Submerge Scooters NiMH nickel metal hydride, NiMH DPV, long range NiMH underwater scooters / NiMH diver propulsion vehicle SCUBA DPV

2006 finally saw the introduction of the "2D" NiMH cell with a nominal capacity of 20.5 A/h compared to the "F" cell with only 13 A/h. Now it was possible to meet several goals:

-Under 50 pounds
-Over 100 minutes runtime
-Simple, single 20 cell pack.

The new model N-19 SALTWATER is instantly recognizable as a Submerge... using many standard Submerge components such as the driveline/motor, pioneering single handle operation and construction from the formidable UV range of scooters.

Why change a winner!

Includes Battery pack and Charger. Replacement battery pack is $600

Our warranty for Nickel Metal Hydride battery packs is the same as other DPV manufacturers:

30 Day warranty only, from delivery date.
No warranty for decease in capacity of NiMH batteries.
No warranty for floods-scooters are tested at factory.
30 day warranty: covers other pack failures and is completely at our discretion.

In other words, the high replacement cost of the packs does not allow us to offer
an extended warranty, only the minimum offered across the industry for NiMH batteries.

The rest of the scooter carries the normal Submerge warranty 5+ years against any defects in manufacturing and workmanship.
Low voltage cut-off electronics warranty: 1 year. Excludes flood damage and user error.

Features of the N-19 SALTWATER:

Waterproof motor compartment. Not only protects motor from water if the main hull leaks, also isolates the rest of the scooter if the shaft seal leaks. Motor compartment also prevents any objects, dust, dirt, moisture, salt spray or water from entering motor when the scooter is opened up for battery charging. ALLOWS SIMPLE, USER FRIENDLY TEST OF THE REAR SHAFT SEAL with a vacuum pump and guage.

Waterproof battery pack is transparent, for easy inspection without disrupting sealing surfaces. Additionally, the top and bottom lid of the battery pack act as overpressure relief valves, not allowing more than a few psi pressure inside. This allows any explosive hydrogen gas buildup to escape from the battery pack. BATTERY PACK INTEGRITY CAN BE EASILY CONFIRMED with a vacuum pump and guage.

Battery pack is waterproof at ALL times: Even when outside the scooter hull... so it won't receive water damage if splashed carrying from the boat deck to the cabin for charging.

Significance? For live aboard diving, Submerge N-19 battery pack is waterproof when being charged: it can be charged in a salt spray environment without concern; expensive Nickel Metal Hydride batteries are protected at all times; the worst that can happen is some corrosion on the external wires which can be easily replaced.

Main hull o-ring design is user friendly, with large cross section o-ring and the most reliable type of seal design. (Barrel o-rings can extrude during assembly, and cause the scooter to leak, this is a risk every time you re-assemble the scooter, whereas the large section face seal is easier to assemble, will not extrude, is not required to be greased, and is more tolerant of small grains of sand or hairs because of the large cross section)

Speed/power: From Diver magazine test: "clearly the fastest scooter" which must mean we have the most powerful scooter in it's class! More specifically, the Submerge/Tekna motor provides a lot of torque, which means higher speeds, especially when you have a lot of equipment/dry suit/stage cylinders, have to tow another diver ect.

N-19 SALTWATER scooter is the only scooter in it's class with a full size carry handle on the nose.

All aluminum (which is naturally corrosion prone) on the N-19 is MIL SPEC dichromate sealed and black hard coat anodized for superior corrosion protection. For 2007, this includes the motor end cap, which also has the additional protection of a MIL SPEC epoxy coating. For divers that want a scooter that can last a lifetime, it should be noted that all external aluminum parts can be replaced at low cost with brand new parts; aluminum does not comprise any major/primary component of the scooter such as the hull, nose cone or tail cone.

waterproof, clear see through NiMH battery pack

The N-19 SALTWATER is a lightweight, high power and high performance DPV, but it does have trade-offs when compared to the traditional UV scooters, and additionally the Nickel Metal Hydride batteries which are at the heart of the machine have many compromises when compared to Lead Acid Batteries:

LEAD ACID	Nickel Metal Hydride
At end of dive, lead acid batteries gradually become slower, allowing the diver to safely return to the shore of boat if the burntime has been slightly exceeded.	NiMH batteries will cut-off suddenly at as soon as they have been fully discharged, possibly leaving the diver stranded. At best, the diver will always have to make the dive shorter than necessary, to ensure the scooter does not completely shut off requiring the scooter to be towed or swum back to shore.
Lead acid batteries are a very mature technology, having proven characteristics of reliability and low cost. This chemistry should long outlast NiMH batteries.	NiMH batteries are a relatively new technology, hence they are more expensive. Also, they may be obsolete in less than 10 years, replaced by lithium chemistries.
The high quality Genesis batteries have 200 to 500 cycles (standard quality lead acid may not perform well after 50 to 100 cycles in a deep discharge device, such as a scooter)	NiMH manufacturers claim up to 100 cycles. In a deep cycle application, however, expect closer to 300 cycles. Shelf life: don't expect more than 3 years service life out of any battery chemistry.
Lead acid batteries are double the weight of similar capacity NiMH batteries.	NiMH batteries are lighter than lead acid batteries (This allowed us to build a 60 to 120+ minute N-19)
Genesis lead acid batteries recover well from over discharge, if re-charged as soon as possible.	NiMH batteries can suffer from "cell reversal" when charged as a pack, if the individual cell voltage is allowed to drop lower than 1 volt per cell. Our NiMH scooters have a low voltage protection circuit to prevent over discharge. However this in itself is another failure point which does not exist in the lead acid scooters.
Lead acid batteries are really easy to charge, and have an extremely low rate of self discharge. Only problem with charging is if ambient temperature is less than about 5 degrees Celsius.	NiMH have as much as 10% self discharge on the first day after charge. The higher the temperature, the higher the self discharge. Unfortunately, the batteries heat up during charging, especially at the end of charge, so you loose a noticeable amount of capacity during the first few hours after charging.
Lead Acid batteries perform and charge better the higher the temperature (up to a temperature of about 55 degrees Celsius)	Nickel Metal batteries are extremely difficult to charge to full rated capacity if the ambient temperature is high. ie, if it's hot, don't expect full capacity.
Lead acid batteries are not prone to mechanical damage	NiMH "packs" contain multiple individual cells which are connected by spot welded nickel tabs, (20 tabs, 40 welds) and each connection is a failure point. As of June 07 we have seen < 1% this kind of failure in our packs.
Our lead acid scooters do not use fuses to protect the batteries.	We do use a fuse on our NiMH packs and this is point of failure. Our UV-N-37 scooters have 2 separate packs, and the scooter will still run on the remaining pack if the other pack's fuse has blown. (as opposed to some competitors)
Unaffected by temps up to 110 degrees F	Performance degrades if stored at high temperatures.
low maintenance, re-charge every 3 months in storage	Very high maintenance. Packs need to be "excercised" every 3 months to maintain capacity.

We also want to inform divers, especially those used to the incredibly stable UV-26, that one of the trade-offs when choosing the N-19 is stability and torque offset... the N-19 is manouverably, yet relatively unstable. This is true of any scooter 50 pounds or less.

With the N-19 there is no torque offset, so the smaller scooters are not recommended for those doing long dives; this is also why it's a questionable idea to make a small scooter with a huge runtime over 2 hours... the diver will be physically exhausted.

By comparison, you could scooter with a UV scooter for 3 + hours without any fatigue: you can completely let go of these scooters, and they will not veer of course for some time: they are incredibly stable, and require no diver input to maintain course, they require no more effort to guide than an automobile on a highway.

NiMH "memory" effect.

If NiMH batteries are not used regularly (weekly) or fully (using only a fraction of full capacity) there will be a temporary reduction in available capacity. Technically this may not be a true "memory" effect but a voltage depression. Ether way, the result is reduced run times. We have had a few calls from divers who have only had 30 or 40 minutes runtime. After the packs have been "excercised" the full capacity has reutuned, and along with it 70 to 100 minute runtimes.

To correctly excercise the packs, we recommend the use of our burntester and watts up meter. This way you can cycle the pack until it has returned to the normal capacity. It may take more than 1 cycle, and using the watt's up meter is the only way to accurately determine the status of the pack.

The procedure is simple: charge the pack (following charging instructions supplied with scooter), then discharge, recording the capacity (A/h). Repeat until capacity has returned, or maximum 3 cylces. It is recommended to exercise the pack after any prolonged storage (as little as 2 weeks, but definately after 6 weeks).

Expected life of NiMH batteries:

Whilst it is theoretically possible to achieve hundreds of discharge cycles from NiMH packs (or indeed any re-chargable battery) the expected lifetime of a NiMH (or Lithium) pack is limited to approximately 3 years. Furthermore, the capacity over the lifespan of any battery is not constant. During the first 12 months, expect at least a 20% reduction in capacity. If the battery is stored at temperatures below 20 degrees Celcius or 70 degrees F, this will prolong the average life expectancy.

Here are some approximated, no BS ranges of NiMH expected capacity over a lifetime:

0-12 months: 70 to 100% capacity

12-24 months 60 to 75% capacity

24-36 months 50 to 65% capacity

36 months : end of expected life. (Loss of 50% capacity or more).

As a comparison, we have seen Genesis lead acid batteries with HIGHER capacity after 12 months, than when new. Indeed, it is not uncommon to have Genesis lead acid batteries performing at 80% capacity after 3 years, something NiMH or common Lithium technologies can not even approach. The ONLY reason to choose NiMH or Lithium is WEIGHT. Genesis lead acid wins hands down in simplicity, longevity, robustness, reliability and affordability.

Recommended accessories:

Mityvac (tm) vacuum pump ($65) can be used to test integrity of NiMH sealed battery pack.
We have manufactured the N-19 and UV-N-37 battery packs with a separate, sealed compartment.
This tool allows this compartment to be leak tested, via the vent screw. This tool can also be used to
test the motor compartment and rear shaft seal on any Submerge scooter (UV or N-19) in addition to
the motor compartment on a Gavin scooter, and the battery compartment on a Tekna scooter
(via the charging port)

Instructions: it will take about 30 hand pumps to pull a 10 inch vacuum. The guage should stay steady
if tested for a few minutes, or overnight. If there is a leak, be sure to check your connections to the Mityvac pump.

NiMH battery pack leak tester

Burn tester:

Scooter burn testers consist of a large resistor which simulates the approximate load of
the scooter motor, in this case 24 volts and 16 amps. This is the best way to check the condition
of your batteries.

Submerge Burn testers include a battery over-discharge protection circuit (LAC), which switches off the
tester at the correct time.. when the batteries voltage drops to 21 volts. At the end of the test, a piercing alarm sounds for 1 minute to alert you that the test is complete. At this time, the duration of the test should be recorded.

Approximate burn test times for new batteries:
UV-18 40-45 minutes
UV-26 85-90 minutes
N-19 60-75 minutes

We also recommend a "Watt's Up" meter (sold separately... $60). This meter is connected in line (between the battery pack and the burn tester). It will record the exact A/h of the battery, as well as giving you a real-time voltage measurement.

Ever wonder how much scooter time you had left after a dive? You can use the burn tester after the dive, to test how many minutes you had left at full power. Simply plug it in after the dive and record the time until the alarm sounds.

The resistor and LVC is mounted an aluminum channel to offer limited protection from the heat generated (~350 watts). It is important that you exercise extreme caution when using this burn tester. It becomes extremely hot, hot enough to melt solder (500 degrees F) At this temperature it can melt any plastic close the to resistors (such as your scooter!) It is also a fire hazard if placed near any flammable material. We recommend at least 12 inches/300 mm separation between the resistor and any flammable material.

This tester is designed to test 24 volt batteries only.
This includes: Any UV battery pack (2x 12 volt lead acid, 24 volt pack)
Any Gavin scooter battery pack
Any X scooter battery pack.

scooter burn tester