Exhibit
4.21


THIS
WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”),
OR ANY STATE SECURITIES LAW, AND MAY NOT BE OFFERED FOR SALE, SOLD OR
TRANSFERRED UNLESS A REGISTRATION STATEMENT UNDER SUCH ACT AND APPLICABLE STATE
SECURITIES LAWS SHALL BE EFFECTIVE WITH RESPECT THERETO, OR AN EXEMPTION FROM
REGISTRATION UNDER THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS IS
AVAILABLE IN CONNECTION WITH SUCH OFFER, SALE OR TRANSFER.




CLASS
A WARRANT




TO
PURCHASE COMMON STOCK




OF





ENER1,
INC.




Issue
Date:  August 3, 2010




This Class A Warrant (this “Class A
Warrant”) entitles BZINFIN, S.A., a British Virgin Islands company, or
any subsequent holder hereof (the “Holder”),
to purchase from ENER1, INC., a Florida corporation (the “Company”),
up to 863,806 fully paid and nonassessable shares (the “Warrant
Shares”) of the Company’s common stock, par value $0.01 per share (the
“Common
Stock”), at a price per share equal to $3.40 (the “Exercise
Price”), on the terms and subject to the conditions set forth herein.
This Class A Warrant is issued pursuant to the terms of a Conversion Agreement,
dated as of August 3, 2010 (the “Conversion
Agreement”), and the date on which this Class A Warrant is referred to
herein as the “Issue
Date.” Capitalized terms used herein and not otherwise defined have the
meanings set forth in the Conversion Agreement.




1.           Exercise.





(a)          Right to Exercise; Exercise
Price.  The Holder shall have the right to exercise this
Class A Warrant at any time and from the Issue Date and ending on the fifth
(5th)
anniversary of the Issue Date (the “Expiration
Date”); provided, however, that if the
Expiration Date occurs on a date that is not a Business Day, the immediately
following Business Day shall be deemed to be the Expiration Date. The Holder may
pay the Exercise Price in either of the following forms or, at the election of
the Holder, a combination thereof:





(i)           through
a cash exercise (a “Cash
Exercise”) by delivering immediately available funds, or







(ii)          through
a cashless exercise (a “Cashless
Exercise”) by noting on the Exercise Notice that the Holder wishes to
effect a Cashless Exercise, in which case the Company shall issue to the Holder
a number of Warrant Shares determined as follows:





X = Y x (A-B)/A





where:
            X =
      the number of Warrant Shares to be issued to the
  Holder;





Y =
      the number of Warrant Shares with respect to which this Class A Warrant is
      being exercised;





A =
      the Market Price (as defined below) as of the Exercise Date;
      and





B =
      the Exercise Price.





For
purposes of Rule 144, it is intended and acknowledged that the Warrant Shares
issued in a Cashless Exercise transaction shall be deemed to have been acquired
by the Holder, and the holding period for the Warrant Shares required by Rule
144 shall be deemed to have been commenced, on the Issue Date. “Market
Price” means, as of any date, the arithmetical average of daily VWAP
during the ten (10) trading days immediately preceding (but not including) such
date, and “VWAP”
means the volume weighted average price of the Common Stock on the Principal
Market as reported by Bloomberg Financial Markets or by a comparable reporting
service





(b)          Exercise
Notice.  In order to exercise this Class A Warrant, the Holder
shall send to the Company by facsimile transmission, at any time prior to 6:00
p.m., eastern time, on the Business Day on which the Holder wishes to effect
such exercise (the “Exercise
Date”), (i) a notice of exercise in substantially the form attached
hereto as Exhibit A
(the “Exercise
Notice”), (ii) a copy of the original Class A Warrant, and (iii) in the
case of a Cash Exercise, the Exercise Price by wire transfer of immediately
available funds.  The Exercise Notice
shall state the name or names in which the shares of Common Stock that are
issuable on such exercise shall be issued.In the case of a
dispute between the Company and the Holder as to the calculation of the Exercise
Price or the number of Warrant Shares issuable hereunder (including, without
limitation, the calculation of any adjustment to the Exercise Price or the
Warrant Shares pursuant to Section 5
below), the Company shall issue to the Holder the number of Warrant Shares that
are not disputed within the time periods specified in Section 2
below and shall submit the disputed calculations to a certified public
accounting firm of national reputation (other than the Company’s regularly
retained accountants) within two (2) Business Days following the date on which
the Holder’s Exercise Notice is delivered to the Company.  The Company
shall cause such accountant to calculate the Exercise Price and/or the number of
Warrant Shares issuable hereunder and to notify the Company and the Holder of
the results in writing no later than three (3) Business Days following the day
on which such accountant received the disputed calculations (the “Dispute
Procedure”). Such accountant’s calculation shall be deemed conclusive
absent manifest error.  The fees of any such accountant shall be borne
by the party whose calculations were most at variance with those of such
accountant.


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(c)          Holder of
Record.  The Holder shall, for all purposes, be deemed to have
become the holder of record of the Warrant Shares specified in an Exercise
Notice on the Exercise Date specified therein, irrespective of the date of
delivery of such Warrant Shares subject, in the case of a Cash Exercise, to
payment of the Exercise Price.  Except as specifically provided
herein, nothing in this Class A Warrant shall be construed as conferring upon
the Holder hereof any rights as a shareholder of the Company prior to the
Exercise Date.





(d)          Cancellation of
Warrant.  This Class A Warrant shall be canceled upon its
exercise in full and, if this Class A Warrant is exercised in part, the Company
shall, at the time that it delivers Warrant Shares to the Holder pursuant to
such exercise as provided herein, issue a new warrant, and deliver to the Holder
a certificate representing such new warrant, with terms identical in all
respects to this Class A Warrant (except that such new warrant shall be
exercisable into the number of shares of Common Stock with respect to which this
Class A Warrant shall remain unexercised); provided, however, that the
Holder shall be entitled to exercise all or any portion of such new warrant at
any time following the time at which this Class A Warrant is exercised,
regardless of whether the Company has actually issued such new warrant or
delivered to the Holder a certificate therefor.





2.           Delivery of Warrant Shares
Upon Exercise.  Upon receipt of a fax copy of an Exercise
Notice pursuant to Section 1
above, the Company shall, no later than the close of business on the third (3rd)
Business Day following the later to occur of (i) the Exercise Date specified in
such Exercise Notice and (ii) such later date on which the Company has received
payment of the Exercise Price (such later date being referred to as a “Delivery
Date”), issue and deliver or caused to be delivered to the Holder the
number of Warrant Shares determined as provided herein.  The Company
shall effect delivery of Warrant Shares to the Holder, as long as the Company’s
designated transfer agent (the “Transfer
Agent”) participates in the Depository Trust Company (“DTC”) Fast
Automated Securities Transfer program (“FAST”) and
no restrictive legend is required pursuant to the terms of this Class A Warrant
or the Conversion Agreement, by crediting the account of the Holder or its
nominee at DTC (as specified in the applicable Exercise Notice) with the number
of Warrant Shares required to be delivered, no later than the close of business
on such Delivery Date.  In the event that the Transfer Agent is not a
participant in FAST or if the Holder so specifies in a Exercise Notice or
otherwise in writing on or before the Exercise Date, the Company shall effect
delivery of Warrant Shares by delivering to the Holder or its nominee physical
certificates representing such Warrant Shares, no later than the close of
business on such Delivery Date.  Warrant Shares delivered to the
Holder shall not contain any restrictive legend unless such legend is required
pursuant to the terms of the Conversion Agreement.





3.           [Intentionally
omitted]





4.           Anti-Dilution Adjustments;
Distributions; Other Events. The Exercise Price and the number of Warrant
Shares issuable hereunder shall be subject to adjustment from time to time as
provided in this Section
4.  In the event that any adjustment of the Exercise Price
required herein results in a fraction of a cent, the Exercise Price shall be
rounded up or down to the nearest one hundredth of a cent.


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(a)          Subdivision or Combination
of Common Stock.  If the Company, at any time after the Issue
Date, subdivides (by any stock split, stock dividend, recapitalization,
reorganization, reclassification or otherwise) the outstanding shares of Common
Stock into a greater number of shares, then effective upon the close of business
on the record date for effecting such subdivision, the Exercise Price in effect
immediately prior to such subdivision will be proportionately reduced and the
number of Warrant Shares issuable hereunder proportionately
increased.  If the Company, at any time after the Issue Date, combines
(by reverse stock split, recapitalization, reorganization, reclassification or
otherwise) the outstanding shares of Common Stock into a smaller number of
shares, then, effective upon the close of business on the record date for
effecting such combination, the Exercise Price in effect immediately prior to
such combination will be proportionally increased and the number of Warrant
Shares issuable hereunder proportionately reduced.





(b)          Distributions.  If,
at any time after the Issue Date, the Company declares or makes any distribution
of cash or any other assets (or rights to acquire such assets) to holders of
Common Stock, as a partial liquidating dividend or otherwise, including without
limitation any dividend or distribution to the Company’s shareholders in shares
(or rights to acquire shares) of capital stock of a subsidiary) (a “Distribution”),
the Company shall deliver written notice of such Distribution (a “Distribution
Notice”) to the Holder at least thirty (30) days prior to the earlier to
occur of (i) the record date for determining shareholders entitled to such
Distribution (the “Record
Date”) and (ii) the date on which such Distribution is made (the “Distribution
Date”) (the earlier of such dates being referred to as the “Determination
Date”).  In the Distribution Notice to the Holder, the Company
shall indicate whether the Company has elected (A) to deliver to the Holder,
upon any exercise of this Class A Warrant after the Determination Date, the same
amount and type of assets being distributed in such Distribution as though the
Holder were, on the Determination Date, a holder of a number of shares of Common
Stock into which this Class A Warrant is exercisable as of such Determination
Date (such number of shares to be determined at the Exercise Price then in
effect and without giving effect to any limitations on such exercise) or (B)
upon any exercise of this Class A Warrant on or after the Determination Date, to
reduce the Exercise Price applicable to such exercise by reducing the Exercise
Price in effect on the Business Day immediately preceding the Record Date by an
amount equal to the fair market value of the assets to be distributed divided by
the number of shares of Common Stock as to which such Distribution is to be
made, such fair market value to be reasonably determined in good faith by the
Company’s Board of Directors.  If the Company does not notify the
Holder of its election pursuant to the preceding sentence on or prior to the
Determination Date, the Company shall be deemed to have elected clause (A) of
the preceding sentence.




(c)          Adjustments; Additional
Shares, Securities or Assets.  In the event that at any time,
as a result of an adjustment made pursuant to this Section 4,
the Holder of this Class A Warrant shall, upon exercise of this Class A Warrant,
become entitled to receive securities or assets (other than Common Stock) then,
wherever appropriate, all references herein to shares of Common Stock shall be
deemed to refer to and include such shares and/or other securities or assets;
and thereafter the number of such shares and/or other securities or assets shall
be subject to adjustment from time to time in a manner and upon terms as nearly
equivalent as practicable to the provisions of this Section
4.


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5.           Fractional
Interests.





No fractional shares or scrip
representing fractional shares shall be issuable upon the exercise of this Class
A Warrant, but instead shall be rounded up or down to the nearest whole share
amount.





6.           Transfer of this
Warrant.





The Holder may sell, transfer, assign,
pledge or otherwise dispose of this Class A Warrant, in whole or in part, as
long as such sale or other disposition is made pursuant to an effective
registration statement or an exemption from the registration requirements of the
Securities Act.  Upon such transfer or other disposition (other than a
pledge), the Holder shall deliver this Class A Warrant to the Company together
with a written notice to the Company, substantially in the form of the Transfer
Notice attached hereto as Exhibit B
(the “Transfer
Notice”), indicating the person or persons to whom this Class A Warrant
shall be transferred and, if less than all of this Class A Warrant is
transferred, the number of Warrant Shares to be covered by the part of this
Class A Warrant to be transferred to each such person. Within three (3) Business
Days of receiving a Transfer Notice and the original of this Class A Warrant,
the Company shall deliver to the each transferee designated by the Holder a
Class A Warrant or Warrants of like tenor and terms for the appropriate number
of Warrant Shares and, if less than all this Class A Warrant is transferred,
shall deliver to the Holder a Class A Warrant for the remaining number of
Warrant Shares.





7.           Benefits of this
Warrant.





This Class A Warrant shall be for the
sole and exclusive benefit of the Holder of this Class A Warrant and nothing in
this Class A Warrant shall be construed to confer upon any person other than the
Holder of this Class A Warrant any legal or equitable right, remedy or claim
hereunder.





8.           Loss, theft, destruction or
mutilation  of Warrant.





Upon receipt by the Company of evidence
of the loss, theft, destruction or mutilation of this Class A Warrant, and (in
the case of loss, theft or destruction) of indemnity reasonably satisfactory to
the Company, and upon surrender of this Class A Warrant, if mutilated, the
Company shall execute and deliver a new Class A Warrant of like tenor and
date.





9.           Notice or
Demands.




Any notice, demand or request required
or permitted to be given by the Company or the Holder pursuant to the terms of
this Class A Warrant shall be in writing and shall be deemed delivered (i) when
delivered personally or by verifiable facsimile transmission, unless such
delivery is made on a day that is not a Business Day, in which case such
delivery will be deemed to be made on the next succeeding Business Day, (ii) on
the next Business Day after timely delivery to an overnight courier and (iii) on
the Business Day actually received if deposited in the U.S. mail (certified or
registered mail, return receipt requested, postage prepaid), addressed as
follows:


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If to the Company:





Ener1, Inc.


1540
Broadway, Suite 25C


New York,
NY 10036


Attn:      Chief
Financial Officer


Tel:        212-920-3500


Fax:       212-920-3510





and if to
the Holder, to such address for such party as shall appear on the records of the
Company. Any party may change its address for notice by sending notice in
accordance with this Section
9.





10.         Applicable
Law.





This Class A Warrant is issued under
and shall for all purposes be governed by and construed in accordance with the
laws of the State of New York applicable to contracts made and to be performed
entirely within the State of New York. Each party hereby irrevocably submits to
the exclusive jurisdiction of the state and federal courts sitting in the City
and County of New York for the adjudication of any dispute hereunder or in
connection herewith or with any transaction contemplated hereby, and hereby
irrevocably waives, and agrees not to assert in any suit, action or proceeding,
any claim that it is not personally subject to the jurisdiction of any such
court, that such suit, action or proceeding is brought in an inconvenient forum
or that the venue of such suit, action or proceeding is
improper.  Each party hereby irrevocably waives personal service of
process and consents to process being served in any such suit, action or
proceeding by mailing a copy thereof to such party at the address in effect for
notices to it under this Class A Warrant and agrees that such service shall
constitute good and sufficient service of process and notice
thereof.  Nothing contained herein shall be deemed to limit in any way
any right to serve process in any manner permitted by law.





11.         Amendments.





No amendment, modification or other
change to, or waiver of any provision of, this Class A Warrant may be made
unless such amendment, modification, change or waiver is set forth in writing
and is signed by the Company and the Holder.





12.         Entire Agreement.




This Class A Warrant constitutes the entire agreement
among the parties hereto with respect to the subject matter
hereof.  There are no restrictions, promises, warranties or
undertakings, other than those set forth or referred to herein and
therein.  This Class A Warrant supersedes all prior agreements and
understandings among the parties hereto with respect to the subject matter
hereof.


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13.         Headings.




The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning
hereof.




[Signature
Page to Follow]


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IN
WITNESS WHEREOF, the Company has duly executed and delivered this Class A
Warrant as of the Issue Date.





ENER1,
      INC.By:Name:Title:


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EXHIBIT A to
WARRANT




EXERCISE
NOTICE




The undersigned Holder hereby
irrevocably exercises the right to purchase  __________
shares of Common Stock (“Warrant
Shares”) of Ener1, Inc. (the “Company”) evidenced
by the attached Class A Warrant (the “Class A
Warrant”).  Capitalized terms used herein and not otherwise
defined shall have the respective meanings set forth in the Class A
Warrant.





1.           Form
of Exercise Price.  The Holder intends that payment of the Exercise
Price shall be made as:





______ a Cash Exercise with
respect to _________________ Warrant Shares; and/or





______ a Cashless Exercise
with respect to _________________ Warrant Shares, as permitted by Section 1(a)
of the attached Class A Warrant.





2.           Payment
of Exercise Price.  In the event that the Holder has elected a Cash
Exercise with respect to some or all of the Warrant Shares to be issued pursuant
hereto, the Holder shall pay the sum of $________________ to the Company in
accordance with the terms of the Class A Warrant.




Date:Name
      of Registered HolderBy:Name:Title:





EXHIBIT B to
WARRANT




TRANSFER
NOTICE




FOR VALUE
RECEIVED, the undersigned Holder of the attached Class A Warrant hereby sells,
assigns and transfers unto the person or persons named below the right to
purchase _________shares of the Common Stock of _____________________ evidenced
by the attached Class A Warrant.





Date:Name
      of Registered HolderBy:Name:Title:Transferee
      Name and Address: