checking battery OFF bike - charge level checker

[dave_uk]

I am trying to check the charge on my Shimano battery OFF the bike.
(why? Cus the battery is inside and the bike in the garage)

The charge tester unit I am trying to use is: 12V - 72V ACID Lead Battery Charge Level Indicator Capacity Test Gauge Voltmeter | eBay

The battery is a 36V DC (Shimano Steps E7000), but fail to get any power out of the battery?!? There is some charge in there as the button flashes green when I push the button on the battery.

Anyone know what I am doing wrong?

Cheers

 

[jimbob]

The first one is that you are trying to use a tester for lead acid batteries, whilst you have a Lithium based battery. Unfortunately the two won't work together.

The shimano battery has some electronic switches inside which disconnect the terminals unless plugged into the bike. I 'think you can fool it by shorting one of the data connectors to ground, but I haven't spent any time looking into it, and don't want to accidentally brick a rather expensive battery!

I think if you press the power button the led flashes between once and five time to give you a rough level of charge, so could try that?

 

[dave_uk]

Hi Jim, Thanks. At least I no know I am not going mad.

I had tried the multimeter on it and got zero volts so eventually worked out it was switching the power off internally some how.

Seems it just needs a "connector" which joins the correct data connections to allow power to be checked.

Anyone know if such a "connector" exists?

Cheers

 

[jimbob]

You could try using your multimeter set to continuity to test which connectors shirt on the bike when turned on and then replicate that on the battery with a wire?

NB: not advising doing this as it could damage the bike or battery, but that would be a way to do it. Just be aware of the risks!

Not aware of a connector which does this I'm afraid.

 

[eMullet]

The newer shimano satelite button sends some kind of order to the battery to power up. The satelite button has it's own battery that provides this command pulse. So turning on the battery with out it could be a little tricky.

But of course, when the battery is connected to the bike, pressing the battery's own button also turns it on, so there are some trickery going on with the battery.

 

[dave_uk]

ahhh, its bloody sorcery thats what it is!

Would have been really useful to know the charge level off the bike, still seems its too much effort so I will shelve it.

Thanks for the enlightenments.