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[das boot]

Can someone explain to me the best ways of fast charging two 6volt 4300a/h nicad packs from a car battery please?

What would be a good charger to buy?
What would be a good sized 12volt battery to buy borrow 'acquire'? 
What else should I be knowing?

I have found my old sea fishing trolley, so transporting a car battery shouldn't pose too much of a problem...I hope!

Rich

[das boot]

Hi Rich, what is your idea of 'fast-charging'? Minutes? an hour or two?, I have various chargers in my workshop, I will get there details and times a bit later. Cheers, Dan.

Hi Dan,

I guess my idea of a fast charge is 'as soon as possible'...once the cells have dropped off I'd like to be back on the water without sitting around for ages. Back in the old days( )if I remember correctly a set of six cells took about twenty minutes to recharge...something like that. I haven't used fast charge cells for years now, so I'm unsure of what modern technology can do.

The cell packs in question (see pic attached) with modded connectors...Euan tells me that the Tamiya ones as supplied will melt under load from the motor, so they are changed to gold bullet type connectors.

I'd appreciate your help when you get five minutes please..

Rich

[barriew]

Rich,

Drop an e-mail to Model Power - John or James will put you right.

Barrie

[Seaspray]

If your car is close to the water, charge from that while your using your other battery in the boat.

I would buy a battery charger that charges the many different types of batteries that are in use today.

Try your local fast fit for an old battery that has come in and has enough power for your purposed, there is always one there.

Silly question you can't go up to 7.2v pack. I run my Graupner 600 Speed 7.2v on 8.4v packs. I use Tamiya connectors

Seaspray 

[das boot]

If your car is close to the water, charge from that while your using your other battery in the boat.

Car is parked a good 100 yards away Dan...I'd need a long set of charging leads!

I would buy a battery charger that charges the many different types of batteries that are in use today.

I'll have a sniff round the 'net for something suitable.

Try your local fast fit for an old battery that has come in and has enough power for your purposed, there is always one there.

No problem there Dan, our workshops at work are always ready to donate things like this for a coffee or six...

Silly question you can't go up to 7.2v pack. I run my Graupner 600 Speed 7.2v on 8.4v packs. I use Tamiya connectors

The motor in question is a water cooled Speed 700 Turbo running a 42mm prop, Euan had it set up for a 12volt system, including the w/cooled esc...I'm assured Tamiya connectors will melt under full load, hence the gold plated bullet type connectors.


Rich,
Drop an e-mail to Model Power - John or James will put you right.
Barrie

Barrie...thanks for that, I'll go take a look round.

Rich

[andrewh]

Rich,

If you need to charge 2 at once the best setup is two cheap "buggy pack chargers" which are around 10 to 15 pounds each.  It might be wirth checking the maximum current they can put out - as ideally your packs would like about  4.3 Amps (each).  At this current they will take an hour to charge  To charge two packs just use both at the same time with one pack on each.

Safety note - what you call nicd packs could well be NiMh - nickel metal Hydride. 
In this case it is a very bad idea to charge a pack until it has cooled to ambient temperature - serious users use bits of drainpipe with computer fans to gently speed cooling.
I have heard of, but have no experience of, these large NIMH packs suffering rapid disassembly with (and without) abuse. 

Car battery will do fine so use either what you have or the largest you can afford or carry - I use a time-expired 56AH Varta which has carrying handles .  A leisure battery is even better but very much more expensive to buy.  Just don't abuse the car battery by  over-discharging it repeatedly, and do fill it up again as soon as possible.

Tamiya connectors are reckoned to be OK to 20 amp continuous, and possibly a little more for the gold-plated version - it seems very unlikely that a S700Turbo (5-pole) will pull this with a 42mm prop.  If you want to try it remember that Tamiyas come with a visible distress indicator  - the nylon housing shows darkening long before the connector lets go.

andrew

[Seaspray]

Thought you were on 6 v running system .....  700 speed turbo 9.6v max is 12v .

I have tamiya connectors in the r/c cars and they are on big motors  ..no problem.

Watch the difference between battery types as andrewh says

I charged 2 packs on the car battery under the bonnet ( hood, stateside)  when flying, spent all day in the air. the chargers  shutdown on fully charged batteries.

Right of to the workshed got a sanding job on zee go

[das boot]

Andrew...Seaspray...thanks very much for the information, much appreciated. I guess one way round the fast charge problem will to buy four packs of cells..two on the go and two on charge. Hmm...that's nearly forty five quid...hmm.

Right, thanks again guys, time for some more revision on batteries and battery charging, methinks...

Rich

[amdaylight]

Rich,

I have tried to standardize my battery packs so I can move them from boat to boat, this way I don't have to have as many spar packs hanging around. When I was flying more than I do now I used to have three (3) sets of batteries , one set running, one set cooling down and one set on the charger. The one that was cooling down was put in a plastic container with a tight sealing lid and then put in the cooler with the soda and dry ice (best way I have found to keep the soda cold). The only time that I use a non standard battery pack is if the boat or plane won't fit a standard pack. I also soldered my own packs with good batteries and saved quite a bit of money, this also allowed me to configure the pack any way I needed it.

Andre
over yonder in Portland Oregon