TecMate

Lithium ion battery tech – your questions answered at AIMExpo

The piece we carried last month by Martin Human, CEO and Chief Technical Officer for TecMate - the manufacturer of the OptiMate brand of battery chargers and diagnostic/maintenance tools – “Lithium Battery Technology Headed for Center Stage” – got quite a reaction. What follows are the salient points from a follow-up interview I did with Martin about some of the reactions the piece got and the advice that he and his team will be offering from their AIMExpo booth …

 

In last month’s piece, it was the remarks concerning lithium ion battery technology being destined to eventually become standard battery technology for most motorcycle manufacturers on most models that appears to have got people’s attention.
Without even speaking about its importance of the future evolution of electric bikes as part of the mix, the impact that OE replacement of conventional lead acid and AGM battery technology with lithium ion technology will have on motorcycle starting, on-board power opportunities and battery maintenance issues will require the motorcycle service sector to embrace a reboot of its habits and knowledge base.
It will represent a change that will probably be at least, if not more, as significant than that caused in the V-twin sector by the advent of fuel injection and stricter emissions and noise regulations.

As Martin said to me following publication of the last edition: “Now, with the OEMs entering, batteries will have to meet specific standards. The problem is, those standards are being taken from generic lithium battery standards, as there is no specific standard as yet for 12.8V lithium starter batteries”.
One of the issues that Martin and others operating in battery and battery-related markets bemoan is the low knowledge base and widespread misunderstandings and conflicting opinions there are about lithium technology.
He told me about a paper he was asked to present to a class at a technical training college recently: “The biggest problem is that very few people are aware of just how important it is to embrace a full and proper understanding of just how different the technology is – as things stand, a lot of batteries, and even bikes, are going to get damaged or destroyed before the market wakes up.”

 

The Technology
“The technology in use as starter batteries is Lithium Iron Phosphate, also known as Lithium Ferrous Phosphate, chemical formula LiFePO4, abbreviated as 'LFP'. It is made up of 4 x 3.2V cells (nominal voltage, like a 12V is made up of 6 x 2V cells). Nominal essentially means the base voltage after a full discharge, or approximately 10% charge level. It can be safely charged to 4 x 3.6V (14.4V), with the absolute maximum at 14.6V.
“It is a type of lithium ion battery (Li-Ion), but only one of many Li-Ion technologies - both rechargeable and non-rechargeable (primary). A good rule of thumb is that LFP/LiFePO4 4-cell batteries are used as starter batteries in power sport applications, and in nothing else.
“A lithium battery will last longest if always operated within the range of 30 to 95% of charge - for a LFP battery that is between 13V and 14.4V.

The three best ways to kill a lithium battery
Martin told me that in order to galvanize the attention of the class he titled his presentation ‘How to kill a lithium battery and burn out your bike’. “That got their attention,” Martin said.

Charge it too much…
“The simplest and most reliable way to kill a lithium battery is simply to charge it too much. Charge it above 14.6V, and what occurs is rapid cell damage, causing a short circuit in the weakest cell, which then rapidly increases voltage across the others and it becomes a domino effect.
“All power entering the battery is converted as heat until the run-away temperature of 270°C is reached within the battery, at which point the battery goes into a self-consume state, in other words, it burns itself out and possibly takes everything with it – not least the bike.”
To make that battery live longer, if you're fitting it as an aftermarket replacement into a motorcycle, check the charge voltage of the motorcycle with the original lead acid in place - if it remains at 14.4/14.5V or lower (at 2000rpm or higher), then the bike qualifies for a lithium battery, otherwise you are better off simply buying a better quality lead acid, or better still, just look after it better. 

Discharge it really low
Lithium battery destruction technique # 2 … let it discharge to the point where it is at least below 10V (but the lower the better) and then jump start it (or bump start the bike).
“What happens next,” says Martin, “is that as the battery is in an unstable low impedance state, and with the cells are unequal in impedance/resistance, it demands a very high current from the vehicle's charging system and, sometimes, that charging system cannot cope.
“The voltage regulator may become damaged, and it becomes an overcharge situation very rapidly. The high current also damages the weakest cells, which then becomes a liability when exceeding 14.6V.
“If you want it to live, use a charger that automatically starts with low current and grows it whilst automatically monitoring the performance of the cells against the known LFP charging curve.”

Martin Human, CEO and Chief Technology Officer for TecMate says: “Lithium Iron Phosphate is the safest and only lithium battery technology used in modern SLI (starter-lighting-ignition) batteries, but there is a widespread confusion about how they charge - confusion that will result in burned out batteries and motorcycles!”

Use the wrong charger
Lithium battery killer method #3? When the battery is discharged really low, “charge it with a powerful lead acid battery charger instead of a lithium specific device.
“Lead acid battery chargers are designed to deliver high current at low voltage and then taper off, whereas a lithium battery at low voltage needs a controlled low current charge so that cells can receive and retain charge and therefore stabilize their internal impedance (resistance) BEFORE it can receive high current charge.
“So, in other words, charging of a low voltage lithium is 'inversed' compared to a low voltage (but healthy) lead acid battery - current starts low and then slowly increases until the voltage reaches 12.8V and then it can be charged at full current.
“I've seen pictures of burnt out bikes - most recently a new Husqvarna that was taken home, and despite the dealer asking (but not insisting) if the user has a lithium battery charger, the owner went and connected a 'supermarket' type lead acid charger, and by the time he smelt the smoke from his garage, it was too late. His new bike was burnt - damaged beyond repair.”

Lack of maintenance
Killer method # 4: don't maintain it. “LFP batteries are typically 1/3 to 1/4 the Amp-hour of the equivalent lead acid battery and it will drain 3-4 times faster in a bike with a parasitic draw (most bikes now have parasitic draw due to always on circuitry). The result? Terminal low discharge syndrome – see killer technique #2!
To make it live longer, make sure that your lithium specific battery charger has a genuinely lithium specific maintenance program. “What a lot of people don’t yet realize, is that lithium does not need maintenance charging if it remains at full charge, so a genuine lithium charger senses only what is drawn and makes sure it supports that battery, keeps it at 100% whilst providing power to always on circuitry.
“The other negative of LFP's high CA (cranking amps) to Amp-hour ratio is that OEMs cannot resist the temptation to embrace the opportunity to make their batteries smaller so they fit, which unfortunately means they sacrifice Ah capacity. That means that an OEM fitted battery absolutely always needs to be fully charged to deliver the rated CA. So, the fact is, lithium batteries place a premium on having a (suitable) maintenance charger – they need one more than the lead acid batteries they replaced.”

TECMATE
www.optimate1.com