What happens when a cell fails? My understanding is that NiMH cells fail in short circut. So a pack with a failed cell would discharge the other packs, if they are in parallel. I am not real clear what the results would be. Anyone know?
I don't know when a cell would actually fail unless the pack is a 4 - 5 years old. Most people replace NiMh packs after a few years anyway ... at least I do once the pack's depleted voltage rises high enough that my charger refuses to actually charge the pack. heh. A short circuit will damage any battery, no matter if it's SLA, Nicad, or NiMh. Thats where fuses work wonderfully to prevent battery damage due to a short in the ship's circuit.
I've had a cell fail in one of my packs last year. It didn't short circuit. It just went dead with no volts. I'm pulling the other cells off of it for something else. Most of the NIMH cells that I've seen go belly up, have just died, they didn't short circuit. HOWEVER, with that said, a cell is more likely to short circuit when abused, I've done that one too with std consumer grade NIMH. Oddly enough, just the one cell burned itself out luckily. A good reason to use high discharge cells rather than cheap consumer grade. (Funny thing, is Fry's has a big markup typically for NIMH making them expensive compared to HD cells.) Yes, NIMH costs more, but for cruisers and small BB's, they're pretty much necessary in order to carry more/better weapons on the ship or a bigger gas bottle. For USS Dallas, moving from 7.9AH of SLA to 15AH of NIMH allowed me to move from a 6oz CO2 bottle to a 9oz bottle, and expand some of the electronics on board and increase the rear magazine size as well. For my new USS Montana (BB-51), I had to have SLA for ballast. She's got 24AH of SLA which will probably last for 2 days or more of battling when combined with the energy sipping speed 280 5:1 geared drive train (based on Espana lasting all day on 3AH with the same drivetrain).
I am planning to use a 5 cell pack of 3300maH 1.2V NiMH purchased from batteryspace.com for my USS Des Moines. Now from what I've gathered from the thread is that should be enough right? Also, while I don't have any Skotchkote, I did manage to find the tool dipping stuff, and that should work at water proofing the batteries without messing up the vents though? If that one pack isn't enough I've got enough batteries to make 4 more packs so that won't be to much of an issue, but the water proofing thing has kinda got me worried a bit. I mean I like explosions as much as the next guy but maybe just not in my boat. It is one thing to let you guys try and sink me, it's entirely different when it's sabotage.
3300mah (Also known as 3.3 amp hours) is not enough for a Des Moines. Light cruisers, like Gloire, Karshure, take at least 5 amp hours. Heavy cruisers, like Houston & Lutzow take 5-7 amp hours. Larger heavy cruisers like Baltimore & Des Moines need 10 amp hours. Now this assumes using SLA batteries. You can double that for NIHM. I'd use 10 amp hours or more in a Des Moines. You need to use trip sterns and a 1/2 unit pump. Your pump should be a full size pump with a stinger or titan motor. In a Des Moines your drive will take around 8 amps, a high speed pump is around 18 amps. A 3.3 amp battery will last a few min. You also need to have enough packs to do 2-3 battles a day. That would be 6 packs of 10 amp hour batteries.
MY Boston is a little bigger but not much I run 2 550 with gear box (from BC) and ran 6 volt 7.2 SLA but changed to 7.2 NMH4500mAh high drain and run every thing off of it I have 2 and charg one as i use one and have no trouble at all []
The skotchkote works a lot better than the tool dip, it doesn't peel off as easily and its more pleasant to work with. If you have a lowes near you look for it there. The tool dip will work but it peels up easier in my experiences. I agree with Bob on going with a 5-10amp hour battery setup.
I remember back in the old days(OMG..did I just say that?..sigh)I ran a Lutzow with 2 SLA at 6v 5amp each and tied them in parelle.It was a little cramp but it got the ship to max weight on the waterline and the ship could battle hard for a good 1hr and a half without changing the battery. For cruising 2 hrs was the norm. Small swampy pump was used and a pair of small stock swampy motors. I don't remember but I think they were 380s as I had to use a speed adjust resisitor to tune the speed. Never had issues with it running. These days you can get away with a single SLA that would free up more space. I used the same setup in a Houston and it too ran very well for a long time with no issues.
okay so new D cell 10AH NiMH batteries on the way...just cost me a couple of fingers, but the good news is that since my fiance is thinking about a convoy ship I can use the 3.3AH NiMH I bought earlier to power her boat when ever we make it.
So lets revive this old thread and see what is now recommended for a large battle ship. NC to be exact. Also, just confirming, I need to run and esc for each motor correct?
