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Old Jan 20, 2006, 08:53 AM
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Joined Jan 2006
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Battery upgrading for Aquacraft Hammer EP

I've recently began RC boating and purchased an Aquacraft Hammer EP. I'm very happy with the performance and not planning any major modifications to the boat but would like to upgrade the batteries i'm currently running.

Currently i'm running 1500 mah 7.2V 6 cell NiCd batteries. These are giving about 6-8 minutes of run time at mostly full throttle.

I'm looking at purchasing a few IB3600 3600 mah 8.4V 7 cell NiMH batteries from Offshoreelectrics.com for $32.99. Has anyone happened to have run this particular battery or recommend another 7 cell battery with similar performance?

Another question is that the charger i'm using for the NiCd's and the compatability with the NiMH batteries. It is a wall charger that doesn't have any indicator lights on it at all, but works well for charging the NiCd's. I just hook them up and time them. Would this charger be appropriate for charging the NiMH batteries? I'm not looking to break the bank on a charger, but what would be a lower cost recommendation for a charger that can handle the NiMH batteries?

Thanks all...
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Old Jan 20, 2006, 11:14 AM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
4,927 Posts
Hi VmcFlyer,

By getting a 8,4V 3600mAh battery, you're upgrading two things; the speed and the runtime.

Both require a watercooled motor, or you'll get smoke on the water, unfortunately the stock cooling on the Hammer covers the slots in the motor, which will get very hot, as not only the runtime will double, but also the heat build-up in the motor.

I'll would ask other Hammer owners to respond, how they solved this.

My suggestion would be to add brushtab cooling and reduce the number of cooling-coil windings so the slots become unblocked.

Make sure to check the motor temperature every few laps, most certainly don't run the new battery empty in one, uninterrupted, full throttle run, it might be your last, if the motor overheats...

Should the 550 motor get too hot, get a speed 600 Race, which can cope better with the 7 cell battery.

Charger: a Nicad wallcharger is not suitable for charging NiMH, you'll need a (quick)charger with a adjustable (or factory adjusted) Delta Peak cut off, to have the most of your NiMH.

Also, NiCads can be charged and run cold the next day.
NiMH will perform best when hot from the charger, running them cold (the next day, or even the same day when they've cooled down) will substantually reduce the lifespan.

Regards, Jan.
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Old Jan 20, 2006, 12:26 PM
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Joined Jan 2006
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I've already fixed the cooling slot problem by moving the cooling jacket so that the slots are exposed inbetween the coils as mentioned by other Hammer owners. Right now i'm upgrading the water cooling system to 2 low drag intakes on the bottom of the hull that will have a better water pickup than the stock cooling system, and also will work better when I upgrade to an aftermarket ESC and will put in water cooling plates for that. Also i'm already looking at a 600 size motor once the 550 craps out. Steering fins will probably be added with that so that its less prone to spinouts.

I purchased the 7-cell battery today and also a MegaPeak Charger from Offshoreelectronics. I only picked up one of these batteries since i'll probably be upgrading to atleast an 8-10 cell when I change out the motor and ESC.

So far i'm very happy with this boat in its stock performance, but also with the availability of modifications to push it even farther.

Here is my Hammer (Paradise City) with its paintjob:



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Old Jan 20, 2006, 01:23 PM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
4,927 Posts
Very nice paint job, makes it stand out!

I would be careful with running a 600 motor on more than 8 cells, unless the motor is rated for those cellcounts, even with can-& brushcooling I've seen them evaporate with high cellcounts...

Regards, Jan.
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Old Jan 20, 2006, 05:12 PM
Elroy68
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Battery upgrade for aquacraft hammer ep

addition
Last edited by Elroy68; Jan 27, 2006 at 08:50 PM. Reason: addition
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