Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: tugboattam on June 11, 2013, 06:26:17 pm

Title: Battery help please
Post by: tugboattam on June 11, 2013, 06:26:17 pm
Iam starting work on a small tug (18"x6")  I would have like to put a 6v 4.5ah jelly cell in it but due to size restrictions I can't. I can fit a 5 cell 6v 2600mah in, can I charge this from my 6v jelly cell charger ?  also how will this compare speed wise and duration of run time ?    Thanks in advance.  Ian.
Title: Re: Battery help please
Post by: Stavros on June 11, 2013, 06:32:34 pm
Sorry no you can not charge a nimh with a gell cell batt you will need the right charver for it...as for run times it depends on your hull shape motor size prop size more info needed please



Dave
Title: Re: Battery help please
Post by: tugboattam on June 11, 2013, 07:11:40 pm
Hi Dave,  its just a small tug boat hull so not very areodynamic, the motor looks about the same size as the one in my Seaport, a 380 maybe, there are no markings on it. It has a a prop shaft and rudder fittrd but no prop.Im afraid thats all the info I can give you about it, my real ignorance is I have no idea how the 6v 2600mah nimh would compare to a 6v 4.5ah jelly cell, would I maybe need to go higher say a 6v 4000mah ?  Im pretty useless when it comes to understanding batteries.   ian.
Title: Re: Battery help please
Post by: Stavros on June 11, 2013, 09:43:05 pm
Obviously a 2600minh would have less of a running time than a gell cell of 4.5 amps so a 4000nimh would be closer to the mark BUT without the spec of the motor and knowing how much current it draws it is difficulty to hazard a guess....but a speed 400 will draw 4amps so a rough ball park figure and I will stand corrected on this would last an hour on a 4000nimh batt
 
 
Dave
Title: Re: Battery help please
Post by: hmsantrim on June 11, 2013, 09:54:01 pm
Hi tam.
 pic to go with PM sent.
 frank
(http://imageshack.us/scaled/landing/11/s5000147.jpg)
Title: Re: Battery help please
Post by: malcolmfrary on June 11, 2013, 10:00:57 pm
A 380 might be a bit much for an 18" tug anyway.*  A 285 might fit and, depending on the combination of voltage that the motor can handle and what the battery can supply, could give a run time over an hour.
And a proper NiMH/NiCad charger is cheaper than the same charger and a replacement new battery.  After the SLA charger has killed the NiMH, a new NiMH will be needed.....

*unless its a springer, but that would take the SLA anyway.
Title: Re: Battery help please
Post by: tugboattam on June 12, 2013, 10:45:28 am
Hi, Thanks for all your replies, Im slowly begining to understand how all these batteries function. I think now that I will junk the motor and go for a 9.6v battery as I have already got two of these battery packs + charger.
Frank, thanks for the offer of the battery charger but as the above says I may now go down a different route, though the offer was much appreciated.
Can anyone tell me what SLA stands for ?
Title: Re: Battery help please
Post by: Netleyned on June 12, 2013, 10:48:46 am
Sealed lead acid aka gel cell

Ned
Title: Re: Battery help please
Post by: tugboattam on June 12, 2013, 10:55:16 am
DOH !!!!!!   :embarrassed:
Title: Re: Battery help please
Post by: inertia on June 12, 2013, 01:58:42 pm
A 385 would be OK on 6v. It's the five-pole version of the 380 and much less fierce. http://http://mfacomodrills.com/motors/385.html (http://http://mfacomodrills.com/motors/385.html)
DM