Do both batteries discharge after using snow thrower?

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  • Updated 2 years ago
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One battery discharged some - Second Battery still fully charged.  I bought the snow thrower last year and used it only 2 times.  It seemed to have a lot of power.  This year I have used it only 2 times so far, but it does not perform as powerfully even at full throttle.  The last session took about 20 minutes.  I had put both batteries into the thrower and cleared my driveway.   As I said, it was not powerful at all.
When I brought the batteries in to recharge, one of the batteries went through the recharge cycle successfully.  Then I put the other battery on the charger, but it indicated that the battery was fully charged and did not even start up.
Is this normal, that one battery can require recharge while the other is still fully charged? And why does the snow thrower perform with less power?  It throws snow only about 1/3 to 1/2 as far as it did last year during my first two uses.
Thank you.
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walt dutchak

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  • unsettled about possible snow thrower problems.

Posted 2 years ago

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Blue Angel, Champion

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Official Response
Very strange, Walt. It’s supposed to draw power from both batteries at the same time, not one then the other.

Try running the snowblower with one battery and see if it works with a battery in either compartment. If it doesn’t work with one battery in one of the two sides, and with equal power, you may have found the issue.
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walt dutchak

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Thank you Blue Angel.  I will try that.
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Michael G

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Make sure the batteries are latched down well too. Maybe if one wasn't engaged this would have happened?
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Jacob

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Exactly what I was hoping is the issue. Hopefully it wasn't latched.

My boss had this problem at one time he thought, but now it's working correctly. I think he did the same thing.

To make sure both batteries are being used, a good indicator is the lights on the battery are both green.
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walt dutchak

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_ I did the driveway again this morning.  The batteries were both latched properly and both indicator lights were green during operation.  I used the thrower for about 15 minutes. 
_ When I brought the batteries inside to recharge, battery "A" went through the recharge cycle as expected;
_ Battery "B", however, demonstrated the same properties as previously.   The charger hiccuped a startup noise, the battery light flashed from red to green and the charger showed all green lights (fully charged) and was not running.
_ It appears that my machine is only using one battery at a time.
_ Could it be a battery flaw or a power distribution problem in the machine works?
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Blue Angel, Champion

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It’s hard to say, but if you wanted to be sure and isolate the batteries from the problem try using the same batteries labeled the same way but in the opposite battery slots in the snowblower.

If the problem follows the batteries then the batteries might be the issue. If it shows that the battery located in a particular battery slot is never discharging, then the problem is surely with the snowblower.
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(a)Typical Engineer

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2nd on trying only a single battery as Blue suggested in the first response.
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Jacob

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Are you using 2 same ah batteries?

Here is how it works.

If one of the batteries has a lower voltage than the other, I assume it has to pull from the higher voltage battery. Due to voltage drop from the battery as it's being used, it will drop below the voltage from the 2nd battery. Basically the lower voltage battery kicks in to help the other one with the load. If you aren't needing the voltage, or one of the batteries are actually getting bad and experiencing a larger voltage drop internally, it won't be able to use that battery at all without some sort of magic or switching circuit.

I can say Im pretty confident on knowing how the electronics work on this to say you probably have a bad cell in one of the batteriss, or if it doesn't follow the battery, instead it follows the battery bay, then the electronic circuit on that bay is actually reading the battery voltage incorrectly.
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walt dutchak

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_ Thank you guys for all your input. 
_ Yes Jacob; using 2 5ah batteries that came with the snow thrower.
_  I will record how the batteries are used (battery and bay combinations) the next couple of times that I  have to clear the driveway.  No snowfall since two days ago.
_ Thank you all for the logical steps for investigating this problem.  Hopefully it will reveal something tangible for warranty consideration.
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Jacob

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Great. I look forward to the results. This interests me alot. Start out by sticking a label on one if the batteries to isolate them

Thanks again.
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walt dutchak

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Thanks Jacob.  I already noticed that one battery's serial number ends in "A" and the other ends in "B". So I have battery "A" and battery "B" immediately identifiable for warranty purposes.  Also I will put a larger label on each battery for ease of identity.
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Jacob

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walt dutchak

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Today, Dec. 22, 2017 - I telephoned tech support and spoke with Daniel - really pleasant exchanges.
He gave me the procedure that he wants me to follow to determine if the problem is in the battery or in the snow thrower itself.  Here is the outline:
1. Insert the batteries into both bays. Note which battery is in which bay.
2. Run the snow thrower until a battery shows that it is exhausted.  (Red Light).
3. Put each battery on the recharger and fully charge each battery. 
4. Note/Mark the battery that did not require recharging or required very little recharging.
----------------------------------------------------------------------------------------------
5. Re-insert the fully recharged batteries into bays opposite to which they initially occupied.
6. Repeat steps 2. to 4. above.
7. Note if a) the same batteries stayed charged and discharged, or
    b) battery charge behavior has changed and how.
-----------------------------------------------------------------------------------------------
This outline is in my own words, so it is not the tech's fault if I goofed it up.
====================================================================
I will do this and hopefully the warranty process goes through smoothly.

Any comments? points to highlight? etc.?
(Edited)
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Blue Angel, Champion

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Seems like a good test.  Let us know how it works out!
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Scott Martin

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How did it go, Walt? I have the same problem.
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walt dutchak

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Hi Scott, - This particular situation does not appear to be consistent in my case.   It has happened about 3 times along with some other oddities.  The power light flashed on a couple of times after I finished a job but had not yet removed the batteries.  Maybe there is an inconsistent short happening in the wiring behind the lamp, or maybe moisture from the snow that piles up on the machine surface sometimes penetrates whatever gaskets should be there and causes an electrical short across some component.  Who knows.   I kept a log and sent it to EGO with all the details.  They did not respond immediately, but about a week later they sent me an email saying that they would be shipping new batteries.   Well, I thought, perhaps they have figured it out from my log data. 

The batteries arrived about 15 days later (I'm in Canada) and I thought that I should make sure they are fully charged.  I unpackaged both from their plastic blisters and began charging.   The first battery was on the charger for over an hour and there was no indication that it had charged any at all.  The charger's first green light was blinking, but the battery light was dead (no activity at all, on or off the charger).  This battery was DEAD right from the package.  The second battery charged fine - no problems. 

I sent EGO an email about the DEAD battery they sent me,   That was back in January 23, 2018.  They sent me an email indicating that they are opening a case number on this matter (automatically generated, I am incllined to think), and I have not heard from them since then regarding this matter.   So it appears that either they are very busy with various problems to respond to or else something is poorly organized with customer service.  They seem nice enough but no solid results yet.
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Jacob

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So your still without batteries???????
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walt dutchak

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Hi Jacob, - I have not received a replacement for the dead battery.  They told me on the telephone that I should discard the old batteries (removing serial numbers) and use the new ones when they arrived.  I have not yet discarded the old batteries and have been using the new one along side one of the old ones. 

I have started a log to see if I can isolate which one of the old batteries is not working properly.  As I indicated before,  the problem does not repeat in a consistent manner.  In my opinion, the problem may be in the machine circuitry, or one of the batteries, or possibly a combination of certain conditions, along with a particular battery and the machine circuitry that may cause this intermittent problem to occur.

So far it does not appear to be a charger problem.  I am not an expert in this area.  Maybe someone has experience or knowledge that may help.
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Jacob

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I'm pretty sure the batteries get pulled from equally.

But it's based on voltage at load. If one. Battery has a higher voltage than. The other, it will pull from the higher voltage battery until voltage drop has gone below the other battery, then the both engage. There is no priority battery, just the one with the higher voltage.

It is I believe 2 op amps. I haven't traced the circuit yet.

This is all speculation on my end.
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Walt, hopefully Ego gets you sorted out soon. It’s frustrating when a piece of gear works inconsistently!

Once you get things sorted out, if you do have batteries that are not working properly I would take them and pay the shipping (I’m in Ottawa). I have a few projects in mind that I could use them for.
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Simon

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A quick note on this. I also noticed that the batteries do not discharge equally on my show blower. I have a fair length of driveway and sidewalk to clean and we had a fair amount of snow this weekend. At some point, I noticed that one of the battery flashed red, while the snow blower was still at heavy work, while the other one remained green for quite a while longer. They ended up both depleted (both flashing red), but at a quite significant different time.

My thoughts on why this is happening (all speculations and food for thoughts...):

1-    Maybe both pack were not 100% full to start with, or more precisely, the “Full” state was not interpreted the same on each battery. As all chargers, I am quite sure the EGO one stops charging when it detects a delta V smaller then “x” (I do not know the exact value, but should be fairly small). This delta V might not be detected at the exact same point for several reasons and since the pack has a fair amount of cells (I have 2x7.5A batteries), it may end up that some cells on the pack which depleted faster were not at full capacity, impacting the “full” Wh to a noticeable level.

2-    The cut off (snow blower BCM?) detecting the remaining 20% capacity (just guessing on the %, I don’t know exactly how deep EGO has set the safety to prevent cells damage, I just know nobody set s it to 0% for Li-ion cells...) has hit a weaker cell and triggered it to be deemed empty before the other pack.

In any case, if one of the two use case above is exact, it means there might be a weaker cell (full SoC or empty SoC) in the pack which lead to “detecting a depletion” faster than the other pack. It does not mean a defective cell yet, but can indicate a weaker cell, still within the capacity boundaries agreed upon in one of the too lengthy agreements we probably signed when purchasing the product without paying too much attention to it...

My other thought was that the snow blower does not draw equally from both battery at the same time/same level and can still work at peak torque (motor at full 2000W) from only one battery, which could be bad. This could happen if the “battery availability detection” process is made out of having two batteries locked in the bays, not on analysis of available capacity in each pack. Even if one is fully depleted, the snow blower could not “know” (it just knows there is a pack in there) it and just asks more from the healthy one. If it is the case though, it means the load on the healthy pack is 35.7A (assuming 56V for a 2000W motor). Are there cells able to handle this kind of load today...?? This kind of load could damage a cell quite rapidly. Time will tell...

Long story short, I did experience the same behavior as the OP. Just don’t know why yet... and not too worried about it... yet... 
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1. My theory is that cell balancing happens at the end of the charge cycle. Next time, try charging both batteries fully until the charger shuts off completely (no fans and steady lights), as well as allowing both batteries to sit for some time to make sure they’re at the same temperature. Note: this isn’t necessary, just a troubleshooting thing to rule out some potential variables.

2. With an average pack voltage of 50V, the peak draw would be around 40A. Each battery has three strings of fourteen cells in parallel (14S3P), so that current is divided between six strings in total. Each cell only sees 40/6=6.7A peak. This is no sweat for modern high-draw lithium cells. The cells Ego uses are good for 20A continuous.