Gavin DPV battery replacement? What Ah?

[the_dragon_no1]

Is it 8c direct to the motor? Would not it be too hot for gavins motor?

Hmm yeah. Only nominally voltage was mentionen.. i didnt think about the max, that is around 29.2v then... hmm.

So, that should be around 3v more then with lead accid i guess

Wouldn't a voltage regulator/buck converter sort this? Would it be pricey for this application? I dont now amp draw

 

[the_dragon_no1]

But i guess the cheapest and most easy solution would be to add a simple voltage regulator. Like a DC-DC 36-24v, 11-15amp or so. Motor is 300w right? So max draw at around 29v would be just about 10A.

Right?

 

[Gone for diving]

It's not a problem, at 29.2V just back off the prop pitch, and the current draw will drop,
3volts per cell is usually what I limit on the low end because the cells drop in AH very quickly... and that's still 24v.
The gavin is one is just a on, off sw,
And on my heavily mod Farallon I use a
Pwm good for like 9v-50v. Works really well. Has 30 AH battery

We have talked about installing a pwm in the gavin, but will have to design a fixed blade prop for it, (which is not that hard)
But his variable pitch prop is still good, we'll wait till it breaks....

 

[the_dragon_no1]

It's not a problem, at 29.2V just back off the prop pitch, and the current draw will drop,
3volts per cell is usually what I limit on the low end because the cells drop in AH very quickly... and that's still 24v.
The gavin is one is just a on, off sw,
And on my heavily mod Farallon I use a
Pwm good for like 9v-50v. Works really well. Has 30 AH battery

We have talked about installing a pwm in the gavin, but will have to design a fixed blade prop for it, (which is not that hard)
But his variable pitch prop is still good, we'll wait till it breaks....

Hmm Yeah guess adjusting the pitch might help.

Not familiar with PWM, what kinda price are we looking at for something like that?
And why do you need fixed prop when using PWM?

Guy im thinking of buying from says he has around 30 dives on this setup without problem, but... Man i dont want a everlasting project scooter either. lol

Thanks

 

[tbone1004]

@the_dragon_no1 the gavin motors are capable of pulling 500-600w for reference.

The higher voltage will cause the motor to spin at higher RPM even with the prop turned back which will cause more heat. Even though the voltage may only seem like 3v higher, the issue is more about the voltage drop under load. The original AGM batteries drop down considerably as soon as you turn the motors on where the lithium won't.

If you want this thing to last then I would strongly recommend contacting @Jona Silverstein at getting a Smart-DPV which will give you multiple gear options and you can set the final gear to be similar to the stock speed so you won't cook the brush boards.

 

[tbone1004]

It's not a problem, at 29.2V just back off the prop pitch, and the current draw will drop,
3volts per cell is usually what I limit on the low end because the cells drop in AH very quickly... and that's still 24v.
The gavin is one is just a on, off sw,
And on my heavily mod Farallon I use a
Pwm good for like 9v-50v. Works really well. Has 30 AH battery

We have talked about installing a pwm in the gavin, but will have to design a fixed blade prop for it, (which is not that hard)
But his variable pitch prop is still good, we'll wait till it breaks....

you don't need to change away from the variable pitch prop when you go to something like a Smart DPV or other motor controller. You do tend to leave it on whatever the steepest pitch is because it is more efficient that way, but fixed pitch is not critical as evidenced by all of the Silent Submersion dpv's out there with variable pitch props and motor controllers

 

[Whitrzac]

you don't need to change away from the variable pitch prop when you go to something like a Smart DPV or other motor controller. You do tend to leave it on whatever the steepest pitch is because it is more efficient that way, but fixed pitch is not critical as evidenced by all of the Silent Submersion dpv's out there with variable pitch props and motor controllers

DiveX ones too.
But the fixed pitch prop is a cheap upgrade that gains a noticeable of speed/efficiancy too. I'm waiting on a smartdpv+prop for my uv26 now

 

[the_dragon_no1]

@the_dragon_no1 the gavin motors are capable of pulling 500-600w for reference.

The higher voltage will cause the motor to spin at higher RPM even with the prop turned back which will cause more heat. Even though the voltage may only seem like 3v higher, the issue is more about the voltage drop under load. The original AGM batteries drop down considerably as soon as you turn the motors on where the lithium won't.

If you want this thing to last then I would strongly recommend contacting @Jona Silverstein at getting a Smart-DPV which will give you multiple gear options and you can set the final gear to be similar to the stock speed so you won't cook the brush boards.

Hmm.

I did already look at the smart-dpv esc, but man over 400 buck, plus VAT and shipping is to much to put into this thing i think. Might as well look into other dpv's then i think.

 

[tbone1004]

Hmm.

I did already look at the smart-dpv esc, but man over 400 buck, plus VAT and shipping is to much to put into this thing i think. Might as well look into other dpv's then i think.

You can at least move the Smart-DPV to other dpv's, but yes it is very difficult to justify investing in Gavin's and old Silent Submersions when the Blacktip is available *essentially with a Smart-DPV, same hardware, same concepts though doesn't work with brushed motors* for about $2500 all in with more power and similar range as the 26ah Gavin's.

 

[Whitrzac]

You can at least move the Smart-DPV to other dpv's, but yes it is very difficult to justify investing in Gavin's and old Silent Submersions when the Blacktip is available *essentially with a Smart-DPV, same hardware, same concepts though doesn't work with brushed motors* for about $2500 all in with more power and similar range as the 26ah Gavin's.

I have a black tip, I chose to spend $2k refurbing a uv26 vs buying another one after it overheated on a run to the hinkle.
Its fine if everyone else you dive with has a bt, but trying to push past spd 5 for any length of time has issues.