[GMCnet] Li batteries

[Thomas Phipps]

I'm thinking of Li battery pack for the house batteries. Any opinions on using a Li battery with combiner attached to SLA battery?
Willing to give up the SLA as it is ageing out.
I am will aware of the different charging cycles. Without changing charger, Li battery would only be about 80% charged. I can live with that.
Tom
--
2012 Phoenix Cruiser model 2552
KA4CSG
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[RICHARD/MARLI SHOOP]

If you change out the existing battery for a different chemistry, be SURE to disable the battery boost switch! Paralleling different types of batteries does damage to both!

[Billy Massey]

This is what I use.
https://battlebornbatteries.com/product/lifepo4-battery-isolation-manager/
And for a charger,
https://www.boatandrvaccessories.com/products/progressive-dynamics-pd9180alv-12-volt-80-amp-lithium-power-center?gclid=CjwKCAjw_sn8BRBrEiwAnUGJDsjEnvefRGwxbOeNBuQsuxDX8Dm0hX0hwZOIgXP33V39sV3jLfH2eBoCeasQAvD_BwE

I still use the OEM battery boost switch.
bdub

On Wed, Sep 1, 2021 at 10:54 AM Thomas Phipps <tph...@outlook.com> wrote:

> I'm thinking of Li battery pack for the house batteries. Any opinions on
> using a Li battery with combiner attached to SLA battery?
>
>

[Larry Davick]

Tom,

As fast as the price (and quality) of lithium batteries is falling this presentation from Jerry Work is already somewhat dated. Still his advice about BMS and the need to update your cables still holds.
(http://gmcws.org/blog/lithium-battery-presentation-gmcws-2019-fall-rally/)

Larry Davick
1976 Palm Beach

> On Sep 1, 2021, at 8:54 AM, Thomas Phipps <tph...@outlook.com> wrote:
>
> I'm thinking of Li battery pack for the house batteries. Any opinions on using a Li battery with combiner attached to SLA battery?

[Carl Stouffer]

I believe you'll need to invest in a B.I.M. like Billy stated. According to Jerry Work's presentation, you should be able to get an add-on module for
your current converter/charger.

I think the B.I.M. takes the place of the isolator and likely eliminates the combiner as well.

Also, according to Jerry, the boost can be used momentarily without hurting anything.

I plan on doing the above soon as well, and upgrading my cabling at a later date to add more efficiency.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member

[Bruce Hislop]

Tom,
Here is an excellent article about LiFePO4 (LFP) batteries. It's written for boaters, but it applies to RV's as well. Its a few pages, so get a
coffee before you start.

https://marinehowto.com/lifepo4-batteries-on-boats/

An LFP battery has a very low internal resistance and needs to be charged with a constant current, then finished with a constant voltage, then its
charges. Since LFP has a very low self-discharge, there is no "float" charge required... but since we have equipment connected to the house battery
(fans etc), a float charge of about 13.5V is Ok as long as it isn't connected during storage.

Automotive alternators (until recently) are a constant voltage output, so a LFP battery in a lower state of charge will suck all the current the
alternator can deliver and quickly burn it out. A BIM is like a long cycle PWM regulator. It connects the LFP battery to the chassis for about 15
minutes, then disconnects for about 20 minutes to let the alternator cool down.

I went with a DC-DC charger instead. It takes the DC power from the chassis (alternator) and converts it to the proper Constant Current/ Constant
Voltage/ Float voltage charge curve that the LFP battery requires for longest life.

JWID

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

[slc]

I am a fan of the Lithium batteries but they need some care in cold weather.

You cannot let them freeze so they need a space inside the coach if you travel in winter weather.

If the battery freezes, it wont charge because of the circuitry for protection.
I dont remember the specifics, but if the protective circuit fails and forces power
to a frozen Lithium battery, it will heat up and can catch fire.
As you know, a lithium battery fire is almost unstoppable. you cant use water to put
a lithium battery fire out. You almost have to have an extinguishment for metal to
put it out and it will be a battle even then.

It is recommended to remove the battery when the coach is stored for winter, and keep
the battery in a warm place in the house. I am not sure why they suggest this as if it
is not charging, the battery should be safe. but you have to disconnect the solar panels.

the power increase from a lead acid is about 75%, not 100%.
The sites I have looked at state that the lithium battery does not like being charged to 100%
and you should not discharge it to its lowest point. This will cut away from the batteries
life span. We see this in the electric car batteries.

Im not going to say not to try lithium batteries but you need to be aware that to be
safe you need to take care of them, especially for storage in cold weather.

And be aware of what to do if your lithium batteries catch on fire.

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center

[tomk...@comcast.net]

I was so much interested in installing lithium batteries. It came to the point in my construction where I had to make the purchase and I had to settle
for AGM batteries due to the cold temp operation problem. They will get better and cheaper down the road. until then I have to ride with AGM as I am
not convinced of the heated battery box at this time.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D.

[Bruce Hislop]

LiFePO4 (LFP) batteries cannot be charged below freezing, but they can be discharged and stored. They do live longer at temperatures at temperatures
from about 10 to 45C. I installed my LFP batteries in the clothes closet so they are right beside the electrical cabinet where my charger/inverter
lives. This reduces the length of wire from the charger to the batteries for minimal voltage drop.

There are LFP batteries rated for charging in freezing temperatures. The Battery Management System (BMS) of these batteries will use the available
charging current to warm the battery with an internal heating element to above freezing before applying the charge current to the battery cells.

LFP batteries live longer when stored with only a partial charge. So charge (or discharge) your LFP battery to about 60% then bring it into your
house for the winter. Do NOT recharge over the winter! The self discharge rate is very low on LFP batteries at about 5%, so even after storing for 6
months you will still have about 30% state of charge.

You cannot permanently parallel batteries of different types, but you can temporarily connect them... That is what the BIM charge controller is doing.
A BIM connects the house and chassis batteries together for 15 minutes, then disconnects for 20 minutes to allow the alternator to cool. Since LFP
batteries are not designed for extremely high currents (this is more the BMS maximum current rating rather than the cells) I would suggest to press
and hold the Boost switch for several minutes to allow the chassis battery to recharge a bit from the LFP house battery, then try starting. This will
reduce the maximum current being drawn from the LFP house battery by the starter.

Again, this is a very good article on LiFePO4 batteries:

https://marinehowto.com/lifepo4-batteries-on-boats/

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that