rgrove

I have several boats, electric, gas and sail. I have recently taken on getting a Lindbergh PT-109 running again. It is equipped with a pair of speed 400's direct drive. I used to run it with a 6 cell, 1800 mah car ni-cad pack. However, I was wondering if I could run it on a 2-cell, 2000mah, 15c li-po pack i had in a plane? Anybody have any thoughts?
Thanks!!

LtDoc

rgrove,
What little I know about 'li-po' batteries wouldn't fill a fly's watch pocket! BUt, I've heard that they don't like water at all. If that's true then I'd certainly think about water-proofing them some way. Other than that, I think they should work. One of the 'other' things batteries do is act as ballast, so I'd think about that part too.
- 'Doc

green-boat

I don't know much about Li-Po's either but a battery is a battery, right. It's just the way they need to be charged. I think the Li-Po's would be great in the smaller plastic model boats, less weight means faster speeds.

rgrove

Thanks for the replies. Ballast and water are certainly concerns, but im first trying to figure out whether they would work at all. Im not very well versed in electrics, so im not sure about calculating current draw vs. the "15c" rating on the lipo, as my understanding is that if you draw too much current "bad" things happen!

LtDoc

rgrove,
I Think I would do a stall test on the motor to be used, see what the maximum current draw would be. The '15C' tells you that the most acceptible current draw for that particular battery is 15 amps. If the motor draws less than that I wouldn't worry about excessive current draw from the battery. From what I can gather, the 'bad' things about 'lipo's is associated with charging them. A charger specifically for lipo batteries is the only way to do it, I think. Having seen what happens when one isn't charged correctly, I do not want to be around when it happens! At least not with my batteries, and definitely not in my boats!
There appear to be 'things' and 'ways' of using lipo batteries that are a bit different from the usual run of nicads, nimhs, etc. Not knowing much about any of that, I'm reluctant to try telling anyone how to do it (or @#$$, I'd be doing it myself!... maybe).
- 'Doc

UltraMagnus

LiPoly cells are generally factory sealed (well, so are most batteries) so, getting them abit wet shouldn't be a problem, although given their nature i would be inclined to attempt to keep them dry. the biggest problems with LiPoly batteries are the fact that they are temperamental, if they are over charged or you attempt to discharge them too quickly, they will catch fire or explode.

for charging, their are commercially available chargers, or you could use an AVR microcontroller quite easily to perform the same function.

well, i hope that helped

e-sailpilot86

15C means the maximum discharge is 15 times the capacity. (LtDoc got it wrong, unless the battery capacity was 1000mah)For a 2000mah battery, that's 30,000 ma, better said as 30 amps. I don't know if the current draw is nearly as high as electric aircraft for a speed 400 (11 amps usually, maybe higher sometimes), but two in parallel on a 2000 mah 2S1P would be fine. The cells only get tempermental when you treat them poorly. Dont get them hot, Don't overcharge them (just set the charger to 2 series, and a charge current less than the rated capacity, less than 1C, battery has to be intended for lithium batteries), don't short them, and you're fine. Basically, 1 lithium polymer is the equivalent of just over 3 standard NiCd or NiMH cells, so a two cell is like a 6-7 cell, a 3 cell is like a 9-10 cell. As a note, an 1800 mah NiCd pack is probably three times heavier than a lithium polymer. Get a larger capacity for a speed 400, aim for 4000 mah or even 6000 mah. That would probably be more appropriate unless you really have to loose weight for something like a hydromite.

LtDoc

e-sailpilot86,
You're right and I was wrong, you're right! Gee... first mistake I ever made about lipos (also the first post about them ). Batting average still typical, so far...
- 'Doc

DONS BOAT WORKS

My Feedback: (3)

Oh my God, Doc is human!!!

Don M.

e-sailpilot86

misfitsailor

My Feedback: (6)

I can only add...if you use LIPO cells in a boat, make sure you take them out of the hull to charge them. I have used a lot of lipo batteries in planes, and I have only had one "vent with flames". It swelled up, then burst, shooting white/yellow flames like some kind of flare. It had only been on the "smart charger" for a few minutes.

Also make sure not to drain a LIPO like you would a nicad, ect. If you deep cycle a LIPO you kill it. Better speed controls have programable voltage cut-outs for the motor but allow the BEC to still power the servos. Small protective circuits are now available that you can hook up to do the same thing with any ESC.

desertpilot

They sell "Battery Bunkers" to put them in while you charge them, if that gives you any idea.

When they burn, they burn the model and then the table the model is sitting on. It's not a pretty sight.

Taxidriver

Lipos are fine running in boats. If fact you can run them completely wet (the submarine guys with small subs use lipos in the freeflooding area of their boats. In fact one of the safe ways of deep discharging a lipo prior to disposal in immersing them in salt water (so the battery slowly self-discarhges) for a few days.

Lipos don't like getting too hot (drawing more current than designed for, improver/over charging or short circuiting.

Ron S

My Feedback: (2)

When I used to run my Lindberg PT109 (oh, say about 22 years ago!) I remember running an Astro 05 motor in it with a dozen or so Radio Shack NiCads... It ran pretty good, and would plane for the first several minutes, but the rear of the boat was always a little heavy from the battery load.

With LiPos and a reasonable motor, I think this would be a very good performer.

Good luck, and take pics!

Stiletto

I wouldn't recommend using a lithium battery of any kind in a boat. They are used quite successfully by serious indoor and park flyer modelers, but they require a much higher level of attention than most casual modelers are willing (or able) to devote. They are touchy and quite risky for casual use. Here's what [link=http://www.raidentech.com/lilircba.html]Raiden Tech[/link] - a company that sells every sort of LiPoly battery you can imagine - has to say about them:

ATTENTION/CAUTION

NEVER charge Lithium Polymer batteries with a charger designed for NiCd, NiMH, or any other type of battery chemistry. Use ONLY the chargers listed under REQUIRES or equivalent substitutes.
Do not allow LiPo cells to overheat at any time. Cells which reach greater than 140?Fahrenheit (60C) will usually become damaged and could catch fire.
Do not charge LiPo cells on or near combustible materials including paper, plastic, carpets, vinyl, leather, wood, inside an R/C model or full size automobile.
Do not discharge, doing so will damage the pack.
Do not expose LiPo cells to water or moisture at any time.
Do not store batteries near an open flame or heater.
Do not assemble LiPo cells or pre-assembled packs together with other LiPo cells or packs.
Do not leave a LiPo battery unattended during charging or discharging
Always store LiPo batteries in a secure location away from children
Always remove a LiPo battery if model is involved in any kind of crash. Carefully inspect the battery and connectors for even the smallest damage. CAUTION: cells may be hot!
Do not allow the electrolyte to get into eyes or on skin. Wash affected areas immediately if they come into contact with electrolyte. Do not alter or modify connectors or wires of a Lithium battery pack.

Rob

Steve Collins

My Feedback: (8)

I have an electric helicopter which I managed to crash into a small pond. It had a 2600ma lipo battery on it. It was in the water from 45 minutes to an hour before I found and retrieved it. There was no damage to the battery or any of the electronics(except stripped gears in the servos). Everything was still connected. I expected everything would be toast but it wasn't.

The point is, the battery was just as usable afterward as it was before the plunge.

I am not saying that water won't damage a lipo battery. On the other hand, I don't think contact with a small amount of "bilgewater" is as great a problem as it may sound.

green-boat

At our last regatta there was a guy using Li-Po's in his runabouts. He said that he also uses them in his go-fast boats with no problems. I spoke with him for at least a 1/2 hour regarding Li-Po's, he has me convinced to give then a try. I'm a stick in the mud when it comes to something new. You can give me all the reports and spec sheets you want but until I talk to several actual users, I'm reluctant to change. I have an old Lindberg PT-109 set up for twin Ni-Cd's that I will now be converting over.

martno1fan

lipos will explode if you get them wet!! never use them in a boat or you will have a serrious explosion on your hands!!,mind you would look cool in a war games scenario lol.

tractor1964

2 cell lipo pack= 7.4 volts wont work to good unless you use a 6 volt motor. 3 cell lipo pack puts out 11.1 volts, if you used a 9 volt motor that baby will fly. think brushless motors. i got a 3 cell 1320 that i fly my 15 oz cub with and i can fly it for 40 min. need lipo charger, about 100.00 for decent one. lipos make big BOOOOMMM so be carfull

martno1fan

BIG BOOM IS RIGHT!! ive seen a guys boat blown to bits when running lipo,s what a sight that was ,absolutely nothing left of it quite funny to see but lucky it was far out or someone could have been hurt .lipos are very unpredictable and unstable if not used right id stay well clear of them full stop.

turbotb0205

My Feedback: (31)

lipo batteries.. to my knowledge.. HAVE NO PROBLEMS with water.. i use them in my stadium truck 2 cell 3600mah 20c pack these "Explosions" these guys are talking about are most likely from abused lipoly packs if you over amp lipoly packs they heat up when they vent and under heat they will the lithium in the packs contact with oxygen and create a fire.. about a 2000degree fire to be more precise and then everything around them melts burns and gets considerably charred if your interested in using lipoly packs in your boat these are the steps to ensuring safe operation

get the fma direct amp load meter.. or equivalent put a 3300mah nimh pack in the boat with the meter connected between the battery and speed controll put your boat into a small pool hold it steady and stab it full throttle youll instantly know its "max load" amperage and as it leads in youll know its highest possible "running" amperage simply because in motion it will draw less amps

now that you know how many amps your drawing the math is quite simple say you had a max of 40amps on initial load you need a battery capable "in my opinion the best way" of doing 50 amps safely the extra ensures a cool running pack constantly so if it were a 10c pack youd need a 5000mah if its a 20c you need a 2500mah pack

now of course thats a guess on my part on amperage but you get the idea a 7.4 lipo emits the same current density almost as a 9.6 volt nimh pack "we see the same speed between the 2 packs on our trucks usually if not very close to eachother"

and after all that when you install the lipo battery check it again with your handy dandy meter to ensure that your not over on your amperage and you will enjoy a long life from your lipo's as well as being lighter and a much stronger performing boat

martno1fan

listen mate if lipos come into contact with water theres usually one outcome!!BANG!!!.THESE THINGS ARE DANGEROUS IN MY VIEW, UNSTABLE AND HIGHLY DANGEROUS TO BE EXACT!!.ive seen and heard of far too many fires etc caused by these things so id stay well away from them but thats just my opinion,by all means use one and when it goes bang make sure you post a video for us all to see!!

e-sailpilot86

Just keep water off of any battery pack you have.... if you get any battery pack in water with enough volts, and assuming the water is your usual not so clean pond water, you'll have charge carriers in the water, and the lipo or NiCd or NiMh will short. Just treat the battery packs accordingly. The attention necessary to maintain them is not as horrendous as it's being made out to be. They're not a bag of C-4 carrying an electrical charge. They don't generally explode, the burst into intensely hot flames and put out smoke, but no grenade. They aren't used only by highly experienced park flyer pilots or experts, you can use them if you're an average joe, using them correctly. You'll be seeing a lot of negative posts on these forums as warnings and reminders, but if you've never seen them in use, you don't understand how often they are used safely.

LtDoc

...I think that pretty well sums it up, e-sailpilot86.
- 'Doc

unclecrash

Thats kind of funny put them in water and they go bang.You put them in salt water to dispose of them! I had a pack ballon a cell the new 1320TP and put it in water nothing happened till I poked a hole in the pack like your supose to do. And then only a spark and a lot of bubbles comes out and I think the only reason it sparked is because it was shorted by the knife I poked a hole in it with. Ive been using them for several years in planes with no problem. I have heard if a 3s2p 2100 vents it will put out a six foot flame ball. With the proper percautions they are fine in my opinion. The most trouble is charging them at wrong currents or wrong cell count. Charge them in the garage away from everything on a cement floor. Or buy the bunker buster made to store and charge them in. Dave