THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED
(THE “ACT”), OR APPLICABLE STATE SECURITIES LAWS. THIS NOTE HAS BEEN ACQUIRED
FOR INVESTMENT AND NOT WITH A VIEW TO ITS DISTRIBUTION OR RESALE, AND MAY NOT BE
SOLD, PLEDGED, OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE ACT AND APPLICABLE STATE SECURITIES LAWS, OR AN OPINION OF
COUNSEL SATISFACTORY TO THE DEBTOR TO THE EFFECT THAT SUCH REGISTRATION IS NOT
REQUIRED.

AMENDED AND RESTATED UNSECURED PROMISSORY NOTE

$273,500.00
April 30, 2014

This Amended and Restated Unsecured Promissory Note (this “Note”) amends and
restates in full the Unsecured Promissory Note dated as of September 17, 2010,
(the “Original Note”) executed by Greenman Technologies, Inc. (now known as
American Power Group, Inc.), 7 Kimball Lane, Lynnfield, MA 01940, a Delaware
corporation and payable to the order of Dr. Allen Kahn (the “Original Holder”)
for the principal sum of $273,500. The Original Note was amended by the letter
agreement dated as of March 11, 2011, the letter agreement dated as of October
27, 2011 and Amendment No. 1 dated as of April 27, 2012 and was assigned by the
Original Holder to the Allen Kahn Revocable Trust AKA Allen Kahn, M.D. Revocable
Trust (the “Holder”) on April 27, 2012. American Power Group, Inc. (formerly
known as Greenman Technologies, Inc.) is the maker of this Note (the “Debtor”).

FOR VALUE RECEIVED, the undersigned Debtor hereby promises to pay to the Holder
the principal sum of Two Hundred and Seventy Three Thousand and Five Hundred
Dollars ($273,500.00) or such lesser principal amount then outstanding, together
with all accrued and unpaid interest thereon, as follows: (a) payment of $15,000
on each of May 15, 2014, June 15, 2014, July 15, 2014, August 15 2014 and
September 15, 2014, which payments shall be applied exclusively to reduce the
outstanding principal on the Note; and (b) payment of the remaining principal
amount plus any accrued and unpaid interest thereon on September 30, 2014.
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 eight percent (8%) per annum. Interest only shall be payable
commencing on the date of this Note in lawful money of the United States of
America, in immediately available funds. The first interest payment shall be due
and payable on July 31, 2014, for the three-month period ending on such date,
and the remaining interest due under this Note shall be paid on the September
30, 2014 maturity date of this Note, or earlier in an Event of Default. 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 an Event of
Default, the entire outstanding amount

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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, and without discount, premium or penalty. Any permitted
payment of principal by the Debtor will be accompanied by payment of all accrued
and unpaid interest on the principal sum being repaid.
The Debtor agrees to pay all costs, charges and expenses incurred by the Holder
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 Holder'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 Holder 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, unless otherwise set forth herein.
The Holder 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 Holder. This Note is
payable in any event and is not subject to offset or reduction because of any
other claims of Debtor against the Holder.

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 holder 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:

AMERICAN POWER GROUP, INC.,
formerly known as Greenman Technologies, Inc.

By: /s/Charles E. Coppa            
Charles E. Coppa
Chief Financial Officer