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Understanding and Using EGO Power+ Batteries

EGO is about to start selling a 10-Ah pack. Previously, the largest they made in the "56V" (14S) format is 7.5-Ah. I suspect it uses the 21700 cells, but it remains to be seen. It may not fit in the 2019 and earlier model mowers. As many of you know, the weed wacker, leaf-blower, chainsaw, etc usually allow the pack to be any width or length, but the mowers have a fitted socket for the pack to slide into. The 10-Ah is reported to be slightly longer and possibly a bit fatter.


They also now have a small 150W inverter for only $120. I suspect it is not a "true sine wave" model, but that also remains to be seen. This is a plug and play inverter for 14S packs, so I am anxious to see if EGO has limited them to only using authentic EGO packs by some proprietary "handshake" signal.



The 3000W model (which could run a refrigerator and TV) is $500, with no batteries included.


A new EGO inverter thread.
Has anyone connected two 14S EGO batteries in series to get 28S? (116V when fully charged).

I'm wondering if this can be done without damage to the packs. It may be possible that only one pack would be damaged if they were put in series, and in view of that possibility, does anyone have a 2.5-Ah EGO pack they would donate for a death-match?

I have several EGO batteries, and I rarely use my 2.5-Ah that came with the string-trimmer, so I am unconcerned if it dies...

Hmmm...just remembered that there is a handshake built-in. This is why, if you plug-in the small battery to the large lawn mower or chainsaw, it will not work...The large mower will only use a high-amp pack.

edit: I have the larger 21-inch diameter-blade model with a power-wheel electric drive. It requires a 5.0-Ah pack or larger to run.
spinningmagnets said:
Hmmm...just remembered taht there is a handshake built-in. This is why, if you plug-in the small battery to the lawn mower or chansaw, it will not work...The mower will only use a high-amp pack.
A 2.5Ah pack will make my non-self-propelled mower blade spin. Didn't try cutting grass with it though. Don't know whether an older 2.0Ah pack would do same.

Update: mowing with 2.5 vs. 5Ah pack works ok.
This is from the parts diagram from a dual battery EGO snowblower and mower. You can see what looks like capacitors on both the expensive items, so I assume those are the controllers. I'm guessing the $80 & $117 items are diodes and/or power mosfets for switching batteries off.

Will running an AC motor directly from a 52v battery hurt the battery/BMS?

I have several EGO 52v batteries. I have some AC tools that will run directly from the batteries but I haven't done it much because I am afraid I will hurt the battery or BMS in some way. The tool I especially want to use is a AC 110v 6A angle grinder. Will doing so hurt the batteries? I just made an AC female plug to a XT60 male adapter.


Stu Summer
2013 DB Haanjo Commuter with BBSHD and Zzipper fairing
Marin Rift Zone FS with BBSHD
Ryan Vanguard recumbent LWB with a 36v Cyclone 350w middrive and a 56v MAC 5t in the front hub.
The +\- terminals on the ego battery bypass any electronics, and are connected straight to the cell string. The tools decide when to stop accepting battery power. Any BMS is only for the charging/charge display.
Hi, and please excuse what might be a silly question.

I want to experiment with using a Ego battery charging from a 120 watt portable solar panel. I bought a configurable MPPT to step up the voltage to Ego charge.

The idea is that I could set out the panel with an Ego 7.5Ah to gather rays while I used bike and then use the 7.5 to top up my ebike battery.

Since I had extra Ego chargers I planned to hack one for the battery connection. While doing this I first thought would do away with the AC power supply but while doing so I thought hmmm... why not have both AC and MPPT output options toted with me.

So my question is should I make a 5 wire to 2 wire adapter or simply parallel my MPPT 2 wire connection to the battery connector and leave the 5 wire connector on the AC power board which of course will not be plugged in. Would having the MPPT send 58v on the red and blue (+ and -) back to the AC supply board not connected to AC cause a problem?

I can try both and see what happens because I am a “wild and crazy guy” but thought I would through it out here.

Alan B said:
Since this happens anytime the AC is unplugged or the power goes off while a battery is sitting on the charger it probably won't hurt anything. I have not tested it that I know of, but this kind of thing happens frequently with battery chargers so they are generally designed for it.
Should have been more clear. I was wondering about whether the MPPT voltage would be off back charging capacitors or something. I will report but yeah I get the normal circumstance.
Lithium chargers, as I understand it, gradually up their output, staying just ahead of the voltage charge of the battery. The question I have is whether having 58v come constantly from the MPPT cause a shortened battery life?
Stu Summer said:
Lithium chargers, as I understand it, gradually up their output, staying just ahead of the voltage charge of the battery. The question I have is whether having 58v come constantly from the MPPT cause a shortened battery life?
I cuts off but no mention of ramping up. I will research. This is new to me but even if it does not work for the ebike; I know 120 watt would be a multi-day affair for the 14s6p GA cells but I also want to power up phone, tablet and notebook with bike camping as well.



Update after reading some I was comfortable to do a trial run from the MPPT directly to the ebike battery. Good sun and voltage from the panel is about 19v and I set the MPPT battery side to 58.2v. I am getting 2 to 2.4 amp charge and the Bafang display is at 57v up .2v already! The Bafang display always reads .4v down from my meter so we shall see if it stops at 58.2. Two amps is perfect... happy so far!

seen these??

Looks awesome for tangent / cyclone riders...

There's a guy on facebook who can't get it going though, the pack needs to talk to a tool to drive the output.

Ideas anyone?

EGO Community ... I've converted an ATV to electric powered by EGO 7.5ah batteries but it limits current to about <20A which is no where near what's required for "fun". It serves my intended purpose but have ventured down the path of building my own pack (14S8P) but haven't determined my charging solution. Thought I might be able to tweak the EGO charger but suspect that pesky D terminal needs to be satisfied to handshake with the charger (haven't tried yet). Was hoping someone has already cracked that nut and can share.

125cc ATV Conversion https://endless-sphere.com/forums/viewtopic.php?f=34&t=109518
Alan B said:
One of my EGO 2.5 amp hour 56 volt batteries was working a few days ago on the hedge trimmer, and yesterday it did not work. Today I put it in the standard charger and it cycled and did not stay in the charge mode.

I measured the pack voltage around 10 volts, and was not responsive to pushing the button.

I put a small current into the battery of about 60 milliamps, and after a few minutes the voltage was in the low 30's. After that the charger accepted the battery and started charging. I kept watch over it as it charged. I charged it in several short periods when I could watch it.

Before it stopped charging I noticed that the battery LED was flashing once per second. This behavior continued after the battery stopped charging and the charger indicated full.

I removed the battery from the charger and it continues to flash green. I did a brief test in a tool and the battery powered the leaf blower as usual.

This green flash normally indicates the 30 day discharge to storage level. Clearly we don't have 30 days of non-use to trigger that now. I wonder if this is instead an indication that it is balancing, which would be likely after a deep discharge such as this.

Anyone have experience with this?

I had a similar problem on a BP 800adv karcher similar to ba4200e EGO, 14s 3p architecture, it was blinking green but i am not sure if i purchased it with this defect, i charged and used it, but it still blinking green, after two weeks unused is was totally drained, one rack was dead zero one rack was 3,5 volt per cell, I reused them for other purposes.
This battery was already repaired when I purchased it, BMS was mistreated, one connector was damaged, but the root defect was the MJD117 PNP darlington transistor, It was shorted collector to emmiter and drained out the battery same defect presented on YT.

I tried to figure out the reason that that transistor fail so frequently, My experience in switch mode power supplies tells me that slow transistor does not cope with residual pulses generated by motor driver, especially in cold weather when cell internal impedance is hi.
This transistor is partially damaged by switch pulses and drains the battery.
I literary baked countless slow devices, transistors and diodes with residual pulses (not filtered enough) from silicone carbide devices.

I added a circuit diagram that shows MJD117 is the power gate of this BMS, and takes full brunt of switch pulses because it has no input filter (device numbers are ones of the original BMS)View attachment BMSgate.pdf
My 2.5-Ah pack (from my weed trimmer) cannot run the mower, which came stock with a 7.5-Ah.

I decided to buy a 5.0-Ah as a spare, which can run both. On ebay, there is a site that advertises new-in-box items from a US shipping warehouse where the pallet has crane or forklift damage.

Apparently its easier for insurance to write off any lithium batteries instead of risking them going to customers, no matter how small the "scratch and dent" damage might be.

I took the risk and purchased a 5.0-Ah pack for $140 with no warranty. It does appear new, and so far it works fine.

Retail price now when new with 30 day warranty is $250.
spinningmagnets said:
Retail price now when new with 30 day warranty is $250.

While that's true, you can get a 5ah battery and a yard tool for $200-$300. And the warranty is actually really nice and easy to use.

Still, great to have options for getting the batteries cheaper. Did you crack it open or otherwise test it to make sure the batteries aren't counterfeit or really old?
Jenming said:
spinningmagnets said:
Retail price now when new with 30 day warranty is $250.
While that's true, you can get a 5ah battery and a yard tool for $200-$300. And the warranty is actually really nice and easy to use.

When I bought a refurb EGO mower with a 5A battery I grabbed a 580 CF blower with a 5A for $200 mostly for the battery, but also to qualify for $50 off. $500 for a mower, blower, and two 5A batteries. I'm seeing many of my neighbors using electric mowers this year, almost as if the peak has been reached for gas mowers.
mart498 said:
I have reverse engineered some messages between my quick charger and 7.5 Ah battery. Used protocol is similar to 1-wire but bit timing is different.

Here is one message from the charger:
Packet 1.png

CRC calculation method is the same as used for 1-wire:
width=8 poly=0x31 init=0x00 refin=true refout=true xorout=0x00 check=0xa1 residue=0x00

The full set of packets when full battery is inserted to charger is the following:
Full battery charging.png

Each messages (except the header messages) consist 72 bits (6 bytes command/query name + 2 data byte + 1 CRC byte). For GET_VM query the battery is answering:
"OUT_VM" + 0x2E + 0xE0. Converting it to 0xE02E is in decimal 57390 mV = 57.390 V.

I haven't had time to decode GET_CM (current?) and GETCG1 (charge level?) value bytes as it would need testing it on different charge levels.

Any more info on the protocol in use? How did you connect to it? Arduino? If so, do you have code you would be willing to share?

I'm curious if there is more data available, such as the number of cycles on the battery. I've got a 7.5AH battery I've been using with the 21" mower. Was looking at some batteries off eBay, including one listed as new, but it's anybody's guess if it really is.

I recorded the signal with an oscilloscope and analyzed it in Excel. I have not written any code for this.
Stu Summer said:
Lithium chargers, as I understand it, gradually up their output, staying just ahead of the voltage charge of the battery. The question I have is whether having 58v come constantly from the MPPT cause a shortened battery life?

The phenomenon you describe is actually under the control of the cells, natural, inevitable, nothing to do with charge regulation by the charger.

Amps are amps, volts are volts.

Charging lithium is nothing special, in fact healthiest for longevity is also the simplest, CC (bulk stage) only, charge to a precise adjustable voltage setpoint and Stop, no holding CV (absorption stage)

At a low C-rate can get you to 100% Full at little cell stress.

For li-ion at 14S the cutoff should be between 57.4V (bit gentler, sacrificing a little cap utilisation) and 58.1V, no higher in normal cycling.

Yes sitting at high SoC when not actively cycling is going to reduce lifespan

Sitting on a charger longer than necessary even more so
Has anyone played with the "terrafirma battery adapter"?
I specifically am interested if it can handle the weight of a battery hanging from it + bumpy road. I would rather click the batteries to this than build a mount.