ION/ IRON

With regard to Graham Lampkin’s ‘Charge Query’in RC152 on the subject of lithium iron or lithium-ion batteries, you need to distinguish the two chemical types, as operation and charging conditions can be quite different. There are several useful references online: ‘Be careful about grouping all lithium batteries into one group, there are actually many different chemistry mixes involved. Traditional Li-Ion batteries are a no-no for replacing lead-acid in motorcycles. The ones available on the market for this application are LiFePO4 – Lithium Iron Phosphate. This is a very stable configuration and very tolerant of abuse that would cause a Li-Ion battery to explode. Main benefits are weight-savings since they weigh only 20% of what a lead-acid would for the same capacity. And take up about 50% as much space.’

The critical factors, as when charging any type of battery, are the charge voltage, charge rate or current and charge duration. If you charge a battery at too high a rate, it will get hot and if there is no way to vent the gases produced by charging, this will result in an explosion. Similarly, batteries will get hot if charged for too long, so it is important also to limit the length of the charging period.

The best advice is to do some research and read the forums before you buy. Oxford Products produce a charger for lithium iron phosphate batteries.

From what I read, it is important to restrict the charge rate for these batteries, both in order to avoid damaging the charger and to restrict the voltage in order to avoid damaging the battery. It appears that lithium iron phosphate batteries also need to be charged at a slightly higher voltage than lead-acid batteries. John Blackburn, member 11,656