Will I cook my batteries?

[ozoneone]

I was planning on running a single 3S 3300 (30C) pack in a DF26 with a Feigao 540 9L 2,887 Kv, but I see most people are using 5000mah packs for just about anything. Sorry for the elementary question, but I have been out of the FE boat scene for years. Also there's not really enough room for two 3300's in there. Any thoughts? Thanks.

[ED66677]

3300mAh at 30C gives you 99A constant, that should be ok as the 9L is given for 68A at its max efficiency you don't really want to go higher

[Steven Vaccaro]

I agree that its fine with a 9L.

[ozoneone]

Thanks guys. You're making me feel much better. I'll let you know how I make out.

[785boats]

Depends a bit on the prop size. What prop are you running?

[ozoneone]

Well funny you ask, I was going to start with a X440 but I don't think so anymore! Maybe 35-38 mm? Any suggestions?

[Meniscus]

Depends a bit on the prop size. What prop are you running?

Good call.

I'd start around 37-38mm personally and see what your runtimes are. You can then determine what the amp draw is before you prop up.

[785boats]

In order of progression I would try 437, 637, 437/3 blade. Checking for heat along the way of course.
Paul.

[ozoneone]

Sounds like a good plan. I have been looking for my Raytek temp gun for the past two weeks and finally found it yesterday. I bought it way back before the affordable ones were available. I was mostly concerned with battery temperatures presently.

Wait, I just checked and there is no X437 at offshoreelectrics. 435 & 438. Trim it? Or am I missing it?

[ozoneone]

Okay. Seems too heavy. Next question if I may. If I substitute TWO 2S 1800 30-40C packs in parallel, will that give me 3600mah and will that be enough at 4S? This is with an X438 most likely.

[Meniscus]

With two 2s 1800mah lipos in parallel, you end up with 2s2p at 3600mah. If you run in series you end up with 4s1p at 1800mah. Does that make sense?

[Jeff Wohlt]

Your run time will be pretty limited on 3300 with any decent prop.

[ozoneone]

Yes, completely. I brain farted when I wrote that. See my problem is that I mounted the motor toward the front, thinking I would put two 3S 3300mah packs in back alongside the stuffing box. I found out the two packs are way too heavy, even one pack is still heavy. Even with no pack the transom is almost completely submerged. So now when I put one pack in, across the stuffing box, it sits very high in the boat, which I don't think will be good for stability. I'm trying to come up with a solution that won't require grinding the motor mount out and cutting back the drive shaft to mount the battery forward of the motor.

[ozoneone]

Your run time will be pretty limited on 3300 with any decent prop.

Not to mention 1800 on 4S! I know, that's why I was thinking 2x 3300 packs, but it's too heavy.

[ozoneone]

Okay. I just ordered some more 3S 2200 30C packs. I will try two (3S2P) and hope for the best. If this is un-doable, let me know, otherwise I will let you know how I make out. I don't want to be at the end of the summer with no runs on this boat! Heavy or not!