Mojave Wi-Fi
Hilltop Relay
Update

The previous battery installation had become unreliable, with poor charging performance and a difficult-to-service wiring arrangement. The replacement batteries have restored normal solar charging, and the electronics have been reorganized onto a plywood mounting board inside the enclosure.

This represents a major improvement in both system reliability and future maintainability.

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System Status

Location: Mojave Wi-Fi Hilltop Relay
Purpose: Off-grid solar-powered internet relay
System voltage: 24 V nominal
Battery type: Flooded lead-acid deep cycle
Charge controller: BZ Products M20+
Network equipment: Ubiquiti radio/fiber relay system

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Battery Bank Replacement

The old battery bank was removed and replaced with two EverStart Marine & RV Group 29DC deep-cycle batteries.

Configuration:

• - Two 12 V batteries
• - Wired in series
• - 24 V nominal battery bank

The batteries are now located outside the electronics enclosure, allowing:

• - easier inspection,
• - easier terminal access,
• - better separation between batteries and electronics,
• - easier future replacement.

The outdoor battery location will require continued attention to:

• - weather protection,
• - terminal corrosion prevention,
• - battery watering,
• - sun exposure mitigation.

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Charging Performance Restored

After battery replacement, the solar charging system began operating normally again.

Field observation:

Charging voltage in full sun: approximately 31 V

This confirms:

• - solar input is present,
• - charge controller is functioning,
• - battery bank is accepting charge.

However, 31 V is higher than expected for normal daily float operation of a 24 V flooded lead-acid bank and may represent:

• - absorption charging,
• - equalization,
• - or a high float adjustment setting.

Further adjustment and observation are required.

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Charge Controller Investigation

The BZ Products M20+ charge controller contains two adjustment potentiometers (“pots”).

Observed controls:

Left Pot — “I CAL”

Purpose:

• - Current calibration adjustment.

Accidental adjustment:

• - The I CAL pot was accidentally turned during troubleshooting.
• - It was only moved approximately ¼ turn.
• - It was not forced past its stop.

Expected effect:

• - May affect the accuracy of the current display.
• - Should not affect battery charging voltage.

Action:

• - Leave unchanged until proper calibration can be performed.

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Right Pot — “FLOAT ADJ”

Purpose:

• - Adjusts the controller float voltage.

Future adjustment procedure:

1. 1. Wait until the controller enters float mode.
2. 2. Confirm FLOAT LED operation.
3. 3. Measure voltage directly across the 24 V battery bank.
4. 4. Adjust only in very small increments.

Target range:

• - Approximately 28 V range for normal 24 V flooded lead-acid operation.

The adjustment should be done slowly because the pot is a single-turn adjustment with a limited range.

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Float Indicator Investigation

The controller’s red FLOAT LED is now an important diagnostic because the LCD display is no longer functioning.

Expected behavior:

• - Morning / depleted battery:
• - FLOAT LED normally off.
• - Controller is actively charging.

• - Battery fully charged:
• - Controller transitions into float.
• - FLOAT LED should illuminate.

The FLOAT LED will be used as the indicator for when to check and adjust final charging voltage.

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Display Failure

The M20+ display is no longer functioning.

Current condition:

• - LCD screen: blank
• - Controller LEDs: active
• - Charging operation: confirmed

The failed display does not currently prevent operation, but it reduces monitoring capability.

Future options:

• - repair/replace display,
• - add independent voltage monitoring,
• - integrate battery voltage monitoring into the Fieldstation monitoring system.

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Electronics Reorganization

The internal enclosure has been significantly improved.

Previous condition:

• - loose wiring,
• - difficult troubleshooting,
• - components mixed together,
• - “rat’s nest” configuration.

Current condition:

• - electronics mounted on plywood,
• - components separated,
• - wiring easier to trace,
• - service access improved.

This creates a better foundation for future upgrades:

• - proper fuse labeling,
• - cable strain relief,
• - terminal blocks,
• - weatherproof battery connections,
• - remote monitoring.

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Current Status

| Component | Status |
|---|---|
| Solar charging | ✅ Working |
| Battery bank | ✅ Replaced |
| 24 V system | ✅ Operational |
| Charge controller | ✅ Operating |
| Controller display | ⚠️ Failed |
| Float adjustment | ⚠️ Needs verification |
| I CAL setting | ⚠️ Accidentally adjusted, monitor only |
| Electronics mounting | ✅ Improved |
| Network relay | ✅ Operational |

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Next Field Tasks

1. Confirm battery voltage when FLOAT LED activates.
2. Adjust FLOAT ADJ if necessary.
3. Verify batteries are not held at excessive voltage.
4. Add battery protection:
- terminal covers,
- corrosion protection,
- enclosure/shade improvement.
5. Add permanent voltage monitoring.

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Field Note

This repair marks an important transition for the Mojave Wi-Fi Hilltop Relay. The system has moved from an improvised installation into a serviceable off-grid infrastructure node.

The battery failure became an opportunity to simplify the system: new batteries, cleaner wiring, easier troubleshooting, and a clearer path toward long-term autonomous operation.