Is Apollo AV1 the same as the Tusa Sav-7

[AceszHigh]

Looking at buying a DPV (I want one that has the saddle, so hands can be free for hunting!) .. these two look identical. From my understanding the AV1 is out of production, but I see a lot of cheap used ones (compared to a new sav-7 at $2300 or so). Are these basically the same scooter?

Edit: Or maybe the AV-2?

 

[ft.lauderdale diver]

consider getting a refurbished dive xtra sierra---it's 2500 comes with a brand new battery--and is upgradable to a lithium battery (which I recommend to ensure you have enough juice)---or you can consider a silent submersion or other lithium powered scooters.... these are hands free as well--as you attach them via a crotch strap so they are hooked on to you at all times and you can push away when hunting---

 

[jamesb]

AV1 is brush type motor, on off with three speed prop. Well used ones have overheating problems without expensive modifications. On high they give you a pretty good bump on startup.

AV2 and SAV7 are brushless motors, infinitely variable speed, soft start, still with a three position prop. Much better suited for hunting or photos.

All have plastic cases and need to be treated as 40 pound eggs and kept out of the sun or can become brittle after several years. They don't do well as rentals but in private use can do thousands of trouble free dives.

They are completely hands free, no tow cord or hand on the throttle, you just to reach down and set the speed. When hunting it will stay pushed between your legs, or shut it off and grip on the saddle with your legs. It will also allow you to hover with it below you or move sideways.

The lead acid batteries are heavy and limited, NiMH or lithium is a better choice but the OEM NiMH is expensive. A NiMH battery can be assembled from 40 D cells spot welded or solder tabbed together for a lot less, but it is not exactly a simple DIY project the first time.

 

[AceszHigh]

James, do you have any more information on assembling the battery for an AV-2 using 40 D cells? And what kind of run time can be expected from this? I may be getting a good deal on a second hand AV-2 so this information would be very helpful

 

[AceszHigh]

Update: I just bought the Tusa Sav 7 evo! I would appreciate if anyone has information on assembling a nimh battery for this scooter. Jamesb, I had read in a previous post of yours you got a custom battery from tenergy made up of 40 NiMH D cells with spot welded connectors configured into 24 volts and 20 amps (Square NiMH 24V 20000mAh 4x5x2 w/ Bare Leads). I had contacted tenergy about this same battery and they had asked a few additional questions (such as size and wire gauge to use) that I didn't know. Anyone have specifics on this? Thanks!

 

[cool_hardware52]

A word of caution; Series / parallel battery packs using Ni-Cads or NiMh cells are a bad idea.

Using 40 cells Nickel cells to produce a 24 volt nominal pack requires series / parallel configuration.

Ni-Cad or NiMh packs should be pure series.

Tobin

 

[jamesb]

Never use them in parallel......

Surely that is the best practice, but Tenergy, the manufacturer, assured me there would be no problem. I have 8 batteries, some several years old with hundreds of dives, and they are still at full capacity. I measure them with a discharge unit that draws the same amps as full speed, and shuts off at 21 volts, records the runtime, and label the batteries with runtime.

The SAV7/ AV2 draws 11 amps on high, so #12 or #14 wire is suitable for the connector with minimum voltage drop. It would be rare to run it on high until dead, about 95 minutes. More common for us is to run 75-120 minutes on medium and not fully discharge the batteries, drawing about 8 amps.

Last price quote was.....

Item 11848 (NiMH square 24v 20ah)

$300 per pack

For the price, I am satisfied. Haven't had one fail, which is more than I can say for SLA batteries other than Odyssey, but they are 13 Amps and 23 pounds.....The Tenergy battery is 20 Amps and 14 pounds.

Requires a power connector, suitable charger, and temperature sensor.

It is smaller and lighter than the lead acid. Requires ballast and something to hold it in place.

I added a 4 1/2 pound molded lead weight to make it neutral buoyancy, and glued together a case from rigid foam. Others use lead bean bag weights.

I started with these years ago, today I would also look into Lithium, but these last longer than our air and are a mature design.

 

[cool_hardware52]

Never use them in parallel......

Surely that is the best practice, but Tenergy, the manufacturer, assured me there would be no problem. I have 8 batteries, some several years old with hundreds of dives, and they are still at full capacity. I measure them with a discharge unit that draws the same amps as full speed, and shuts off at 21 volts, records the runtime, and label the batteries with runtime.

The SAV7/ AV2 draws 11 amps on high, so #12 or #14 wire is suitable for the connector with minimum voltage drop. It would be rare to run it on high until dead, about 95 minutes. More common for us is to run 75-120 minutes on medium and not fully discharge the batteries, drawing about 8 amps.

Last price quote was.....

Item 11848 (NiMH square 24v 20ah)

$300 per pack

For the price, I am satisfied. Haven't had one fail, which is more than I can say for SLA batteries other than Odyssey, but they are 13 Amps and 23 pounds.....The Tenergy battery is 20 Amps and 14 pounds.

Requires a power connector, suitable charger, and temperature sensor.

It is smaller and lighter than the lead acid. Requires ballast and something to hold it in place.

I added a 4 1/2 pound molded lead weight to make it neutral buoyancy, and glued together a case from rigid foam. Others use lead bean bag weights.

I started with these years ago, today I would also look into Lithium, but these last longer than our air and are a mature design.

No cell manufacturer I've ever dealt with, i.e. Sanyo, Gates. LG, etc. has ever recommend Nickel batteries in parallel.

"
[SIZE=+1]NiMH Charging[/SIZE]
Basics
NiCad and NiMH batteries are amongst the hardest batteries to charge. Whereas with lithium ion and lead acid batteries you can control overcharge by just setting a maximum charge voltage, the nickel based batteries don't have a "float charge" voltage. So the charging is based on forcing current through the battery. The voltage to do this is not fixed in stone like it is for the other batteries.
This makes these cells and batteries difficult to charge in parallel. This is because you can't be sure that each cell or pack is the same impedance (or resistance), and so some will take more current than others even when they are full. This means that you need to use a separate charging circuit for each string in a parallel pack, or balance the current in some other way, for example by using resistors of such a resistance that it will dominate the current control. "

more hereHow to charge Nickel Metal Hydride Batteries.

Tobin

 

[jamesb]

Thanks for the link, good info. Been mislead again.

If they wear out before I do, I'll switch battery chemistry

 

[AceszHigh]

So I bought this tusa sav 7 evo used from someone who said its been used a total of 6-8 hrs and then sitting in storage for the past 2 years. It looks almost brand new. I charged the battery and took it on a 60 minute dive today..at top speed the scooter didn't really seem to go any faster than my girlfriend who was beside me kicking at a moderate pace. The battery light indicator also turned to red(empty) after about 15 min of operation (and i checked the indicator without the motor running)..but I continued to use the scooter for the rest of the dive. I came home and plugged in the battery to charge and the charge now shows a green light after about an hour (it did this the first time I charged it also, but I figured the previous owner had already charged it). I had the prop pitch set in position 2. Do I have a bad battery? Its the SLA battery. I'd used a sav 7 a while back and seem to remember the top speed being faster than a diver could kick...