cancel
Showing results forย 
Search instead forย 
Did you mean:ย 

Lithium Batteries

msmith1199
Explorer
Explorer
Just downsized from a Class A DP to a Class B+. I got the residential fridge in the new motorhome so power when off the grid is going to be more of an issue that it was before. Iโ€™ve been looking at Lithium batteries and they look like a good solution for me. Only problem I see is physical size. The two current batteries I have are 11.5 inches long and they are a tight fit in the battery compartment. All the lithium batteries Iโ€™ve seen are at least 12.5โ€ or longer. So they wonโ€™t fit in the existing battery compartment without modifications. But those are all 100AH batteries. I see they also have 200AH lithium batteries. They are a lot longer, over 20 inches, but one of those batteries will fit in the compartment versus two 200AH batteries. So not only does the 200AH battery have a smaller footprint than two 100AH batteries, they are also quite a bit cheaper than buying two 100Ah batteries.

Anybody see any issues in going with one 200ah battery versus two 100ah batteries?

2021 Nexus Viper 27V. Class B+


2019 Ford Ranger 4x4

121 REPLIES 121

FWC
Explorer
Explorer
I think it is the other way around, an LiFePO4 battery will actually (slightly) charge the the starting battery, and draw itself down if left connected to the tow vehicle. The LiFePO4 sits at 13.2 - 13.3V, compared to 12.6 - 12.8V for the lead acid starting battery. As a result there might be a small current that flows to the truck battery, and any parasitic loads from the truck will be carried by the lithium battery.

01tundra
Explorer
Explorer
pianotuna wrote:
I think the issue is over voltage to the LI battery bank, not protection of the alternator.


LI batteries have been known to burn up some alternators due to the high charging demand, they've also been known to draw down tow vehicle batteries due to the higher resting voltage of LiFePO4 vs LA, if left hooked up with the engine off with a constant hot charge wire.

There is no overvoltage worries due to the voltage drop on inadequate factory wiring for charging purposes. If you upgraded you wiring such that you could get higher than 14.6V at the batteries then the BMS would kick in on high voltage.

For MY application the DC charger is there to actually provide enough amps to charge the batteries while running and isolation from the TV when the engine is off.

DC chargers have many benefits and one is absolutely protecting the alternator -

https://www.victronenergy.com/blog/2019/10/07/careful-alternator-charging-lithium/
2020 Rockwood Mini Lite 2109S
2017 GMC 2500HD Denali Duramax

pianotuna
Nomad II
Nomad II
I think the issue is over voltage to the LI battery bank, not protection of the alternator.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

01tundra
Explorer
Explorer
I'm running a Victron Orion 12/12-18 DC-DC charger with a dedicated 4AWG charging circuit from the truck. I get 25A out of it at peak charging and don't have to worry about the truck's alternator voltage fluctuation or it being harmed.

The charger has settings that allow it to sense alternator current to automatically start/stop to prevent the trailer LiFePO4 batteries from drawing down the truck lead acid batteries when the engine is off.









2020 Rockwood Mini Lite 2109S
2017 GMC 2500HD Denali Duramax

BFL13
Explorer II
Explorer II
Going around in circles here ๐Ÿ™‚ This came up earlier and explains it all for DC-DC and some good diagrams. Just get your guy to do which applies to yours. The MH builder is behind the times it seems.

https://shop.pkys.com/Alternator-Lithium-Battery.html
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

msmith1199
Explorer
Explorer
Okay, for the latest. I contacted an installer recommended by the battery company. He told me since my motorhome was so new I may already have a DC to DC converter in it and he suggested a contact the motorhome builder to see. So I contacted my motorhome builder to see if they had already installed a DC to DC converter and told them what I was trying to do. This is their reply to me:

Mark,

A DC / DC regulator / converter is unnecessary to use lithium ion batteries on the house side, our BIRD (bi-directional relay/ delay ) already serves that purpose. There should not be any modifications necessary to use lithium ion batteries on the house side.


So I called the tech at the Battery Manufacturer and told them about this BIRD thing, and they disagree that it will replace the the DC to DC converter. So now I have no idea what to do! Any ideas? I do have an appointment to meet with the installer on Thursday and Iโ€™ll see what he has to say.

2021 Nexus Viper 27V. Class B+


2019 Ford Ranger 4x4

steveh27
Explorer
Explorer
Hope this works for the 4 pages of battery specs:









Thanks for the help.

msmith1199
Explorer
Explorer
steveh27 wrote:
Here's a site I found:

https://shop.pkys.com/Alternator-Lithium-Battery.html


The info in this article is pretty much exactly what the techs at Battleborn batteries told me. And I have purchased the DC to DC converter. Now just a matter of finding someone to install it. Everybody around here is booked and I donโ€™t have the knowledge to install it myself. It looks easy but it needs to be installed and the old wires need to be disconnected. Hopefully the old wires can be used on the DC to DC converter so new wiring doesnโ€™t have to be run throughout the motorhome. But thatโ€™s all above my pay grade. I donโ€™t even change my own oil!

2021 Nexus Viper 27V. Class B+


2019 Ford Ranger 4x4

BFL13
Explorer II
Explorer II
steveh27 wrote:
need to learn again about posting jpgs. DO I need to have them on some other online site first?


http://photoposting.is-great.net/?i=2
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

steveh27
Explorer
Explorer
need to learn again about posting jpgs. DO I need to have them on some other online site first?

pianotuna
Nomad II
Nomad II
Steveh27,

The LI are fine.

The wiring is also fine.

The alternator needs to have a duty cycle that will accommodate 50 amps continuous. Research the make and model of alternator.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

Itinerant1
Explorer
Explorer
No it didn't work. Take a screen shot and post as a picture. Or use a free pfd uploading host site, it will give options on how you want to post it in a thread.
12v 500ah, 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 2,500+ partial cycles.

steveh27
Explorer
Explorer
I think my 2 100AH LiFePo4 batteries are ok. I have not used them yet other than on 2 day trips due to my health. My alternator has a max capacity of 117 amps. It connects via #8 wire through 2 40 amp mini breakers to a battery isolator and then to the house batteries. I am attaching the specs for those batteries including the BMS protection, not sure if it will come. I hope you guys can confirm I am OK.

I do not know how to change this pdf file to a jpg I can attach. I could scan it into my pc then attach.
file:///C:/Users/Steve/Downloads/12V100Ah%20with%20BMS%20specs.pdf

It says max continuous charge current is 50 amps, and the max charge current is 60 amps or less.

pianotuna
Nomad II
Nomad II
I guess it depends now the ecu is adjusted? Are they adjustable?
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.