Lipo Questions

[kburrows]

Going Lipo for Xmas need some advice feedback. I read allot of the threads here but still have very specific questions.

Whats the best charger to get that will charge/balance two packs at the same time?

Do i have to monitor the packs when charging or does the balancer keep them from over charging?

Does the balancer come with the charger, or separate and how do you know which is which?

Do you use a balancer in the boat when running the boat?

How do you know how long the packs will last, before over discharging?

Has anyone ever had a pack explode on them? how big is the blast? how harmful is it? What causes a pack to blow? Do packs blow when they get wet? Are there packs that are sealed and can take a beating?

I will be using it in my SV so do i need to set my controller? or its good already?

Do i have to run a rx pack when running lipos?

What volts should i use and i want long run times so who makes a high mah rated pack?

Whats the S thing refer to and How should i go about looking for packs that will fit in the hull and be safe?

Best packs for price? Safest packs? ANy leads on a Good deal?

Thanks for any response, i want to be on the safe side

[Boatman]

Thats alot of questions and I understand why. Safety and investment. I was same as you when I switched. For quality and warranty I would buy lipo packs from tower hobby or Rc Lipos. Tower Is nice because you can see what manufacture recommends and just read instructions and you will be ok. I have never seen a pack blow in person.

[AntronX]

Whats the best charger to get that will charge/balance two packs at the same time?

There are dual chargers out there, google for dual chargers.

Do i have to monitor the packs when charging or does the balancer keep them from over charging?

You should not have to monitor the voltage, charger should do everything itself and just beep when all done. You SHOULD be in the same room when charging, or stay withing range so you can hear if packs hiss, puff or burn. Have fire extinguisher near to put out fire that burning lipos can cause, not lipos themselves. I read that once they burn, its a chemical fire and nothing but a bucket of sand will stop LiPos burning. Don't leave them charging in a car. Search youtube for lipo fire.

Does the balancer come with the charger, or separate and how do you know which is which?

The balancer is usually built in with the charger as one unit. Some balancers are stand alone. Balancer monitors each cells voltage, and brings charge current down if one cell has reached 4.2V cutoff voltage, while letting others catch up. There are few different ways that can be done by different balancer designs. Some are simple, some are more complicated. It will say if the charger has balancer built in. If there is a balance plug on the unit, its a balancer.

Do you use a balancer in the boat when running the boat?

Its not required, so i guess many don't. Its required if you are using permanently mounted battery in the boat and only want to connect two pin charge connector to the boat to recharge, without worrying about connecting balance plugs into the charger. I never seen anyone do that.

How do you know how long the packs will last, before over discharging?

Its best to program voltage cutoff on your ESC. Set it at 3.2V per cell and start adding 0.5 volts to your total cutoff voltage untill ESC cuts out at 80% depth of discharge for longer cycle life of your batteries. Example: My miss vegas pack is 5S1P 6000mAh 18.5V LiPo. 3.2V * 5 cells = 16V. Set voltage cutoff to 16 volts. Run your boat untill it cuts out. Charge your pack at 0.5C (2 hours) untill 100% full. Note how many mAh went into the pack (your charger should have a read out). In my case, the battery took 5600 mAh. 5600/6000 = 93.3% depth of discharge. Increase cutoff to 16.5V and repeat untill battery recharges to 100% taking only 4800 mAh (80% DoD).

Has anyone ever had a pack explode on them? how big is the blast? how harmful is it? What causes a pack to blow? Do packs blow when they get wet? Are there packs that are sealed and can take a beating?

Never had one burn. Its not really a blast, more like a fast, hot burning fire. Over charging, puncture, overheating, deformation (dropping it, bending) short circuit can either cause a fire or smoke venting. Also, impurities in raw materials used to make cells can short it later and cause fire. That's why using high quality cells from reputable manufacturer is important. They may cost more than some others.

Do i have to run a rx pack when running lipos?

Depends on a voltage of your system. If you are replacing NiMH pack with LiPo of same voltage, then you don't have to. Capacity of LiPo does not matter.

Whats the S thing refer to and How should i go about looking for packs that will fit in the hull and be safe?

"S" as in 2S1P means 2 cells connected in Series, and no cells connected in parallel, or 2 single cells are used to make a pack. 2S2P - 2P means 2 cells are in parallel, or 2 cells are paired together, and 2 of those pairs connected in series. 4 cells are used total.

Best packs for price? Safest packs? ANy leads on a Good deal?

I think cells manufactured by Enerland are good if not best. PolyRC, PolyQuest, FlightPower use Enerland's cells in their packs.

[Heath M]

check out rclipos.com he has everything you need.
Elite 5300's are good cells for the price.
Hyperion makes a dual charger with built in balancers..
Make sure you charge in a lipo sack, this will help to contain any fires that may accure during charging..
Also use 5.5mm bullet connectors on all wires..

Heath

[Fluid]

Has anyone ever had a pack explode on them? how big is the blast? how harmful is it? What causes a pack to blow?

Most fire are caused by overcharging - and they can "blow up" rather than just slowly catch fire. This does not happen as often today because chargers are much better than they were five years ago, and the cells are much more robust. But you can still do it: http://video.google.com/videoplay?do...60570423705609

Are there packs that are sealed and can take a beating?

Some packs designed for cars come in a hard plastic box, and some battery suppliers sell boxes for packs. I use the packs just as they come from the maker, although I sometimes put another layer of shrink wrap on them to stick Velcro to.

I will be using it in my SV so do i need to set my controller? or its good already?

If you use the same voltage you shouldn't have to change the controller settings - maybe. I don't have an SV but if the ESC can be programmed for a low voltage cutoff, you should do so (12 volts is good). If the controller does not have the cutoff, I strongly recommend getting a stand alone cutoff like this one:

http://www.dimensionengineering.com/LipoShield.htm

It can save your packs from permanent damage if you over-discharge them.

Whats the S thing refer to and How should i go about looking for packs that will fit in the hull and be safe?What volts should i use and i want long run times so who makes a high mah rated pack?

For your SV use a 4S pack. Each LiPo cell has 3.7 volts, so 4S = 4x3.7=14.8 volts. To get the best balance in the boat you should probably get two 2S packs and wire them in series to get 4S voltage. This lets you put one pack where each NiMH pack went.

Best packs for price? Safest packs? ANy leads on a Good deal?

Capacity costs money, high capacity cells (4500-6000 mAh) are the most expensive. You also want to consider the discharge rating - you want packs with at least a 20C rating, more is even better. The C rating lets you know how much amperage the packs can deliver before damage. Personally I get the very best packs I can afford, from ThunderPower or FlightPower. But I race and need more power than the normal sport boater. Get the best packs you can afford from a reputable seller - don't buy off eBay unelss you know the seller. All Enerland cells are NOT the same...


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[kburrows]

Thanks guys this info is good, So how about the balancer plugs does the charge come with this addition plug or is it an add on to the charger.

[Ub Hauled]

Anton has good point, here is my take:

Whats the best charger to get that will charge/balance two packs at the same time?
It's usually a preference, there are a few chargers (like Hyperion) that are more reliable then others, but among the reliable ones you should find your preference.

Do i have to monitor the packs when charging or does the balancer keep them from over charging?
They should never over charge by themselves unless something is really wrong... being in the vicinities is a good idea just in case.

Does the balancer come with the charger, or separate and how do you know which is which?
It depends on the brand, but they come in both ways, each will say what it does or doesn't do on the description... nothing to worry about.

Do you use a balancer in the boat when running the boat?
You do not use a balancer while running your boat.

How do you know how long the packs will last, before over discharging?
This will depend on the mAh on your cells, the more mAh the longer your runs before you need to come in... you'll get to know your packs, if you don't have a safety cutoff programmable feature on your ESC (I don't think the SV ESC has one) you SHOULD get an external one... if you really don't want one, as soon as your boat STARTS to slow down you need to bring it in for recharging (not very safe like this)... if you over discharge your packs you may damage the one or more cells (NOT EXPLOSIONS).

Has anyone ever had a pack explode on them? how big is the blast? how harmful is it? What causes a pack to blow? Do packs blow when they get wet? Are there packs that are sealed and can take a beating?
It is pretty hard to get a pack to explode. I have puffed a few cells but they never exploded... I even melted a couple of wrappings... never fire, never ka-booms.
You kinda don't wanna throw them around like they were an old pair of tennis shoes,
they like to be pampered.

I will be using it in my SV so do i need to set my controller? or its good already?
it should be good to go already, but read the manual, I think it does not have a "cutoff " feature.

Do i have to run a rx pack when running lipos?
Not with the SV ESC... always read the manuals/instructions of your electronics.

What volts should i use and i want long run times so who makes a high mah rated pack?
You should use the equivalent of 14 Nixx (14.4v), which is 4 cells LiPo(14.8v). What you wanna look for on lipos is a high "C rate" (20+) and a good amount of mAh.

Whats the S thing refer to and How should i go about looking for packs that will fit in the hull and be safe?
There are a couple of ways you can go, either 4s1p (2+2 cells in series forming 1 pack parallel)
usually two 2cell packs in series w/ higher mAh... or 4s2p (4+4 cells parallel 2packs parallel), usually two 4 cell packs w/ lesser mAh (since the parallel adds mAh) and another way not very used is one 4 cell pack with a lot of mAh... not sure I answered your question but here...
S = Series
P = Parallel


Best packs for price? Safest packs? Any leads on a Good deal?
Any of the Enerland cells are excellent (Thunderpower, RCpoly, Poliquest), a bit more expensive but top notch. There are the Elite packs less $$$ and still good cells, similar in price with the NEU cells also good stuff.
http://www.rclipos.com/ offers a bunch of stuff and no shipping... very good prices.

Thanks for any response, i want to be on the safe side

You may need to get the proper balancing harness as only certain ones come with the charger... it'll depend on amount of cells you have PER PACK and what brand of battery... see, different battery brands come with different types of balancing connectors... once you decide what battery you want to use, stick with it for the long run so you don't have to by adapters or even different type of harnesses.

[kburrows]

Thanks i guess its always read and then ask but can anyone list a good charger with balancer plugs and batteries that will fit with it, I notice the plugs are diffrent and Deans connectors is a must with charger and lipos, some suggestions would be good.

[Ub Hauled]

main leads are different from balancing connectors...
you can use deans on the charger and the batteries. just make sure that you get the right type of connectors on your harnesses.
I use Hyperion as my charger, w/ Hyperion balancer and my harnesses are all the Poliquest type...
These days the cells you purchase usually ask you what type of balancing connector type you want,
that makes it a lot easier. When you are ready to purchase batteries, make sure you read the manual of the charger and ask for the same type of connector...
I kinda feel you are a bit overwhelmed, just take it in at your pace, it seems a lot but it gets easier as you go...

[Heath M]

Thanks i guess its always read and then ask but can anyone list a good charger with balancer plugs and batteries that will fit with it, I notice the plugs are diffrent and Deans connectors is a must with charger and lipos, some suggestions would be good.

Thunder Power 1010 is a very good charger with many features but will only charger i pack at a time and you need a seperate balancer to go with it..

Hyperion are also good charges with a built in balancer and depending on the model can charger 2 packs at the same time..You need to choose the balancer plug type with this charger as there are different types.
Like Jan said, stick with one type of balancer plug ie: Thunder Power or Polyquest..
You should use 5.5mm gold plated bullet connectors on the power leads as apposed to deans plugs... It's quite easy to do, just solder a male to one lead and a female on the other lead, then a male and female on the apposite leads on the esc and you shouldn't have any accidental mis-match plug ins :) you'll also need to make up a charge lead for the charger to battery with the bullet plugs..

heath

[Fluid]

You do not need to charge through the balancer, particularly with good packs. I never do, but I do make certain to balance the packs regularly - at least once each day of running. Cheap, poorly-matched packs may require balance charging, but I don't own any cheap packs. My packs are all working very well.



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[Eodman]

Hey KB --- if you look in back issues of Radio Control Boat Modeler there are a couple of back to back issues that Jay Turner wrote on the Basics of Lipos! A good read well worth the time spent finding & ordering those issues ... I think the last two issues of 2007 but not sure!

I have them home I'll try to remember to look tonight! Even if you get your answers here they are still good references!