Size of deep cycle battery

[Sputs2001]

Hello:
Ive been scouring the threads for info about deep cycle batteries, but have not been able to put my finger on the details I need.

I currently have a general purpose marine battery (24ms) and want to upgrade to a deep cycle, but don’t know what size to buy.

My goal is to be able to run the furnace while boondocking for an entire night without draining the battery to a state where the furnace will not run. Ive spent a couple too many mornings waking up to a cold trailer. (I do have a standalone generator to run during the day to recharge.)

A friend of mine suggested an interstate 29 series deep cycle marine battery. but I don’t know if that is an accurate statement. I’m looking for an improvement over what I have but want to make sure I don’t get something that is going to damage my current components.

Ive also considered upgrading to 2 12v deep cycles to run parallel, but I’m only off shore power for a few days in the spring.

This is going on a 2010 291TG Laredo. Any comments/help/suggestions would be appreciated.

Mark

[cookinwitdiesel]

I have read very good things about the AGM batteries from VMAXtanks but they are expensive. You can do a set of 6v batteries in series or they also have well rated 12v options that you could run stand alone or in parallel.

This 6v seems to be the one that everyone goes for:
https://www.amazon.com/VMAXTANKS-Volt-225Ah-AGM-Battery/dp/B009MOR58A/

4 of those in a 2s2p configuration would get you 450 Ah @ 12V (5400 Wh)

[Wingerdinger]

It sounds to me like your group 24 battery is on it's last legs, although, a great deal depends on what else is running during the night in your unit.
Generally, the battery that comes with your unit is in the 60Ah to 70Ah capacity range, and that should take you through the night, if you are pretty conservative about other uses, and it's not real cold so your furnace runs all night.
The typical group 29 deep cycle batteries are in the 85Ah range, so maybe 20-25% more capacity, and certainly enough for a night, unless you are running a TV or some other big draw appliance. You can find them in the $100 range.
I do a fair amount of dry camping, and don't like running my generator any more than I have to, so I took a big step, and got 2 - 6 volt golf cart batteries. They are 210Ah each (and combined), so I can go 2 or 3 days. I usually run the generator a while in the morning to keep from depleting the batteries too much, and bring them back to full charge at home, after a long weekend. Those were $100 each.
I ran two group 24 deep cycle batteries prior to my upgrade, and could run pretty much anything I wanted for a day, and if I ran nothing but the furnace I could go two nights, but I ran the batteries lower than I liked.. it shortens the life cycles of them if you go below 50% capacity.

[Lee]

In regards to AGM batteries,.... You need to ensure that the on board Converter is rated to charge this kind of battery as the charge profile is different than conventional lead acid batteries.

Lee

[Sputs2001]

How would one check this? (The on board converter?)
Thanks.

[Wingerdinger]

You can look at the converter panel, there is a make and model either on the door or inside the door. Most of them are WFCO units.
Those units aren't generally customizable for an AGM battery. However, I'm not sure how much you need to be concerned about that. If you decide to go with a AGM battery for the convenience and better power, you will potentially shorten the number of life cycles you get out of it by using the lead-acid charging profile, but if you are an occasional Weekender, and you get 200 life cycles out of it instead of 400, I'm not sure how much that will matter. 200 life cycles might be 10 years.
Otherwise, you can change just the charger portion of it relatively simply, and probably get a good AGM charger for $150.
JMHO

[HitFactor]

Should be a manual with the paperwork that came with the unit. It might describe the charging capabilities. If nothing else, it should have the model number, you could post it here or search the internet for info.

[busterbrown]

FwIW, I just upgraded my single 64AH group 24 battery to dual 6 volt GC2 Duracell"s from Sam's Club. Cost was $178 and increased AH to 215. Booddocked for 3 nights so far this week with general use of furnace, lights, water pump and multiple televisions. Woke up to 3/4 full battery bank each morning. Use the generator for a couple hours in the morning and bank is topped off for the next night. Best setup for our needs.

[Lee]

Should be a manual with the paperwork that came with the unit. It might describe the charging capabilities. If nothing else, it should have the model number, you could post it here or search the internet for info.

Hi,

I would try the Manufactures website for the units Manual.... Hopefully it's stated in it. If not contact the manufacture.

Lee

[JRTJH]

Lots of "I think" or "you might be able to" type responses.

Here is the WFCO FAQ response on AGM/GEL battery use:
Can I use AGM or Gel batteries?

AGM batteries are OK. We do not recommend the use of GEL batteries except when using the WF-6800 Series. See the Owner's Manual for more information

You can access the WFCO website here: https://wfcoelectronics.com/
The WFCO 8900 power center/converter/charger here: https://wfcoelectronics.com/product-category/power-centers/wf-8900-series/
The WFCO FAQ section here: https://wfcoelectronics.com/faq/

[B-O-B'03]

I replaced my 2 group 24, 12 Volt batteries with 2 Duracell Ultra High Capacity 6V Golf Cart batteries from Batteries +, they are 235 amp hour batteries and I have been very happy with them.

I bought online and picked up in store and they had a 10% off coupon.

I also replaced the WFCO converter board, with one from Progressive Dynamics at the same time, since the OEM unit was toast (WFCO sent me a replacement board, since mine was just a few weeks older than their 2 year warranty and I sold it)

-Brian

[Sputs2001]

Thanks for the info... It was on the inside of the panel WF-8900 series.

[Sputs2001]

Thank you everyone! You all have helped put my mind at ease.. and am now on the right track for my upgrade. Definitely considering the 2 6volt solution! Just gotta find a box for both of them to fit into so they can be placed on the rails behind the propane tanks.

[B-O-B'03]

I bought this (https://allbatterysalesandservice.com/century-plastics-heavy-duty-battery-box-holds-2-6-volt-golf-cart-batteries-gce-g) box, for the 2 6 V batteries, it fit perfectly in the frame rails that used to hold the individual boxes for the 2 12V batteries.

-Brian

[IMASAP]

Thank you everyone! You all have helped put my mind at ease.. and am now on the right track for my upgrade. Definitely considering the 2 6volt solution! Just gotta find a box for both of them to fit into so they can be placed on the rails behind the propane tanks.


You are on the right track with the 2 6 volt GC batteries.

[TJO]

Don't think you will go wrong with the GC batteries.

[Wingerdinger]

I got the same Century Plastics box, it is real nice and heavy. I drilled some holes in the bottom in case I spill or rain gets in. It fits like it was designed for the RV.
My WFCO-9865 converter does a nice job charging the two GC2s. At least so far.. it will be a few weeks til I can give them a real test, but sure like what others have said about them.

[SkiSmuggs]

As with most, our 2012 Cougar fifth wheel came with the barely adequate Group 24 battery. At the start of our second season, I replaced the 80AH battery with a Group 27 110AH and dry camped 3 nights in the Grand Tetons with no generator or solar and still had enough power to bring in the slides and bring up the landing gear. I've since gone with solar panels and dual GC2 Trojans, but the upgrade from Grp 24 to 27, 29 or 31 is also worthwhile and is easy.

[bbells]

Don't even consider marine batteries. They are not deep cycle batteries, they are a compromise. Go to batteries plus and get real 12v or 6v deep cycle batteries. Golf cart batteries are the safest way to go. On sale you can get a 12v for around $100. Next, if it has CCA written on it, don't buy it. Next, forget about the group or size number, it is meaningless. Next, make sure the battery clearly states amp hours. Next, figure out the amps your furnace uses and do the math. Ex. A 100ah deep cycle battery, divided by the amps of the furnace, let's say 5 amps. Can run a furnace for 20 hours. But, to not damage your battery you will only want to drain it down halfway, so make it 10 hours.

[Sputs2001]

Installed 2 new Duracell 6volts today in the century plastics box. Fits the existing rails on my TT perfectly!:)

[SR71 Jet Mech]

Sputs, I too have the Duracell GC2’s (4 ea.). The factory battery chargers in pretty much all the units are not adequate for most batteries. Most RV’s are built with the intention of being plugged in. The charging profile of the charger and the state of charge of the battery (s) is extremely important to long life of batteries as well as keeping the water level full. The “battery level” indicator in all RV’s lies. Full is not actually full. A good charger will have a least 3 levels of charge rate. Bulk, absorption and float. A good charger will use all 3 of these in every charge cycle and adjust itself accordingly to properly charge your bank. Even better chargers will be 4 stage and offer an equalization charge (programmable) to help keep the cells in an equal state.

Not allowing batteries to go below a 50% state of charge is super important. As I stated the factory monitor lies. Look into a battery monitor that has “state of charge indication” www.thornwavelads.com. Victronenergy.com and there are others as well. I personally use the thornwave labs.

Third is battery water level. Check often when boon docking until you figure out the duration they need topped off. NEVER let them have the level get to where the plates are out of the water.

Last but not least, buy a cheap hydrometer. It will tell the true state of the batteries. A must have tool for good battery management.

Lots of you tube videos on battery charging, chargers and maintenance.

Happy camping,
Scott