Minimal Battery/Electrical setup for a night or two...

[Herk7769]

Originally Posted by BackInAction

The handful of parks we are looking at visiting do not.

ok, Here is my experience in this area.

When I knew I would be dry camping a lot in Florida, I was really new at this. All I knew was I needed a second battery and it HAD to be identical in size, capacity and age to work as a paired cell (parallel connection).

So the easiest and quickest fix was to trot down to the dealer and by another Deka DC24. I rewired everything (putting in a kill switch, TriMetric TM-2025-RV and a 2400 watt inverter at the ame time). Everything works great but...

What I would have done NOW is a little different. You can use my experience is you want to.

1) The 2400 watt inverter is a cheaper model (modified sine) and is WAY too large. A 1000 Watt (pure sine) one would have been better for my battery stack (150AH) and only slightly more expensive.

2) I should have ditched the single crappy battery; sucked it up; and bought a matched pair of Trojan SCS225 12V batteries. That would have given me 260 AH

http://www.batteriesinaflash.com/dee...-cycle-battery

for only 300 dollars more.

[Triguy]

Originally Posted by BackInAction

What if I use a Wave 6 (or 8) or a Mr. Heater Buddy for heat rather than camper's heater? Would the cheapo battery be good enough for the rest of the work? I'm guessing it would be. And running my gennie (connected to the trailer) for a couple of hours in the morning would allow it to charge a bit. Allowing me to go 48+ hours without shore power.

Thoughts?

Here's a couple of thoughts.

Note that the Olympian Wave 6 is around $350, I believe. Nice, but expensive if you only use it twice.

I think the cheapest route is to replace your current battery with a battery or batteries appropriately sized to your intended use and then plan to run the genny as needed. A couple more thoughts about this...

• You really should calculate your planned Amp hours usage for these trips in order to understand the size battery or batteries that you need. Its really just a wild guess without that number.

• Once you have a better handle on your power usage, especially with the furnace, than replacing your single marine battery with a decent group 27 or 31 battery may give you enough Ah's because of your daily generator use but you need to more closely calculate your exact usage.

• Lastly, I would be concerned that the small generator you mentioned could actually charge a battery enough in only two hours. That's not really my area so I'll defer to others to answer that.

[BackInAction]

Originally Posted by herk7769

2) I should have ditched the single crappy battery; sucked it up; and bought a matched pair of Trojan SCS225 12V batteries. That would have given me 260 AH

Why the SCS225 and not the more commonly talked about T105?

[Triguy]

Originally Posted by BackInAction

Why the SCS225 and not the more commonly talked about T105?

More to the point; why SCS225 rather than T-145's? Better comparison.

[BackInAction]

Originally Posted by Triguy

You really should calculate your planned Amp hours usage for these trips in order to understand the size battery or batteries that you need. Its really just a wild guess without that number

Understood. Another forum member gave me his xls for all of his Roo's components (thanks Chuck). I was looking at it last night trying to guess how much usage I'd expect in 24 hours (primarily evening/morning usage)....

I determined (guessed) it would be ~27 Amps. His xls would round all "Hours of Use" up to the next hour. Here's what I was guessing.

1. 13.5 -- 4 hours of furnace (don't know if that is enough to maintain ~55F when the outside lows are in the mid-30s).
2. 3.1 -- 1 hour of water pump (seems high but his xls rounds up to the next hour)
3. 3.6 -- 24 hours of LP and Radio parasitic draws
4. 2.9 -- 24 hours of Refrigerator electronics
5. 2.3 -- 3 hours of "reading light" (this is to cover short-term usage of builtin lights when our hockey puck and/or lantern-style LEDs don't meet our needs.
6. 0.8 -- 2 hours of idle water heater and 1 hour of running heater
7. 0.7 -- 1 hour of range light?? Not sure if he meant stove or not

He has quite a few other entries on his sheet but I've ignored them (Radio, Ceiling light, bath fan, etc.). Any thing else I should consider?

[miatared]

If this can be of any help, in July I picked up a pair of GC2 batteries at Costco for $79 each, I now have 220AH - I've been able to get 4-5 days of dry camping in parks, even using the heater a bit - with no problem whatsover, never even going below 60% charge state.

I do have a Xantrex 1000 inverter, but have yet to install it. To be honest I really have no need for anything requiring 110V when I camp. We love our Melitta drip coffeemaker.

I plan on taking really good care of my batteries and see where they take me. I'll be putting them in my garage for the winter soon and connect my BatteryMinder to them.

A good buy I think.

[Glenn5995]

Originally Posted by Triguy

More to the point; why SCS225 rather than T-145's? Better comparison.

I am using a pair of paralled Trojan SCS225s. In my case I believe the 2 12-volts meet my needs better than 2 6-volts.

It works well for us. They each (6V or 12V) have advantages and disadvantages, so everyone needs to decide which will work best for their situations and needs. In our case we have the ability to recharge because we have 2 Honda EU2000i generators with a parallel kit, so maximum use is not of prime concern. I just want to be able to go a few days without running the generators. The two Trojan SCS225s in parallel result in a 260AH 20-hour rating and 450 minutes @ 25 amp capacity, which allows me to go three to five days without recharging, depending on electrical usage/demands.

We frequently "dry camp/boondock" and resources/supplies can easily be 50+ miles away. If I went with 2 6-volts in series and one went bad, I am out of business. With 2 12-volts, I can isolate the bad one and operate on one, although at a reduced capacity. If I do need to replace one, 6-volts can be difficult to find in rural areas, but almost any small town with an auto parts store will have some type of 12-volt RV/Marine battery. It may not be exactly what I want, but it will get me back up and going. Also if the battery in my tow vehicle dies, 6-volts have no cranking amps available with which to jump start your vehicle. 12-volt RV/Marines can be used to jump start your vehicle.

12-volts in parallel are not the answer for everyone, but I believe they are the best for my situation. If I were going to dry camp for extended periods without the use of a generator, I might have decided otherwise.

Just my .02

[MtnGuy]

Originally Posted by BackInAction

What if I use a Wave 6 (or 8) or a Mr. Heater Buddy for heat rather than camper's heater? Would the cheapo battery be good enough for the rest of the work? I'm guessing it would be. And running my gennie (connected to the trailer) for a couple of hours in the morning would allow it to charge a bit. Allowing me to go 48+ hours without shore power.

That is what we do while using just a single 12 volt battery. Some lights at nite, maybe catch up on the news and weather with the TV, and the water pump will bring the battery down some, but I will run the genny the next day for 1 to 2 hours charging via the converter, and the process starts all over again. You can a get a bunch of nites doing that....until your genny runs out of gas.

We use a Big Buddy Heater (2 tank model) when needed. Our heater will run about 10 hours on low.....and that heats plenty good into the low 30s. We crack a window near the heater, and another near the bed. I make sure the CO detector batteries are good, and that the unit functions via the test button. So far, that has served us well.

If the temps are just down into the upper or mid 40s, then we will just throw an extra comforter on the bed, and not bother with the heater. 1st thing in the morning, I will run the furnace for a while to get things comfy before the missus gets up. The perculator on the stove, and biscuits in the oven help heat the camper, also.

Running the furnace for a cycle or 2 will not kill the battery, but running it off and on for a nite will test even a 2 battery system.

[Triguy]

Originally Posted by BackInAction

Understood. Another forum member gave me his xls for all of his Roo's components (thanks Chuck). I was looking at it last night trying to guess how much usage I'd expect in 24 hours (primarily evening/morning usage)....

I determined (guessed) it would be ~27 Amps. His xls would round all "Hours of Use" up to the next hour. Here's what I was guessing.

1. 13.5 -- 4 hours of furnace (don't know if that is enough to maintain ~55F when the outside lows are in the mid-30s).
2. 3.1 -- 1 hour of water pump (seems high but his xls rounds up to the next hour)
3. 3.6 -- 24 hours of LP and Radio parasitic draws
4. 2.9 -- 24 hours of Refrigerator electronics
5. 2.3 -- 3 hours of "reading light" (this is to cover short-term usage of builtin lights when our hockey puck and/or lantern-style LEDs don't meet our needs.
6. 0.8 -- 2 hours of idle water heater and 1 hour of running heater
7. 0.7 -- 1 hour of range light?? Not sure if he meant stove or not

He has quite a few other entries on his sheet but I've ignored them (Radio, Ceiling light, bath fan, etc.). Any thing else I should consider?

This will work. You can probably reduce it further by pulling the fuse for the radio - assuming you don't want to use it.

So, 27 amps a day will require a battery that has at least 54Ah, which is basically any group 24 or larger. But that group 24 battery will be at 50% after 24 hours (The life of the battery is shortened dramatically by depleting below 50% too often).

Also, the cold temps you intend to camp in at this time will reduce the battery capacity. Temps of 40-50 degrees reduce the cap by about 20%.

So it seems that you will need a battery with a minimum of 70Ahs to last one day at your daily requirement.

But there's a catch. Once the battery is at 50%, you will need to recharge daily (as you had planned to). The battery will rapidly recharge up to about 75% capacity. After that, the charge needs to slow down and it will take much longer to get from 75% to fully charged than it took to get from 50% to 75%.

The point is that I am not convinced that a generator running for just two hours a day can fully charge your battery.

The solution would be to increase your battery capacity even more than the minimum of 70Ah. I think that three times your daily requirements or, if you want to be conservative, four times would be good. So, that's 81-104Ah (or 100-125Ah adjusting for cold temps), which will give you one day of power followed-up with a daily recharge. Any less than this capacity means you would need to spend more time charging your batteries to bring them up to 90-100%.

[Triguy]

Originally Posted by Glenn5995

I am using a pair of paralled Trojan SCS225s. In my case I believe the 2 12-volts meet my needs better than 2 6-volts.

It works well for us. They each (6V or 12V) have advantages and disadvantages, so everyone needs to decide which will work best for their situations and needs. In our case we have the ability to recharge because we have 2 Honda EU2000i generators with a parallel kit, so maximum use is not of prime concern. I just want to be able to go a few days without running the generators. The two Trojan SCS225s in parallel result in a 260AH 20-hour rating and 450 minutes @ 25 amp capacity, which allows me to go three to five days without recharging, depending on electrical usage/demands.

We frequently "dry camp/boondock" and resources/supplies can easily be 50+ miles away. If I went with 2 6-volts in series and one went bad, I am out of business. With 2 12-volts, I can isolate the bad one and operate on one, although at a reduced capacity. If I do need to replace one, 6-volts can be difficult to find in rural areas, but almost any small town with an auto parts store will have some type of 12-volt RV/Marine battery. It may not be exactly what I want, but it will get me back up and going. Also if the battery in my tow vehicle dies, 6-volts have no cranking amps available with which to jump start your vehicle. 12-volt RV/Marines can be used to jump start your vehicle.

12-volts in parallel are not the answer for everyone, but I believe they are the best for my situation. If I were going to dry camp for extended periods without the use of a generator, I might have decided otherwise.

Just my .02

I know what you're saying Glenn .

One of the biggest reasons, by the way, that I opted for the T-145s vs the SCS225 is tray size. Very practical - I would never be able to fit those two 12 volts on my current battery tray without modification because of their length. The two 6-volts are taller but that's not an issue.

Also by the way, you can crank a starter if needed with a deep cycle battery like the T-145s. Its just not as good at it as something rated for CA.

[Herk7769]

Originally Posted by Triguy

So, 27 amps a day will require a battery that has at least 54Ah, which is basically any group 24 or larger. But that group 24 battery will be at 50% after 24 hours (The life of the battery is shortened dramatically by depleting below 50% too often).

Also, the cold temps you intend to camp in at this time will reduce the battery capacity. Temps of 40-50 degrees reduce the cap by about 20%.

So it seems that you will need a battery with a minimum of 70AH to last one day at your daily requirement.

Scott,

I am curious as to how you arrived at the 54AH number for a load of 27 amps? What was your reasoning as I am having a hard time coming up with your figure.

At 1 amp draw, a 54AH battery will deliver that 1 amp for 54 hours (thus the 54AH rating). Assuming a flat discharge curve (which it is not), a 27 amp load will kill a 54AH battery in 2 hours. Since the discharge curve is not flat, the most you will get at 27Amps is about 54 minutes (reduced 100% capacity estimate of 30AH).

Otherwise your logic is right on.

[Triguy]

Originally Posted by herk7769

Scott,

I am curious as to how you arrived at the 54AH number for a load of 27 amps? What was your reasoning as I am having a hard time coming up with your figure.

At 1 amp draw, a 54AH battery will deliver that 1 amp for 54 hours (thus the 54AH rating). Assuming a flat discharge curve (which it is not), a 27 amp load will kill a 54AH battery in 2 hours. Since the discharge curve is not flat, the most you will get at 27Amps is about 54 minutes (reduced 100% capacity estimate of 30AH).

I took his 27 amps as being the load for the entire day.

[Herk7769]

One single 921 bulb left on all day is over 24 amps.
A two bulb fixture left on for 24 hours draws almost 50 amps.
The 200 milliamp Propane detector is 4.55 amps a day.
I think 27 amps a day is wildly low.

[Triguy]

I know what you're saying but it can be done.

We mostly dry camp in our hybrid and my minimum daily requirement seems to be about 34 amp-hr when camping with the family. I calculated that on one 4-day trip this July and it was confirmed when my 260Ah bank was at 12.0 volts or 45% at the end (oops).

I'm lower when I've taken out the trailer on my own.

[Herk7769]

How many hours a day did you run your furnace in July?
4?
I think not.

45% of 260AH is 117AH

My 150AH set would be flatter than my Aunt Tillie.

A 54AH battery would be... Oh, wait...

Seriously, your setup is what is needed for the camping you do. For a weekend, 150AH would be the minimum I would consider.
Winter camping I am back to 230 Plus bank.

[BackInAction]

As mentioned above, the 27 Amps/day came from someone spreadsheet who recorded current draws for each appliance/fixture of his Roo using his TriMetric.

Reading the above converstation, I'm leaning toward purchasing a Mr. Heater and a touch more battery capacity "just-n-case". The heater I can use elsewhere, but a "significant" battery upgrade can only be used in the RV.

The cheap-o Group 24 that came with the camper is brand new (less than a month), so I'm thinking I go buy (though I need to check the price) another of the same and wire them up in parallel (and add a on/off switch in the process).

That appears to be a simple cost-effective approach that should meet my needs and not any additional complexity to my camping experience. Gadgets are cool and I can certainly relate, but I've learned that simple is sometimes just eaiser and less stressful.

[Herk7769]

BIA,

Yes, the Full Monty is not every one's cup of tea for sure.
Whatever you decide, use great care with the Mr. Heater.
Ventilation is critical as your don't want to wake up dead.

[miatared]

Originally Posted by herk7769

Ventilation is critical as your don't want to wake up dead.

That would be somewhat very, very difficult:

[BackInAction]

Originally Posted by miatared

That would be somewhat very, very difficult:

Zombies!

[BackInAction]

Originally Posted by BackInAction

Reading the above converstation, I'm leaning toward purchasing a Mr. Heater and a touch more battery capacity "just-n-case". The heater I can use elsewhere, but a "significant" battery upgrade can only be used in the RV.

The cheap-o Group 24 that came with the camper is brand new (less than a month), so I'm thinking I go buy (though I need to check the price) another of the same and wire them up in parallel (and add a on/off switch in the process).

That appears to be a simple cost-effective approach that should meet my needs and not any additional complexity to my camping experience. Gadgets are cool and I can certainly relate, but I've learned that simple is sometimes just easier and less stressful.

Everyone has been so helpful I really appreciate it. Now i have a pricing question...

I just called the RV dealer where I purchased the Roo. A new "basic" Group 24 battery runs $77 (plus tax) and an additional battery box is $12. I assume I can find a local source for the additional lengths of wire to connect the two in parallel.

For roughly the same amount could I higher capacity Group 27 or 31? Ex. if $100 gets me a single high (enough, see above thread) capacity Group ZZ battery, I'd ditch the cheap-o 24 that came with it.

Thoughts?