Lithium based chemistry for starting batteries

[shade]

I saw Full Spectrum Power batteries mentioned in the SEMA 2019 article, and took a look.

"[C]ustom chemical compositions to suit the load"?

https://cdn.shopify.com/s/files/1/0249/2618/files/Full_Spectrum_Power_Pulse_IPT_Battery_Details.pdf?16222509600014304953

I'm not sure what custom chemical compositions FSP uses, but they dance around cold weather charging issues. There may not be a problem for an initial cold start, but I don't think it would take long for a lack of charging to become a problem. For fair weather use, the weight savings may be worth it, but people won't be very happy when their "1000 Cranking Amp" battery dies from improper charging.

Maybe I'm missing something, but I don't think one of these batteries would work well for many start battery applications.

 

[dreadlocks]

those are for racers, not general purpose use.. 2lb starting battery vs 20lb for the Deka ETX-30L ive got in my race car.. for about $100 more, eh not bad.. Ive spent more to save less weight I suppose.. both output 400 cranking amps, fact I'd never drive my race car in the winter w/no wipers and slicks means cold performance dont matter.. but being able to store it w/out a maintenance charger would be nice.

 

[Oilbrnr]

Wouldn't the OEM charging system not be ideal as well?

 

[john61ct]

They likely do not route output through FETs in order to get the CCA required.

And yes no matter what needs warmth for recharging.

But hundreds of cranks per charge is easy, very short high-amp bursts hardly pull SoC down at all.

 

[luthj]

The biggest consideration with a battery like that is the electrolyte composition. It is a complex brew of chemicals (some quite large). These provide oxidation and breakdown resistance at high temps, improve low temperature performance etc. Since these cells don't see deep cycling, they can forgo those requirements and focus on a battery that can survive the temperature extremes seen in an engine bay.

Since your average start cycle uses 0.1AH (or less), they can recover that amount of charge even at very low temperatures. Lithium batteries can typically still be charged at 0.01-0.005C even when pretty cold.

 

[dreadlocks]

most engine bays get quite warm, id be more worried about high heat abuse than cold temp abuse.. I'd imagine after 20-30mins of driving it'd of soaked up enough heat to charge just fine if the internal BMS controls low temp charging like it should.. and then it'd charge back full in like no time at all.

 

[shade]

those are for racers, not general purpose use.. 2lb starting battery vs 20lb for the Deka ETX-30L ive got in my race car.. for about $100 more, eh not bad.. Ive spent more to save less weight I suppose.. both output 400 cranking amps, fact I'd never drive my race car in the winter w/no wipers and slicks means cold performance dont matter.. but being able to store it w/out a maintenance charger would be nice.

I know they were originally developed for racing applications, but they don't appear to be marketing them as such at SEMA, and their datasheet indicates a move into non-racing applications.

https://cdn.shopify.com/s/files/1/0249/2618/files/Full_Spectrum_Power_Pulse_IPT_Battery_Details.pdf?16222509600014304953

 

[shade]

Wouldn't the OEM charging system not be ideal as well?

Not at typical winter temperatures seen in many areas. I also didn't see any overcharging protection mentioned, but that's not unique to this brand.

 

[dreadlocks]

at SEMA

Ok, so they expanded to wanna be racers and mall crawlers.. Big market for selling worthless stuff to people with too much money. however, they are not really suitable for this crowd I suspect with very long days on the road and very extreme temps.. if anyone here needs a lightweight starting battery its because they want a bigger/heavier house battery setup, the little Deka AGM's are still ideal for that.

 

[shade]

Ok, so they expanded to wanna be racers and mall crawlers.. they are not really suitable for this crowd I suspect with very long days on the road and very extreme temps.. if anyone here needs a lightweight starting battery its because they want a bigger/heavier house battery setup, the little Deka AGM's are still ideal for that.

I agree, which is why I wondered if I was missing something special about these batteries. Everything I've learned indicates that outside of some specialized use cases, lithium chemistry isn't a great idea for start batteries. Overland Journal thinks they're "perfect" for the ExPo crowd, though.

"Why not start with something super tech’y? These Full Spectrum Power lithium batteries are some of the best we have seen, with custom chemical compositions to suit the load, and multiple (and robust) threaded posts. It has a multi-stage built in low voltage disconnect too. 1000 cold cranking amps from a battery the size of a six pack? Perfect."

 

[shade]

The biggest consideration with a battery like that is the electrolyte composition. It is a complex brew of chemicals (some quite large). These provide oxidation and breakdown resistance at high temps, improve low temperature performance etc. Since these cells don't see deep cycling, they can forgo those requirements and focus on a battery that can survive the temperature extremes seen in an engine bay.

Since your average start cycle uses 0.1AH (or less), they can recover that amount of charge even at very low temperatures. Lithium batteries can typically still be charged at 0.01-0.005C even when pretty cold.

What about charging at 20°F/-6°C?

That's pretty common to see in winter across North America. Maybe the BMS in these batteries has a low temp disconnect, and it won't allow charging until the engine bay & battery warm up enough, but the company didn't mention that feature.

 

[luthj]

What about charging at 20°F/-6°C?

That's pretty common to see in winter across North America. Maybe the BMS in these batteries has a low temp disconnect, and it won't allow charging until the engine bay & battery warm up enough, but the company didn't mention that feature.

With currently limiting, and the right electrolyte composition, you should be able to charge slowly, even at 20F. Its also possible they use a heating film to bring the batteries up to temp for faster charging. The real question, is if that type of design is incorporated.

Most vehicle electrical systems need the battery as a buffer, which smooths out voltage peaks/sags created by the alternators small lag in regulation. So I figure they have to allow at least some charging.

 

[shade]

When these start showing up in ExPo builds, I guess we'll find out if they're a good choice. Maybe FSP really has developed a reliable way to knock 50 lbs or more off of a vehicle's weight. I'm not arguing for or against them, but I was a little surprised to see a lithium based battery promoted for this use.

 

[luthj]

There are lots of folks who have the image of a bro-dozer lifted 37" tire, JKU weighing 8,000lbs with a 700lb RTT as the ultimate "overland" vehicle. Lets just say promotion has only a passing connection with reality. Though the dopamine release from buying another widget to bolt on to ones rig is real.

I would love to replace the big lead chunk under my hood as well. So I will be paying attention.

 

[TantoTrailers]

Interesting topic, don't have much to add but sub'd for learning! Here in the midwest 20F is rather warm in the winter, especially for morning work commutes.