Can I Use a Battery Tender on my Shorai Battery?
Will your old Battery Tender Maintenance Charger still work with your new Shorai battery?
The answer: YES. Well, mostly yes anyways.
While your typical Battery Tender charger is compatible with these LiFeP04 batteries, Shorai says you should use a Battery Tender "only if you really need to". The reality is, Shorai's powersports batteries have a much slower self-discharge rate than lead acid batteries. Typical scenario: your bike would have trouble starting in the Spring after sitting unused in the garage all winter and the battery has dropped in charge. That would not happen so easily with Shorai batteries. The optimal storage charge rate for these batteries is actually between 60-80%, so there is no danger is leaving the battery without a charger hooked to it for a few months. After the period of inactivity, it's okay to use the Battery Tender to charge them back to full capacity.
Another important note: Although the Battery Tender is known as a maintenance charger, this is not the case if hooked to a Shorai battery. Because of the voltage differences found in a Lithium battery pack, the charger may not enter "float" or "maintenance" mode. Rather than simply keeping the battery at a proper float level, it may stay in boost mode for long periods. There is then the risk of overcharging the battery, one of the many causes of early battery failure.
One last bit of advice. It is absolutely NOT SAFE to use a charger with an automatic de-sulfation pulse mode. Such brands such as Battery MINDer and Pulse Tech offer great products to help restore old lead acid batteries, but because there is no lead sulfate in Shorai batteries it would prove harmful to the lithium cells. If your charger has a de-sulfation mode that is not automatic, you may use it as long as this mode has been turned off.
Truth be told, the best charger to use on a Shorai Battery is their Sho-BMS01 LFX charger. This is specifically designed for these batteries, and they connect directly via the 5 pin BMS port betweeen the terminals. Using Shorai's own charger will enable the battery to reach the possible lifespan of 5-7 years.
If you have a Shorai battery, proper charging is important. One of the nicer features of the Shorai batteries is their long shelf life. But if they are improperly charged, the can fail just like any other battery. Be aware of what Shorai says is considered safe and not safe when it comes to charging their batteries. If you have any other questions, give us a call at 541-474-4421.