Ampt V750 Series User manual

Ampt String Optimizer
V750 Series
Installation Manual
57070010-1 H
hdpv.org

Copyright 2017-2020 Ampt, LLC.
All rights reserved.
2
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H

Copyright 2017-2020 Ampt, LLC.
All rights reserved.
3
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Copyright 2017-2020 Ampt LLC. All rights reserved. No part of this document may be
reproduced, retransmitted, or copied in any form without the expressed and written
permission of Ampt.
This document contains information needed to install and commission an Ampt optimizer
(including Smart String Technology®optimizers, String Stretch®optimizers, Ampt Mode®
optimizers, String View®optimizers, V-match®optimizers, and Direct-to-Battery®optimizers)
within a photovoltaic (PV) installation. The result? Energy realized®.
All Ampt trademarks are the property of Ampt, LLC. All trademarks are recognized even if
they are not marked separately. Visit www.ampt.com/trademarks for a list of Ampt
trademarks. Any unauthorized use of Ampt trademarks is prohibited. All other trademarks
are the property of their respective owners.
U.S. and international patents apply to this product. For details visit:
www.ampt.com/patents.
Read This First
To help avoid problems during the system installation, familiarize yourself in advance with
the installation process by reading this entire document before starting the installation.
Risk of electric shock, do not remove covers. No user serviceable parts inside.
Refer servicing to qualified service personnel. When the photovoltaic array is
exposed to light, it supplies a dc voltage to this equipment.
Le risqué de décharge électirque n’enlènvent pas la couverture. Aucunes
pieces utiles d’utilisateur à l’intérieur. Référez-vous l’entretien au personnel de
service qualifiè. Quand la range photovoltaïque est exposée à la lumière. Il
fournit une tension CC à cet équipement.
Hot surfaces –to reduce the risk of burns –do not touch.
Les surfaces chaudes - pour réduire le risque de brûlures - ne se touchent pas.

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4
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Important Safety Instructions
This manual contains important instructions for Ampt optimizers that shall be followed
during installation and maintenance. The optimizer has been designed and tested according
to international safety requirements, but requires certain precautions are observed when
installing and/or operating the optimizer. To reduce the risk of personal injury and to
ensure the safe installation and operation of the optimizer, please be sure you carefully
read and follow all instructions and safety messages in this manual.
SAVE THESE INSTRUCTIONS
Safety Message Types
The following messaging is used to identify a hazard to equipment or personnel:
DANGER
Indicates a hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING
Indicates a hazardous situation which, if not avoided, could result in death or
serious injury.
CAUTION
Indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.
NOTICE
Indicates information considered important but not hazard, or personal injury,
related - for example, property damage.

Copyright 2017-2020 Ampt, LLC.
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5
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
General Safety
Installation and maintenance should be performed only by qualified persons. Installers and
maintenance personnel assume the risk of all injury that might occur during installation or
maintenance including, without limitation, the risk of electric shock. Follow your safety
procedures and protocols.
All electrical installations must be done in accordance with the local and National Electrical
Code ANSI/NFPA 70; Canadian Electrical Code, Part I; or the applicable standards, codes,
and regulations for your region.
Failure to follow this manual will void warranty.
The Ampt product contains no user-serviceable parts. All repairs and maintenance should
be handled in accordance with the instructions and terms contained in the product
warranty.
Before installing or using the Ampt optimizer, read all of the instructions and safety
messages on the optimizer and in this manual. Follow the safety precautions for this
product as well as the other components in the PV system.
PV modules produce electrical energy when exposed to light and thus can create an
electrical shock hazard. Wiring of the PV modules should only be performed by qualified
personnel.
NOTICE
Opening the optimizers, performing any other service to the optimizers, or
using the optimizers in a way that is not specified by the manufacturer voids
warranty.

Copyright 2017-2020 Ampt, LLC.
All rights reserved.
6
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Disclaimer of Liability
Ampt makes no representations, expressed or implied, that with respect to this
documentation or any of the equipment and/or software it may describe, including (with no
limitation) any implied warranties of utility, merchantability, or fitness for any particular
purpose. All such warranties are expressly disclaimed. Ampt shall not be liable for any
indirect, incidental, or consequential damages under any circumstances. (The exclusion of
implied warranties may not apply in all cases under some statutes, and thus the above
exclusion may not apply.)
The following information is subject to change without notice, even though every attempt
has been made to make this document complete, accurate and up-to-date. Readers are
cautioned, however, that Ampt reserves the right to make changes without notice and shall
not be responsible for any damages, including indirect, incidental or consequential
damages, caused by reliance on the material presented, including, but not limited to,
omissions, typographical errors, arithmetical errors or listing errors in the content material.
WARNING
Any use of the Ampt String Optimizer that is not expressly authorized in this
manual or associated documentation is expressly prohibited by Ampt. Ampt
disclaims any responsibility or liability for such prohibited use.

Copyright 2017-2020 Ampt, LLC.
All rights reserved.
7
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Table of Contents
Read This First .........................................................................................................................3
Important Safety Instructions.......................................................................................................................4
Safety Message Types...................................................................................................................................4
General Safety...............................................................................................................................................5
Disclaimer of Liability....................................................................................................................................6
Chapter 1: Product Overview .......................................................................................... 9
Dimensional Drawings ...........................................................................................................10
Physical Overview..................................................................................................................11
Bar Code Label.......................................................................................................................11
Specifications.........................................................................................................................12
13.5A Output Models..................................................................................................................................12
12.8A Output Models..................................................................................................................................13
12A Output Models.....................................................................................................................................14
Chapter 2: Planning Installation..................................................................................... 15
Overview...............................................................................................................................15
Input Criteria .........................................................................................................................15
Acceptable Input Configurations ................................................................................................................15
Unacceptable Input Configurations ............................................................................................................16
Acceptable Input Configurations Between Parallel Optimizers..................................................................16
PV System Configurations ......................................................................................................17
Ungrounded PV Systems.............................................................................................................................17
Resistively Grounded PV Systems (positive or negative)............................................................................17
Fuse Sizes ....................................................................................................................................................17
DC-coupled Storage ....................................................................................................................................18
Inter-row Shading Wiring Example .............................................................................................................18
Output Connector Polarity..........................................................................................................................19
Chapter 3: Installing the Ampt String Optimizer............................................................. 21
Getting Started ......................................................................................................................21
Parts and Tools Needed..............................................................................................................................21
Mounting and Grounding the String Optimizer .......................................................................22
Steps............................................................................................................................................................22
Making Electrical Connections................................................................................................23
Connecting the Inputs.................................................................................................................................24
Connecting the Output ...............................................................................................................................27
Uninstalling an Optimizer.......................................................................................................28
Parts and Tools Needed ..............................................................................................................................28
Steps............................................................................................................................................................29

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8
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Appendix........................................................................................................................31
Compliance............................................................................................................................31
Model Numbering System ......................................................................................................................... 31
Markings..................................................................................................................................................... 32
FCC Compliance.......................................................................................................................................... 33
Avis IC......................................................................................................................................................... 34
Reference: Electrical Connection Order...................................................................................35
Mechanical Installation Best Practices....................................................................................................... 36
Electrical Commissioning Best Practices .................................................................................................... 36
Ampt Support Contacts.............................................................................................................................. 36

Copyright 2017-2020 Ampt, LLC.
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9
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Chapter 1:
Product Overview
Ampt String Optimizers are DC/DC converters with multiple features that lower the cost and
improve the performance of new and existing PV systems.
•Dual MPPT per optimizer - Ampt String Optimizers put maximum power point tracking on each of
its two input strings of PV modules. This mitigates or eliminates mismatch losses to deliver more
energy under changing environmental and system conditions over the lifetime of the power plant.
•High Fixed-Voltage Bus (HFVB) –Ampt’s advanced DC power management technology allows for
HFVB system designs which turn the variable voltage of the PV array into a fixed and predictable
DC bus voltage to achieve system-level economic advantages. HFVB designs lower the cost per
watt of inverters, battery converters, and trackers while reducing ampacity requirements and the
number of home runs. Ampt’s HFVB technology can also restore lost revenue from
underperforming systems suffering from “voltage sag.”
•Ampt Mode–Inverters with Ampt Modeoperate in a fixed or narrow input voltage range that
is closer to the maximum system voltage. This allows the inverter to deliver a higher AC output
voltage at the same current which raises the rated output power of the inverter to lower the
inverter's cost per watt.
•Direct-to-Converter –For DC-coupled energy storage systems, Ampt String Optimizers include
Direct-to-Converter technology which allows the DC bus to operate at a higher fixed voltage so the
converter only needs to buck when charging and boost when discharging. This simplified
operation reduces battery converter costs by up to 50% with less circuitry and a higher power
density.
•High DC/AC –Ampt’s unique combination of output current limits and a higher DC bus voltage
allows PV system designers to achieve optimal DC/AC ratios (up to 3:1). With Ampt, system
owners can expand the DC power on existing systems without replacing inverters, combiners, or
cables; optimize inverter utilization on new systems to lower the cost per watt; and lower capex
while increasing storage durations on systems with DC-coupled energy storage.
•V-match–Ampt’s patented V-matchtechnology allows the output of our optimizers to match
the DC bus voltage set by the inverter or battery while delivering full available power from the PV
modules. This uniquely allows PV arrays with Ampt to automatically adapt to legacy or future
power equipment to repower existing systems, upgrade inverters, mix new and legacy PV
modules, deploy optimized DC-coupled storage systems, and other applications.
•Wireless Communication –Ampt String Optimizers incorporate optional wireless communication
to provide string-level data that is highly accurate, synchronous, and scalable to improve O&M, as
well as enhanced controls for storage applications.
For more information on Ampt’s product features and applications, visit www.ampt.com.

Copyright 2017-2020 Ampt, LLC.
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10
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Dimensional Drawings
The dimensions for the String Optimizer shown below are in millimeters and inches.
Figure 1: Dimensional drawings
100
3.94”
37.5
1.48”
208
8.19”
220
8.66”
225
8.86”
~272
10.71”
75
2.95”
75
2.95”

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11
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Physical Overview
Figure 2: Physical overview of the string optimizer
Bar Code Label
The image below shows the bar code label with model and serial numbers.
Figure 3: Bar code tag with the model and serial numbers
Mounting holes
(6.5 mm) x 6
Input A connectors
Input B connectors
Output connectors
Grounding stud
(10-32) x 2
Bar code label
+-
+-
+-

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12
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Specifications
13.5A Output Models
V650-13.5
V675-13.5
V700-13.5
V725-13.5
V750-13.5
Model Number
31570017-0650
31570017-0675
31570017-0700
31570017-0725
31570017-0750
Electrical
Input
Maximum voltage per input1
1
V
750
750
750
750
750
Maximum current per input2
2
A
12.8
12.8
12.8
12.8
12.8
MPP tracking voltage range
V
190 –700
190 –700
190 –700
190 –700
190 –700
Startup voltage per input
V
400
400
400
400
400
Number of inputs
2
2
2
2
2
Output
Output voltage range
V
0 –650
0 –675
0 –700
0 –725
0 –750
Maximum output current
A
13.5
13.5
13.5
13.5
13.5
Max continuous output
power
kWdc
7.4
7.7
8.0
8.3
8.7
Efficiency (max, CEC, Euro)
%
99.5, 99.3, 99.2
Mechanical
Input & output connector type
Amphenol H4
Dimensions
10.71" x 8.66" x 3.94"
(272 mm x 220 mm x 100 mm)
Weight
9.0 lbs. (4.1 kg)
Ambient temperature operating
range
-40 °F to +122 °F
(-40 °C to +50 °C)
Cooling
Convection
Environmental
Environmental category
Outdoor
Pollution degree
2
Maximum operating altitude3
9843 ft (3000 m)
Overvoltage category
OVII
Ingress protection
IP66 / 4X
General
Maximum system voltage
750 V
Compliance
ETL to UL 1741;
IEC 61000-6-1, 61000-6-3, 62109; CE;
Giteki 2-1-19; FCC Part 15, class A
1. Voc at coldest design temp. Follow Ampt’s design guidelines to determine the number of modules per input and max. system voltage.
2. Module Imp at standard test condition (STC) - irradiation level of 1000 W/m2at 25°C.
3. Optimizer derates above this altitude.

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13
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
12.8A Output Models
V650-12.8
V675-12.8
V700-12.8
V725-12.8
V750-12.8
Model Number
31570015-0650
31570015-0675
31570015-0700
31570015-0725
31570015-0750
Electrical
Input
Maximum voltage per input1
1
V
750
750
750
750
750
Maximum current per input2
2
A
12.8
12.8
12.8
12.8
12.8
MPP tracking voltage range
V
190 –700
190 –700
190 –700
190 –700
190 –700
Startup voltage per input
V
400
400
400
400
400
Number of inputs
2
2
2
2
2
Output
Output voltage range
V
0 –650
0 –675
0 –700
0 –725
0 –750
Maximum output current
A
12.8
12.8
12.8
12.8
12.8
Max continuous output
power
kWdc
7.0
7.3
7.7
8.0
8.3
Efficiency (max, CEC, Euro)
%
99.5, 99.3, 99.2
Mechanical
Input & output connector type
Amphenol H4
Dimensions
10.71" x 8.66" x 3.94"
(272 mm x 220 mm x 100 mm)
Weight
9.0 lbs. (4.1 kg)
Ambient temperature operating
range
-40 °F to +122 °F
(-40 °C to +50 °C)
Cooling
Convection
Environmental
Environmental category
Outdoor
Pollution degree
2
Maximum operating altitude3
9843 ft (3000 m)
Overvoltage category
OVII
Ingress protection
IP66 / 4X
General
Maximum system voltage
750 V
Compliance
ETL to UL 1741;
IEC 61000-6-1, 61000-6-3, 62109; CE;
Giteki 2-1-19; FCC Part 15, class A
1. Voc at coldest design temp. Follow Ampt’s design guidelines to determine the number of modules per input and max. system voltage.
2. Module Imp at standard test condition (STC) - irradiation level of 1000 W/m2at 25°C.
3. Optimizer derates above this altitude.

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14
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
12A Output Models
V650-12
V675-12
V700-12
V725-12
V750-12
Model Number
31570014-0650
31570014-0675
31570014-0700
31570014-0725
31570014-0750
Electrical
Input
Maximum voltage per input1
1
V
750
750
750
750
750
Maximum current per input2
2
A
12.3
12.3
12.3
12.3
12.3
MPP tracking voltage range
V
190 –700
190 –700
190 –700
190 –700
190 –700
Startup voltage per input
V
400
400
400
400
400
Number of inputs
2
2
2
2
2
Output
Output voltage range
V
0 –650
0 –675
0 –700
0 –725
0 –750
Maximum output current
A
12
12
12
12
12
Max continuous output
power
kWdc
6.7
6.9
7.2
7.5
7.8
Efficiency (max, CEC, Euro)
%
99.5, 99.3, 99.2
Mechanical
Input & output connector type
Amphenol H4
Dimensions
10.71" x 8.66" x 3.94"
(272 mm x 220 mm x 100 mm)
Weight
9.0 lbs. (4.1 kg)
Ambient temperature operating
range
-40 °F to +122 °F
(-40 °C to +50 °C)
Cooling
Convection
Environmental
Environmental category
Outdoor
Pollution degree
2
Maximum operating altitude3
9843 ft (3000 m)
Overvoltage category
OVII
Ingress protection
IP66 / 4X
General
Maximum system voltage
750 V
Compliance
ETL to UL 1741;
IEC 61000-6-1, 61000-6-3, 62109; CE;
Giteki 2-1-19; FCC Part 15, class A
1. Voc at coldest design temp. Follow Ampt’s design guidelines to determine the number of modules per input and max. system voltage.
2. Module Imp at standard test condition (STC) - irradiation level of 1000 W/m2at 25°C.
3. Optimizer derates above this altitude.

Copyright 2017-2020 Ampt, LLC.
All rights reserved.
15
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Chapter 2:
Planning Installation
Overview
This chapter defines the acceptable criteria for input connections, describes the appropriate
electrical connections based on the grounding configuration of your PV system, and explains
the mating connector polarities for the inputs and output of the String Optimizer.
Input Criteria
This section defines the acceptable criteria for the two input connections of the Ampt String
Optimizer.
NOTICE
The inputs of the optimizer are not intended for connection to a battery or any
other type of DC source except PV modules.
The following information applies to 60- or 72-cell c-Si/p-Si modules. If you are using
another type of module (e.g. thin film), please contact Ampt for configuration rules.
In the figures that follow, the number of modules connected in series is representative only.
Follow Ampt’s design guidelines to determine the number of modules for each input.
Acceptable Input Configurations
It is common for inputs A and B to have the same number of modules (i.e. A = B). However,
if the number of modules between inputs is different, then input A can have one more
module than input B (i.e. A = B + 1).
Figure 4: The number of modules on each input can be the same as illustrated by String Optimizer 1, or input A can have
one more module than input B as shown by String Optimizer 2.
A = B
A = B + 1

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16
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Unacceptable Input Configurations
The figure below illustrates input configurations that do not meet the criteria described in
the previous section.
Figure 5: Unacceptable input configurations.
Acceptable Input Configurations Between Parallel Optimizers
The number of modules on each input between parallel optimizers can vary within an array
so long as they meet the criteria described in the Acceptable Input Configurations section
and are within the minimum and maximum limits determined by Ampt’s design guidelines.
An example is shown below.
Figure 6: The number of modules per input between parallel optimizers can vary so long as they follow the acceptable input
configuration criteria and Ampt’s design guidelines.
Input A has fewer modules
than input B
The number of modules connected to
Input A is greater than the number of
modules on Input B + 1
16 modules per input
15 modules per input
Optimizer output
strings to combiner

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17
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
PV System Configurations
String Optimizers can be installed in ungrounded and resistively grounded PV systems.
Ungrounded PV Systems
Figure 7: Electrical connections for an ungrounded PV system
Resistively Grounded PV Systems (positive or negative)
Figure 8: Electrical connections for a grounded PV system
Fuse Sizes
CAUTION
Over-current protection devices and conductors shall be sized in accordance
with the National Electrical Code (ANSI/NFPA 70); Canadian Electrical Code,
Part I; or the applicable standards, codes, and regulations for your region.
The output current limit of the Ampt String Optimizer eliminates the need for the 1.25
multiplication factor for over-sun conditions when calculating ampacity. The 1.25 multiplier
for continuous use is still required.
Optimizer Max Output Current (A)
Minimum Fuse Size (A)
12
15
12.8
16
13.5
16.875

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18
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
DC-coupled Storage
When used in DC-coupled storage applications, the optimizer does not function as a
blocking diode.
Inter-row Shading Wiring Example
When inter-row shading is expected, the best practice is to wire the modules on the two
inputs of the Ampt String Optimizer to be on the same row as shown below.
Figure 9: Wiring example when inter-row shading is expected
Ampt String Optimizer
not to scale
to combiner
to combiner

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19
Ampt String Optimizer V750 Series
Installation Manual: 57070010-1 H
Output Connector Polarity
The optimizers have Amphenol H4 bulkhead connectors. Use the polarity markings on the
faceplate instead of the polarity markings on the connectors.
Figure 10: Output connector polarity
Optimizer
Front View
Optimizer
Top View
Output Mating
Connectors
Top View
Use the polarity markings
on the faceplate to avoid
damaging the device.
Ignore polarity markings on the
bulkhead connectors on the output
!