Wet vs AGM battery

[Bainford]

Surfguitar, I like your battery location. Is there a weight savings in the Odyssey battery over a small, wet cell battery?

Lithium batteries must never be charged when the battery temperature (not necessarily the ambient temperature) is below zero degrees centigrade.

Not really too much of an issue as most of our Europas are tucked up nice and snug in a garage but just something to be aware of.

I'm curious about this. Is there a danger in attempting to charge a cold battery, or will it simply not accept a charge? Many years I run my car until the first salt appears on the roads, which may mean overnight or early morning temps below zero deg c (and therefore a battery temp below zero). I am interested in a light weight battery solution and have been wondering about lithium.

[gideon]

The EarthX batteries are a lithium iron phosphate (LiFePO4) battery, which is a different chemistry than the batteries used by Tesla (LiNiMnCoO2 I think).  The energy density is a little lower, but it's significantly safer (1).  In addition EarthX include a battery management system (BMS) on the battery, which in their words "protects the cells from over discharge, over charge, short circuit, temperature, plus cell balancing to ensure charge levels are equal".   Most other brands selling LiFePO4 starter batteries don't include the BMS and are therefore cheaper. 

EarthX sell their starter batteries for aircraft, ATVs, motorcycles, scooters, race cars and snowmobiles.  Batteries for snowmobiles must be able to accept a charge in cold weather.  But then I suppose aircraft batteries have to cope with a range of temperatures too. 

What I would like to know is why EarthX and other sellers of LiFePO4 starter batteries don't market them to weight conscious road car owners.  I guess it's a regulatory issue rather than a practical one.

Edit: I just found their FAQ (2) - it sounds as though cold weather isn't a huge problem, but you must have a charging system that will regulate the voltage between 13.8-14.6V, or you could damage the battery.  Older cars and motorcycles might not have well behaved charging systems, so not recommended without upgrading the charging system.

(1) https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf
(2) https://earthxbatteries.com/faqs

[Bainford]

Thanks for that, Gideon. A lot of great info there. Reading up, it does indeed seem important for the charging system to be of a particular specification, and to be in good form. It would seem prudent, in my case anyway, to consider an alternator/regular upgrade if considering a lithium battery. I must say, the potential weight savings is certainly tempting.

[Pfreen]

I just have a modern alternator on mine.  It is a 95 amp Triumph TR7 alternator.  It fits fine.  It is more amperage than is recommended (60amp) but it works fine.  If the battery was dead, I would definitely bench charge it.  As is,  it never goes over 30 amps.

I have the big alternator because I have ac and I don't want a heavy discharge at idle.

I think Earthx just ants a modern alternator charging system.

[surfguitar58]

Surfguitar, I like your battery location. Is there a weight savings in the Odyssey battery over a small, wet cell battery?

Not a lot of weight savings, I had a size 51R wet cell up in the frunk that weighed 29 lbs, and the Odessey PC925 weighs 28 lbs. Both are overkill in the CCA according to Lou's formula.
Tom

[TurboFource]

So a motorcycle battery for something like a Harley would crank over a Twin Cam ?

[Pfreen]

The modern gear reduction starters seem to crank the engine a lot faster so I assume the required cca is less.  The Earthx battery cca  is 320.

It cranks great on a tc.

[Clifton]

So a motorcycle battery for something like a Harley would crank over a Twin Cam ?

It cranks my 10.8:1, 3.5 liter  V6 no problem. I know a lot of Miata guys run similar batteries with 1.8l engines and longer cables too.

[Bodzer]

Agreed that LiFePo4 batteries are a lot safer than Tesla’s NMC batteries. However, the problem of dendrite formation on the anode is common to both chemistries. These are tiny tree like spikes that grow on the anode under certain conditions. They can eventually grow enough to touch the cathode causing a short. This will degrade your battery over time. Treating them well, like anything, will vastly increase its life. Don’t overcharge, don’t over discharge and don’t charge when the cell temperature (not necessarily ambient temperature) is below freezing. You can get heating pads rather like the sump heaters you have in Canada/Northern US. Perhaps not as hot though.

[Richard48Y]

I must be missing something here as this looks too easy.
Some of the Shorai batteries weigh next to nothing and cost about the same as a standard lead-acid battery.

I've also wondered about using one of the new very small modern Japanese alternators.
The combination should be good for 20 Lb. in weight savings. 

Currently my car is fitted with a very heavy and oversize battery mounted up front.
The very long cables cannot be helpful and an oversize battery as ballast is a poor crutch for correcting the front becoming "Too Light" at speed. 

So a 14 AH 250 CCA battery should work fine with my Hi-Torque starter?

[surfguitar58]

Currently my car is fitted with a very heavy and oversize battery mounted up front.
The very long cables cannot be helpful and an oversize battery as ballast is a poor crutch for correcting the front becoming "Too Light" at speed. 

My battery was up front when I bought the car. I was advised the long cable run through the chassis was an invitation for insulation wear and eventually a catastrophic short circuit. Maybe, maybe not, but the thought scared me enough to relocate the battery.
t

[rjbaren]

I have the same series battery as Surfguitar, a 51R lead acid flooded wet cell and it weighs 28lbs.  It is a Duracell battery which is made by Eat Penn Mfg. in PA. 
The size is 9 1/2inches long x 5inches wide x 8 3/4 inches high.  The 51 worked in my Twin Cam because the terminals were in the proper place and the battery resides on the LHS in the engine compartment.  I was $125.00 but now I see it listed on Amazon for $139.99.  In Illinois we have a chain of stores call Batteries Plus and their Ray O Vac batteries are made by East Penn.

I do have a single Ray O Vac 48 AGM in another car and it has been fine so far.  I do not keep it on a trickle charge and I don't use the car very often.  It is garaged kept.  I say a single battery because it is replacing two groups 91s that I felt were overkill.  I make sure to start and run the car every couple of weeks though.  It is about three years old.