Exhibit 10.44

                            UNSECURED PROMISSORY NOTE

$400,000                                                    September 30, 2003

      FOR VALUE RECEIVED, the undersigned, GreenMan Technologies Inc., (the
"Debtor"), hereby promises to pay to the order of Robert H. Davis and Nancy
Karfilis Davis, 95 Audubon Road, Unit 611, Wakefield, MA 01880 (the "Holders")
on or before, March 31, 2004 the principal sum of Four Hundred Thousand Dollars
($400,000) or such lesser principal amount then outstanding, together with all
accrued and unpaid interest thereon. Interest on the principal amount of this
Note will accrue from and including the date hereof until and including the date
such principal amount is paid, at a rate equal to twelve percent (12%) per
annum. Interest only shall be payable, in quarterly installments commencing on
January 1, 2004 in lawful money of the United States of America, in immediately
available funds. Interest shall be computed on the basis of a 360-day year and a
30-day month.

      The outstanding balance of this Note shall be rendered immediately due and
payable, without the necessity of a Demand Notice, in case of any of the
following acts (individually, an "Event of Default"): (a) entry of any judgment
or order against the Debtor for the payment of money, if the same is not
satisfied or enforcement proceedings are not stayed within sixty (60) days or
if, within sixty (60) days after the expiration of any such stay, the judgment
or order is not dismissed, discharged or satisfied; (b) appointment of a
receiver, trustee, custodian or similar official, for the Debtor or any property
or assets of the Debtor; (c) conveyance of any or all assets to a trustee,
mortgagee or liquidating agent or assignment for the benefit of creditors by the
Debtor; or (d) commencement of any proceeding under any law or any jurisdiction,
now or hereafter in force, relating to bankruptcy, insolvency, renegotiation of
outstanding indebtedness, arrangement or otherwise to the relief of debtors or
the readjustment of indebtedness, by or against the Debtor. Notwithstanding
anything contained herein to the contrary, upon the occurrence of any such Event
of Default, the entire outstanding amount of principal and interest of this Note
shall become immediately due and payable, without presentment, demand, protest
or other notice of any kind, all of which are hereby expressly waived.

      The Debtor may prepay this Note, in whole or in part, at any time prior to
demand or acceleration. Any permitted prepayment of principal by the Debtor will
be accompanied by payment of all accrued and unpaid interest on the principal
sum being repaid plus a prepayment penalty equal to three months interest.

      The Debtor agrees to pay all costs, charges and expenses incurred by the
Holders and its assigns (including, without limitation, costs of collection,
court costs, and reasonable attorneys' fees and disbursements) in connection
with the successful enforcement of the Holders's rights under this Note (all
such costs, charges and expenses being herein referred to as "Costs").
Presentment for payment, demand, protest, notice of protest and notice of
nonpayment are hereby waived. The Debtor agrees that any delay on the part of
the Holders in exercising any rights hereunder will not operate as a waiver of
such rights, and further agrees that any payments received hereunder will be
applied first to Costs, then to interest, and the balance to principal. The
Holders shall not by any act, delay, omission, or otherwise be deemed to waive
any of its rights or remedies, and no waiver of any kind to enforce this Note
shall be valid unless in writing and signed by the Holders. This Note is payable
in any events and is not subject to offset or reduction because of any other
claims of Debtor against the Holders.

<PAGE>

      This Note applies to, inures to the benefit of, and binds the successors
and assigns of the parties hereto. This Note is not negotiable or transferable
to any other Holders without the written consent of the Debtor. This Note is
made under and shall be governed by the internal laws of the Commonwealth of
Massachusetts.

      IN WITNESS WHEREOF, the Debtor has executed this Note as an instrument
under seal as of the date first written above.

DEBTOR


/s/ Charles E. Coppa
-------------------------
GreenMan Technologies Inc.
Charles E. Coppa
Chief Financial Officer