Battery life

[Mikecorn]

I have a 2018 Jayflight 265rls tt. Does anyone have an idea of how long one battery will be able to run the furnace (set to 60 degrees) if the outside temp is at or just below freezing? I’m planning a trip to Yellowstone in September and generators can only be run between 8:00 AM and 8:00 PM so I want to make sure we have enough battery life to last the night. Thanks

[MichaelO]

Need more info on the battery. I take it since it’s one battery that it’s a 12 volt. What size and amp hours is the battery. The bigger the better. It might be worth upgrading to a pair of 6 volts with high amp hours. But first off we do need the current battery size to try and give an answer.

[tennistime99]

It will be dead by the time you wake up. Possibly permanently damaging the battery.

If you have a 100 amp hour battery you have 50 amp hours usable before you start damaging the battery. It's advised not to drop your battery below 50% charge.

Just guessing a draw of 7.5 amps for the furnace blower you're looking at around 6.66 hours run time.

Are you going to be hooked up to electric service? I use lots of blankets and take the chill off in the morning with a small electric heater. Set my heater to 40 or 50 to keep pipes happy.

[Mikecorn]

It’s an Interstate SRM-27 , 750 Marine cranking amps @ 32 degrees and, according to the Interstate website it has 88 amp hours.
Is it reasonable to assume that the furnace will draw 5 to 6 amps ?

[Jay2504]

If you run the generator until 8 in the evening you will make it ok through the night. Just charge it back up in the morning. Jay.

[RogerR]

That is 88 amps, brand new total max capacity. But at 50% draw max to avoid any damage you have 44 amps at most. As batteries age that total goes down. The only way to tell what you actually have in usable reserve is to test it at full charge and then run it down with a know draw.

As yours has a CCA, cold cranking amps it is a split purpose battery and won't hold up to deep discharge the way a true deep discharge battery would.

All considered, you may have 30 amps available and 5 hours run time less TV, pump, lights, etc. use. Should be OK but wouldn't hurt if you can to upgrade to a bigger battery.

[MichaelO]

An upgrade to a bigger battery would be real handy all the time. I’ve got a pair of 6 volts at 225 ah and I couldn’t imagine boondocking with anything less.

[Emichie]

I have 2 of the same batteries in my 28bhok. Keeping the furnace at 65 when it was around 30 outside I would be right at 50% battery life reaming in the morning.

[Sola123]

Speaking of batteries....it seems there is a lot of recommendations for the Trojan T105 @225 amp hrs....why not use the Trojan T145 @260 amp hrs....is one better than the other? Cost difference does not seem to be that much.... I am putting in solar and plan to upgrade to 4 - 6 volts....so why not get the higher amp hr batteries....?? Thanks for any and all opinions...

[MichaelO]

Originally Posted by Sola123

Speaking of batteries....it seems there is a lot of recommendations for the Trojan T105 @225 amp hrs....why not use the Trojan T145 @260 amp hrs....is one better than the other? Cost difference does not seem to be that much.... I am putting in solar and plan to upgrade to 4 - 6 volts....so why not get the higher amp hr batteries....?? Thanks for any and all opinions...

I had some t105’s and they were good and stood up to my abuse well. If the t145s are available I think I would step up to those for the higher amp hrs with all other things being close or equal.

[Mikecorn]

That was my thought, that I would add a second battery to extend the time. Thanks

[RogerR]

I noticed that the T105 weights 62 pounds and the T145 is 72lbs. Always want to make sure you can lift it. Also, dimensions count based on space available.


Last but very important, do you have enough cargo capacity left to install what you decide would work for you.

[Mikecorn]

Originally Posted by RogerR

I noticed that the T105 weights 62 pounds and the T145 is 72lbs. Always want to make sure you can lift it. Also, dimensions count based on space available.


Last but very important, do you have enough cargo capacity left to install what you decide would work for you.

So I just read the Jayco Owners Manual and it says that the furnace in my trailer draws 12 AMPS !! That's about twice what I expected. I did test the system the other night and with nothing else on but the furnace set to 65 (the outside temp started at around 40 and fell to mid 30's later), the battery was drawn down to 12.2 V in about 6 hours.

I'm definitely going to have to have a new battery bracket made to hold two batteries, there's not enough room between the frame rails where the battery currently sits to hold two.

I can see some extra blankets coming into play !! Thanks for your help Roger & everyone else that commented.

[craigav]

In my experience, the Jayco manuals rate things for the higher numbers (sometimes lower), so for example they may have several furnace options for your RV with the highest one using 12 amps operation. I would look up the exact model number furnace you have from the mfg's website and see if they show a different amp rating as 12a is usually the largest of RV furnaces, most I have seen are around 8a give or take an amp or two.

In any case, I would add one or more batteries as that is still your best bet. I would also consider something like this perhaps. It is supposed to hold 300 lbs so it should hold a couple more batteries for you. ~CA

[Mikecorn]

Thanks Craig, I’ll check the unit itself like you suggested. And thanks for the tip on the rack, that may be the easiest solution for me !

[Jagiven]

Originally Posted by Mikecorn

So I just read the Jayco Owners Manual and it says that the furnace in my trailer draws 12 AMPS !! That's about twice what I expected. I did test the system the other night and with nothing else on but the furnace set to 65 (the outside temp started at around 40 and fell to mid 30's later), the battery was drawn down to 12.2 V in about 6 hours.

I'm definitely going to have to have a new battery bracket made to hold two batteries, there's not enough room between the frame rails where the battery currently sits to hold two.

I can see some extra blankets coming into play !! Thanks for your help Roger & everyone else that commented.

This turned into a long reply!

It might be pulling 12 amps, but that is only when the furnace fan is spinning.

Luckily what you have going for you is time, so you can do some investigating. Many years ago I took an amp reading of all the devices in my TT. Unfortunately the list is in the TT tool box, in deep hibernation.

This could be a good reason to buy yourself a new multimeter with an amp clamp. I bought a $20-$30 Sperry, when my good multimeter broke (opps - I should not have dropped it down a staircase ). You have all summer to make your plan.

On my list, is all the items that use power. In most cases, I took the reading at the battery (hot wire), with the TT unplugged from shore power. I first determined the parasite power drain. Then went through one by one to various system and turned them on and took a measurement. In some cases it was very easy to take a measurement at the device. Sometimes, I took the reading at the battery and subtracted the parasite. On my list, each item is listed individually except for the parasites, they are listed as one big group. The furnace is a big ticket item, so was my incandescent lights before I changed them to LEDs. I believe my radio was a big draw too. I purchased a switch so I could disconnect it, but I have not installed it.

Furnace use; 1st thing to note, Sitting in standby, it does use some power. When the fan is circulation it uses a lot of power. So lets say the 12 amps noted above is correct. That is 12 amps for every hour of use. So, if it is only cycling on 30 minutes per every hour, the power draw is 6 amps. With that knowledge, you can monitor your power consumption and get a good feeling how long the battery will last.

So, lets say your battery is rated at 88amps. You can realistically only get 44 amps out of it. So if your furnace is cycling 50% of the time, you use 6 amps every hour. If it is the only thing pulling power (its not), you can calculate how long the battery will last, 44/6= 7.33hours. But that does not include your frig, lights, parasites, etc. So you will need a power plan.

Until recently I just had the cheap OEM group 24 dual purpose battery. In the summer I could go for 4-5 days between charges. In the cooler months being careful we can go two days. As old backpackers, we had learned power management early on. So being careful in the TT is no big deal.

Some of the things we do;

When we get to camp, the slide-out and awning goes out while we are still hooked to the TV. Sometimes I will keep the 7 pin connected while finishing setting up to help top off the battery (extremely slow charge). Ceiling lights; we can reach all of them. So we turn on the master wall light switch, then turn off each ceiling light at the fixture. When we need a light, we turn on the one or two lights that we really need, not all. This was very critical when we still had incandescent. We also have candles in our TT. DW really likes them. Not always the best for reading by, they do produce a little heat (I have read a candle is equivalent to an 80W light bulb).

We have an open underbelly, we have camped many times down to the very low 20's without any issues. Pending on the weather, typically the furnace is off during most of the day. If it is wet and cooler, we may manually cycle it on and off over the course of the day. Sometimes we do this at night too. If one of us gets up to go to the bathroom, turn on the furnace as we walk past, and let it run for 10 -15 minutes, go back to bed.

Have extra blankets, and warm slippers, a few light weight jackets for layering.

Dual batteries; I only have one battery on our TT. Until recently it was the cheap group 24 battery, probably like yours. However, sometimes we carried a second battery in the TV. This battery is for the kids trolling motor. If we need more power I could pull it out. I also made a custom jumper cable so I did not have to pull the TT battery out of the box.

We purchased a generator this past fall, and new deep cycle batteries right before our last trip of the season. We were a bit extra cautious on that trip. We were out for 5 nights, overnight lows were 20-25 every night. Some days never got above 35, it snowed and rained almost every day. Nothing froze. I have a new CPAP, and was unsure of its power draw, and how well the new battery would preform.

Every morning I would take a voltage reading, I would measure 12.2 volts. Run the generator for 1.5 hours or so each morning. Again each evening for an hour or so. After a few days, I started running electric heater, while the generator was on. I never pulled out the second battery during the trip, I did consider it, just so we could run the furnace a bit more.

Note; I state batteries above. I now have two 105amp/hour AMG 12V batteries. One on the TT, the other is for the kids trolling motor. I will toss it the back of the truck if we think we may need some extra power. We have only ever used it on extended trips when it was cold. I also made a custom jumper cable so I can leave the battery in the back of the truck, or have it placed next to the tongue so I do not have to remove the TT battery.

FYI, if you are monitoring the battery voltage as a method to determine how depleted your battery is, there is two trains of thought. I have no clue which one is right. Some people say a depleted battery is when the voltage reaches 12.2V, what I have read this is for thin plate batteries. Other use 12.06V, which is for thick plate batteries, and this is the voltage I have used as my baseline for a depleted battery. I can tell you my old cheap battery was almost 9 years old when it died. More than once, I did drain it well below 12 volts.

Good Luck, play around this summer and you should be able to determine how long you can go.

[Mikecorn]

Originally Posted by Jagiven

This turned into a long reply!

It might be pulling 12 amps, but that is only when the furnace fan is spinning.

Luckily what you have going for you is time, so you can do some investigating. Many years ago I took an amp reading of all the devices in my TT. Unfortunately the list is in the TT tool box, in deep hibernation.

This could be a good reason to buy yourself a new multimeter with an amp clamp. I bought a $20-$30 Sperry, when my good multimeter broke (opps - I should not have dropped it down a staircase ). You have all summer to make your plan.

On my list, is all the items that use power. In most cases, I took the reading at the battery (hot wire), with the TT unplugged from shore power. I first determined the parasite power drain. Then went through one by one to various system and turned them on and took a measurement. In some cases it was very easy to take a measurement at the device. Sometimes, I took the reading at the battery and subtracted the parasite. On my list, each item is listed individually except for the parasites, they are listed as one big group. The furnace is a big ticket item, so was my incandescent lights before I changed them to LEDs. I believe my radio was a big draw too. I purchased a switch so I could disconnect it, but I have not installed it.

Furnace use; 1st thing to note, Sitting in standby, it does use some power. When the fan is circulation it uses a lot of power. So lets say the 12 amps noted above is correct. That is 12 amps for every hour of use. So, if it is only cycling on 30 minutes per every hour, the power draw is 6 amps. With that knowledge, you can monitor your power consumption and get a good feeling how long the battery will last.

So, lets say your battery is rated at 88amps. You can realistically only get 44 amps out of it. So if your furnace is cycling 50% of the time, you use 6 amps every hour. If it is the only thing pulling power (its not), you can calculate how long the battery will last, 44/6= 7.33hours. But that does not include your frig, lights, parasites, etc. So you will need a power plan.

Until recently I just had the cheap OEM group 24 dual purpose battery. In the summer I could go for 4-5 days between charges. In the cooler months being careful we can go two days. As old backpackers, we had learned power management early on. So being careful in the TT is no big deal.

Some of the things we do;

When we get to camp, the slide-out and awning goes out while we are still hooked to the TV. Sometimes I will keep the 7 pin connected while finishing setting up to help top off the battery (extremely slow charge). Ceiling lights; we can reach all of them. So we turn on the master wall light switch, then turn off each ceiling light at the fixture. When we need a light, we turn on the one or two lights that we really need, not all. This was very critical when we still had incandescent. We also have candles in our TT. DW really likes them. Not always the best for reading by, they do produce a little heat (I have read a candle is equivalent to an 80W light bulb).

We have an open underbelly, we have camped many times down to the very low 20's without any issues. Pending on the weather, typically the furnace is off during most of the day. If it is wet and cooler, we may manually cycle it on and off over the course of the day. Sometimes we do this at night too. If one of us gets up to go to the bathroom, turn on the furnace as we walk past, and let it run for 10 -15 minutes, go back to bed.

Have extra blankets, and warm slippers, a few light weight jackets for layering.

Dual batteries; I only have one battery on our TT. Until recently it was the cheap group 24 battery, probably like yours. However, sometimes we carried a second battery in the TV. This battery is for the kids trolling motor. If we need more power I could pull it out. I also made a custom jumper cable so I did not have to pull the TT battery out of the box.

We purchased a generator this past fall, and new deep cycle batteries right before our last trip of the season. We were a bit extra cautious on that trip. We were out for 5 nights, overnight lows were 20-25 every night. Some days never got above 35, it snowed and rained almost every day. Nothing froze. I have a new CPAP, and was unsure of its power draw, and how well the new battery would preform.

Every morning I would take a voltage reading, I would measure 12.2 volts. Run the generator for 1.5 hours or so each morning. Again each evening for an hour or so. After a few days, I started running electric heater, while the generator was on. I never pulled out the second battery during the trip, I did consider it, just so we could run the furnace a bit more.

Note; I state batteries above. I now have two 105amp/hour AMG 12V batteries. One on the TT, the other is for the kids trolling motor. I will toss it the back of the truck if we think we may need some extra power. We have only ever used it on extended trips when it was cold. I also made a custom jumper cable so I can leave the battery in the back of the truck, or have it placed next to the tongue so I do not have to remove the TT battery.

FYI, if you are monitoring the battery voltage as a method to determine how depleted your battery is, there is two trains of thought. I have no clue which one is right. Some people say a depleted battery is when the voltage reaches 12.2V, what I have read this is for thin plate batteries. Other use 12.06V, which is for thick plate batteries, and this is the voltage I have used as my baseline for a depleted battery. I can tell you my old cheap battery was almost 9 years old when it died. More than once, I did drain it well below 12 volts.

Good Luck, play around this summer and you should be able to determine how long you can go.

Thank you so much for this detailed reply, it's very helpful information !! I definitely plan to create a log of the draws of all of the major juice consumers so I can come up with the best plan. I'm feeling better about the whole situation based on what people have been telling me in this forum.

[craigav]

BTW, if you want to know how long a battery will last (being able to be recharged and discharged) my experience is that every battery I have purchased will be a good battery until about two weeks after the free warranty replacement period ends...

[Harold N]

My 265RLS will not run the furnace fan all night with only one battery. A second battery will fit side by side with the one on the tongue. Wire in parallel with the original one. Also when stopping overnight in cold weather, l turn up the thermostat in the trailer about an hour before I stop for the night. That way the trailer gets warmed up while still being charged by the tow vehicle which will cut down the amount of time that the fan runs after you stop.

[jimmoore13]

Originally Posted by MichaelO

An upgrade to a bigger battery would be real handy all the time. I’ve got a pair of 6 volts at 225 ah and I couldn’t imagine boondocking with anything less.

What he said!
A pair of 6 volt golf cart batteries will deliver about 110 to 115 USABLE AH. A typical group 24 marine battery supplied by an RV dealer can deliver about 35 AH usable. You WILL need to run your generator for quite a few hours to recharge after a big draw down, but you will have the capacity to run your furnace and other equipment overnight with no danger of damaging your battery.