Including Gavin short body, Mako, Silent Submersion UV-18, and possibly Farallon 7 scooters. During the development of Jetboots it became obvious the battery technology we were using that enabled this new concept in diver propulsion could also be adapted to conventional scooters and DPVs. The advantage of replacing a scooter's conventional lead acid batteries with NiMH battery packs is simple - about twice the battery life in a package of similar size and weight. There are also other nice features: about 10% higher thrust as the cells hold a higher voltage during discharge, better cold weather performance, faster recharge times, a flatter discharge curve providing consistent performance over most of the discharge cycle, and longer life span (cycle life). Most 24V scooters use two Genesis NP18-12 or Yuasa NPX-80 batteries or the equivalent. The table below compares these batteries to our NiMH battery solution.

	2 NP18-12	MST NiMH	MST Super NiMH (Saft Cells)
Rated Capacity (1 hour rate, room temp)	10.3 Ah*	25 Ah	30 Ah
Rated Capacity (1 hour rate, 32° F, est.)	8.2 Ah †	23.8 Ah	28.5 Ah
Actual Burn Time, 1. 5 Ohm Burn Tester	48 minutes	87 minutes	98 minutes
Actual Capacity, 1. 5 Ohm Burn Tester	12.8 Ah	22.8 Ah	25.1 Ah
Weight	27.28 lbs	24 lbs	24 lbs
Life Span (cycles)	~100	~500-1000	~500-1000
Cost/hour of thrust	$1.57 ‡	NA ‡	$1.71‡
Price	$128	NA	$1600

* The quoted "18 Ah" capacity of these battery is for a 20 hour discharge rate. The one hour discharge rate is what is important in a scooter.
† Low temperatures can also seriously effect the capacity of sealed lead acid batteries. See this plot from the Powersonic web site.
‡ The NiMH packs are quite a bit more expensive then the lead acid, but their longer life span means that if you dive a lot and aren't in the habit of flooding your scooter, you can actually save money. This number is calculated by taking the cost of the battery pack and dividing by the total number of hours of discharge the battery should provide.

Replacing your scooter's battery pack with our NiMH pack will approximately double your scooter's battery life. The actual burn times listed in the table above simulate current drains that exceed those observed in actual use, so these burn times should be considered very conservative lower limits to the actual battery life you will experience. For those of you who need the longest possible burn time, the MST Super NiMH Pack uses the new SAFT VH-F 15 Ah cells, the highest quality cells on the market. These cells offer about 30% better performance than the standard NiMH cells - about three times the battery life of the standard lead-acid batteries!

The packs are designed to be drop in replacements, and all the necessary connectors are included. The packs also include a microprocessor based cutoff circuit designed to protect the batteries from over discharge. This circuit board includes a battery charge indicator LED that can replace the fuel gauge on some scooters and an on/off switch. There are two options on the battery cutoff - a hard cutoff that cuts off sharply in order to protect the batteries or just a visual or auditory indication when the controller thinks the battery should stop discharging. Ignoring this indication WILL cause battery and/or scooter damage. Please specify which type of cutoff you would like when ordering.

Some trim weights will be required to get the weight and balance right as our battery pack is several pounds lighter than the standard lead acid battery packs.

These NiMH batteries require a smart charger. This charger is approved by the battery manufacturer and uses a NTD thermistor to stop the charging process. Using a different charger will void the warranty.

All our battery packs are tested before they leave the factory, and a discharge curve is included. A six month limited warranty against defects of material and workmanship is included. Packs sold with the soft cutoff or without the smart charger do not come with a warranty.

Pictures and Technical Information:

	Burn Test of our regular battery pack and a Yuasa 18-2 pack on a standard WKPP burn tester (1.5 Ohms). This provides a fairly accurate estimate of the scooter battery life of the Gavin Scooter under the worst case (most drag) scenario.
	Burn Test of our super battery pack and a Yuasa 18-2 pack on a standard WKPP burn tester (1.5 Ohms). This provides a fairly accurate estimate of the scooter battery life of the Gavin Scooter under the worst case (most drag) scenario.
	Photo of the battery pack
	Photo of the pack installed in a Mako scooter.

For more information, or to place an order please call MST at (626)449-1960 or e-mail sales@jetboots.com.