SkooterG
Purveyor of Crooked Facts
Did you use the proper type of Battery Tender? From the Shorai website:The weather this morning was in the low 40's so I decided to ride the FJR to work. It has been sitting since before Thanksgiving (yeah yeah yeah ... gimme a break) but on the battery tender.
Q. Can I use Lead-Acid battery chargers or charger/tenders?
A.Yes. HOWEVER, you may NOT use a charger/tender if it has an automatic "desulfation mode", which cannot be turned off. We have confirmed with Deltran, makers of the "Battery Tender" brand, that their products do NOT have a desulfation mode, and are therefore OK for use with Shorai LFX, for example. But the best possible charger/tender for Shorai LFX is the SHO-BMS01, which will be released on about March 15th 2011, we expect. It uses the 5-pin BMS port in the LFX batteries, in order to monitor, diagnose, and balance the individual cells during charge. And it also has an optimized storage mode that will give the longest possible service life to your LFX.
If you are storing your vehicle and want to check the remaining capacity, or you're a racer with a constant-loss system, you'll want to know how resting voltage (i.e. with no load or load under 200mA) maps to remaining capacity. LFX batteries should be maintained such that 20% capacity remains at minimum, as best practice. Use a good-quality voltmeter to check remaining capacity, and consider recharge whenever the battery capacity falls to about 50% remaining. Of course, if you get the Shorai dedicated BMS01 charger, you can just hit the "Store Mode" button and leave it to do the work for you.
And....
Q. Should I use a battery tender?
A.The short answer is "only if you really need to". Most powersports enthusiasts have gotten used to hooking up a tender to their lead-acid batteries, all the time. Shorai LFX have much slower self-discharge than the best lead acid do (1/6 to 1/7, on average), they do not sulfate as capacity drops, and they are the ultimate "deep cycle" battery, which means that they can still crank your vehicle even if the remaining capacity is quite low. Therefore most riders will not need to use a tender at all. Even a charger or tender uses energy you have to pay for, and there is always the possibility that a charger or tender can fail in some way, so if not really needed the best practice is to not use one.
A fully charged LFX can sit for a year or more and still retain adequate starting capacity, without damaging the battery. As such, any vehicle which has no current flowing when the key is OFF should never need a tender. At most it should be charged every 6 to 12 months, depending on the average storage temperature (cool storage is much better for any battery). Many older vehicles and most dirtbike/atv fall into this category.
Newer vehicles may have a significant draw even when the key is OFF, to maintain clocks and computers, etc. In this case we expect that a few hours of riding per month will be all that is needed to avoid tending. If you know that you will go a number of weeks or months without riding, you can either attach a tender, or disconnect the negative cable from the battery. In any case, during storage you may use the voltage chart above and an accurate voltmeter, and consider recharging when the battery is around the 50% capacity remaining mark, or above
I would call Shorai and see what they say of your issues.
