Locating lithium batteries

[Northerngirl]

Mid April we still over 3 feet of snow on the ground

Snow cover from October to May

[rubicon327]

Originally Posted by gbaglo

And, it seems there are issues with overwintering lithium batteries in an unheated space.

Originally Posted by Ullrich

Li batteries are fine stored in the cold, it’s just charging and discharging in extreme cold is not a problem. The battery managment system inside a quality battery would prevent that from happening.

Lithium batteries do take some more thought as far as operation/storage than lead acid. As I believe Ullrich was trying to say it is more limited on charging than discharging in cold temperatures. My battery has to be above freezing for charging. I designed mine inside to make it easier to manage temperature of battery when camping in cold weather and for better overall security. I wanted to avoid having to have a parasitic electric heating device or needing expensive Battleborn's with integral heaters (which use equivalent DC power as the Escape furnace @ ~2A). Inside is definitely my recommendation for lithium for anyone actually using their trailer in cold climates. For someone who is always in warmer climates, removes their battery or stores their trailer all winter with no need to charge then it is a different conversation with these circumstances. Lithium have a very low self-discharge rate but they do like certain temperature ranges and they do not like to sit constantly at full charge. With the proper electrical system design and some modified operational behaviors this is easily managed for most owners.

[cpaharley2008]

Originally Posted by Northerngirl

Mid April we still over 3 feet of snow on the ground

Snow cover from October to May

Wow. we have maybe a 90 day Winter season here......

[alanmalk]

Originally Posted by rubicon327

Lithium batteries do take some more thought as far as operation/storage than lead acid. As I believe Ullrich was trying to say it is more limited on charging than discharging in cold temperatures. My battery has to be above freezing for charging. I designed mine inside to make it easier to manage temperature of battery when camping in cold weather and for better overall security. I wanted to avoid having to have a parasitic electric heating device or needing expensive Battleborn's with integral heaters (which use equivalent DC power as the Escape furnace @ ~2A). Inside is definitely my recommendation for lithium for anyone actually using their trailer in cold climates. For someone who is always in warmer climates, removes their battery or stores their trailer all winter with no need to charge then it is a different conversation with these circumstances. Lithium have a very low self-discharge rate but they do like certain temperature ranges and they do not like to sit constantly at full charge. With the proper electrical system design and some modified operational behaviors this is easily managed for most owners.

Good advice for current and future Lithium battery users.

I installed a pair of Lithium 100 Ah batteries in place of 7 year old lead-acid AGM batteries, under the sitting area as originally installed by Escape. But to help with thermal management I added a couple of additional layers of the silver bubble wrap (aka Reflectix) on top of the original. The objective is to keep that compartment warm while the trailer is in use. Expecting no charging problems since I like to keep the living area at 20C-68F.

To be done soon: Install an easy-to-use On-Off switch for the solar charging system to disconnect the batteries when the trailer is unoccupied and the interior is below 0C-32F. I do not trust the BMS to isolate the batteries in cold temperatures. In fact, I see very few advertisements for Lithium batteries that explicitly say their BMS will protect against cold weather charging. Over current, over/under voltages, high temp - yes. Cold? No mention. So buyer - pay close attention and plan a cold battery strategy.

[rubicon327]

Originally Posted by alanmalk

Good advice for current and future Lithium battery users.

I installed a pair of Lithium 100 Ah batteries in place of 7 year old lead-acid AGM batteries, under the sitting area as originally installed by Escape. But to help with thermal management I added a couple of additional layers of the silver bubble wrap (aka Reflectix) on top of the original. The objective is to keep that compartment warm while the trailer is in use. Expecting no charging problems since I like to keep the living area at 20C-68F.

To be done soon: Install an easy-to-use On-Off switch for the solar charging system to disconnect the batteries when the trailer is unoccupied and the interior is below 0C-32F. I do not trust the BMS to isolate the batteries in cold temperatures. In fact, I see very few advertisements for Lithium batteries that explicitly say their BMS will protect against cold weather charging. Over current, over/under voltages, high temp - yes. Cold? No mention. So buyer - pay close attention and plan a cold battery strategy.

Alan: You reminded me I want to get back in and better insulate my battery compartment (passenger side dinette seat) with additional Reflectix. I hear you on not wanting to depend on the BMS to isolate the batteries in cold temperatures but it seems that several I've checked do at least have the feature available including Battleborn, the Bestgo battery I installed and also the GoPower versions installed as an Escape option. Biggest concern is probably when towing in really cold weather. I am wired to be able to turn off my DC-DC charger when towing via battery disconnect switch (with breakaway safety still hot) and don't have solar yet to worry about. When I do install it will have a disconnect like you mention.

[alanmalk]

Originally Posted by rubicon327

Alan: You reminded me I want to get back in and better insulate my battery compartment (passenger side dinette seat) with additional Reflectix. I hear you on not wanting to depend on the BMS to isolate the batteries in cold temperatures but it seems that several I've checked do at least have the feature available including Battleborn, the Bestgo battery I installed and also the GoPower versions installed as an Escape option. Biggest concern is probably when towing in really cold weather. I am wired to be able to turn off my DC-DC charger when towing via battery disconnect switch (with breakaway safety still hot) and don't have solar yet to worry about. When I do install it will have a disconnect like you mention.

Yes, some brands do have cold temperature disconnect - but how do they stay connected for discharge but disconnect for charge? There is a 32F difference between the charge limit and discharge limit (actually more for some brands). And the issue you mention when towing: For safety reasons you must have power to the breakaway switch (to activate the emergency brakes). If towing in very cold weather, unheated interior, and no DC-DC converter; is the weak 12V really a charge to a Lithium battery? (I don't know.) On the other hand, if you are towing then there should be plenty of power to run a dedicated battery heater.

Really, the only point I am trying to make is that potential Lithium buyers should be aware of all the variables. Yes, there are some really good reasons for going Lithium, but also some good reasons with staying with tried-and-true Lead-Acid. Personally, I am in about the middle of the learning curve.

[rubicon327]

Originally Posted by alanmalk

Yes, some brands do have cold temperature disconnect - but how do they stay connected for discharge but disconnect for charge? There is a 32F difference between the charge limit and discharge limit (actually more for some brands).

Not sure but it appears the BMS on my battery is sophisticated enough to allow amps out but not allow amps in.

[John in Santa Cruz]

Originally Posted by rubicon327

Not sure but it appears the BMS on my battery is sophisticated enough to allow amps out but not allow amps in.

thats actually pretty simple. an ON transistor (mosfet, whatever) only allows current one direction, so you have two mosfets back to back, one allows charging, the other allows discharging, if they both are on, then the battery is 'normal'.

[JohnE3]

Originally Posted by alanmalk

"Yes, some brands do have cold temperature disconnect - but how do they stay connected for discharge but disconnect for charge?"

In a well designed lithium battery, specifically the LiFePo4, there's the Battery Management System (BMS) that controls the charge and discharge temperature parameters separately. In colder climates, to ensure battery longevity, temperature protection is a must.

All off-the-shelf LiFePo4 batteries have (or should have) a BMS to control at least charge and discharge limits for current and voltage, as well as certain protections for individual cells. Some batteries, including ones I've built, are Bluetooth enabled to allow programing of these parameters. Battery state-of-charge, and real time current in/out of the battery can also be seen on the associated smartphone app.

A BMS is really a battery geek's dream come true!

[Jack!]

Originally Posted by rubicon327

Borrowed a scale from a buddy the other day and it is now on the list of things to get. His was a Sherline LM 1000. Anyone have others that they recommend?

https://www.amazon.com/Sherline-LM-1.../dp/B007REJTGI

We used to get creative with regular home scales but never looked back after biting the price bullet on the Sherwood. It's really good to have.

[alanmalk]

Originally Posted by JohnE3

In a well designed lithium battery, specifically the LiFePo4, there's the Battery Management System (BMS) that controls the charge and discharge temperature parameters separately.
...

In the sub-$400 100Ah Lithium batteries with funny sounding Chinese names, I rarely, if ever, see the necessary cold temperature BMS circuits. Buyer beware - at least - aware.

[Vermilye]

Originally Posted by Jack!

We used to get creative with regular home scales but never looked back after biting the price bullet on the Sherwood. It's really good to have.

I have a Tow Ball Nose Weight Scale that I purchased from Amazon. At $65.00, it is cheaper than the Sherline scale, but reads in kilograms. I can't compare the accuracy to the Shoreline - it was within 20 pounds of the calculated weight at a CAT scale. It appears that Amazon no longer has them but Walmart is listing them.

[DougO]

Relative to previous comments about battery placement, Lithium, etc. I just got my E19 “lithium ready” meaning lead acid in the front storage box but electronics compatible with lithium. After reviewing the wiring, since I don’t want to put my SOK LiFePO4 batteries in the front box, I think I can splice them into the 2awg wires going to the inverter under the front u-shape dinette and just leave the positive & negative wires connected in the front storage box, just without the battery. That seems much simpler than figuring how to remove the wiring from the front box. As for BMS & temperature, I am relying on Will Prowse of YouTube fame that the temperature controls in the Internal BMS are functioning correctly.

[Northerngirl]

DougO

This seems like a great plan

We signed off on items build a couple of weeks ago on our 21 NE, which has the same layout as the 19

We also chose lithium ready

We’ll be picking up our trailer in May abs after the Oosoyos Escape rally we’ll head across the border and getting the battle born batteries. We’ll locate them in the passenger side dinette storage space