Battery Upgrade Question

[Bill.vannuys]

My Montana 3735MK I purchased new in July 15 came with a Crown Marine Deep Cycle Group 24, Model 24T-800 Battery. The 20 HR AH capacity is 75 AH. I know this is about the smallest battery one can buy, hence, the short endurance.

Problem: The battery quickly weakens when dry camping (overnight parking at rest area and running the heater/water/refrigerator). My refrigerator remains on propane, but eventually will not light as the battery weakens.

I have been scanning many forums and it seems many elect to have dual golf cart batteries in series, but this needs a vented battery box large enough to hold the 2 batteries unless I use AGMs.

Question: I'm looking for any advice or suggestions on upgrading to a more suitable power source that will better support my rest area stops without noticing a significant reduction in heater fan speed and battery depletion during perhaps a 12 hour stop.
-Is there an advantage of using golf cart batteries?
-How about 6 or 12 volt AGM battery(Are charging modifications needed?)?
-Is there a vented battery box solution large enough? Source?
-Should I just stay with 12 volt wet cell in larger group size?

A few Trojan Battery possibilities I've looked at are:
T125 6 Volt Flooded with AH/20hr Cap of 240 each. (66 lbs/ea)
GC2 6 Volt T105-AGM with AH/20hr Cap of 217 each (68 lbs/ea - no venting needed)
SCS225 12 Volt Flooded with AH/20hr Cap of 130 (66 lbs).
T1275-AGM 12 Volt with AH/20hr Cap of 140 (81 lbs).

Any thoughts will be appreciated. Thanks.

[Dmcgrew]

I use two Trojan T145 batteries and have no problem for a three to four days of dry camping with only two hours of generator running per day, just enough to run coffee maker and keep hot in the morning and a an hour in the evening while making dinner. The batteries a a little more expensive than the Trojan T105's but are doing excellent for my occasional dry camping. Trojans seem to be a great battery even if not using solar panel and dry camping a lot like most people who use them.

[Dmcgrew]

Dual vented bbattery box is available, I purchased mine at an Interstate battery store.

[poloace]

We dry camp a lot. We have 2 6volt Trojan batteries. They do a great job.

[1retired06]

We have the Trojans in our golf cart. Great batteries

[ranch560]

I for one suggest you add at least a second battery. And, you should add in pairs, you can't just add a second Crown Marine battery now as it won't charge or discharge correctly because it's probably too old and it has gone through too many cycles.

As always, it boils down to how much do you want to spend.

Most people (not all) upgrading their systems choose 6 volt golf cart batteries as they are built for the many charging and discharging cycles we go through. The standard lead acid batteries are the most economical. You can spend $90 per battery for an Interstate battery at Costco or $140 for a Trogan battery. AGM batteries are much more expensive and if you win the lottery, Lithium batteries could be your choice.

As for a battery box, there a lots of choices. Here is a site that has a good selection. And it has other battery accessories also. http://www.allbatterysalesandservice...cfm/2,619.html

Bottom line - When your batteries die in the middle of a cold night and won't run your furnace or keep your refer lit, what's it worth to you?

[DQDick]

Before we went to AGM's we had a dual vented battery box I bought from a Marine supply store.

[TLightning]

We all know the AGMs are expensive. The trade off is they are literally install and forget batteries. You can mount them any way you want...side ways if necessary, no need to add water, and don't give off odors or fumes.

[twindman]

I installed a box for 2 6V batteries. I made my own vent in the top from something at homedepot for a few dollars. Only problem is I think you need a hole in the bottom for air flow(???) so I cut a hole in the bottom of the storage area and a hole in the box to match.

[Justme44]

Next week I am planning to buy two interstate golf batteries from Costco for $96 plus $15 for the core because I don't have a trade-in. I am told the batteries are 230 AH's.
Dennis

[kingdaddy]

I replaced my 12v Interstate "Deep Cycle" (not really) with a pair of Crown 6CRV260 6 volt batteries with individual battery boxes and vents.
You can find them on sale and they are rated at 260 20 AH capacity. Awesome quality, but heavy (about 75 lbs each!). Should do the job, I just changed out all my interior, and some exterior light bulbs with LEDs which should help dry camping ability too.

[WaltBennett]

Everyone has given you all you need to know about batteries, but what I noted was you may need to rethink power management while dry camping. If you've an inverter (converter makes AC into DC, inverter makes DC into AC), you'll certainly need to have more than one battery to run anything. Have you replaced all the lights you use with LED ones? Don't need to replace all, just the ones you need to use and then only use the LEDs while dry camping. Also, consider getting a Big Buddy or something similar for heat instead of running the furnace - that fan uses a lot of current. Your bedroom TV is DC and will also draw a lot of current while the antenna amplifier can be a hidden draw as well. Then there's the water pump. Taking a shower or washing dishes will run that motor and use current, but limiting it as much as you can will help.

[Phil P]

Hi

Powertron P2000 6V deep cycle batteries. They are the same sizes as Golf Cart batteries and made by Trojan but cost less.

http://www.trojanbatterysales.com/se...100&type=1&n=2 the new part number is GBAP 2000
Trojan also makes AGM golf cart batteries.

I have had P 2000 batteries in my golf cart for 4 years without any problems.

Phil P

[mazboy]

trojan are great but 2 6 volt batteries from sams or something like that are fine, it just depends on what you want to spend and how long you want to dry camp.

for 2 batteries just buy 2 separate cases from walmart or wherever and add ventingto both of them. you can get the flex tubing from an rv place.

[kdeiss]

No question in my opinion I would go with 2 Trojan T105 or upgrade to the T125.
I have had Trojan's in our Golf Cart for 10 years.

[Bill.vannuys]

All,
Thanks for all the input, ideas and suggestions! I appreciate it!!! I've digested all feedback. My wife said "Fix it once" (and she doesn't care about cost - I'm a lucky guy!).

So, to meet what I think our power needs are within a reasonable budget, I am planning to purchase 2 new Trojan T145 6 Volt Deep Cycle batteries tomorrow locally ($192.00 each with no core charge). They are 260AH each at 20 Hr rate (6 volt). This will be a significant upgrade from my one current 75 AH 12 volt battery to 260 AH for the two 6 volt batteries at 12 volt output ( I think I have this right). I will modify a second vented battery box so both outgas hoses join to vent thru my current vent (as one suggestion said - just a few parts from Home Depot to join the hoses).

I was impressed with the AGM prices (much more $$) and the fact that they don't seem to provide any additional output or significant weight reduction when compared to the flooded deep cycle battery. Maintenance free is nice, but I need something to do!

Thanks again for all your assistance. Please provide any additional comments, as I appreciate any advice.
Bill

[Bill.vannuys]

My Battery Upgrade is complete and here is what the final product looks like. The 2 Trojan T45 6 volt batteries provide 260 AH at 12 volts. Unbelievable performance improvement compared to the original single 75AH 12 volt battery that came with the unit. I also added a LED light to illuminate the forward compartment. Thanks for all the advice!

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[chris199]

BILL
Doing the same project. I see you wired them in serie. Exlected that. Would you mind if I asked a cpl questions?

I have the same box. Did you screw to gloor?

What cables did you buy/use?

I see the positive/red cable. Hard to see how neg terminals are wired. What are the several small cables coming off the neg terminal up front?

[Bill.vannuys]

Chris,
Glad to answer questions. I hope I'm doing the pictures IAW the rules; If not someone let me know and I'll correct my ways.
1. I did bolt the box to the floor thru the 4 corner mounting holes. As you can see, I placed a 1/2" piece of plywood on the floor as I felt it gave a sturdier mounting surface than just the steel sheet metal floor. Then I drilled a 1/4" hole in the box mounting hole corners thru the plywood and sheet metal floor. I then used 2 1/2" Stainless Steel 1/4" bolts with a washer between the bolt head/box and a lock washer underneath with the nut.

2. Battery Wiring. Enlarged picture below may help. The batteries are placed in the box with the positive terminals to the left of picture and the negative terminals to the right. The lower right negative terminal is connected to the 2 negative connections that were from my RV on my original 12 volt battery. In addition, I added a negative connection (its the black wire in picture - I didn't recode/color it) from a Schumacher WM-12 Cable Connector for Battery Charger/Maintainer and a second negative wire for an LED light I installed in this compartment (thin red wire running across picture to negative terminal - which I did recolor white near the terminal). Next, Looking at the positive terminal at the top left of the picture, again the 2 trailer connections that were on my original battery and the positive wire for the battery charger and the positive LED light wire. {{I had 2 cables from my trailer connected to each battery terminal; I think one is for the leveling system and the other goes to the inverter - this is just a guess as I didn't care or check what they powered. I just knew they required 12 Volts.
The 4 gauge red wire in the middle connects the bottom battery positive to the top battery negative. It is from some auto parts store about 15 years ago - just waiting to be needed):-)
(NOTE) The Schumacher WM-12 Cable Connector for Battery Charger/Maintainer is permanently connected, so I don't have to open the battery box every time I store the RV and want to connect the battery maintainer. I can just plug in to the connector outside the box.
3. I only needed one cable - the 4 gauge red one to connect in series. The small red wire on the series connection does nothing; I just didn't remove it from the battery cable.

This is a picture of the 1" 45 degree elbow I used for the box top vent to the hose. I had modified a 1 1/4" elbow by reducing the OD to fit the hose, but it was very tight, thin walled and and I found the 1" worked better; just need a slightly smaller hole drilled in the top of the box (I must have used a 1 1/2" hole saw). I'm certain it still provides enough ventilation despite the slightly smaller ID size. I did use the 2" OD straight fitting for the box floor vent. Worked perfectly with the 2" hole saw and the current steel floor hole.

Hope this helps. Let me know if you need more answers or pictures. Let us know how it works out and any changes you incorporate. Good Luck!

[chris199]

Wow! Thank you very much for taking the time to answer the questions and take that pic!!! Huge help!!

I really appreciate it!! Looks like a great upgrade!! I need more amps than a single 12v.

I do have one more question....did you go with low profile terminals?