Trojan lithium drop in replacement

[john61ct]

That is a very high % over-provisioning, I bet pretty rare, or limited to the top of the market where you bought your system.

Single digits is much more common at least stateside.

I doubt any margin at all is common outside the top tier prismatic makers, or from the small-shop middlemen here, often dealing in factory QA rejects or second-hand off EV projects.

Among the vast number of smaller / newer / unknown vendors many may not even make their claimed spec.

[Jerry Woodward]

Some have mentioned a warranty on the Trilliums but I can find no mention of a warranty in the brochure or web site. Did I miss something?

[LifePart2]

I know I am late to the party here, but I thought it might be helpful to offer up the free ebook that I wrote on how to set up your own LiFePOf4 system from scratch, using individual cells and creating your own BMS. Very easy to do, fully customizable, and cheaper than buying ready-made drop in systems. Works great for me but, as they say, you pays your money and you takes your choice.

Here is the link. Enjoy:
LIFE: Part 2: Lithium Batteries – best thing since sliced bread

[Jerry Woodward]

Originally Posted by rgleason

These are a pretty nice package, but you will still need:
1.Charging Bus with disconnect relay and Volt sensor for alternator, solarPV and shore charger.
2.Discharge Bus with disconnect relay and Volt sensor for House panel and other loads.
I think a Victron BM-712 would do this and allow you to set your own limits within Trojan's BMS.

I'm not sure I understand why you "need" separate charge and load bus with disconnect relays for these batteries. If I set my charging sources correctly, there should not be an over voltage situation, and if there is, the internal over voltage safety in the batteries would shut them off. Likewise, if I'm dumb enough to leave a load on long enough to completely discharge them, the batteries will shut off, thereby protecting them from damage. I already monitor the charging and discharging of my LA bank and would do the same on a Li bank (with a Victron BM 712). So for me, I would not rely on the battery shut-off protection for everyday use, but it seems it is reasonable to rely on it for an unanticipated over or under-charge situation.

[john61ct]

It makes it possible to isolate the bank from loads but still allow recharging.

Or isolate from charge sources but still service loads.

Can't use inverter/charger combi units though.

[DAS1960]

Trojan does not manufacture the lithium batteries they market. They are manufactured by K2 Energy. Im sure K2 has more knowledge about the product and might be able to provide details on how the battery deals with Low Voltage or DC load dumps from alternators or inverters and chargers and inrush currents. The Trojan dealers I've called have no ide. These are all big hurdles for using lithium versus lead batteries which don't really complain about these abuses until they just die. Maybe its possible to contact K2 to learn more about these details.

[rgleason]

Thanks Noel, will read it several times. I see there is lots about alternators too.

Originally Posted by LifePart2

I know I am late to the party here, but I thought it might be helpful to offer up the free ebook that I wrote on how to set up your own LiFePOf4 system from scratch, using individual cells and creating your own BMS. Very easy to do, fully customizable, and cheaper than buying ready-made drop in systems. Works great for me but, as they say, you pays your money and you takes your choice.

Here is the link. Enjoy:
LIFE: Part 2: Lithium Batteries – best thing since sliced bread

[Cpt Pat]

Look familiar?

https://k2battery.com/product/k2-auxiliary-battery-12-8v-111ah/

One battery appears to be a rebranding of the other.

Besides connection complexity (complexity is the inverse of reliability), the biggest problem with cylindrical cells is unequal heat dissipation. The inside of each cell gets hotter than the outside. I doubt the effectiveness of dissipating heat from inside the plastic outer case, especially for cells in the middle of the pack.

[john61ct]

Yes, we already know K2 is the OEM, but good to get confirmation.

Heat is always bad for longevity, but a properly sized House bank should not get more than slightly warm internally from such low C rates.

EV use cases yes, sophisticated engineering goes into their TMS, thermal management systems, protection against arctic cold as well even more critical.

Putting a small 100Ah pack on a windlass, sure maybe there would be issues. But then a temp sensor with adjustable cutoff should be included in the BMS functionality.

[Cpt Pat]

Since the surface area of cylindrical cells is proportionally smaller than prismatic cells of the same volume, all other factors being equal, the cylindrical cells will dissipate heat less effectively.

A practical high temperature cut-off function wouldn't be practical if it were set anywhere below the threshold where actual damage is occurring. I wouldn't trust it.

Heat is the primary enemy of battery longevity. Even a little heat will have a negative impact (assuming a reasonably temperate ambient temperature). I am very skeptical of the heat dissipating capabilities of cylindrical cells enclosed in a sealed plastic box.

I'm sticking with prismatics. Also, all those on board automatics (cut-offs, cell balancing, monitoring, etc.) are bound to consume power - increasing self-discharge, and adding complexity.

For my application, I only discharge at 0.1C max., and charge at 0.2C max., and never take the voltages into the "knees." Manually bottom balancing and cutting off charge with columb counting (counting amp/hours in and out with a totalizer) is adequate.

(Note: you can't prevent overcharging by monitoring terminal voltage - a LiFePO4 battery can be overcharged at 13.6 volts!) What happens when my LiFePO4 cuts off at the top or bottom of SoC? I have a lead/acid that's always on the bus. It doesn't even begin to discharge until the LiFePO4 low voltage cut-off threshold has been reached (12.95 volts).

[john61ct]

> the cylindrical cells will dissipate heat less effectively

if air freely circulates in the between gaps, better than prismatics jammed up against each other in a box with only the tops exposed.

> I am very skeptical of the heat dissipating capabilities of cylindrical cells enclosed in a sealed plastic box.

True, but as I said, heat does not in practice build up from internal processes in the usual House bank use case. At least not any more than running aircon vs not, or what latitudes I travel in, and I'm not letting my battery bank dictate those decisions 8-)

> I'm sticking with prismatics. Also, all those on board automatics (cut-offs, cell balancing, monitoring, etc.) are bound to consume power - increasing self-discharge, and adding complexity.

With you there, but then we geeks (in my case wannabee) are not the target market for drop-ins.

I think wrt longevity, IMO the real key is the build quality of the cells themselves, especially from a chemistry POV.

Winston, CALB, GBS, A123 & Sinopoly have been well vetted for many years.

K2, have not seen that (yet).

I'd be open to them, if the price per watt hour was steeply discounted, but that's not the case.

[KTP]

Hmm, based on that link it does look like Trojan is totally just slapping a label on the K2 battery, at least the 110 (111) amp hour version. K2 doesn't list a 92 amp hour version so I guess it is possible that is made special for Trojan.

As far as a company, it looks like K2 does a lot of battery work for the US military and is touting some $100 million in sales milestone.

I am holding out my opinion until I hear of the warranty. Anything less than 3 years replacement warranty and it is a pass.

Using the cells out of a electric vehicle might still be one of the best options for EP but the insurance liability makes it somewhat unattractive to me. A drop in battery backed by a major manufacturer is much more defensible.

[KTP]

It is interesting that some K2 batteries have been certified for use by the US Navy. Have any of the other big name brands of batteries (Victron, Lithionics) had similar certifications? It does seem to indicate that the company is in it for the long haul.

https://www.einpresswire.com/article...s-navy-by-nswc

[Paul L]

Originally Posted by KTP

It is interesting that some K2 batteries have been certified for use by the US Navy. Have any of the other big name brands of batteries (Victron, Lithionics) had similar certifications? It does seem to indicate that the company is in it for the long haul.

https://www.einpresswire.com/article...s-navy-by-nswc

That's a pretty strong endorsement of a drop in battery.

[KTP]

Originally Posted by Paul L

That's a pretty strong endorsement of a drop in battery.

Yes specifically:

"(5) K2B12VG27-U3 battery used as part of the prototype Cylindrical Frequency Analysis Recorder (CYFAR) This certification applies to testing of the buoy with two of the K2 Energy batteries installed at the Naval Undersea Warfare Center (NUWC) Seneca Lake testing facility."


This is K2's extreme angler battery, which is a 12.8V 111ah battery that appears to be identical to the Trojan Trillium 12.8V 110ah battery in physical appearance and specs. It gives some confidence to use a battery on a boat which has undergone some of the requirements that the Navy has.

It looks like Trojan is pricing the batteries somewhat cheaper than K2 has, with the K2 111ah battery being around $1300 and the Trojan 110ah being about $1100 (and as cheap as $900 in quantity).

They seem cheaper than the Lithionics by a fair margin. The pricing I have found for a Lithionics 12.8V 150AH battery is $2900 each. That is $1.51 a amp hour. The Trojan/K2 110AH battery at $1100 single quantity works out to be about $0.79 per amp hour.

What do you think John?