a charger even if it did supply a car with emergency power lol. Is charging your lipos at the full 1c really even safe for the battery and wouldnt that decrease the life of it?!

siberianhusky

1C is a safe charge rate for any lipo, won't damage the battery at all. What will shorten it's life a bit is not storing it at proper voltage when your done. Any more than a few days and I bring mine down to 3.8V/cell, or charge them to that when I'm done.
Never really thought about this until now but I wonder if it's storing them fully charged or in a discharged state that damages them, just always followed the directions and stored them at 3.8.
Your boat has brushed motors doesn't it? Do you know if the esc has a low voltage cutoff? Lipos do not like being discharged beyond 20% remaining capacity.
If it isn't lipo ready I'd suggest something like this low voltage buzzer for 4$
http://www.hobbyking.com/hobbyking/s...itor%5F3S.html
I just linked the first one I found, you have to get the right one for you cell count they come in 1S,2S etc. I've never used one so I really don't know how loud it is.
For more money you can get a unit called a lipo shield, acts just like the LVC in an esc, think they are about 18$.

diy-pro

Thanks man i am pretty handy with my multimeter but that would save me the hassle. One it says the lv alarm is at 9v for the 3s so 12v for the 4s version. Is 3v a safe low voltage for all lipos? sounds low to me.

Lol the esc is a 7.2v model and ive been running 21.6 through it. If 4s2p blows it ill laugh and make sure it did a good job toasting it.

siberianhusky

Thats voltage under load, when tested again at rest they should be at 3.6-3.7V which is safe. That unit is plugged in and operating while the boat is on the water, buzzes when the batteries get low.
I'd time your runs anyway, see how long it takes for the buzzer to go off, then set a countdown timer on your phone or watch and run the boat for 30 seconds less than the time it took the buzzer to go off.
I don't normally use a lvc but I have a data logger that gives me accurate info about the run so I can easily calculate my run time then use a timer.
Better safe than sorry one serious over discharge can kill a lipo, sometimes they can be brought back IF you have a programmable charger. To me it's safer to bin it and get another battery, cheaper than burning my house or a boat!
I also store them in a heavy metal box I got from a surplus store, it's not an ammo box I don't think, no seals and simple latches. I keep that on a concrete floor away from anything flammable. For a couple smaller batteries a cash box works.

NobodyFamous

I have 2 of those lv buzzers.  They are both for 2s.  They are NOT water proof.  one of mine already died, the other is very quiet.

srt10

My Feedback: (20)

I have many lipo packs that can charge at 5c without issues...

diy-pro

Oh yeah I have a dog that bites on command! lol 5c?!!!! wow for a 5000 mah pack that would be 25amps of current???? or am i doing the math the other way around. Whats the charge time on that 12 min?

srt10

My Feedback: (20)

You are correct my friend!