R/C Naval Combat

I was thinking 5 pack to keep it at 6 volts I was running every thing off of the Brick (with no trouble) but now will run separate pack for pump or due you think I should stay with one?

Umm, LiPO is fine with water, as the lithium is bonded to the polymer base. It's LiION that's the boomer since the Lithium isn't bonded to anything, it reacts to water. But for a large small ship like a Baltimore, NIMH is the most cost effective.

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Originally posted by VVaholic

Lipo goes BOOM when mixed with water. NimH is the way to go.

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The cell listed is low capacity for a reasonably sized Cruiser like a Baltimore. It is better suited for smaller Destroyers. I keep forgetting about the vendor. Lot of cool stuff, but they seem a little high on pricing though.

I typically get my cells from All-Battery http://www.all-battery.com/ or Batteryspace http://www.batteryspace.com/. My Des Moines class is running on 15AH total (5 6v 3AH packs) of High Discharge NIMH packs. This arrangement weighs less than when she was running on 7.8AH total of SLA. I was able to switch from a 6oz bottle to a 9oz with the weight savings.

Critical part of the previous - High Discharge. Each pack is capable of discharging 30A, and I've got 4 allocated on main power for 120A max discharge at any given point. If you want 6V packs, you are probably going to have to solder them yourself, and in that case I recommend getting the tabbed cells, unless you have the fancy spot weld equipment as NIMH cells really don't take too kindly to being soldered on. The failsafe vent on the positive end is temperature triggered. Once it vents, you are safe from the battery going boom, but it won't ever reach a full charge again. Make sure to use decent/flexible high strand count silicone wire coming off the packs. Stiff wire will result in some breakage, and unexpected pond side failures, particularly if used on battery packs.

The really nice part of building your own, you can create the battery in the shape needed to fit the space. :) Long cylinder, pyramid, split across, doubled up, fluffy bunny shapes, whatever. :)

Here's a package of 20 3800mah HD tabbed cells that would get you 4 battery packs: http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=373

25 3300mah that will do the trick, a little more cheaply ($67):
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3467

Here's some 4200mah for a $20 more:
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2919

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Originally posted by Powder Monkey

http://www.cheapbatterypacks.com/cellinfo.asp?invid=ELITE1500A
Looking at these ones what do you think ?

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I'd say pool them together. That keeps you with less "wasted" potential power sitting around not getting used should the need arise.
cheers
Jeff

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Originally posted by Powder Monkey

I was thinking 5 pack to keep it at 6 volts I was running every thing off of the Brick (with no trouble) but now will run separate pack for pump or due you think I should stay with one?

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so I could run them off of one 6v pack and not have power issues ?

PM,

I generally just use stock 7.2v 6 subC packs that I pick up from batteryspace.com They often have a 2 pack plus basic charger on sale for a very reasonable price (used yo be about $35, but I believe it has gone up since then). I also have some of the saddle-pack versions. I do use the BEC of the ESC for the RX and servos, but that is because I have tested my electronics suite and it all fits within the BEC's capacity. You can also get add-on voltage regulators to bring the 7.2v down to 4.8-6v.

Batteryspace also has some 6v packs, but not near the selection. Or the tabbed cells to roll your own.

Do be careful to note the C rating for charge and discharge. Many of the subC batteries are high discharge and are happy with a 10C draw (in other words, a 3300mAh or 3.3Ah can hit a 30+amp discharge rate. Many of the AA's and others are closer to 1C, meaning that a 2500mAh (2.5Ah) AA is subject to damage if you try to suck more than a 2.5A load off of it. Surprisingly, some of the 3/4A and 2/3A are much higher discharge rates, though lower capacities, and may work better in some really small ships.

Cheers,

how would this work http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=432 for a 4 unit vdt and would i use one or two

Two in parallel would be okay. That's almost the same as the 6 volts, 12 AH that I use a lead-acid battery for my I-boat. It'd be good for 2 sorties, but probably not good in a 3rd.

this is the battery i have in my vdt 6v-12.oah/20 so its a 12 ah yes?if so is that ok?

If it's a 6V, 12AH lead-acid, then that's one that a lot of people use. If you're talking about the one in your post above (the one from all-battery.com), then it should only give 10AH in parallel (5+5). I think that if you have weight for the lead-acid, that's the one to use, as it's cheaper and doesn't require a special charger. Also, because a lot of people use them, if you have a problem with one of your batteries, you might be able to get a ready-to-fit loaner battery without messing up your trim.

i was thinking about that

so the one i have is good then 6v-12.oah/20

Yup, it's great :)

thank you Tugboat

Happy to help, happier that you have a good battery and don't need to buy new ones :)

Okay I think I found my Battery what do you all think it runs every thing including my Radio (Spektrum )

http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1890

Should work great for your cruiser.

Thanks Rob it's on the way see you soon

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Originally posted by Powder Monkey

Okay I think I found my Battery what do you all think it runs every thing including my Radio (Spektrum )

http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1890

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The older, lower amperage, version of that, is what I have been using in almost all of my ships for years. Finally some are starting to wear out, and new ones are on order. They run everything from a 22" 3 Island Tramp to the Dunkerque, but this is in Big Gun, with more efficient, lower draw, motors than often used in Small/Fast Gun.

The tramp (the most energy efficient) has one 500TB, aka the Tamiya Solar Motor 02, which draws less than one Amp at full stall and pushes her to about 33 knots (about 34sec/100') if allowed, and the Dunkerque uses two geared Speed 400s (two of these these will push a Richelieu to 42-43 knots, or about 26.5 sec/100' if unleashed).

If you are using a couple of 550's of course, you can harm the batteries with a full stall, as 550's can draw over 70-80A each, depending on model, on stall (some older models closer to 90A ea), and those battery packs, if like min, are rated for about a 30A maximum draw each.

Some people have a hard time believing the the motors draw so much, but I have observed them frying some heavy duty (12 ga high-strand count) wiring and switches, and it is in the motor spec sheets on Mabuchi. Visit this site.

Cheers,