Help, I need an EE

[Scorpio64 5,156]

I'm trying to reset a very expensive Echo 57V battery pack and have a wee problem.  According to the YT videos I've watched the problem is with the on board power mgmt system.  When this particular battery pack goes below a certain voltage, the IC that manages charging does not know what to do and fails to signal the charger to start charging.  The solution, according to the YT monkeys, is to disassemble the pack and force a charge.  Once charged the IC has to be "reset".  There is a built in and labeled set of pads for just this purpose GND and Reset.  If the IC is not reset, whatever tool the pack is attached to will work for like three seconds, then cut out.

So here's my problem, I don't have a 58V DC power supply to get the process started.  I have all kinds of power bricks from old laptops and other gear, but the highest output I have on hand is probably 48V.  So the question is; Will a 48V DC supply push enough electrons into the batteries to at least get a 2% charge, is there any danger in making the magic smoke escape from the ICs if I undervolt the battery pack?

[JohnnyB 4,326]

I think you will get what you need from the 48V. Just watch the polarity!

[Displaced Texan 11,752]

48V might do. I’d have to see the circuit

[45Doll 5,877]

Does the battery in the pack measure any voltage at all, or is it dead? As in 0.

[Displaced Texan 11,752]

First of all, do you have a DVM?

[Scorpio64 5,156]

2 hours ago, Displaced Texan said:

I’d have to see the circuit

I've reached my limit for posting pictures but you can see the pcb in the first couple of videos (Echo 58 volt battery pack reset) on YT that demonstrate the reset procedure.  It looks like a universal design used in

1 hour ago, 45Doll said:

Does the battery in the pack measure any voltage at all, or is it dead? As in 0.

It's dead flat, hence the issue of not being able to reset.

 

3 minutes ago, Displaced Texan said:

First of all, do you have a DVM?

Klein CL390

[Displaced Texan 11,752]

Just watched the video. 
 

48V will work just fine. 

You won’t let the magic smoke out of the charge circuit by pushing less voltage. Current could get you in trouble…
I probably wouldn’t go more than 0.5A.

I find the lack of cell balancing circuitry a bit baffling. 
 

Whatever you do with this…BE FUCKING CAREFUL!!! 
 

I shouldn’t have to explain the dangers of lithium batteries.  Please do this outside and well away from anything that can burn. 
 

I’m really curious as to why they don’t have balancing circuitry built into that pack…

[Scorpio64 5,156]

12 minutes ago, Displaced Texan said:

I’m really curious as to why they don’t have balancing circuitry built into that pack…

As am I.  The only thing I can think of is they got super cheap, I mean SUPER cheap, or there was a flaw in the pcb design and it was just easier to omit than to re run 100,000 revised boards.

[gleninjersey 2,141]

1 hour ago, Displaced Texan said:

I’m really curious as to why they don’t have balancing circuitry built into that pack…

Trump's fault!

[Displaced Texan 11,752]

@Scorpio64

Just for reference: 

Max charge voltage for a lithium cell is 4.2V. 
 

You are charging at 48V for a 14 cell pack, at .5A. 
This is 3.42V per cell, and 1.71 Watts per cell. You should be just fine. 
Your Echo charger puts out considerably more current then .5A (it’s probably 2A+). You’ll be charging at a lower rate, which is good in your case, for safety. It will take longer to reach your voltage threshold for the pack, but it will minimize the risk of charging too quickly. 
 

In any case, I’ll reiterate, do this outside. Away from crap that can burn. Be careful!
These batteries can hurt you. They are very energy dense,  shorting the cells, charging damaged cells, or charging at too high a rate can have horrific consequences.
I know that you know this, but it makes me feel better to say it again, my friend! 
 

 

[45Doll 5,877]

I clearly have some studying to do. So I'm out. Good luck and I'll be watching for the (successful) results.

[Scorpio64 5,156]

1 hour ago, Displaced Texan said:

You are charging at 48V for a 14 cell pack, at .5A. 

The max output on the Echo charger is 4A, so I should be fine.  I only need to get enough juice into it to wake the lazy bastard up.  Honestly, for a $225.00 battery, you'd think they put in a cutoff to prevent full discharge.

Another thing I noticed just by happenstance.  For whatever reason I decided to shine a UV flaslight on the PCB just for whatever.  The UV light is a recent new toy and the novelty hasn't waned yet so I'm treating everything like a black light poster to see what pops.  It seems the pcb has a thin coating of something, probably some kind of waterproofing because it's expected to be used outdoors in the damp.  Well, like I said there is no correlation to my reset issue, but the film is delaminating and flaking off.  I give them an E for effort.

[JackDaWack 2,895]

If you get this to work, it might just barely work. 48v is still pretty dead for a battery fully charged at 63v. 

1 hour ago, Displaced Texan said:

@Scorpio64

Just for reference: 

Max charge voltage for a lithium cell is 4.2V. 
 

You are charging at 48V for a 14 cell pack, at .5A. 
This is 3.42V per cell, and 1.71 Watts per cell. You should be just fine. 
Your Echo charger puts out considerably more current then .5A (it’s probably 2A+). You’ll be charging at a lower rate, which is good in your case, for safety. It will take longer to reach your voltage threshold for the pack, but it will minimize the risk of charging too quickly. 
 

In any case, I’ll reiterate, do this outside. Away from crap that can burn. Be careful!
These batteries can hurt you. They are very energy dense,  shorting the cells, charging damaged cells, or charging at too high a rate can have horrific consequences.
I know that you know this, but it makes me feel better to say it again, my friend! 
 

 

It's a 15 cell pack, so your looking at 3.2v per cell. Which might still be below low voltage cutoff. 

Definitely agree on the lowest amp charging possible. 

3 minutes ago, Scorpio64 said:

The max output on the Echo charger is 4A, so I should be fine.  I only need to get enough juice into it to wake the lazy bastard up.  Honestly, for a $225.00 battery, you'd think they put in a cutoff to prevent full discharge.

Another thing I noticed just by happenstance.  For whatever reason I decided to shine a UV flaslight on the PCB just for whatever.  The UV light is a recent new toy and the novelty hasn't waned yet so I'm treating everything like a black light poster to see what pops.  It seems the pcb has a thin coating of something, probably some kind of waterproofing because it's expected to be used outdoors in the damp.  Well, like I said there is no correlation to my reset issue, but the film is delaminating and flaking off.  I give them an E for effort.

There should be a low voltage cut off, why your charge got so low could be a number of factors. 

But keep in mind, the battery may never fully recover and could be a potential hazard when charging. Most of these batteries already don't like to be stored full or empty. 

[JohnnyB 4,326]

Full discharge often happens by depleting a battery then letting it sit uncharged for such a period that leads to that point of total discharge!  Best to charge immediately after any total discharge!

[Displaced Texan 11,752]

43 minutes ago, JackDaWack said:

It's a 15 cell pack, so your looking at 3.2v per cell. Which might still be below low voltage cutoff. 

Definitely agree on the lowest amp charging possible. 

It’s a 14 cell pack. 14 x 4.14V(nominal) = 57.96V

[JackDaWack 2,895]

10 hours ago, Displaced Texan said:

It’s a 14 cell pack. 14 x 4.14V(nominal) = 57.96V

That's an incredibly high nominal voltage per cell. It's confusing because Echo has a number of 56v and 58v batteries. 

Hard to tell when there is no  industry standard. Almost every battery I have used its 3.8 or 3.7. I know dewalt uses 4v per cell...

@Scorpio64 have you had a chance to open in and count the cells?

 

[Displaced Texan 11,752]

I’m no battery expert, but from what I’ve read, lithium cells run about an average of 3.4V min to 4.2V max. 
 

It is quite confusing, with different chemistries in various types of cells. 

[Displaced Texan 11,752]

11 hours ago, JackDaWack said:

But keep in mind, the battery may never fully recover and could be a potential hazard when charging. Most of these batteries already don't like to be stored full or empty. 

This. 
 

 

11 hours ago, Scorpio64 said:

Another thing I noticed just by happenstance.  For whatever reason I decided to shine a UV flaslight on the PCB just for whatever.  The UV light is a recent new toy and the novelty hasn't waned yet so I'm treating everything like a black light poster to see what pops.  It seems the pcb has a thin coating of something, probably some kind of waterproofing because it's expected to be used outdoors in the damp.  Well, like I said there is no correlation to my reset issue, but the film is delaminating and flaking off.  I give them an E for effort.

Probably a varnish, as you pointed out, for waterproofing. 
I wouldn’t worry too much about the flaking of the varnish. 

While you’re in there, inspect the cells for swelling or discoloration. If any of them are, do not charge the pack. 
I don’t know your level of comfort, but you CAN replace individual cells, but they must be exactly the same chemistry and type. Do NOT mix cell types in a pack. 

[JackDaWack 2,895]

28 minutes ago, Displaced Texan said:

I’m no battery expert, but from what I’ve read, lithium cells run about an average of 3.4V min to 4.2V max. 
 

It is quite confusing, with different chemistries in various types of cells. 

 It's should either be a LIPO or LifePO4, very different with respect to charge parameters. 

Lipo is 4.2 max, and typical cutoff should be about 3.4 volts. However, that cut off is also dependant on load when the circuit cuts. So if it cuts a 3.4v under load, the battery will rest at about 3.5. 

I keep my lipos above 3.7 volts for longevity. 

The "industry standard" is 3.7v per cell when buying a lipo battery. The only times I've seen this deviate is with power tools to put a bigger volt number on the product. 

[Displaced Texan 11,752]

10 minutes ago, JackDaWack said:

 It's should either be a LIPO or LifePO4, very different with respect to charge parameters. 

Lipo is 4.2 max, and typical cutoff should be about 3.4 volts. However, that cut off is also dependant on load when the circuit cuts. So if it cuts a 3.4v under load, the battery will rest at about 3.5. 

I keep my lipos above 3.7 volts for longevity. 

The "industry standard" is 3.7v per cell when buying a lipo battery. The only times I've seen this deviate is with power tools to put a bigger volt number on the product. 

I’ll have to check this when I get home. I have a Mikita electric chainsaw (which is surprisingly good!), offhand it’s 60V. I’d be interested to see cell voltage. Also charge rates. 
 

EDIT: nope, it’s 36V. 

I’m not a battery expert, but it might be a fun little learning process. I might be interested in buying a refurb pack, if I can get one cheap, to do a little sacrificial testing. 
 

[JackDaWack 2,895]

1 minute ago, Displaced Texan said:

I’ll have to check this when I get home. I have a Mikita electric chainsaw (which is surprisingly good!), offhand it’s 60V. I’d be interested to see cell voltage. Also charge rates. 
 

I’m not a battery expert, but it might be a fun little learning process. 

I've been using these batteries for model airplanes for over a decade now. 

Which is why I often get a chuckle when people talk about the convenience of electric power. Like everything, they are great when they work as intended. 

[Displaced Texan 11,752]

2 minutes ago, JackDaWack said:

I've been using these batteries for model airplanes for over a decade now. 

Which is why I often get a chuckle when people talk about the convenience of electric power. Like everything, they are great when they work as intended. 

Nice! 
 

I used to fly turbine jets years ago. Fun (but stupidly expensive) hobby.

[JackDaWack 2,895]

41 minutes ago, Displaced Texan said:

Nice! 
 

I used to fly turbine jets years ago. Fun (but stupidly expensive) hobby.

When I got started in the hobby electric really started to pick up, it was incredibly convenient even with the charging discharging and storage issues of lipos. But those challenges are still around today entirely due to the chemistry. 

Turbines are nuts considering the associate cost, we have large EDFs now running on 10 and 12 cell lipos. I have a kit P-51 that will eventually run on 12s, 44.4v battery. 

To this day I still have not fully created a safe solution to storing these batteries. I have them in fire safe bags and charge outdoors, but I still store them in a less than ideal location for tempature reasons, and still see pack degradation in the off season at storage charge. 

It's always been a point of caution when a battery goes dead, you can try and save it in the short term, but its better to just replace it. 

@Scorpio64 do you have any soldering skills? Those cells can usually be replaced fractions of the cost if they are easily accessible. It's ussually just a 18650 battery in series. 

[Scorpio64 5,156]

1 hour ago, JackDaWack said:

 It's should either be a LIPO or LifePO4,

LG HB4 18650 Lithium Ion 3.6V, 1500MAh, nominal charge rate .75A, Max charge rate 4A.

Here's a link to detailed spec sheet. https://www.megacellmonitor.com/pdf/vendor_specs/SPEC_LG_LGDAHDB41865_ICR18650HD4.pdf

1 hour ago, Displaced Texan said:

I have a Mikita electric chainsaw

I almost bought an Echo 16" saw that uses this battery pack, I'm pissed that I didn't as it was on display clearance.  Coulda had it w/o battery for $150.  I had momentarily forgotten the correct answer to the question "do I need this".  At the time I had no pressing need because I have a Homelite XL 18" that sometimes works.  Three months later we had a severe storm that downed a neighbors tree in my yard.  Ended up buying a mid-range Echo 2 cycle 20" saw because I'm getting too old to fuck around with hard to start power equipment.

1 hour ago, JackDaWack said:

do you have any soldering skills?

Mad skillz.  I built an intercom in 1973 when I was 9, I used to repair motherboards.  I have to admit, I detest working with SMT, some components are so small now, the solder sucker tries to suck them in.  The batteries are all in good shape, they have a lovely figure, no bulging at all.  I was contemplating upping the pack to 4Ah by adding 14 cells to the empty "slots" but I use the trimmer so infrequently that it's more hassle than it's worth.

After looking at the spec sheet, I feel comfortable pushing 48V @  2Amps.  I'll keep an eye (and occasionally one hand) on it while charging.  Hopefully it will work out.

 

[Displaced Texan 11,752]

10 minutes ago, Scorpio64 said:

After looking at the spec sheet, I feel comfortable pushing 48V @  2Amps.  I'll keep an eye (and occasionally one hand) on it while charging.  Hopefully it will work out.

2A will be ok. 

[Tunaman 552]

7 hours ago, Displaced Texan said:

I’ll have to check this when I get home. I have a Mikita electric chainsaw (which is surprisingly good!), offhand it’s 60V. I’d be interested to see cell voltage. Also charge rates. 
 

EDIT: nope, it’s 36V. 

I’m not a battery expert, but it might be a fun little learning process. I might be interested in buying a refurb pack, if I can get one cheap, to do a little sacrificial testing. 
 

Looks like you have a nice Black Walnut there.....

[Displaced Texan 11,752]

1 hour ago, Tunaman said:

Looks like you have a nice Black Walnut there.....

Nope. That’s mesquite. 

[Tunaman 552]

22 minutes ago, Displaced Texan said:

Nope. That’s mesquite. 

Ahhh.  Looks like it would make some nice grips...

[Scorpio64 5,156]

15 minutes ago, Tunaman said:

Ahhh.  Looks like it would make some nice grips...

mesquite smoked feral piglet

[Displaced Texan 11,752]

28 minutes ago, Tunaman said:

Ahhh.  Looks like it would make some nice grips...

I’ll send you some if you want to make a set