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Group 27 Deep Cycle RV Battery Guide: Pro-Guide 27M160
Short answer: The Pro-Guide 27M160 is a 12V Group 27 flooded deep cycle battery with 160 minutes of reserve capacity at 25 amps, 600 CCA and 750 MCA, in a 12 1/16 x 6 13/16 x 8 7/8 in case weighing 47 lb. For RV and camper owners, that makes it an affordable, serviceable house battery that drops into a standard Group 27 tray and runs lights, the water pump, the furnace fan and device charging between hookups.
Group 27 is one of the most common house-battery sizes in travel trailers, pop-ups and fifth wheels, and it is just as popular on boats. This guide explains what a Group 27 deep cycle RV battery is, how reserve capacity translates into a weekend of dry camping, how flooded compares with AGM and lithium, and how to charge, water and store the 27M160 so it keeps up season after season.
Key Takeaways
- 160 minutes of reserve capacity: about 67 amp-hours delivered at a steady 25-amp draw.
- Standard Group 27 size: 12 1/16 x 6 13/16 x 8 7/8 in, a common RV tongue-tray and marine size.
- Plan on about 33Ah per cycle: use roughly half of the battery before recharging for the longest life.
- Serviceable flooded design: check and top up with distilled water from time to time.
- Charging: 10A standard, 15A maximum charge current, flooded lead-acid profile.
- Warranty: 12 months free replacement and 30 months total pro-rata.
What Is a Group 27 Deep Cycle RV Battery?
"Group 27" is a Battery Council International (BCI) size standard for the outside dimensions of the case. A Group 27 is longer than a Group 24 and shorter than a Group 31, which makes it a popular middle ground: more capacity than a Group 24 without needing the larger tray a Group 31 requires. Many travel trailers ship with one Group 24 or Group 27 house battery on the tongue, and upgrading to a Group 27 is one of the easiest ways to add runtime.
A deep cycle battery is designed to be drawn down and recharged over and over. That is exactly what an RV house battery does: it runs 12V lights, the water pump, the furnace blower, the refrigerator control board, vent fans and USB chargers when you are not plugged into shore power, then recharges from the converter, the tow vehicle, a generator or solar.
A flooded lead-acid battery uses lead plates in liquid electrolyte with vent caps on top. It is the most affordable deep cycle chemistry, and it is serviceable, but it must stay upright, it needs periodic water checks and it typically releases hydrogen while charging, so it belongs in a vented battery box or an outside tray.
Pro-Guide 27M160 Specifications
| Model / SKU | Pro-Guide 27M160 (PGM27M160) |
| Type | 12V flooded lead-acid deep cycle |
| BCI group size | Group 27 |
| Reserve capacity | 160 minutes at 25 amps |
| Cold cranking amps (CCA) | 600 CCA |
| Marine cranking amps (MCA) | 750 MCA |
| Cranking amps (CA) | 750 CA |
| Charge current | 10A standard / 15A maximum |
| Terminals | 1 SAE post, 1 stud terminal |
| Dimensions | 12 1/16 x 6 13/16 x 8 7/8 in (306.4 x 174.6 x 228.6 mm) |
| Weight | 47 lb (21.3 kg) |
| Warranty | 12 months free replacement, 30 months total pro-rata |
The height listed is the case height. Leave extra room above it for the terminals, cable lugs and the battery box lid.
The 27M160 fits a standard Group 27 tray or box. The molded carry handle helps when you pull it for winter storage.
How Long Will a Group 27 Battery Run Your RV?
Start with reserve capacity. RC is the number of minutes a fully charged battery can supply 25 amps before it drops to 10.5 volts. For the 27M160 that is 160 minutes, which works out to about 67 amp-hours delivered at a 25-amp draw (25A x 160 / 60). RV house loads are usually much lighter than 25 amps, and lead-acid batteries typically deliver a little more total capacity at light loads, so this is a conservative starting point.
To protect a lead-acid battery, plan to use only about 50% of that before recharging. That gives the 27M160 a working budget of roughly 33 amp-hours per cycle. Here is how a typical dry-camping day might add up. Your loads will differ, so check the labels on your own appliances.
| 12V load | Typical draw | Use per day | Amp-hours |
| LED interior lights | About 2A total | 4 hours | About 8Ah |
| Furnace blower | About 4A | 3 hours of run time | About 12Ah |
| Water pump | About 5A | 30 minutes | About 2.5Ah |
| Phone and tablet charging | About 1A | 3 hours | About 3Ah |
| Detectors, control boards, standby loads | About 0.3A | 24 hours | About 7Ah |
| Total | About 32.5Ah |
In that example, one 27M160 covers about one cool night off-grid before it needs a recharge. In warm weather without the furnace, the same battery might stretch close to two days. If you dry camp for whole weekends, wire two 12V batteries in parallel to double the amp-hours at 12V, add solar or run a generator in the morning.
Flooded vs. AGM vs. Lithium for RV House Power
| Factor | 27M160 (flooded) | Group 27 AGM | 12V 100Ah lithium (24M100) |
| Reserve capacity | 160 min at 25A | 175 min at 25A | Not rated by RC; 100Ah |
| Usable capacity | About 50% for long life | About 50% for long life | Nearly all of 100Ah |
| Weight | 47 lb | 50 lb | 23.8 lb |
| Maintenance | Water checks, keep terminals clean | Sealed, no watering | None |
| Venting | Needs a vented box or outside tray | Sealed design | Sealed |
| Upfront cost | Lowest | Middle | Highest |
| Best fit | Weekend campers on a budget | Inside compartments, no-maintenance lead-acid | Frequent boondocking and solar |
Most campers who use hookups most of the time, or dry camp a few nights a season, get the best value from flooded. If your battery lives inside a compartment that is hard to reach or vent, AGM is worth the extra cost. If you boondock often, live on solar or want to cut weight on the tongue, lithium's nearly full usable capacity and long cycle life usually justify the price. Note that the 24M100 is a Group 24 size, so it will also fit most Group 27 trays with room to spare.
What Is the 27M160 Best For?
- RV and camper house battery: travel trailers, pop-ups, truck campers and vans with a Group 27 tray. Browse more RV and van life batteries.
- Small solar systems: a budget storage battery for a cabin, shed or camper solar kit. See solar and off-grid batteries.
- Boat house loads and trolling motors: the 27M160 is also sold as a marine deep cycle battery for 12V trolling motors and electronics. Read Should You Run a Separate Battery for Your Boat Electronics?
- Utility and backup power: sump pump backup, fish house power, portable power boxes and other steady 12V loads.
Its label also shows 600 CCA and 750 MCA, but the 27M160 is sold as a deep cycle battery. If one battery has to start an engine and run accessories, a dual-purpose model such as the Pro-Guide 27M800 Group 27 Flooded Dual Purpose is built for that job.
The front label lists the ratings that matter when you compare house batteries: 750 MCA, 600 CCA and 160 minutes of reserve capacity.
How to Charge a Group 27 Flooded Battery
The 27M160 is rated for a 10A standard and 15A maximum charge current. A rough charge-time estimate is the amp-hours you used divided by charger amps, plus about 20% for the absorption stage. From about 50% (roughly 33Ah used), a 10A charger needs about 4 hours.
- Use a flooded lead-acid profile. Many RV converters charge lead-acid by default, but check yours. For a dedicated charger, the Pro-Guide 12V 10A 1-Bank Battery Charger has a lead-acid mode (14.1 to 14.3V) and is designed to stay plugged in year-round.
- Respect the 15A maximum. If your converter or solar controller can push more current, consider two batteries in parallel so each one sees less.
- Recharge as soon as you can. Lead-acid batteries left partially discharged sulfate, which permanently reduces capacity.
- Charge in a vented space. Flooded batteries typically give off hydrogen near the end of a charge. Keep the box vented and keep sparks away.
- Solar: set your charge controller to its flooded lead-acid setting.
RV Battery Maintenance and Storage Tips
Check the water every few weeks of use
With the battery cool and upright, open the vent caps and confirm the electrolyte covers the plates. Top up with distilled water only, typically after charging, since the level rises during a charge. Never add acid, and don't overfill.
Read state of charge with a meter or hydrometer
Check resting voltage after the battery has been off the charger for a few hours. On a serviceable flooded battery you can also measure specific gravity with a hydrometer for a cell-by-cell picture of charge.
Equalize only if your charger supports it
Some chargers have an equalization mode for flooded batteries. Pro-Guide does not publish an equalization procedure for the 27M160, so follow your charger maker's instructions and call our team if you are unsure.
Kill parasitic loads in storage
RV detectors and control boards can drain a battery over a few weeks. Use the battery disconnect switch or pull the negative cable when the RV is parked, fully charge the battery first and check it periodically. Flooded batteries self-discharge and should never sit discharged.
Keep it upright, secured and clean
Mount the battery upright in a box or tray sized for Group 27, such as the NOCO Group 27 Snap-Top Battery Box or the NOCO Group 27 Battery Tray. A coat of battery corrosion preventative spray keeps the terminals clean. More care tips are in Marine Battery Maintenance: 7 Tips to Keep Your Batteries Ready.
27M160 vs. 27M180: Which Should You Choose?
| Spec | Pro-Guide 27M160 | Pro-Guide 27M180 |
| Reserve capacity | 160 min at 25A | 180 min at 25A |
| Approx. Ah at 25A | About 67Ah | About 75Ah |
| CCA / MCA | 600 / 750 | 675 / 825 |
| Weight | 47 lb | 50 lb |
| Case size | Same Group 27 case: 12 1/16 x 6 13/16 x 8 7/8 in | |
Both batteries share the same Group 27 case, so the choice comes down to runtime versus budget. Choose the 27M160 if you mostly camp with hookups or dry camp a night or two at a time. Choose the 27M180 if you want about 12% more reserve capacity for longer stretches off-grid or a harder-working trolling motor. If your tray only takes a Group 24, look at the Pro-Guide 24M140.
Frequently Asked Questions
Is a Group 27 battery good for an RV?
Yes. Group 27 is a common RV house-battery size. The Pro-Guide 27M160 offers 160 minutes of reserve capacity in a standard Group 27 case that fits most RV tongue trays and boxes sized for Group 27.
How many amp-hours is the Pro-Guide 27M160?
Pro-Guide rates the 27M160 by reserve capacity: 160 minutes at 25 amps, which works out to roughly 67Ah delivered at that rate. Plan on using about 33Ah per cycle for long life.
How long will a Group 27 deep cycle battery last overnight in an RV?
With typical loads of lights, a furnace fan, the water pump and device charging, one 27M160 usually covers about one night of dry camping before reaching 50%. Lighter use can stretch further.
Can I charge the 27M160 with solar?
Yes. Set your solar charge controller to its flooded lead-acid profile and keep charge current at or below the 15A maximum.
Do I need to add water to the 27M160?
Yes. It is a serviceable flooded battery. Check the electrolyte level periodically and top up with distilled water only.
Can I install the 27M160 inside my RV?
Flooded batteries typically release hydrogen gas while charging, so install the 27M160 upright in a vented battery box or an outside battery compartment, never in a sealed living space.
What warranty comes with the 27M160?
The 27M160 has a 12-month free replacement warranty and 30 months of total pro-rata coverage. Register your battery online to activate coverage.
Power Your Next Trip with the 27M160
If your camper, boat or solar setup has a Group 27 tray and you want proven lead-acid house power without the price of lithium, the Pro-Guide 27M160 is an easy, serviceable choice. It is sold through our dealer network, so give us a call and we will point you to the closest dealer and help you plan the right battery bank and charger.
Not sure which battery fits your rig? Call our team at 1-800-827-3232 or browse all RV and van life batteries and lead-acid batteries.
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