Single Lithium Replacement for 2xGrp 24s?

[BikeCamper]

Originally Posted by DCPAS

I don't know what I am talking about either, but I would stay with the 100 amp on the logic that since you are not changing the capability of the trailer to accept higher amps, you wouldn't want more than 100 amps freely going into the trailer.

Not an expert, either, but this was my thought, too.

[JeffKim]

Originally Posted by mastree

Thank you, JeffKim.

I appreciate the suggestion for the T Class fuse. After a quick search, I thinking that something similar to this: https://www.amazon.com/uxcell-Multi-...ef_=ast_sto_dp would work. I would install it on the wall of the battery box and run a jump line from the battery and then connect all of the positive feeds to the protected side.

My question now is about the size of the fuse needed- Stick with the 100amp that was removed? I still running the stock 1000w inverter and do not foresee upgrading it.

I am using the stock converter/charger for now but I will be installing a lithium compatible unit soon. (Probably progressive dynamics). https://www.etrailer.com/RV-Power-Co...cs/PD79RR.html

Thanks

I'm not an expert but I can pretend. Fusing is mostly to protect the wiring. So fusing higher than the wire can carry is bad. If Airstream in its infinite wisdom has fused the wire to 100A then I wouldn't go any higher. (As an aside, when I was rewiring our camper I used a wire gauge guide like this one knowing what the approximate loads were going to be.)

As I said I believe there should be two fuses, one leading to the positive bus bar and the other to the inverter. Assuming the wiring is adequate, the inverter is 1000W so the most load it could provide is approximately 1000/12 = 83A. Usually, a 20% buffer is added so that's about 100A fuse.

Looking at our 2023 wiring diagram the inverter is 4AWG and the positive bus bar wire is 6AWG and has a 50A MRBF. The inverter has one as well in the diagram but it's unspecified but I think it's the 100A you have. The positive bus bar also has a 50A breaker but I doubt it would hold up to a large current so you need something like a T-class or MRBF at the battery.

As a real-life example, I was foolishly trying to fish a live wire from the positive bus bar through the rats nest and the exposed end brushed against the copper grounding wire. Sparks flew and it blew my 100A MRBF. Not something that's ordinary but it's there for a reason.

[mastree]

Great suggestions about the fuzes main role to provide protection of the wiring, thank you.

I will do some additional investigation and try to determine if the positive bus in the birds nest has a fuse installed.

It might make the most sense to install a new positive bus bar in the battery compartment and then fuse the inverter feed with a 100amp t type and the positive feed to the in-camper bus bar with a smaller fuse to match its wire size.

I have to mention that I am really impressed so far with the additional capacity of this new 300ah battery! On Monday I charged it up to full capacity with the stock lead acid converter/charger to 13.8v (vs 14.6v that a lithium charger will provide). After 3 days of being unplugged from shore power and with the 12v fridge running there is still 63% of power remaining (13.3v). There has been minor charge from the solar panels since it is parked under a large oak tree.

This seems to be the solution I was hoping for with added boon docking ability without reconfiguring the entire battery / electrical configuration of the trailer. Once I get the proper charger installed and fusing of the power supply, I will be ready to go!

Here are some screenshots from the Epoch app from Monday and the morning and also from the Victron app which are not calibrated properly until a few charging cycles with the proper controller can be run.

[3OnOurWay]

Sorry I added to the confusion, yes 100% fuses protect the wiring / cables which must be sized to the load. I should have included the battery is capable of a significantly higher load and to not forget that the electrical system ( new battery) won’t perform to its full max load capacity if the system isn’t matched.

When I reread your last post i understand you are looking for increased length of time between discharge / not an increased draw/ demand of load on the system. Sorry about the confusion

[BikeCamper]

Originally Posted by mastree

Great suggestions about the fuzes main role to provide protection of the wiring, thank you.

I will do some additional investigation and try to determine if the positive bus in the birds nest has a fuse installed.

It might make the most sense to install a new positive bus bar in the battery compartment and then fuse the inverter feed with a 100amp t type and the positive feed to the in-camper bus bar with a smaller fuse to match its wire size.

I have to mention that I am really impressed so far with the additional capacity of this new 300ah battery! On Monday I charged it up to full capacity with the stock lead acid converter/charger to 13.8v (vs 14.6v that a lithium charger will provide). After 3 days of being unplugged from shore power and with the 12v fridge running there is still 63% of power remaining (13.3v). There has been minor charge from the solar panels since it is parked under a large oak tree.

This seems to be the solution I was hoping for with added boon docking ability without reconfiguring the entire battery / electrical configuration of the trailer. Once I get the proper charger installed and fusing of the power supply, I will be ready to go!

Here are some screenshots from the Epoch app from Monday and the morning and also from the Victron app which are not calibrated properly until a few charging cycles with the proper controller can be run.

Wow, that is great performance with a 12V fridge. Our fridge runs on propane when off-grid, so I am confident this is going to be a great solution for us to replace our 2xGrp 24 lead acid batteries. Thanks for this feedback.

In colder weather, our biggest power draw seems to be the propane furnace. Were you also operating your furnace during this recent test?

[mastree]

No worries - 3OnOurWay. All input is appreciated and helps with the learning process.

BikeCamper - No, I was not running the furnace but based on the limited draw so far and the fact that the battery was not charged to its full lithium capacity, I believe that at least a 2-3 time my original boon docking ability while running furnace and fridge with the upgrade.

The previous owner of my trailer swapped the fridge for a 12v only model which some say is a benefit but I probably would have preferred having the ability to run it off of propane as well. That being said, the new setup with my recently added solar and this battery should serve future boondock camping well especially if there is some sun on the panels.

[jeffmc306]

Selecting the proper fuse can be very confusing. The size of the wire should be used when selecting the proper fuse. Remember, the purpose of a fuse is to protect the wire.

Defender’s website has a great explanation of this here.

If you are not upsizing your existing Airstream wiring, refer to this chart before increasing the size of a fuse.

[BikeCamper]

Currently, the Epoch 300 would be my first choice. I didn’t go ahead and purchase one on the recent sales because our 2xGRP 24 lead acid batteries are only 8 months old. If they were 2-3 years old I might have….

My hope is that prices will continue to come down. I am also hoping that manufacturers of li-ion batteries will take note and realize there is a market specifically for a single-battery replacement for two Group 24 batteries.

If they can replicate the dimensions (LxWxH) of two Group 24s combined, they would have a battery guaranteed as a drop-in fit to the same battery boxes used for one of the most common arrangements. And it could be a battery with even more reserve capacity than the Epoch 300. Imo, 300ah is great, but 400ah is even better!

[Runamuk13]

The Epoch 300 is a great choice.
Another option to consider is the LiTime 12V 230Ah Bluetooth Lithium RV Battery With Low-Temp Protection for about $475.

I replaced 2 Group 24's in my battery box with no trouble at all.

I've been using the non-bluetooth version of this battery for about 8 months. So far it's been a great battery.https://www.litime.com/products/12v-...ium-rv-battery

[waninae39]

best to but Lion soon as US plans to raise prices and cut back on subsidies

[BikeCamper]

Originally Posted by waninae39

best to but Lion soon as US plans to raise prices and cut back on subsidies

That’s definitely a consideration. My thriftiness prevented me from replacing new, functioning lead acid batteries. Hopefully this won’t come back to bite me in 1-2 years.

[gypsydad]

Originally Posted by BikeCamper

Currently, the Epoch 300 would be my first choice. I didn’t go ahead and purchase one on the recent sales because our 2xGRP 24 lead acid batteries are only 8 months old. If they were 2-3 years old I might have….

My hope is that prices will continue to come down. I am also hoping that manufacturers of li-ion batteries will take note and realize there is a market specifically for a single-battery replacement for two Group 24 batteries.

If they can replicate the dimensions (LxWxH) of two Group 24s combined, they would have a battery guaranteed as a drop-in fit to the same battery boxes used for one of the most common arrangements. And it could be a battery with even more reserve capacity than the Epoch 300. Imo, 300ah is great, but 400ah is even better!

Just a thought; you could likely sell your 2 12V lead acid batteries since only 8 months old, and likely, you have not used them very often (?). I sold mine (12V Interstate's) within an hour when listed them on FB Marketplace and Craigs list, at the time. I was replacing them with Trojan 6V T105s at the time. This was 7 years ago, but I had several calls; guy at a Used Car dealer, bought them right away. Worth a try perhaps.

[PeterF66]

Originally Posted by BikeCamper

Currently, the Epoch 300 would be my first choice. I didn’t go ahead and purchase one on the recent sales because our 2xGRP 24 lead acid batteries are only 8 months old. If they were 2-3 years old I might have….

My hope is that prices will continue to come down. I am also hoping that manufacturers of li-ion batteries will take note and realize there is a market specifically for a single-battery replacement for two Group 24 batteries.

If they can replicate the dimensions (LxWxH) of two Group 24s combined, they would have a battery guaranteed as a drop-in fit to the same battery boxes used for one of the most common arrangements. And it could be a battery with even more reserve capacity than the Epoch 300. Imo, 300ah is great, but 400ah is even better!

Reporting back on the Epoch 300ah fit, I put it in yesterday and fits right into our battery box of our 2022 23' Flying Cloud, no shaving off the handles required, sits snug and tight, no millimeter to spare though!

[Crackerman]

Lithionics boss302 fits in an airstream battery box, is ul listed and is water resistant as well...

[BikeCamper]

Originally Posted by PeterF66

Reporting back on the Epoch 300ah fit, I put it in yesterday and fits right into our battery box of our 2022 23' Flying Cloud, no shaving off the handles required, sits snug and tight, no millimeter to spare though!

That looks great! Thanks for the feedback.

[BikeCamper]

Originally Posted by Crackerman

Lithionics boss302 fits in an airstream battery box, is ul listed and is water resistant as well...

That battery lists for $4300. The Epoch 300 is around $850.