Battery fuel meter

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I'm sure its been mentioned before, but EGO should definitely consider a fuel meter on their batteries. That's the only negative I've found so far wirth my first peeve of ego equipment.
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Posted 3 years ago

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They already have a status light. Is there something else you are looking for?
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Yeah all of my power tools with li-ion batteries have fuel meters with 4 bars going from green to red giving you a better idea if you need to charge or not before next use. More useful then just an indicator button in my opinion.
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SCDC, Champion

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I get what erik is saying and like it.  There is no way to judge the amount of power left by the light.  It's green then goes red, that's it, your done.  A true meter would be multiple LED's or a analog dial type.

I like it.

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I've noticed on my mower that once the red light comes on, I have about another 150' of cutting time left. I usually change out the battery when the red light comes on.
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Ken, Champion

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Even the battery for my drone has this feature. Red power light, then four green LEDs that are either steady or flashing, in sequence, so you can see eight steps of charge.

I agree, as advanced as Ego's batteries are, this is a much-needed feature.
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Agreed. Even if they're stuck on the one light/one button design, they could use the existing three colors to improve the situation. Right now we get:

Green = Over 15%
Red = 15% or less

If they simply added orange to the mix it could look much better:

Green = Over 50%
Orange = 15-50%
Red = 15% or less

But if we added a slow flashing red to the mix:

Green = 70% or more
Orange = 40-70%
Red = 15-40%
Slow Flashing Red = 15% or less
(Normal fast flashing red would still indicate "dead" when the tool shuts down)

This would allow a 4-stage meter without having to change anything but the software in the battery. Same button, same 3 color LED, same everything, but happier customers who can check the status of their batteries.

Checking the charge level of the batteries right now is pretty much impossible without a voltmeter. Even putting them on the Rapid charger isn't practical since the charger takes a while to settle and indicate the battery level after it starts charging.
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Keep pressing button for 3 seconds to show battary status. Quick press will be just like what it is now.

You can have multiple combinations like following
1) Solid Green 90-100%
2) 1 Flashing Green 80-90%
3) 2 Flashes of Green 70-80%
4) 3 Flashes of Green 60-70%
5) Solid Yellow 50-60%
6) 1 Flashing Amber 40-50%
7) 2 Flashes of Amber 30-40%
8) 3 Flashes of Amber 25-30%
6) 1 Flashing Red 15-25%
7) Solid Red 15% or Less 
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Blue Angel, Champion

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As much as I love Ego's stuff, part of me can't stop wondering whether this is a feature they've planned for since the beginning but are keeping in their back pocket so they can introduce something new and entice people to upgrade.

I mean, it's so common in just about every application the question quickly goes from "why don't they do that?" to "why on earth wouldn't they do that?"

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Yeah why wouldn't you.
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Michael Cook

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I kinda wondered the same thing. I'd finish mowing the lawn, press the battery button it would light up green. I'd put it on the fast charger and it would start charging from the 25% light. In my opinion 25% should light up at least yellow if not red. All other manufacturers in this category have better battery gauges, but EGO is the only manufacturer with multiple battery sizes. The 5 amp is great for the mower or trimmer, but the 2.5 works well on the blower. Of course you can go big and get the 7.5 amp battery!
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(a)Typical Engineer

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Until Ego develops something, I'll be working on this... meter sitting on top of the battery, which you can configure for cell type, as well as cell count.  I need to build some sort of temporary interface so that I can plug/unplug it easily.  Volt meter is connected because you can calibrate it too.

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(a)Typical Engineer

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The documentation is sparse; if you read the reviews I was lucky to even receive an instruction sheet.  No mention of voltage ranges.

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(a)Typical Engineer

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Okay, so I recharged my 5.0 AH, which took 225 WH per my power meter.   The full capacity of the 5.0 is: 280 WH, so 225 / 280 is: 80.4% or 19.6% remaining.  The meter showed 27%, so that's a 7% error.

If we assume a 5% loss due to inefficiency of the system, then of the 225 WH that passed through the power meter into the charger, then only 214 WH was used (225 x 0.95), and that would equate to 76.4% capacity (214 / 280), or 23.6% used.  Which is pretty darn close to 27%; only 4.4% error (higher).

The take away is that a cheap $15 volt meter can give you much better insight into the remaining capacity of your battery.

You can bet I will be installing this meter to my 20" mower.  As well as making some sort of snap on adapter so that it can be plugged into the battery  to take a quick measurement.  And maybe the last project will be to add it to one of my many slow chargers, now that would be cool to have a real  time charging capacity gauge.

Here is the power meter pictured; which I chose over others because it has a battery backup of the data:

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Blue Angel, Champion

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Ego's 280Wh spec is based on a 56V pack voltage X 5.0Ah. In reality, the average pack voltage is 50.4V (3.6x14), so 50.4 X 5 = 252Wh. Also, I don't think Ego is using 100% of the battery cell capacity; they don't charge to 100% (which would be 4.2V x 14 = 58.8V), and I'm pretty sure they cut the battery off before the cells get to the lower limit of whatever the manufacturer specs them to.

Since we don't know the used capacity of the cells and we don't know how much heat is lost during charging, it's impossible to get an accurate calculation. Measuring voltage and current directly into the battery would be better, and if we could estimate capacity based on known discharge curves for the cells we could get close.
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nice job, It's always nice seeing functional stuff like this plus write up's on it.

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