300-03866 7.2V 3700mAh Battery Compatible with Lynx & Lyric

In this review the focus is a simple replacement battery for alarm control panels: the 300-03866 7.2V 3700mAh Ni-Mh pack. The bottom line is that this cell is for homeowners or installers who need a direct, high-capacity swap for Lynx and Lyric alarm keypads and controllers; it delivers a near-identical fit and voltage to the original parts. Our review finds it particularly useful when the original pack is failing or the system reports low battery, since it matches the original part numbers and uses the same three-prong connector.

Key Features

• Compatibility: Matches original part numbers such as 300-03866 and LCP500-4B so it fits Lynx 5100, 5200, 5210 and Lyric devices without modification.
• Battery Capacity: The 3700mAh Ni-Mh capacity provides a higher reserve than older low-capacity packs, helping systems stay powered during short outages.
• Voltage Match: At 7.2V the pack uses the same nominal voltage as factory batteries, ensuring reliable communication with the alarm control board.
• Connector Type: Uses the required 3-prong connector so installers can swap it in quickly without soldering or adapter cables.
• Drop-in Replacement: Marketed as 100% compatible with the original, making it a straightforward maintenance item for security systems showing low battery alerts.

Who It's For

This battery is aimed at homeowners, service technicians, and small alarm companies that maintain Honeywell Lynx and Lyric series control panels and keypads. If the installed system shows a battery fault or you need a preventative replacement for an older pack, the matched part numbers and connector type make this a practical choice.

Users who should look elsewhere include those with alarm models outside the Lynx/Lyric family or anyone who cannot confirm their part number; the listing emphasizes checking the part number before purchase, so do not assume universal fit across different alarm brands.

Pros & Cons

Pros

• Good physical fit and connector compatibility with Lynx 5100/5200/5210 and Lyric units, reducing installation time.
• Higher 3700mAh capacity compared with many older packs, which can extend backup time in short outages.
• Positive reports on build quality and value for money from several users who found it a correct replacement.
• Clear listing of original and compatible part numbers to avoid fitment errors when checked first.

Cons

• Customer feedback on actual battery life is mixed, so long-term runtime may vary by unit and usage.
• Requires verification of the part number and three-prong connector; not a universal battery for all alarm systems.

Specifications

Part Numbers	300-03866, LCP500-4B, LYNXRCHKIT-SHA, OSA214
Compatible Models	Lynx 5100, 5200, 5210, Lynx Touch 5210, Lynx Touch 7000, Lyric Controller/Keypad
Battery Chemistry	Ni-Mh
Voltage	7.2V
Capacity	3700mAh
Connector	3-prong connector

Our Verdict

The 300-03866 7.2V 3700mAh pack is a practical, cost-effective replacement for Lynx and Lyric alarm systems when the correct part number and connector are confirmed. It offers higher capacity than older factory packs and a straightforward drop-in fit, making it a smart choice for routine maintenance or when an existing battery is failing, though actual runtime results can vary.

Frequently Asked Questions

Will this fit my Lynx 5200?
Yes, it is listed compatible with Lynx 5200 provided your unit uses the same original part number and the 3-prong connector.

Is the chemistry the same as the original?
Yes, this replacement uses Ni-Mh chemistry at 7.2V, matching the typical factory specification for these control panels.

Do I need tools to install it?
Installation is usually plug-and-play with the 3-prong connector, but basic access tools for the alarm enclosure may be required.