Need new batteries. Any advice?

[Rycher]

New here, howdy ya'll.. got a new to me travel trailer, 26ft, and am need of new batteries. there are 2 in the front, looked to be wired together. It currently has 2 old interstate deep cycle batteries (see below). looks like they have fill caps on top for water. i know some stuff about batteries but only enough to be dangerous. what would i buy that would be equivalent to the existing? are these lead batteries.. are they considered agm? any advice is greatly appreciated.

[StirCrazy]

BurbMan wrote:
If I go dry camping 5x per year, average trip 3 days, and I draw the batteries to 50% each day, that's 15 cycles/ per year. If they last 150 cycles that's 10 years for me. I don't plan on using the microwave, I only have a 600w inverter for TV and misc device charging, plus lights and fridge. The furnace is my big power hog.

yes that is a aproximat time fram, I would guess more like 5 to 8 years depending how you treat them in the off season and the quality of charge and the speed of discharge and so on..

[StirCrazy]

Gdetrailer wrote:
Steve,



Now, with Lithium batteries the BMS allows only 80% of the capacity to be used, internally the batteries are capable of another 20%.. The BMS limits your use.

Lithium battery manufacturers typically rate their batteries with 3,000 or more charge/discharge cycles.. I am here to say, that is not 100% true in all cases and those are "pie in the sky" overly optimisti
.

the res of your post was a bunch of fear mongering that has nothing to do with this chemistry so I won't make any further coment on it. this part is two but I have to corect this. a BMS will not limit you to 80, or 90 or 60% unless you set it that way. most give you the full capacity of the battery a couple companies we suspect have added extra battery capacity and limited it to 100 AH but nothing has been proven on that front. every battery rip down I have seen on a 100 amp battery has had 100 to 105Ah depening on the batteries. just like when a lead asid battery is made for the same 100AH battery some will test out at 80 some will test out at 110 and are sold as different series.

as for the cycles there is a actual cycle test and its not pi in the sky they repeatadly charge and discharge at 1C from 100 to 0 to 100%.
so one hour to discharge 1 hour to charge and they see how many times they can do it. when they slap the life on it it is a calculated average of so may trials. any time they come up with a new design or capacity they have to redo the trials and then they also have random sample tirals after every so long on established runs. is there going to be the odd one that slips through the cracks, probably would be more if they were manufactured in the US as no one would be watching them as hard.

[time2roll]

Good time to review the maintenance schedule by the looks of the old battery.

[BurbMan]

If I go dry camping 5x per year, average trip 3 days, and I draw the batteries to 50% each day, that's 15 cycles/ per year. If they last 150 cycles that's 10 years for me. I don't plan on using the microwave, I only have a 600w inverter for TV and misc device charging, plus lights and fridge. The furnace is my big power hog.

[Gdetrailer]

Steve,

When camping, I often discharge my cheapo Sams club GC2s well below 50% on a daily basis. I do however make sure they get recharged as soon as possible and doing so easily got 9 yrs of use before I noticed the batteries had lost some capacity and started to use more water. I suspect I could have rode that for another 1-2 yrs but opted to change out the batteries so I didn't end up with accidental food loss.

Usage plays a key role in purchasing decision, we camp only 3-4 weeks per yr with the same discharge pattern.. GC2 batteries ARE rated at a usage of 80% of the capacity unlike a combo RV/marine which would never survive that use.

Now, with Lithium batteries the BMS allows only 80% of the capacity to be used, internally the batteries are capable of another 20%.. The BMS limits your use.

Lithium battery manufacturers typically rate their batteries with 3,000 or more charge/discharge cycles.. I am here to say, that is not 100% true in all cases and those are "pie in the sky" overly optimistic cycles".. Lithium batteries in the whole existence of batteries are a very new technology and absolutely no one really knows just how many real life cycles they will be able to take and you add in the BMS failures which are not accounted for in the cycles rating..

Reminds me of the LED light bulb manufacturers claims of 100,000 hrs of useable life.. Yeah that IS a lie, the LEDs might last that long if they do not overdrive them, but the driver electronics often fails far short of 10K hrs..

I spent many yrs working in a high tech manufacturing job and one of the devices we designed and built was powered via rechargeable Lithium batteries.. It was used in a 24/7/365 setting.. My job was to load the software to those devices when new, and SERVICE the devices when they FAILED.

The FAILURE rates of the Lithium batteries for that device was very high after one yr of use (365 cycles) and was a common complaint of our customers. Nearly every device that came back for a repair ended up going back out with a new battery.. We sold the device with 2 additional batteries which were charged in a external charger and the batteries would get swapped after each shift change.. Basically after 365 "cycles" the Lithium batteries would start failing which puts them BELOW par with FLA..

Lithium batteries also hold a lot of energy potential in a small package, when they go south the damage is far worse than FLA..

Case in point.. Fitbit just announced yesterday a RECALL on their Fitbit ION device.. For guess what?

Yeah, LITHIUM BATTERY MALFUNCTION which has caused severe burns to end users..

"
Recall Date:
March 02, 2022

Hazard:

The lithium-ion battery in the Ionic smartwatch can overheat, posing a burn hazard.


Incidents/Injuries:

Fitbit has received at least 115 reports in the United States (and 59 reports internationally) of the battery in the watch overheating with 78 reports of burn injuries in the United States including two reports of third-degree burns and four reports of second-degree burns (and 40 reports of burn injuries internationally).
"


Catastrophic Lithium battery failures are not new nor unusual, most of those failures never ever make it outside the walls of that company (I know the failures that hurt users of my companies devices didn't). Companies typically find ways to keep things quiet.

Wasn't all that long ago that a huge recall was issued by all laptop manufacturers for faulty Lithium batteries which could short out due to contamination that happened during manufacturing of the cells..

And before you say anything about the size and differences of lithium types, you do need to understand that ALL of the "12V" lithium batteries you are talking about are composed of multiple SMALL lithium cells which are in series and parallel setup inside that case. Each cell has a nominal 3.8V voltage potential so it takes a minimum of 3 cells in series to get you to "12V", each cell is capable of about 2Ahr so it take many series strings to arrive at 100Ahr of capacity..

All it takes is just ONE of those cells to short internally and the whole thing goes out of control.

Many here on this forum do not really understand the firecracker you are playing with.

You also ignore another issue, recycleabilty of the batteries..

FLA is readily and actively being recycled, all of the new FLAs being do have either a percentage or could be up to 100% reclaimed Lead! Very cost effective and less junk going into hazardous waste or landfills.

Lithium batteries, well, no recycled or reclaimed content in them, it is ALL 100% NEW materials.. While there has been some small scale attempts to breakdown and reclaim the base materials in Lithium batteries it is too cost prohibited to scale it up to the same levels as FLA reclaimers can do. When your large scale lithium batteries die, they will accumulate in backlots, warehouses, landfills.

[StirCrazy]

Gdetrailer wrote:




Current price of FLA 6V GC2s at Sams club is running about $90 each or $180 for 168Ahr at 80% use or 105Ahr at 50% use..

$180 FLA is still a lot less than $299 for Lithium.

If weight is a factor, Lithium wins on that aspect.

If cost is the factor, FLA wins hands down.

If it comes down to life, FLA can easily last 7-10 yrs even with using as much as 80% of the capacity.

Track record of lithium life is still in flux and not really known for sure and what little published information is out there is typical manufacturers over hype to sell a product.
.

guess we need a bit more ballance here haha' you forgot the size advantage also 😉

you not going to get full life of a GC2 running at 80% capacity, you will get the min life usaly around 680 cycles and your definatly not going to get 7 to 10 years with a costco or sams club GC2 maybe 3 to 5 running that load level. now if you spend the bucks and get a GC2 like a rolls surrett ya you could probably get 5 to 7 years at that level. but what we forget about in Lead asid batteries is the Peukert effect, so while we thing we can get x apmount of AH the harder you draw the less you actualy get, plus the ineffiencies in resistance that works both on charging and discharge. for example to use a deicent microwave in my 5th wheel I had to install 4 GC2 batteries so the voltage would stay high enough for a reasonable amount of time to prevent the inverter from going into alarm, and even then once I start getting close to that 50% capacity all it does is alarm. thoes are four good quality 6V batteries that were close to 300 each (canadian) using my discout from work so about 1200 worth of batteries proabably close to 1500 with out my discount. so when we look at cost vs preformance then LFP wins hands down. Ill use my expensive lead asid batteries to give a fair comparison .

4 batteries for 480AH = ~240 usable AH for maximum life estimated to be around 1000 cycles for 1200 bucks . so over the life of the battery used at 50% capacity if we asume it dies at 1000 cycles, which would be a good life it will have provided 240000AH at a cost of $1.00 /200AH

now if we take two average LFP say 500 bucks each (kinda a middle price now) for 100AH each and I'll even give you that I'll only use 90% of the battery ... actualy Ill do two, becasue there cycle life is a 100% usage rating. so 200AH for 3500 cycles for 1000 bucks give you 700000AH over the life at a cost of $1.00/700Ah

but this is only the start. thoes two LFP will stay above 12V output untill aproximatly 10% capacity and have such a low Peukert effect it is concidered unimportant, so this means at a high amprage draw you would get the full capacity instead of a lower amount. this combined with the voltage numbers will alow you to dive much deeper into the lower end of the battery before your inverter starts alarming resulting in even more real world capacity.

as for the life bay cycles it is not a unproven number but what people fail to understand when you say the life of a lead asid battery that means it is normaly done and needs to be replaced after the number of cycles. With the LFP the cycle life is just to the point to which the battery is reduced to 80% of its original capacity (kinda like how the life span of solar panels are rated) so lets say that 200AH bank was used at 100% capacity for 3500 cycles (or what ever the manufacture states the life is) it is now a 160AH battery which could last even longer than the original as the degradation slows as time goes on. this is the part that is unknowen, how long can you use it as a 160AH battery , could be 5 year, 10 year or 20 years...

now is LFP the perfect battery, nope close but has some draw backs. cold weather camping being the most significant one, but can be overcome if you want to. charging. to get the best charging to them your going to need to change out your charge section of you power center, but if you have a WFCO I recomend this anyways lol. as for BMS, I wouldnt worry about them as they are part of the battery.. not really many stores of them going bad, probably just as many stores of "I bought batteries at sams club and there no good after 3 months....

the only advantage I see in getting lead asid batteries at the pricepoints out there now is if ou just don't have quite enough to get thoes LFP batteries you buy the cheep sams club or costco batteries to tide you over. thats what I did this last summer when my expensive batteries gave up the ghost after 13 years. bought four costco batteries (160 each up here though). this will last me till shipping comes back down battery cells.

Steve

[jdc1]

Cummins12V98 wrote:
Go to Costco and replace with exactly the same thing!!!

Ditto. Less than $200.00. Be sure to mark which wires go where BEFORE removing them.

Trojan vs Costco 6V battery:
https://www.youtube.com/watch?v=RO4N_V4Azvc

[pianotuna]

Rycher,

In the link to freecampsites that I posted, there is a spreadsheet that may be downloaded to help with an energy audit. There is also a strategy for doing direct measurement of energy used.

[valhalla360]

Rycher wrote:
Wow i woke up to some great advice.. i really appreciate it guys..
and yes if my trailer is on its side i have bigger issues then batteries. ha
usage is still under scrutiny by the wife. id like to boondock for sure. we are in texas so i'd like to go out to crystal beach, big bend, etc. i didnt realize the existing batteries were 6 volt. glad i asked.. i thought they were 2 12 volt batteries wired together. thats what i meant when i said i know just enough to be dangerous. i will be purchasing a dual fuel generator for boondocking so i wont be on battery power the whole time. its sounding like 2 6 volt golf batteries will be my best bang for the buck. able to draw them down farther.. also would give me the power i need while i navigate the rv world. any specific brand or model you all suggest?

I'd still like to see you do an energy audit (look at what devices are going to run and how long you want to run them...then add up the watt-hours to determine what size battery bank you need).

But in general terms, what you describe is probably (not for sure) suitable to a pair of golf cart batteries. With the generator, you can top up the batteries each day if needed.

Keep in mind:
- Don't take them below 50% charge as that will quickly wear them out.
- When charging, up to 80-90% charge goes pretty quick but after that the charging slows down. Consider getting a 100w solar panel (it can be portable), so you can fast charge in the morning up to 80-90% with the generator and then the solar panel will slowly fill the rest over the day.
- Being in Texas, if you plan to use air/con, get a generator of at least 3000w (3500-4500w would be even better). Go inverter generator to keep the noise more reasonable.

[Rycher]

Thanks Burbman. appreciate the reply.. i'll look at the duracells .. im a big fan of reviews and would rather not buy something and replace it in 2 years

[Rycher]

alot of great info there Gdetrailer. appreciate it. i looked at costco and found this battery. is this what im looking for?

https://www.costco.com/interstate-6-volt-golf-cart-battery.product.100476406.html

i notice there is another model of this battery sold elsewhere labeled "extreme".. part number GC2-ECL-UTL. is the price difference worth it?

https://www.campingworld.com/interstate-gc2-deep-cycle-extreme-6-volt-golf-cart-battery-71706.html

i saw another battery called a trojan 105.. but they are pretty high.. read of others buying them for around 130 but i didnt find that price anywhere

[BurbMan]

Lwiddis wrote:
With Lithium battery prices today, lack of need to recharge fully on a daily basis, and their long life, the choice is clear.

Yes...the choice is clear: the best bang for your buck is still 6v flooded lead acid. I just went through this analysis for our new-to-us 5er and really wanted to go with 4 12v 100a/h lithium batteries. You can get a name brand Renogy on Amazon for $399.99, so 4 of them is $1200. Duracell GC-2's that are 6v 230 a/h are $144.99 each, and even with core deposit I'm at half of what lithium batteries cost. Plus I get 460 a/h vs 400 a/h.

When we had our TT I had a pair of GC-2's on the tongue that worked very well for the years we had we had the trailer.

Note to OP: read the reviews on the Costco website, many, many complaints about their Interstate GC2's not lasting even 2 years and Costco just saying the warranty is up, buy another one.

[pianotuna]

Rycher wrote:
New here, howdy ya'll.. got a new to me travel trailer, 26ft, and am need of new batteries.

My next battery bank will be SiO2. Li are FAR too fussy, and I need cold weather use at temperatures far below what LiFePo4 can handle.

Golf cart batteries would be a 2nd choice.

If you plan to boondock--add some solar. For more information on batteries as well as solar surf here:

https://freecampsites.net/adding-solar/

[Gdetrailer]

Lwiddis wrote:
With Lithium battery prices today, lack of need to recharge fully on a daily basis, and their long life, the choice is clear.

Catch fire? Similar to the “you’ll see blown off solar panels all over the road” opinions of years ago.

Blanket statements like this need a bit of balance.

Lithium battery prices today have come down, but they are still substantially much higher than FLA.

Example, the most recent lowest price I have found on 100Ahr Lithium battery is $299, but that is an unknown fly by night import brand with unknown quality, assembled with unknown and untraceable parts, with unknown reputation.

Yes, it is possible you can use all 100Ahr, but keep in mind, the real capacity contained in a Lithium pack is higher than 100 Ahr.. The BMS is designed to allow less usable capacity than what is contained inside the pack intentionally.

One of the major downfalls with the flood of cheap Lithium packs is quality. Cheaper does not mean it is better and cheaper may be made from grey market cells which did not make it through the QA process for top quality which were literally pulled out of the floor sweepings.. Manufacturers do not scrap parts that do not make the top quality specs, instead they often take the "seconds" and sell them to the grey markets.

Additionally you have the possibility of a BMS that may or may not do it's job properly..

BMS malfunction can be catastrophic in nature as it can fail in many different ways and some failure modes can result in less than desirable outcomes..

On the other hand FLA is a well known stable old school battery tech manufactured on a very large scale by well know good reputation battery manufacturers.

FLAs do not need or use a BMS.

one pair of 6V GC2 batteries gives 210 Ahr of capacity, their charge/discharge cycle rating typically allows for up to 80% of that capacity to be used with no reduction to the life of the batteries so in reality you have 168Ahrs to play with. If you want longer life than the rated cycles you can discharge them to 50% and increase the life span which gets you 105Ahrs worth of capacity.

Current price of FLA 6V GC2s at Sams club is running about $90 each or $180 for 168Ahr at 80% use or 105Ahr at 50% use..

$180 FLA is still a lot less than $299 for Lithium.

If weight is a factor, Lithium wins on that aspect.

If cost is the factor, FLA wins hands down.

If it comes down to life, FLA can easily last 7-10 yrs even with using as much as 80% of the capacity. My first set of FLA GC2s which I use to power a home fridge conversion resulted in 9 yrs of use before I noticed a reduction in capacity and I heavily beat those batteries at times.

Track record of lithium life is still in flux and not really known for sure and what little published information is out there is typical manufacturers over hype to sell a product.

A lot of the decision boils down to usage, space, weight, cost..

My own experiences with smaller lithium packs used in industrial settings makes me shy away from going large scale whole hog into them.. Often the BMS would fail after a couple yrs of 24/7/365 usage resulting in batteries that stopped charging and would not power the devices.. A couple of BMS failures resulting in device malfunction and overheating with a few reports of serious burns..

I have a great respect for the energy storage potential in such a small package..

[Cummins12V98]

Go to Costco and replace with exactly the same thing!!!