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The short answer. Xi3-45, Xi3-55 and the 54 lb pontoon model are 12 V: one battery. Xi3-70 and the 68 lb pontoon are 24 V: two in series or one 24 V pack. MotorGuide’s breaker rule is “50-amp (good) or 60-amp (best)”, manual reset, within 6 ft of the batteries; fit the 60. The included 10 AWG cables can grow by 6 ft, no more. The Xi3 manual says nothing about lithium.
Which Xi3 is yours
| Model | Volts | Max draw (2023 catalog) | Batteries |
|---|---|---|---|
| Xi3-45 FW | 12 | 38 A | one 12 V |
| Xi3-55 FW / SW | 12 | 52 A | one 12 V |
| Xi3-54 Pontoon | 12 | 52 A | one 12 V |
| Xi3-70 FW / SW | 24 | 42 A | two 12 V in series, or one 24 V pack |
| Xi3-68 Pontoon | 24 | 42 A | two 12 V in series, or one 24 V pack |
The manual has no spec table; the amps come from MotorGuide’s catalog. Breaker for all: 50 A good, 60 A best. Two of the five draw 52 A, which is above 50, so we’d put a 60 A on every Xi3. That’s our reading, not MotorGuide’s.
Cables: the 6 ft rule and the gauge argument
MotorGuide’s rule: don’t extend the 10-gauge cables more than 6 ft, for 10 ft total. Longer, and it points you to its 8-gauge accessory cable. Yet the troubleshooting page for loss of power says “6-gauge wire is recommended.” We’d take the heavier advice on any 12 V model past 10 ft; run it through the Wire gauge calculator with your real length. Jumpers between series batteries: same gauge as the power cables. Terminals: stainless nylock nuts, per the manual. And bind the positive and negative wires to each other, which the manual asks for under battery installation.
Grounds and chargers
This is the Xi3 manual’s own contribution, in its sonar section: keep separate grounds, with no common ground between the trolling bank (12, 24 or 36 V) and the 12 V engine/accessory bank, and know that a multi-bank charger connected to both banks “can cause interference through the common ground in the charger.” Two banks, two chargers, no shared negative. That’s the clean install for a wireless motor with sonar on board.
Batteries
MotorGuide asks for “12-volt, deep cycle marine batteries” and gives no amp-hour figure, no group size and no word on lithium. Our fit is voltage plus a continuous discharge rating over the catalog draw.
12 V models (45, 55, 54 Pontoon): Pro-Guide 24M100 12V 100Ah Group 24 lithium, 100 A continuous. Charger: Victron Blue Smart IP22 12/30, lithium profile, 14.6 V. Both are store items today.
24 V models (70, 68 Pontoon): Pro-Guide 24VM90 24V 90Ah lithium (90 A) or Pro-Guide 24VM115 24V 115Ah lithium (100 A), or two 24M100s in series. No 24 V lithium charger in the store yet; Pro-Guide’s 24 V packs charge to 28.8 V.
Run time (example)
Run time calculator math, trolling mode: 80% of the amp hours divided by the amps, warm day.
| Model | Pack | At catalog max | At half |
|---|---|---|---|
| Xi3-45 (38 A) | 24M100 | 2 h 06 min | 4 h 13 min |
| Xi3-55 / 54 Pontoon (52 A) | 24M100 | 1 h 32 min | 3 h 05 min |
| Xi3-70 / 68 Pontoon (42 A) | 24VM90 | 1 h 43 min | 3 h 26 min |
| Xi3-70 / 68 Pontoon (42 A) | 24VM115 | 2 h 11 min | 4 h 23 min |
A pontoon in wind pulls harder for longer than a bass boat holding a spot. Budget nearer the left column on the 54 and 68.
The battery light
Green over 30%, red under 30%, flashing red under 10%. That’s the only MotorGuide manual with percentages. It was written for lead-acid, which sags as it drains; a lithium pack holds voltage and then drops fast, so the light may go green to red with little warning. Use the pack’s gauge.
Quick answers
What breaker for a MotorGuide Xi3? MotorGuide says 50 A good or 60 A best, manual reset, within 6 ft. We’d fit the 60; two models draw 52 A.
Can I use a lithium battery on an Xi3? The Xi3 manual and catalog don’t mention lithium. A 12 V or 24 V lithium pack runs it; the approval is the pack maker’s.
How many batteries for an Xi3-70? Two 12 V in series, or one 24 V pack.
Can one onboard charger do the trolling bank and the engine battery? MotorGuide warns a multi-bank charger across both banks can cause sonar interference through the charger’s common ground. Keep them separate.
Sources
- MotorGuide Xi3 Wireless Edition manual 8M0130831 (2017), pages 7-8, 17-25, 33, 39, 41
- MotorGuide 2023 Product Catalog, spec tables: https://www.motorguide.com/content/dam/motorguide/owners-resources/product-catalog/MotorGuide_Catalog_3-1-23_WEB.pdf
- Pro-Guide brochures and product pages; Victron Blue Smart IP22 manual (our product page)
- Trolling motor battery: 12V, 24V or 36V, wired right, Run time calculator, Wire gauge calculator
