I own a Ducati 848 motorcycle which is well known for needing battery tender. Most of the owners of such bikes (along with their bigger brothers 1098) especially since they are not riding them every day report the need for a battery tender unit for these bikes. Mine has started to develop some issues with it's battery voltage. It measures ok in a multimeter but measures 11.2V on the motorcycle instrument (still when engine runs the voltage indication instrument shows 13.8-13.9V so it charges alright) and so i will switch to a new battery. I decided to give li-ion batteries a try due to less weight and i ordered a Skyrich LFP-10 (10Ah 300Amp crank current) battery which is compatible with my vehicle. My only concern at the moment is that a minimal current draw due to immobilizer and an alarm unit might drain this li-ion battery as well and actually much sooner than an alternative lead acid battery. I will also be using a GPS unit on the motorcycle which will be detached after every ride and generally i take care not leaving my bike with lights on etc.

If i measure the current draw on my motorcycle to be 100mA (immobilizer+alarm only) is there any way to roughly estimate how long the battery will last without the need for a charger or for a long ride? Should i reconsider lead acid batteries?

2 Answers 2


With a current draw of 100mA or 0.1A, a 10Ah battery would theoretically discharge completely in 10 / 0.1 = 100 hours or about 4 days.

In practice you need to reduce that figure, because you don't want to fully discharge your battery unless there is some automatic system for disconnecting it before it is damaged. So unless you are going to ride the bike every other day, you need some way to keep the battery charged.

100mA seems a huge current draw for an alarm and immobiliser. I would have thought even 10mA was a high current for that application, unless your bike uses devices that were intended to be powered from the mains electricity supply, not from batteries. There are alarm/immobiliser systems that run for 12 months or longer from an internal "button" cell of the same type used in a digital watch.

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    The 100mA was a figure not the actual current draw. I believe in these bikes the immobilizer draws about 80mA and after a couple of Seconds it goes to sleep mode drawing less than 10mA. The alarm also has a static current draw <3mA...
    – kokobill
    Sep 12, 2019 at 12:03

Without knowing the current draw of the bike when its off its hard to estimate- so I'll relate my own experience instead of trying to answer your question directly.

If you don't take your battery out and put it on a tender for the winter, you might need a new one after in the spring. If you leave it in and have it on a tender, it will likely be ok, but only if it's less than two years old. If its warm out and you leave it without a tender for more than 3-4 days you will not be able to start it. These Ducati SuperBikes' battery cables are undersized for the application- to the point where you can buy kits to put a thicker gauge cable on them. This makes starting easier in all conditions- particularly hard starting (hot and cold).

I have had a 1098 for a number of years, and through some winters with unheated storage of the bike- including through some winters where I rode on warmer days.

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