Ryobi One+ Battey Mystery.

[PeterG]

Hi all, when we were working on a major project the other day my battery drill died. Ended up settling for the Ryobi kit with 2 batteries. The batteries are rated at 18v? at 4AH. Besides 18v not sounding rite, the battery when fully charged has only 8.4v across the terminals.

It seems strange compared to the smaller 1.3AH battery that measures over 20v when fully charged.

Can anyone explain this? 

Regards

[IanB]

18 V is right. Are they lithium or NiCd batteries? Either way the batteries should measure over 20 V when fully charged. I have a NiCd battery that does not hold a charge very well. It's possible you have a duff battery, especially if it is a NiCd one.

[PeterG]

These are new Lithium batteries. They work fine, just weird how they measure 8.4v.

Regards

[IanB]

These are new Lithium batteries. They work fine, just weird how they measure 8.4v.

In that case something's not right. I have a partially drained Ryobi One+ lithium battery sitting right in front of me and it measures 18.3 V.

[Kaptein QK]

Are you measuring the correct terminals?  8.4V is only 2 of the 5 cells in the battery.

[Refrigerator]

I think he's measuring the wrong terminals on the battery, there should be five cells in that battery and a center tap. Since there are 5 cells you wouldn't get symmetrical voltage, and the drill would turn slower when going counter-clockwise.

[IanB]

The battery has three terminals, on the left of the post, on the right of the post and at the front of the post. The left and right terminals are labelled as (+) and (-). Measuring between (+) and (-) should give 18 V or more.

[PeterG]

The battery has three terminals, on the left of the post, on the right of the post and at the front of the post. The left and right terminals are labelled as (+) and (-). Measuring between (+) and (-) should give 18 V or more.

Thats rite, this is whats not making sense. The voltage on the other batteries including an older lithium battery is over 18v but the new Lithium+ batteries are measuring 8.4v. These are the new batteries that have the 4led fuel gauge built in.

Regards

[cybertronicify]

It might be because it needs to detect a drill before it will output pull power, thus avoiding accidental short of the battery? My brushed Makita drill has 9 pins and they all measure different voltages. There could be more circuitry inside the drill.

[Little Brutus]

These are new Lithium batteries. They work fine, just weird how they measure 8.4v.

Regards

Just measured a charged P103 and got 19.6V.

You did charge them with a Lithium compatible charger, and not an orginal ni-cad charger correct?

[PeterG]

Yes the battery and charger are both brand new. The battery is a new P108.
These batteries have 4 terminals on them.

The batteries a got with this kit measue over20v as expected.
http://www.bunnings.com.au/ryobi-one-18v-drill-driver-kit-with-100-accessories_p6210554

These are the batteries i used with the charger that came in the kit above.
http://www.bunnings.com.au/ryobi-one-18v-2x4-0ah-lithium-battery-twin-pack-rb18ll40_p6210431

All were purchased the same day.

Regards

[TheBay]

As these are 4ah, I think there may be some form of protection circuit, imagine these tossed in to a bag with screws and nails etc.

Have you tried a dummy load and then measured it? Or maybe the drill sends a signal down the other connection? The drill may only need 8v to power up circuitry to then activate the full voltage/current?

[PeterG]

Looking at the way these seem to be designed it does seem the main 3 terminals make contact before the last terminal located on the main body of the battery.
There has to be some sort of internal switching taking place.
I will see if i can get hold of one of the batteries. I purchased the kit, my neighbor purchased the 2 battery pack for his drill.

Regards

[neslekkim]

which charger did the kit come with?, in norway they sell a kit Ryobi #5133001912, that is that battery RB18L40 with an charger, RBC18L40, not sure if RBC18L40 is the productname for the charger alone, or the kit though.

[PeterG]

The kit comes with this charger.
http://www.bunnings.com.au/ryobi-one-14-4v-18v-one-hour-battery-charger_p6210373

Note the 2 contacts on the charger. The 4AH battery uses one of these.

Regards

[PeterG]

Just got hold of one of the batteries. It definitely measures 8ish volts across the terminals. However the voltage goes to over 20v when the built in fuel gauge button is pressed. This makes me think the 4th pin may be used for some sort of switching within the battery.

Regards

[TheBay]

Just got hold of one of the batteries. It definitely measures 8ish volts across the terminals. However the voltage goes to over 20v when the built in fuel gauge button is pressed. This makes me think the 4th pin may be used for some sort of switching within the battery.

Regards

This is what I suspected for safety, so it cannot short out and explode when placed in a tool bag and other reasons.