5s or 10s A123 setup for boat?

[nitrostarter]

Originally Posted by gimpygolden

....All the guys over at Offshoreelectrics.com seem a little spooked at the idea of High Volt setups so I wanted the opinions of those more versed in big power setups.

Honestly, I highly doubt this is the case. Most guys there run boats that are setup to spec. N, P, Q classes, etc... They are listed as to which battery setups are used.

Have a look at this chart:
http://www.castlecreations.com/suppo..._boat_apps.pdf

This is a helpful tool for boating.

Honestly, I don't think A123's are worth there salt in boats... Most setups require high quality Lipo cells as boats can pull SIGNIFICANTLY more amps than the car world. For instance, most people that run 1515/1Y use a Hydra 240 because the amps spike up pretty high continuously. Its also very easy to use the wrong prop and burn up something in a heart beat.
Also, most FE boating setups only get 3-7 minutes of runtime. I would want to most mAh available.

Now on to your setup...

Aeromarine Titan 29, a beautiful mono with the ability to take a decent chop. In order to make boats work properly, you want to spin 28-33k rpm's. SO if you're insisting on pushing a 850kv motor, 10s will be necessary.
Honestly speaking tho I would opt for the 5s2p setup for not only more available amperage, but more than likely, more runtime.

Motor choice: The KB45 1700kv would be a great choice, KB's seem to be a hard to beat motor in boats when properly used. However, a Feigao 11XL would work just as well in this hull. This 29" hull doesn't really require more than a feigao 9XL for power. A 10XL would be optimal.

I don't know your asperations for the boat but for anything over 30mph I would run a Feigao 11XL on 5s2p, with a X445 prop. Should be a reliable setup with those A123's being the weakpoint...

Enjoy.

[zeropointbug]

If this helps, here is an Eagletree of my Villain EX on a hard run. After the pack has dumped, there being no airflow through the hull, the pack temps usually around 115F. That being around a 10 min runtime, or 6C average discharge, which is quite a bit. They are still preforming like day one though, discharging over 2250mah. I would say it clips along the water at up to 22mph? Give or take 2mph.

IMO, boats are a good use for A123's... as there is not much "peaking" in currents, more of a constant current relatively, so you can design a setup around your discharge currents and calculate your voltage drop, and adjust your setup accordingly.

EDIT: OOPS, almost forgot the eagletree graph.

[nitrostarter]

Ok, let me rephrase my words.

A123's are ok in a boat. However, Quality high capacity lipo's are a must in Fast Electric Boating.

A Titan 29 would be a waste at speeds of 22mph... Buy Villian or Kyosho for that.
The Titan is a very capable boat and loves to run 40-45mph in light chop. I would run a 4s2p Lipo setup with a Feigao 10XL and a X445 prop and see low to mid 40's all day. Or maybe a 1515/1Y on 4s2p Lipos with a X442 of X640 and see 50's all day.

[zeropointbug]

Actually, I am pretty sure it is 25mph, it is quite fast!

I agree, for fast boating, lipo is probably needed... but then again, NiMH used to be used to extremely fast boats! IIRC, speeds of around 70mph...! A123's are only more powerful than NiMH.

I am not pushing the 5s pack to the limits, and he plans to use twice as many cells, it should be a 1000watt+ setup if done right.

[lincpimp]

1000 watts should get him close to 50mph if he sets the boat up correctly. I have a bone stock supervee running a modded x642 prop that I got close to 40 with 12nimh cells, and beat 44mph with a pair of 3600 12c 2s packs. I have not had a change to get out again with a new set of 3600 12c 4s packs, wired in parallel for 7200mah. I have a feeling that battery combo will do 50 in the sv, but I doubt the hull will like it much. Not that the hull is in the water at all at those speeds, just the trim tabs and half of the prop.

[zeropointbug]

Yeah, keep in mind, I am pushing the Titans past their efficiency range.... brushless would be a big leap in performance/or runtime.

[gimpygolden]

Originally Posted by nitrostarter

Honestly, I highly doubt this is the case. Most guys there run boats that are setup to spec. N, P, Q classes, etc... They are listed as to which battery setups are used.

Have a look at this chart:
http://www.castlecreations.com/suppo..._boat_apps.pdf

This is a helpful tool for boating.

Honestly, I don't think A123's are worth there salt in boats... Most setups require high quality Lipo cells as boats can pull SIGNIFICANTLY more amps than the car world. For instance, most people that run 1515/1Y use a Hydra 240 because the amps spike up pretty high continuously. Its also very easy to use the wrong prop and burn up something in a heart beat.
Also, most FE boating setups only get 3-7 minutes of runtime. I would want to most mAh available.

Now on to your setup...

Aeromarine Titan 29, a beautiful mono with the ability to take a decent chop. In order to make boats work properly, you want to spin 28-33k rpm's. SO if you're insisting on pushing a 850kv motor, 10s will be necessary.
Honestly speaking tho I would opt for the 5s2p setup for not only more available amperage, but more than likely, more runtime.

Motor choice: The KB45 1700kv would be a great choice, KB's seem to be a hard to beat motor in boats when properly used. However, a Feigao 11XL would work just as well in this hull. This 29" hull doesn't really require more than a feigao 9XL for power. A 10XL would be optimal.

I don't know your asperations for the boat but for anything over 30mph I would run a Feigao 11XL on 5s2p, with a X445 prop. Should be a reliable setup with those A123's being the weakpoint...

Enjoy.

Well, posting this same question on HV setups another OSE member looking to do a 10sLiPo setup got every response telling him HV is "not needed" or "I don't know" so I basically took this as not many FE guys are running or have experience with High Volt setups.

Since the whole build is around my A123's (because of charge time) I am trying to pick components to work with these cells in a 10s1p configuration.

This is a play boat as I don't have any clubs close by so high 30's-low 40's is my goal.
Plugging in my proposed setup here
http://www.offshoreelectrics.com/conversion.htm on the
Speed Estimate by Use of Voltage & Constant "Kv" table nets me 38mph
with
Medusa 36x70 880kv
10s A123 (33v)
and a X442 prop
should get 3+ min run times with under 15min charge times plus I have 2 sets of 5s Lipo to run as 10s as well.

Yes the 5s2p setup will have more available amperage but it will also consume 2x the Amps for the same Wattage. So how can it get more runtime having less efficiency?

The 5s2p setup you suggest comes out at 37mph which is bang on what I'm looking for just want to know why you feel 5s2p over 10s1p w/lower kv motor?

I think if the A123's in 10s can handle 2000+ watt loads in todays 3D helis
they can hold there own in my reasonable setup.

[zeropointbug]

Is that 2000watts sustained? or bursts?

2000watts is quite doable with 10 cells sure, but I am just wondering about air flow... Example, I ran a 8s1p A123 pack in my lawn mower at 800 watts sustained, and even higher bursts (~1000watts), that lasted roughly 4 minutes, and discharged 2200mah (of 2300mah 'rated'). NOTE: A123 cells sure do put out their rated capacity, no matter the load on them.

Did you take a look at my eagletree graph I posted?

[zeropointbug]

2000watts, I would design the setup then for 2.4v - 2.5v/cell @ ~90 amps. For a 10s pack. Just a quick calc.

[gimpygolden]

Looking at same kv which will pull less amps a 36mm Xl size or a Kb 45Xl?
Looking at things like weight, space and hardware compatibility I'm leaning towards a 36mm can over the 45mm unless the 45 is a better choice in terms of efficiency.

[gimpygolden]

Originally Posted by zeropointbug

Is that 2000watts sustained? or bursts?

2000watts is quite doable with 10 cells sure, but I am just wondering about air flow... Example, I ran a 8s1p A123 pack in my lawn mower at 800 watts sustained, and even higher bursts (~1000watts), that lasted roughly 4 minutes, and discharged 2200mah (of 2300mah 'rated'). NOTE: A123 cells sure do put out their rated capacity, no matter the load on them.

Did you take a look at my eagletree graph I posted?

I don't intend on running 2000+watts, just an example of their capability.

I did check out the ET graph,was that on the mower?

[lincpimp]

For your setup and desired speed the 36mm can xl would be a better choice.

Just piced up a 32" mono and a mean machine cat... Less than 200 bucks for both shipped, and both have hardware... Not sure what I plan to run in the cat, but the mono will get a 14xl on 8s lipo. Most likely going to snag a turnigy hv esc, and I need another 60 amp esc for 3s usage in my mini mogli boat... Plus the big gas boat needs some work on the hardware, dual rudder conversion and fooling with the surface drive... I have work to do. Tomorrow will be a batt building day for gimpy, I have had his stuff for too long....

[_paralyzed_]

Originally Posted by lincpimp

Tomorrow will be a batt building day for gimpy, I have had his stuff for too long....

I knew you thought about me even when I'm not around...

[lincpimp]

Originally Posted by _paralyzed_

I knew you thought about me even when I'm not around...

HAHA, while you are gimpy, I was referring to the OP, sure you know that anyways. I will build your packs as well Harold, but I seem to be out of 3s align taps, will hyperion do? Or do you want to send me some jst xh taps?

[_paralyzed_]

hyperion will do.......

just such a perfect opportunity