Battery upgrade.. how in a 4winds with....

[bigcitypopo]

an outside battery tray, that will hold one group27...

move the batteries inside and use AGM?

it a 4winds Majestic 23... it is my mom's she got it from reserve america.. its been a great coach. the single skyline battery in it is on its way out. it only holds 12.0v after a full charge.


any recs would be great, or any upgrade ideas?

i'm just now learning the quirks of her class C,

[jwcolby54]

SJ-Chris wrote:
To add an extra battery, I converted (on Majestic 28a RVs) one of the small driver side compartments into a battery compartment. One battery fits with a little room to spare. I drilled some holes in the side of the compartment for ventilation. I also added some straps underneath and to the frame to give it additional support. With this, I was able to add a 2nd battery to my Majestics. No problems for several years so far.

I also have a 23' Class C RV. It came with 2 batteries in the entry step that I replace with GC 6v batteries. I notice that on this 23' RV I also have a small compartment on the driver's side that I have never used, but in theory it could be used for an extra battery. Maybe your 23' Majestic has a similar storage compartment you could convert.

Good luck!
Chris

Chris, I am looking to take possession of a 28a next fall, roughly Sept 15th. Yea I know, a long way out, but I have to clear the decks and it will take a fair bit of coordination. My sis lives in Mesa and so I want to buy through that location so I can fly out and observe the refurb, inspect it, fixing everything found etc.

With no ability to lay hands on one of these units I am a bit nervous.
Do you know where the original battery is located? Is it tight or is there a lot of room around it. I would like to replace the original with a 200ah lithium, or even 300ah if there is enough room. Likewise I'd love to get 800 watts of solar panels up on the roof before heading back home to NC. IIRC you put solar on your roof. It looks like a huge area back at the back of the roof. Any thoughts on these things?

[SJ-Chris]

To add an extra battery, I converted (on Majestic 28a RVs) one of the small driver side compartments into a battery compartment. One battery fits with a little room to spare. I drilled some holes in the side of the compartment for ventilation. I also added some straps underneath and to the frame to give it additional support. With this, I was able to add a 2nd battery to my Majestics. No problems for several years so far.

I also have a 23' Class C RV. It came with 2 batteries in the entry step that I replace with GC 6v batteries. I notice that on this 23' RV I also have a small compartment on the driver's side that I have never used, but in theory it could be used for an extra battery. Maybe your 23' Majestic has a similar storage compartment you could convert.

Good luck!
Chris

[bobndot]

Pianotuna, ok thank u.

[pianotuna]

jwcolby54 wrote:

pianotuna wrote:
Hi,

I think LI are wonderful. They are, unfortunately, not a good fit for me.

When the RV is in storage it gets down to -40, so no you can't help.

I have to laugh. Folks winterize their water systems all the time but can't winterize their batteries? It is called a battery disconnect switch. LiFePO4 batteries have very low self discharge. Charge it and then turn the disconnect switch. Done.

And no, I can't help you.

Perhaps I can help you. Li batteries best practise is to charge to 50% for long term storage. If one really wishes to push the envelope, discharge no lower than 40% and recharge to 85%. Every thirty days do a cycle to 100%.

The exception currently is to use Lithium Titinate. I can't afford $2000.00 per 100 amp-hours.

I hope the new solid state batteries will be usable in extreme cold.

[pianotuna]

Hi bobndot,

Yes, but not for long term winter storage. Best to charge to about 50% then disconnect. Make sure the heating feature is turned off.

I use reconditioned telcom jars. Cost is $1 per amp-hour. Mine are now six years old and meet my needs. They are maintained by a solar charging system during the winter.

[jwcolby54]

Heated batteries do work as advertised. Te problem is that they use part of their own stored energy to heat themselves. There is no free lunch. If you plan to use these then do yourself a favor and insulate the battery storage compartment so that the batteries can use less of their power heating themselves.

If you live in very cold country you have to deal with the cold. You have to insulate your water systems or completely drain them for winter storage. Well... lithium batteries need to be insulated as well, or charged and then disconnected. The lead lovers among us have other tradeoffs.

[bobndot]

Do these heated lithiums work ?
This link also includes a video to explain.

https://rvlifestyle.com/cold-weather-lithium-battery-problems/

[jwcolby54]

pianotuna wrote:
Hi,

I think LI are wonderful. They are, unfortunately, not a good fit for me.

When the RV is in storage it gets down to -40, so no you can't help.

I have to laugh. Folks winterize their water systems all the time but can't winterize their batteries? It is called a battery disconnect switch. LiFePO4 batteries have very low self discharge. Charge it and then turn the disconnect switch. Done.

And no, I can't help you.

[pianotuna]

Hi,

I think LI are wonderful. They are, unfortunately, not a good fit for me.

When the RV is in storage it gets down to -40, so no you can't help.

[jwcolby54]

pianotuna wrote:
jwcolby54,

Lead acid brand new need to have several discharge recharge cycles to reach their full capacity. This was not done prior to the testing.

https://batteryuniversity.com/article/bu-804-how-to-prolong-lead-acid-batteries

Further lead acid do best when discharge is limited to about 1/4 C.

I love li batteries but can't use them due to cold weather. I boondock at -34 F. My first battery bank was 875 amp-hours.

LOL, which has nothing to do with the big picture results. If you like lead acid, use lead acid. Just don't try to do high current long time period draws, regardless of how many cycles you have already used the battery.

More stuff on lead acid

And as for the temp thing, move the battery inside your camper. Or insulate the battery box well. Or heat it. Or both. Unless of course you are letting the inside of your camper reach -34 F in which case I can't help you.

Again, there are those willing to fall on the sword for their lead acid batteries. I am not. What you do with your rig is none of my business, but to claim lead acid is the best thing since sliced bread ... it is not. Sliced bread makes much better PB&J Sandwiches.;)

[pianotuna]

jwcolby54,

Lead acid brand new need to have several discharge recharge cycles to reach their full capacity. This was not done prior to the testing.

https://batteryuniversity.com/article/bu-804-how-to-prolong-lead-acid-batteries

"Formatting is most important for deep-cycle batteries. They require 20–50 full cycles"

Further lead acid do best when discharge is limited to about 1/4 C.

I love li batteries but can't use them due to cold weather. I boondock at -34 F. My first battery bank was 875 amp-hours.

[jwcolby54]

pianotuna wrote:

jwcolby54 wrote:
I found a very good youtube video on lithium vs lead acid. It is by an engineer who did extensive side by side testing in the lab where he could get consistent results for each battery type he tested. It is somewhat long but very thorough.

https://youtu.be/iy3hga_P5YY?si=tr2yG_na_vB5rHmQ

It was done at BattleBorn but the results are the same for other manufacturers.

Thanks for finding and posting this.

Unfortunately they did not cycle the lead acid batteries BEFORE testing.

Lead acid / agm are rated at 25 amps discharge, so testing at 40 amps is not a level playing field.

The low voltage cut out is interesting. I wonder if going to 10.5 UNDER load is the same as discharging capacity to 10.5 volts?

Last winter because of snow cover my house bank went to 8 volts. It has recovered nicely.

I do use my rv at -34 f so Li unfortunately won't be in my future.

Let me start by saying that I am not an EE, however my job for 15 years was fixing electronics, back in the day when a thorough understanding of all things electronics, schematics, o'scopes and soldering irons were the tools of my trade. So I understand this stuff fairly well.

The fact is that lead acid works quite well if you pretty much stay plugged in, or only use the battery for led lights and the water pump etc. Trying to put a high current long draw device on it is where lead acid fails rather spectacularly.

As for 25 amps vs 40 amps level playing field... there is no level playing field. One doesn't get a choice about current draw. Once doesn't get to "cycle before" etc. One turns on a device and one gets what one gets. The Puekert effect is real. Put a 2kw inverter on a lead acid and enjoy the show. Put it on a LiFePO4 and enjoy your hot coffee from your microwave. It really is as simple as that. Even several lead acid batteries in parallel will droop radically under heavy load. I know, I have watched it. Many electric devices do not enjoy trying to run at 11.9 volts which is a very real result of a very high current draw on lead acid.

Every tool has it's uses. Lead acid's use case is low current over long times. Or (for starter batteries) extremely high current over extremely short times. It is decidedly not extremely high current for more than a few seconds. Whatever you do, do not attempt to run an inverter higher than perhaps 500 watts on lead acid, and try to pull full power for long times.

One final thing, LiFePO4 simply doesn't care if you fully discharge it. Lead Acid will die rather quickly if you do that repeatedly.

Every tool has its place.

[DaCarmack]

I ran into the same problem as you are. I have a coachman Concord 275DS. There's only enough room for one battery without extensive modifications that do not want to do. If You have the measurements of your battery box You can look at AGM's in the solar field. I put a battery called a mighty Max It was 135 amp hours that worked really well. Then I came into possession of a battery called NPP that is 155 amp hours. This was the biggest battery high-wise I could fit in my box that's in my step. The only modification I had to do was to extend the threaded rods for the safety strap. Now if I'm at a rest stop I don't have to worry about power. we can turn on this light or that light, we can be wasteful is the best way to put it. You do need to make sure that your converter can charge it at the right voltage which I believe is 14.6v, the one I have is just at the minimum and I haven't had any problems

[pianotuna]

jwcolby54 wrote:
I found a very good youtube video on lithium vs lead acid. It is by an engineer who did extensive side by side testing in the lab where he could get consistent results for each battery type he tested. It is somewhat long but very thorough.

https://youtu.be/iy3hga_P5YY?si=tr2yG_na_vB5rHmQ

It was done at BattleBorn but the results are the same for other manufacturers.

Thanks for finding and posting this.

Unfortunately they did not cycle the lead acid batteries BEFORE testing.

Lead acid / agm are rated at 25 amps discharge, so testing at 40 amps is not a level playing field.

The low voltage cut out is interesting. I wonder if going to 10.5 UNDER load is the same as discharging capacity to 10.5 volts?

Last winter because of snow cover my house bank went to 8 volts. It has recovered nicely.

I do use my rv at -34 f so Li unfortunately won't be in my future.