Using Lipo Batteries for a Grapuner BB700 Turbo

[Rodrigo GonzalezParticipant @rodrigogonzalez71768]

[Rodrigo GonzalezParticipant @rodrigogonzalez71768]

Hello: I have a Model SlipwayTamar Lifeboat with twin Graupner BB700 Turbo 12v motors, with Action Electronics P94 Mixer/controler, running on a 12v PB Battery. It runs nice, but I little bit slow.

I want to put more power on it to get it running faster.

I was thinking in using two 11.1v Lipo Batteries to put more Amps, although its a little less nominal voltage.

Can anyone tell me if this is a good solution?

If not, can you recommend me what motors would be a good upgrade? (the P94 con handle 24v, and there is no problem going to 24v with the batteries)

Thank you very much!!

[Dave MilbournParticipant @davemilbourn48782]

Rodrigo

Lead-acid batteries are not the best solution to any problem – except maybe as weights in the workshop or for doorstops. I would definitely not recommend them for use in a Tamar lifeboat of this scale. They are too heavy and deliver little power under significant load.

Also please don't confuse Amps with Volts. In very simple terms Volts affect the motor speed while Amps dictate the running time. There's an article here which was written for folk who don't quite understand electrical things. But I don't understand electronics

You will certainly find that the much-reduced weight of LiPo packs c/w SLA batteries makes your model faster, and they will also give you greater duration.

I would also say that running those motors @ around 12v is the optimum – if you apply any higher voltage you will reduce their efficiency.

Dave M

Edited By Dave Milbourn on 28/03/2020 20:28:48

Edited By Dave Milbourn on 28/03/2020 20:30:29

[ashley needhamParticipant @ashleyneedham69188]

Hi Rodrigo and welcome to the forum.

You may well find that performance is improved by using at 3s Lipo, due to their ability to keep the voltage up when under load. Several of my models have demonstrated improved performance simply by using a Lipo.

Despite that a 3s cell is rated at 11v, in reality a fully charged cell is about 12.5v and will maintain this voltage for a while even under heavy load.

Ashley

[Malcolm FraryParticipant @malcolmfrary95515]

One of the best ways to get more performance is to add more lightness (Colin Champan, Lotus). For the same Amp-Hour number as a Lead Acid battery, a LiPo of about the same voltage will weigh a fraction. Less weight to push around. Lead Acid batteries are unable to sustain a high current drain (they can do so briefly, else your car would never start) but can not do it continuously without damaging themselves.

Apart from their use as ballast, SLA batteries have the virtue that their voltage drops off progressively as they discharge, so you get plenty of warning. Lithioum batteries give their full output until theu suddenly stop giving volts. They do need either a warning circuit or an ESC that has a safety cut out built in.

[Rodrigo GonzalezParticipant @rodrigogonzalez71768]

Thank you very much for your replies and advise!!!!

I have to tell you that weight was never an issue for me as I wanted this boat to look like when running. But I understand acid batteries limitations.

I'm going to try with lipos and I'll let you know the results!!

Best regards and take care with the virus!!

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