Lithium batteries

[dennych1]

Who has installed lithium batteries but didn’t change your charging from truck to camper batteries by adding DC to DC charger

[StirCrazy]

pianotuna wrote:

mbloof wrote:

pianotuna wrote:
Since Li don't want to be taken to 100% I can't see why a dc to DC booster would be particularly useful.

Since when? Can you quote a source for that information?

The Battleborn battery I own and even the DIY LiFePo4 cells I bought along a with proper BMS have no issue with being charged to 100%.

- Mark0.

Many many many sources.

Some BMS systems have the 90% set to read as fully charged. Battleborn might be one of them.

The ideal is 40% to 90% for most Li chemistries.

They tolerate 20% state of charge well. But lifespan may be shorter.

Here is a source that suggest maximum of 80% SOC:

https://electrek.co/2018/05/04/are-you-killing-your-lithium-batteries/

this is right from your article you posted

"Does this apply to all lithium batteries?
Theoretically yes, though LiFePO4 batteries aren’t quite as affected by high charge levels as the rest of the lithium-ion lineup. "

I have not seen anyone who is making there own cells not charging to 100%. the numbers of cycles is based on a full discharge from 100 to 0 from my understanding, but yes they will probably last longer if you shallow cycle them like any other batery.

I have been using my 6V GC lead asid batteries now for 12 years and they still work great. why because they are cycled very shallow, never droping below 70% due to my solar and the total capacity.

Steve

Steve

[HMS_Beagle]

Also a reminder that those batteries in the article were lithium ion cobalt, not lithium iron phosphate. Cobalt batteries have a much lower thermal runaway temperature, and a much more checkered history of safety compared to LiFPo4. Cobalt batteries are used in the 787 and most electric cars. The storage batteries being used in RVs are LiFePo4.

[Kayteg1]

Article reminding that nothing is accident-proof in this World

[thedavidzoo]

srschang wrote:
I have no need for truck charging for my 2 100ah Battleborn batteries. The 400w of solar keep them charged up. In fact, I disconnected the truck charging wire at the camper converter, I wasn't sure how the AGM truck batteries would handle the 14.6v from the converter when I have the camper plugged in.

We also disconnected the truck charging wire at the converter, actually put in a switch always set to off. My system uses GBS cells with a dedicated "brain" unit (in addition to the individual BMS) through which all charging sources and loads run. Since the wire from the truck/converter does not go through this regulating brain, I didn't want to fiddle with it. When we plug in shore power (never), I disconnect my batteries for the same reason.

[srschang]

NRALIFR wrote:
Srschang, is the changing wire to the camper on your truck not switched by the ignition? Even if it’s not, why would your trucks AGM’s not like 14.6? The AGM charging specs I’ve looked at seem to like up to about 14.9.

That’s assuming that the 14.6 from the camper is even reaching the truck batteries, that is. There’s about 20 or so feet of wire between the camper converter and the truck batteries on a crew cab pickup, so the voltage drop is going to be considerable. At any rate, a few minutes with a volt meter would tell you.

For me, having multiple ways of recharging the camper battery is a good thing. I’m not always in a developed campground, or even in an environment where solar can be totally relied on. It would be nice to have a panel or two on the roof, but the DC-DC charger isn’t dependent on the sun. If I ever get around to adding a solar panel, I’ll just connect it to the solar input on the Redarc.

:):)

I don't know how the truck/camper charging interface works, that's why I disconnected the charging wire from the truck. Didn't want to screw anything up on my one month old truck. And like I said, the solar takes care of all the charging we need.

Scott

[Kayteg1]

On my campers I had about 22' of wire from truck main panel in front to the rear plug, than 10' of cable from the plug to front of the camper where cable went inside, than another 16' of wire from front left camper corner to panel with battery separator and then to battery mounted on right rear.
When it comes to charging, trucks play dirty with it.
For years I've been driving trucks, who charge at 14.5V and Mercedes sedans who charge at 13.9V.
When batteries on Mercedes did last up to 13 years, Ford batteries always promptly die after 3 years warranty
So when B2B charger speeds charging, it can also shorten battery life.

[NRALIFR]

Srschang, is the changing wire to the camper on your truck not switched by the ignition? Even if it’s not, why would your trucks AGM’s not like 14.6? The AGM charging specs I’ve looked at seem to like up to about 14.9.

That’s assuming that the 14.6 from the camper is even reaching the truck batteries, that is. There’s about 20 or so feet of wire between the camper converter and the truck batteries on a crew cab pickup, so the voltage drop is going to be considerable. At any rate, a few minutes with a volt meter would tell you.

For me, having multiple ways of recharging the camper battery is a good thing. I’m not always in a developed campground, or even in an environment where solar can be totally relied on. It would be nice to have a panel or two on the roof, but the DC-DC charger isn’t dependent on the sun. If I ever get around to adding a solar panel, I’ll just connect it to the solar input on the Redarc.

:):)

[srschang]

Great interview with the CEO of Battleborn.

https://www.youtube.com/watch?v=ywn-vBjKblI

Video contents:

Start of video to 6:30, low temps
6:30 high temp/ degradation
8:30 cycling
9:30 longevity/ charge profile
11:30 balancing
12:50 floating
15:40 storage
17:40 cold cranking (which in reality doesn't really apply to lfp) terminology.

[jaycocreek]

Lithium batteries are finally coming down in price if you don't have to have a name brand like Battle Born...

LiFePO4 Battery 100ah 12v Lithium Iron Phosphate $587 at Amazon..

[srschang]

I have no need for truck charging for my 2 100ah Battleborn batteries. The 400w of solar keep them charged up. In fact, I disconnected the truck charging wire at the camper converter, I wasn't sure how the AGM truck batteries would handle the 14.6v from the converter when I have the camper plugged in.

[NRALIFR]

I’ve got a 25A Redarc DC-DC charger in my camper, and I really like it. It has dual inputs, so it can connect to the truck battery and your solar panels, and will prioritize using solar whenever available. It supports lead acid, gel, AGM, and lithium. I currently have a single group 31 AGM battery, but anticipate that someday Li will hit a price point that’s attractive to me.

It also has one benefit that I wasn’t anticipating before installing it, but have come to appreciate. If you have a 3-way fridge in your camper, the DC mode will work noticeably better due to the voltage being maintained about 2.5 volts higher than than it would be with no DC-DC charger.

I like mine enough that I recently noticed that Redarc now has 40 and 50 amp dual input DC-DC chargers, and I will be upgrading mine to a 40 amp.

:):)

[mbloof]

pianotuna wrote:

Nope.lifepo4 don't like to be charged to 100% at least for storage--which is where most RV's are.

It is academic for me--as I need -40 temperature tolerance and only one LI chemistry that can do that. So I'll be going SiO2

-30-

Another link

Nothing about it being "bad", they just might last a bit longer. "Bad" is storing a battery with zero charge as that will damage the battery.

Most RV's have parasitic loads that are constantly drawing power even while in storage. While my camper sits in the driveway each day the solar panels will give it a charge and each night the loads will suck some energy out.

Back on topic: some users will employ a DC-DC supply on their truck charge line to step up the voltage to at least 13.6V or 14.2V-14.6V so that their LiFePo4 battery can be charged while driving.


- Mark0.

[pianotuna]

https://www.power-sonic.com/blog/how-to-charge-lithium-iron-phosphate-lifepo4-batteries/

Mork0,

Nope.lifepo4 don't like to be charged to 100% at least for storage--which is where most RV's are.

It is academic for me--as I need -40 temperature tolerance and only one LI chemistry that can do that. So I'll be going SiO2

-30-

[mbloof]

pianotuna wrote:

mbloof wrote:

pianotuna wrote:
Since Li don't want to be taken to 100% I can't see why a dc to DC booster would be particularly useful.

Since when? Can you quote a source for that information?

The Battleborn battery I own and even the DIY LiFePo4 cells I bought along a with proper BMS have no issue with being charged to 100%.

- Mark0.

Many many many sources.

Some BMS systems have the 90% set to read as fully charged. Battleborn might be one of them.

The ideal is 40% to 90% for most Li chemistries.

They tolerate 20% state of charge well. But lifespan may be shorter.

Here is a source that suggest maximum of 80% SOC:

https://electrek.co/2018/05/04/are-you-killing-your-lithium-batteries/

Keep in mind that there are different Li chemistries and what might be recommended (via the link you provided) for other types does not apply to LiFePo4 batteries.

While LiFePo4 cells have a peek voltage of 3.65V (14.6V for a 4S pack) they can be safely charged to %100 with that voltage without degration. (this is also what BattleBorn recommends (14.2-14.6V).

They do however recommend 50A or less charge rate for a 100AH battery otherwise degration will occur.


- Mark0.