JMI Wheeley Bar Battery Pack Holder

Product Overview

The JMI Wheeley Bar Battery Pack Holder is a heavy-duty steel cradle that bolts to the frame of a Universal Wheeley Bar so the power supply travels with the scope. The cradle takes packs up to 5½″ × 10″ and has a rimmed edge that keeps the pack seated while the bar is rolled over uneven pavement. It mounts with the bar’s existing hardware in about five minutes and weighs 3.625 lb. Made in the USA by JMI.

Who It’s For

This is a good match if you…

• run a mount, dew heaters or a camera from a portable battery and currently set the pack on the ground beside the tripod
• move the scope between observing positions and would rather not drag a power cable across the grass each time
• use a marine or jump-starter style pack that fits inside 5½″ × 10″
• own a Standard Medium, HD Medium, HD Large or AP Pier Mount Wheeley Bar

Key Features & Design

• Steel cradle: heavy-duty steel with a corrosion-resistant finish, sized for packs up to 5½″ × 10″.
• Rimmed edge: the raised lip keeps the pack from walking out of the cradle while the bar is in motion.
• Existing hardware: the holder uses mounting points already on the Wheeley Bar frame, so no drilling and no extra fasteners are involved.
• Five-minute fit: most owners complete the first installation in about five minutes, after which the cradle stays on the bar.
• Multi-bar fit: one part covers the Standard Medium, HD Medium, HD Large and AP Pier Mount bars.
• 3.625 lb: light enough that it changes nothing about how the loaded bar rolls or balances.

Mechanical Design

The cradle is a formed steel tray rather than a strap or a hook, which matters for a battery: lead-acid and lithium packs are dense and concentrated, and a flexible retainer lets that mass swing as the bar crosses a seam in the pavement. A rigid tray carries the pack’s weight through the frame and the rimmed edge takes the lateral load, so the pack stays where it was set down. Mounting at the frame also puts the mass low and inboard, below the tripod feet and close to the wheel base, which keeps the centre of gravity of the whole assembly lower than it would be with the pack strapped to a tripod leg.

Recommended Uses

• Carrying a 17 Ah class power pack alongside a mount on a rolling Wheeley Bar
• Keeping a dew heater controller supply with the scope while moving between observing spots
• Imaging sessions where a camera, mount and dew straps all draw from one field battery
• Outreach nights with cables kept off the ground and away from foot traffic
• Running a second holder for a separate pack when the mount and the heaters are powered independently

Compatibility and Accessory Notes

The standard holder fits the Universal-style Wheeley Bar line: Standard Medium, HD Medium, HD Large and AP Pier Mount. The Triangle Style and Sky Trekker Dobsonian platforms use a different frame and take a different approach to accessories. For the HD Shorty, we are happy to check the fit before you order. On the battery side, the 5½″ × 10″ opening covers most astronomy field batteries — Celestron PowerTank 17 and PowerTank Lithium Pro, Sky-Watcher 17 Ah, Talentcell 12V LiFePO4 packs, marine jump-starter style units and most shoebox-format supplies. Packs larger than that are served by the Battery Pack Holder XL, which takes up to 15¾″ × 11¾″ and fits the HD Medium and HD Large bars only. Send us your bar model and the dimensions of your pack and we will check the combination for you.

Good to Know Before You Order

• The battery pack is sold separately. Product photos show a pack in the cradle for scale; the holder ships on its own.
• The opening is 5½″ × 10″. Packs above that footprint are the XL holder’s territory, and the XL fits only the HD Medium and HD Large bars.
• The Triangle Style and Sky Trekker platforms use a different frame. This holder is made for the Universal-style bars.
• Two holders can share one bar. Most HD Medium and HD Large bars have room for a pair, which suits a separate mount supply and dew heater supply. We can confirm placement and clearance for a specific bar configuration.
• Shipping weight is 3.625 lb. It is a small steel part and arrives in a correspondingly small carton.

Frequently Asked Questions

Is it difficult to install?

No. The cradle bolts straight to the Wheeley Bar frame using hardware that is already on the bar, with no drilling and nothing extra to buy. The first fit takes about five minutes, and the holder then stays on the bar between sessions.

What size battery pack fits?

Packs up to 5½″ × 10″. That covers Celestron PowerTank 17 and PowerTank Lithium Pro, Sky-Watcher 17 Ah, Talentcell 12V LiFePO4 units, marine jump-starter packs and most shoebox-style supplies.

Which Wheeley Bars does it fit?

Standard Medium, HD Medium, HD Large and AP Pier Mount. For an HD Shorty, get in touch and we will check the fit first.

Can two holders go on one bar?

Yes. Most HD Medium and HD Large bars take a pair, which is a common arrangement when the mount and the dew heaters run from separate packs.

Does the pack stay put while the bar is rolling?

The rimmed edge of the cradle is there for exactly that. The pack sits inside the rim rather than on a flat surface, so it is held laterally as the bar crosses uneven ground.

What if my pack is larger than the opening?

The Battery Pack Holder XL takes packs up to 15¾″ × 11¾″. It fits the HD Medium and HD Large bars, and not the Standard Medium, HD Shorty or AP Pier Mount.

Bottom Line

In short: a 3.625 lb steel cradle that bolts to a Universal Wheeley Bar in about five minutes and carries a battery pack up to 5½″ × 10″ with the scope, so the power supply travels on the bar instead of trailing a cable behind it.