Group 24M Lithium Batteries

gurroz · 03-06-2020, 05:54 PM

So we are thinking about upgrading to lithium batteries. Battle Born does not offer a group 24 size battery. We want to make sure we are buying a product that can be replaced as we travel if a problem arises. Has anyone used the 12V 75AH Lithium Battery Replaces BCI Group 24M Starting Marine, RV offered by Walmart? It is priced at $550 and is the same size as my current group 24's so two would fit side by side. Specs are as follow:

ML75-12LI is a 12V 75Ah group 24 Lithium iron phosphate sealed, rechargeable and maintenance free battery. Direct drop in lead acid replacement.
Dimensions 10.16 inches x 6.54 inches x 8.46 inches. Listing is for the battery and screws only. No wire harness or mounting accessories included.
Stronger, Lighter and Longer 2500 cycle life expectancy compared to the traditional sealed lead acid batteries.
ML75-12LI is a 12V 75Ah group 24 Lithium iron phosphate sealed, rechargeable and maintenance free battery. Direct drop in lead acid replacement.
Dimensions 10.16 inches x 6.54 inches x 8.46 inches. Listing is for the battery and screws only. No wire harness or mounting accessories included.
Stronger, Lighter and Longer 2500 cycle life expectancy compared to the traditional sealed lead acid batteries.
Designed for safety with built in Battery protection BMS. BMS provides high voltage protection, low voltage protection, over high current protection, high temperature protection, short circuit protection, and over charge protection. Designed to be used in parallel with a maximum of 4 identical batteries. Do not connect in series. Make sure to only use a compatible lithium charger for this battery. Having loose terminals will cause a buildup of heat resulting in damage to the battery.
Backed by a 30 day refund policy and 2 year warranty.

Winterbagoal · 03-06-2020, 08:54 PM

The question is totally vehicle specific.
The specifics noted mean nothing to the vast majority of us.
As a wild guess, the answer is, "maybe".

gurroz · 03-06-2020, 10:46 PM

On the MW 25B the batteries are located under the step. Two group 25 batteries fill the battery storage compartment. We are restricted from using larger batteries as there is no extra height, width or depth. I am looking for a lithium option. My question is has anyone used the batteries listed in my original post?

**creativepart** · 03-07-2020, 06:48 AM

I can’t answer about those batteries, but there are many other RV owners that change the battery location to accommodate larger batteries. Most seem to use a compartment adjacent to the original location. Have you looked at that?

Also, might one larger battery with 125aH or more replace your two 75aH batteries in that space?

Another option, It costs more, but it’s a name brand, here is a ReLion Group 24:

https://relionbattery.com/products/lithium/rb75

gurroz · 03-07-2020, 07:39 AM

Because the 25B is a smaller MH I do not want to give up any storage. I currently have two 85ah AGM batteries located under the stairs giving me 85ah of usable power. I am looking to increase the AH not decrease. Renogy makes a 200ah AGM battery, however it is too large for our compartment. Two 75ah lithium batteries gives us 150ah a significant increase. The Relion battery looks comparable to Battery Max, however, it's $300 more expensive and most importantly does not have WalMart's nationwide stores to replace a damaged battery. I remember watching a YouTube RV channel where the guy bought new batteries from a battery store in California and one died on the east coast. While it was under warranty he still had to buy two new batteries on the east coast. He ended up buying replacement batteries at Auto Zone because they had stores across the country. Thanks for the Relion link, they do offer alot of specs.

**creativepart** · 03-07-2020, 08:44 AM

I'd take a deeper look if I were you. It's not exactly how you've described it. I doesn't appear that you will be getting the easy Walmart replacement you are looking for:

One, it's only available online. Not in stores. Not even store pickup.
Two, it's actually sold by eComelectronics, Not Walmart
Three, it has 60 1-star reviews and most of those are trouble getting replacements

Here's one of the 1-Star Reviews:

Purchased through Walmart, no returns allowed, waste of time and money, battery left me stranded at a motorcycle rally.

Morich · 03-07-2020, 08:54 AM

Also there may be questions on getting any warranty if used in RV as the charging is going to be a question. At that price point and with the other considerations, I would first look at one of the small cheap generators as an option. Battery tech is coming but I do not find it effective for small RV use yet.

**creativepart** · 03-07-2020, 09:14 AM

Quote:

Originally Posted by Morich

Battery tech is coming but I do not find it effective for small RV use yet.

Morich and I have to agree to disagree on this statement.

Your logic of changing to LiPo batteries is sound and the extra power will come in very handy. However, you do need to take a look at the issue of alternator charging of these batteries.

I've seen three or four schools of thought on this:

1. Don't worry, do nothing and let your alternator charge the house bank
2. Worry a lot and disconnect the alternator from charging the house bank
3. Purchase and install a LiFePO4 Battery Isolation Manager ($175 at Battleborn)
4. Purchase a DC to DC charger that sits between the alternator and the battery bank to control alternator charge rates. ($265 from Victron)

And, in rare cases people install a separate second alternator on their engine to custom charge their LiPo Batteries.

Do you have a plan yet?

gurroz · 03-07-2020, 10:30 AM

Thanks for the feed back. I was planning on running a Victron Battery monitor and a DC - DC charger. We carry a Yamaha 2000 inverter/generator and have a 200 watt Renogy solar suitcase. In addition we use a portable 500 watt solar generator to power the TV at night. Maybe the two Relion batteries will be the answer. We travel 5 months out of the year May - September and boondock a lot (25 nights per month.)

orangeminnie · 03-15-2020, 04:30 PM

A few thoughts:

1. It's unlikely that you'll need a replacement, if they are properly installed, and charged. If you do, you'll have at least the one other battery to tide you over.
2. Most popular brands can be shipped quickly to you, wherever you may be.
3. Lion makes a size 24 in a full 100Ah, as I recall. 10.2" long. The Battleborn GC2 is 10.3" long.
4. For serious boondocking, if you can fit in more than 2 batteries, you'll eventually be glad that you did.

tjwoody · 03-15-2020, 04:41 PM

The Renogy 100 ah battery also fits the group 24 specs. 10.2 x 6.2 x 9.7

A little tall, but it will likely fit your compartment.

Tucsontoy · 03-15-2020, 05:07 PM

I have three of these in a solar power trailer used for remote power. Can be towed anywhere. Can be found for about $650 each.

jerichorick · 03-16-2020, 07:39 AM

Quote:

Originally Posted by gurroz

On the MW 25B the batteries are located under the step. Two group 25 batteries fill the battery storage compartment. We are restricted from using larger batteries as there is no extra height, width or depth. I am looking for a lithium option. My question is has anyone used the batteries listed in my original post?

Picked this spot to pop in.
I need to replace my 10 year old (6ea) AGM battery bank. With much research I have found that I can use re-claimed Nissan Leaf batteries from ebay and a 200A bms. My Magnum inverter will work. Because of the dimensions of the 8V, 66Ah packs they can be stacked in many ways to fit the space available. Even these 70%+ life remaining modules will give me sufficient life and power at about the same cost as a new set of AGM's, or less, and I will have a great reduction in weight.
Just a thought for you to look into.
Happy trails,
Rick

**creativepart** · 03-16-2020, 08:24 AM

Rick, are you making a 24v battery bank?

BobC · 03-16-2020, 09:19 AM

From what I've read, it's not too complicated to install a 24V to 12V DC converter but you're going to give up some energy. I see some that advertise 90% efficiency but that's unlikely to be unobtainable in a real life installation. You'll need to weigh the cost of the converter, plus the efficiency loss to your savings in battery cost and space were you to go the 24V Nissan Leaf battery route.

It's an intriguing solution but keep in mind that the Nissan Leaf batteries are LiMn2O4 vs. the somewhat safer Lithium Iron Phosphate batteries (LiFePO4) such as those sold by Battleborn and others.

There's a Youtube channel, DIY Solar Power with Will Prowse, that has a lot of information on this and other topics. Here's a video that addresses 24v systems. Although he's addressing a solar installation, his comments are valid even if you're skipping the solar part. The discussion about converters starts at about 5:15 (including RV comments) into the video. He also addresses charging from your RV alternator at about 7:58:

https://www.youtube.com/watch?v=Vi7eswWwosk

If you explore his Youtube channel, you can learn a lot. Here's a link to his channel. If you're interested in building your own battery bank, 24V, 12V, etc. from modular cells, he has a number of such DIY videos:

https://www.youtube.com/user/errolprowse/featured

Now that most of us are sticking close to home, it's a good time to hunker down and educate ourselves.

JoeC · 03-16-2020, 09:55 AM

Try RELiON battery (relionbattery.com). They have about any size you would need. The RB75, 75 ah battery, should fit the group 24 space. Happy camping.

jerichorick · 03-16-2020, 11:22 PM

Quote:

Originally Posted by creativepart

Rick, are you making a 24v battery bank?

Great question. Short answer is NO.
Each pack is rated at 8V & 66Ah when new. The ebay packs are rated at 70+%. For best life of a lifepo4 cell it should not be fully charged or discharged. So, 2 banks of 7 cells each in parallel wired in series will give a battery that can be charged to ~13.6V and deliver ~400Ah. I don't do much dry docking so this should be fine for me. I will put a 200A BMS on the bank. The Magnum inverter will work just fine in this arrangement. I like the idea of shedding a bunch of weight. Dropping from ~450# to ~112# is a great weight savings. I do have to do some custom battery box work to keep the environment for them stable, but that will not be a problem.
Happy trails.
Rick

BobC · 03-17-2020, 12:09 AM

Quote:

Originally Posted by jerichorick

Great question. Short answer is NO.
Each pack is rated at 8V & 66Ah when new. The ebay packs are rated at 70+%. For best life of a lifepo4 cell it should not be fully charged or discharged. So, 2 banks of 7 cells each in parallel wired in series will give a battery that can be charged to ~13.6V and deliver ~400Ah. I don't do much dry docking so this should be fine for me. I will put a 200A BMS on the bank. The Magnum inverter will work just fine in this arrangement. I like the idea of shedding a bunch of weight. Dropping from ~450# to ~112# is a great weight savings. I do have to do some custom battery box work to keep the environment for them stable, but that will not be a problem.
Happy trails.
Rick

Rick,
Keep us posted, I'm intrigued.

JoeC · 03-17-2020, 06:52 AM

My $.02. Be careful trying to engineer this stuff on your own, unless you are a trained battery technician or engineer. What are you using to balance the individual cells? This stuff is not "plug n' play". You may end up wasting a bunch of money on an expensive POS.

jerichorick · 03-19-2020, 11:18 AM

Quote:

Originally Posted by JoeC

My $.02. Be careful trying to engineer this stuff on your own, unless you are a trained battery technician or engineer. What are you using to balance the individual cells? This stuff is not "plug n' play". You may end up wasting a bunch of money on an expensive POS.

Thanks, Joe, for your concerns. I do have a bit of battery experience from tech training many long years ago and some power work before I retired from the phone company in '02.
There is a lot of info online concerning this use of Nissan Leaf battery packs. One thing that is stressed is making certain that all of the cells are close to the same condition and charged to the same value. Also, because my 12V requirement is well below the max voltage of the battery, this is a good thing for safety and longevity. The 200A BMS I will be using will provide some protection and balancing. The ebay company will get the cells from has a good reputation for providing matched cells.
The last piece of the puzzle is the "fuel" gauge. A friend has a Victron BMV-712 Battery Monitor on his solar system. Once set up it should keep me advised as to the condition of my Lifepo4 battery bank.

At this moment all of this is just a dream. I hope my old AGM bank will hang in there a bit longer. Because I am retired my available funds are not very healthy now. When the country recovers from this virus in a few months, then I will go for the purchase. I am very optimistic about the future. Panic is the real disease we are suffering from as a nation.
Happy trails.... Rick