Understanding and Using EGO Power+ Batteries

Alan B

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EGO Power+ Outdoor Power Tool Batteries have been around awhile, I found threads mentioning them as early as 2014 here on ES. Since I have a few, and they are suitable, I have decided to try them for a couple of ebike projects. To do this I am making mounts and connectors for them using 3D printing. The plan for this thread is to collect information on these batteries and their related DIY applications as well as share experience and designs for their use. We can also link to other threads that provide information or applications where they are used. This first posting will be updated from time to time with new links or other information. Posting #2 will be about my own initial plans and experience, others are welcome to add their own, the intention is for this to be a shared resource on the EGO Power+ battery experience.

Since the forum search is not suited for 3 character words perhaps the term "egopowerplus" should be included in all such threads. This term is used in the web URL of the products and should make a good search term.

Technical Summary

There are many videos and articles with details on these packs, here I will summarize briefly:

The EGO Power+ batteries are 18650 cell based lithium battery packs with 14 series cells primarily used for outdoor power tools such as leaf blowers, string trimmers and lawnmowers. They come in several sizes with one, two or three cells in parallel, using either 2.0 or 2.5 amp hour high current cells. This produces packs with 2.0 to 7.5 amp hours. The packs have a built in battery management system that is potted for moisture resistance, and they are designed so that cooling air can be introduced to the pack. Each cell is wrapped in a phase change material to absorb heat and moderate the temperature of cells during charging and high current drain applications. Fully charged they are a little higher than the manufacturer's claimed 56 volts, but they behave as other 18650 cell packs with 14 high current cells in series, so the voltage soon drops to about 3.6 per cell under load delivering about 50 volts. They advertise 3 year pack warranties and are available through various hardware store chains as well as online. For many these make them locally available power sources.

Pack model numbers, Capacities (AH), Weights(kg) and Parallel Cell count

  • BA1120 2.0 1.26 1P
  • BA1400 2.5 1.26 1P
  • BA2240 4.0 2.21 2P
  • BA2800 5.0 2.21 2P
  • BA4200 7.5 2.86 3P
Edit: 10-Ah now available

Connections

There are four pins on the battery pack and chargers. They are labelled Negative (-), T, D, Positive (+). The power is present between the negative and positive terminals. From the T terminal to the Negative terminal there appears to be a thermistor that the chargers use. From the D to the Negative terminal there appears to be a one-wire Data protocol that chargers and tools use to communicate with the BMS.

Cell Info

It is reported that the cells in the 2.5, 5.0 and 7.5 AH units may be Samsung INR18650-25R. The cells are rated at up to 20A discharge.
Sanyo UR18650RX cells were found in a 2.0AH pack. These cells are rated at up to 20A discharge as well.

BMS Info

Some reports indicate that the main current does not flow through the BMS. This means it is important to set the proper low voltage cutoff in your controller (42V is 3.0V/cell), and it means that individual cells are not protected for low voltage. This is probably why tools use the third pin in the battery interface - to get better information from the BMS to shut down and protect the pack if any cell goes too low.

Power Output

Theoretically a 1P pack can deliver up to 20A, a 2P pack up to 40A and a 3P pack up to 60A, at least in terms of cell current. These values would require that inter-cell wiring, pack wiring and pack connectors be able to handle these levels of current without excessive heating, which is not necessarily the case. We look to the manufacturer's applications to see what demands they consider normal for these batteries.

Tools such as the 21" self propelled mower reportedly have a 1000W motor, or about 20A at 50V. The Snow blower and trimmer/edger/pole saw power head reportedly have 2000W motors (40A) and two parallel packs or a 2P/3P pack (4.0AH and up) are recommended. There is some concern that the wiring in a 2P/3P pack may get warm at 40A. If 2 packs are used in parallel they should be at the same state of charge before being paralleled. Running a 1P pack (2.0AH/2.5AH) the max current should be limited to 20A due to cell ratings.

Pack Storage

The manual states that after 30 days the battery discharges itself to the 30% storage level. This is a BMS function - the BMS has a clock/calendar chip, probably to trigger this activity. The manufacturer recommends fully charging the pack before storage, and storing them and the charger in a dry temperate environment such as the house. Some people report their packs don't seem to self discharge. Lithium batteries last best when stored in the 30-50% charge state region. The automatic self discharge takes some time to complete, warms the end of the pack with the LED, and the LED blinks green during this process according to the battery manual troubleshooting chart.

Battery Status Indicator

The Pushbutton / LED indicator on one end of the battery is used to determine battery status. Depressing it momentarily activates the display:

Green - OK, 15% more more charge
Flashing Green - Battery has not been used for about 30 days and is in the process of discharging to storage level (30-50%)
Red - Charge level is low, prepare to stop using this battery
Flashing Red - Charge level is very low, stop using and recharge
Orange - Battery is overheated (70C), allow it to cool
Flashing Orange - Battery has been overloaded, allow to cool and reduce load


Other Notes

Some teardown articles indicate that the phase change material was not present on the 7.5AH pack and speculate that it is not needed in this pack, with the lower current per cell due to 3 cells in parallel.

There may be some current drawn by some tools even when power is off. The best defense against this is to remove the packs from any tools when not in use. The pack BMS does not seem to be able to interrupt the output current path so the battery may not be protected against a connected load.

Links to EGO Power+ Battery Resources and Articles

www.egopowerplus.com

https://endless-sphere.com/forums/viewtopic.php?f=14&t=60064

https://electricbike-blog.com/2016/04/18/use-your-cordless-power-tool-batteries-to-power-your-ebike-what-could-possibly-go-wrong/
 
I have a pair of Xootr Swift folding bicycles in the process of conversion to electric. These are light bikes, and the plan is to use them primarily for short range trips, and to keep them fairly light. One has a BBBS02 (purchased from Empowered Cycles) and the other has a Luna Xiongda dual speed hub front wheel (provided by Luna for evaluation). Initially I was planning to test the dual speed hub on the Swift I had already purchased for the BBBS02 project, but later I decided to go ahead and buy a second bike for the dualspeed geared front wheel hubmotor. Unfortunately the projects have been delayed. The Xiongda bike is mostly complete and has undergone some testing, and the BBS02 is partially assembled. Both of these bikes seem well suited to the EGO batteries.

The EGO batteries are not the smallest, lightest or cheapest batteries for ebike use. The other pack I have for these bikes is one of the small 52V 6AH packs I purchased from Luna some time back. I only have one of these, the EGO pack will be useful for the second bike, and since the EGO packs and chargers are already in hand are a low cost and interesting battery to use.

Last spring I decided to get some Lithium powered yard tools for some cleanup projects, and this resulted in an EGO blower, string trimmer, and chainsaw. They came in kits with batteries and chargers. So I have a 2.0 and a pair of 2.5 amp hour 56V EGO packs.

Looking at other folks projects deploying these packs most have cannibalized either a charger (some chargers are quite inexpensive) or a tool for the battery connector. Looking at the battery, it appears to be well suited for a 3D printed connector and mount. So a few days ago I started a design. After a few concepts and a couple of iterations, I settled on the approach I plan to use and printed the first prototype today. It fits a little too snugly, so I will make minor adjustments and should have something that fits properly in the next few days.

My initial plan is to use the pair of 2.5 amp hour packs in parallel. This would yield a useful 5 amp hours at 50 volts and it would divide the current between the two BMS's and the two sets of cells. So I need a mount that will hold two packs. NOTE - placing BMS's in parallel could have some undesirable side effects, and there is the issue of controller capacitor precharge current spikes, and avoiding pitting on the battery connector blades and contacts. I have not decided how I will handle this yet, it could require additional circuitry. The simplest and safest approach may be to use anti-sparking connectors with a built in precharge resistor such as some XT types, and avoid paralleling packs unless they are known to be in the same charge state, or use diodes to block cross currents. These diodes would have to handle up to full controller battery current.

Here is the design at the moment. The seatpost clamps are just concepts, but the rest of the design is fairly worked out. This mounts to the seatpost and places the batteries behind the seatpost. The batteries slide onto the two separate pack mounts, about 1/3 of the pack is above and 1/3 vertically below the slide-in mounts. The pink plates are the contacts that slide into the pack and bring power out. The weight of the packs keeps them on the mounts, and other restraint may be added. There is a locking slot just above the connector that can be used, but no feature in the current 3D design does so.

This mount should fit two of any size EGO Power+ batteries, however the 2 and 3 cell parallel versions are larger and heavier (weights below). Depending on the plastic they are printed with we may need to do some beefing up, even for the single cell packs. It is difficult to predict the strength of 3D printed parts. Testing will be required. Take care. :)

More on these bikes here:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=93580
 

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I like your parallel pack bracket design. For the 2.5 Ah packs I think a seat post mount will work very well. I wouldn't mind modeling up a down tube mounting bracket, but I don't have any egos that I can measure. I do need to get some new yard equipment (my poor neglected yard; I'm always out riding when I should be trimming the lawn), so I may just pick up an ego tool or two so I can get a look at the batteries.

Do all the ego packs fit in the same mount? Like can you pop-in a 7 Ah pack on a tool that came with a 2 Ah pack? And do the packs lock into the tool in any way?
 
As far as I know the EGO 56V packs all fit the same mount regardless of amp hour capacity, there are a couple of slots that might be used to reject smaller packs on a high current tool like the lawnmower but I don't have bigger packs or the mower to look at.

The bigger packs do take more space and weight of course, but the side toward the mount doesn't seem to change in a way that would be a problem. I am concerned about the weight and strength of the printed plastic. I like PETG for strength and temperature resistance but it is hard to get off the PEI bed of my printer. It sticks a bit too well.

The tools do lock the battery via a notch that is just beyond the end of the connector tongue at the top of my 3D design above. I haven't looked into using that. I doubt it would be required for a vertical mount but would be handy in other orientations. The sliding slots are about 100mm deep and the current design engages the deepest half of the slot. So it has a long way to go to come off. It would become electrically disconnected after about 15mm of motion. The contacts are double bifurcated, so there are four contacts on each plate, at least in the 2.0 and 2.5AH packs. There could be more parallel contact terminals in the larger packs, there is room for about double what is present in these.

I would avoid the 2.0, 4.0 and 6.0 amp hour packs if possible. I think the 2.5, 5.0 and 7.5 have better cells and higher current capacity (not verified). I looked briefly today at hardware store prices and it seemed the 5.0AH were the best choice. However for yard work I prefer the 2.5AH models as the larger packs add a lot of weight to the tool. I'd rather take a break and change packs more often.

The 2.0AH packs may be considerably discounted, however, so they might still be a good choice.

If you have a 3D printer I could send you an STL file to try. I have already adjusted it based on today's testing, so it should fit. The design is just the mount/connector part, one side of the combo mount shown above. It has two M6 mounting holes.

The 2.0 and 2.5 amp hour packs I have are about 130mm wide, 70mm thick and 180mm in length. So, depending on the orientation and location they could interfere with efficient and comfortable pedaling.
 
I do have access to a printer, so I'd be happy to fire off a job to print out your bracket. To be honest, I'm not in a major rush to get these batteries, so it may be a while before I do much for my own ride or get the chance to make a down-tube bracket. My current backpack battery is working great, and I just started work on making a second seat bag battery.
 
Made some progress on the seat clamp. Since this will be 3D printed it can be a close fit to the actual seatpost, so it doesn't need a wide adjustment range. It will require some support during printing this way, but it makes it simple and clean. It is easy to install since the seatpost comes out readily and it slides on from the end. This vertical design will require a fair amount of space along the seatpost due to the height of the batteries and the room needed to insert them vertically down into the connectors.
 

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If a person for some crazy reason wanted to carry four put a set of stoker bars and stem on your seatpost and attach 2 batteries on both sides of the bars with your brackets :idea:
 
I'm sure more could be carried. The weight will add up.

I gathered some weight data to compare the EGO batteries with the Luna Mighty Mini. These are all 14S batteries, so the voltage is the same.

Note - it is not my intent to advocate EGO or Luna batteries here, just reporting data.

Code:
Manufacturer, Amp Hours, Kilograms:

EGO  2.0  1.3
EGO  2.5  1.3
EGO  4.0  2.2
EGO  5.0  2.2
Luna 6.0  1.5
EGO  7.5  2.9

This is based on my scales and on the EGO battery manual. They agree to one decimal point on the 2.0 and 2.5, the rest are from the manual. The Luna is from my scale.

The EGO batteries include impact protection, phase change thermal management material, air cooling channels and a 3 year warranty, possibly from your local hardware store. All packs include a BMS. The EGO pack BMS's are potted to resist moisture, but we don't know their current rating. The Luna pack is smaller and lighter. It is protected with heavy rubber heatshrink. It has a 50A BMS and high current cells. I can't find the Luna warranty information. The Luna packs require external impact protection. The EGO packs need a special blade connector. The Luna packs come with XT connectors preinstalled.
 
Somebody was saying previously purchasing the batteries with a tool was usually a good deal. I notice they are currently offering the 21" mower with 7.5ah battery and fast charger for $499.00.

The regular price if you buy the battery alone is $358.75 and the charger $99.00. Is there something I'm not catching here? From taking a quick look at a couple videos where they take the batteries out of the case they look like a pretty sturdy design, BMS is fully potted and waterproof.
 
I bought the weed trimmer first, then a year later I bought the largest mower they had (they have two sizes of mower right now). So...I have two chargers.

The bigger charger for the large mower does charge surprisingly fast, and I like that it has LEDs to show how much the pack is charged, with four LEDs being full. (labeled 25%, 50%, 75%, 100%). The smaller charger just shows charging or done.

When I want to store the packs over winter, I charge them until the 100% just barely starts blinking (the other three are solidly lit), and then I pull the battery off, which I assume is somewhere around 90%.
 
The battery manual states that after 30 days the battery automatically discharges itself to a 30% storage level. So make sure it is over 30% when you are done using it. They do recommend charging it before storage, and storing the battery and charger in a heated space, and the tools in a space protected from the elements. Recharge before re-use after long term storage.

Some people report that this auto self-discharge does not seem to happen. This may be a problem with some batteries. We might want to do some testing ourselves. This self discharge process must be fairly slow as it cannot create a large quantity of heat in the BMS, so it will take some time.

The 21" mower may have a 1000W motor. That gives us some idea of power output capacity. The cells seem to be rated at 20A but clearly the wiring is not up to 40 or 60A in the larger packs. They mention that the small packs will run the big tools (safely if only briefly), so that may imply that the load capacity for all packs is about 1000W (50V times 20A).

The T connector appears to be an NTC thermistor. Only the chargers seem to use this terminal. A broken thermistor appears to prevent charging.

It is claimed that Tools respond to the temperature of the pack. Since they don't connect to the T connector perhaps they read the temperature from the D connector.

The D connector seems to be a one-wire data connection. I haven't found a one-wire 14S BMS chip, but this might be something for us to look for. It could be that they use a micro with a one wire interface or software between the D terminal and the BMS chip, but it any case it should be a fairly low cost subsystem as they need to make a lot of them.

40V is about as low a discharge voltage as should be used.

Sanyo UR18650RX cells were found in one pack, 2050 mAH, 20A discharge rated. This was probably from an early 2.0AH pack.

https://community.egopowerplus.com/ego/topics/electric-bikes-and-other-off-label-uses-for-ego-battery-packs
 
Reviewing an hour long video from Utube channel "Thrifty Tool Shed", the link will be provided at the end of this posting. He actually takes the EGO BMS board and repairs it. It is a far more complex board than I expected, lots of components on this board. So we're not just looking for a simple BMS chip. He figures out some interesting things in his troubleshooting process. Some things he says don't seem to be completely accurate, so regard each comment carefully.

I do see the primary current conductors going to the main connector PC Board, but I also see a number of small conductors going to that board. So I cannot rule out that there is some additional circuitry on that board, as the number of small conductors was more than four, so that would indicate something more on that board than just the four connector pins. More questions. Perhaps they are redundant wires. Perhaps they have temperature sensing on this battery connector.

There is a clock/calendar chip on the board PCF85163T, this is perhaps how they do the 30 day timing without consuming much power.

There are two somewhat proprietary microcontrollers. A DC converter to power the circuits from the battery.

The battery LED flashing green every 2 seconds and the battery end getting warm indicates that the processor induced 30 day discharge cycle is going on, according to the troubleshooting chart in the manual.

A transistor, MJD117 was shorted on his BMS, he replaced it and this seemed to fix it, however his cells had been drawn very low so they may also have suffered some damage.

video: https://www.youtube.com/watch?v=EH0GS0iUzzM
 
Alan B said:
The 21" mower may have a 1000W motor. That gives us some idea of power output capacity. The cells seem to be rated at 20A but clearly the wiring is not up to 40 or 60A in the larger packs. They mention that the small packs will run the big tools (safely if only briefly), so that may imply that the load capacity for all packs is about 1000W (50V times 20A).
Ego support has written that the 21" self-propelled's motor is 1000W, the 21" push 700W, & the 20" 600W.
 
mark5 said:
Alan B said:
The 21" mower may have a 1000W motor. That gives us some idea of power output capacity. The cells seem to be rated at 20A but clearly the wiring is not up to 40 or 60A in the larger packs. They mention that the small packs will run the big tools (safely if only briefly), so that may imply that the load capacity for all packs is about 1000W (50V times 20A).
Ego support has written that the 21" self-propelled's motor is 1000W, the 21" push 700W, & the 20" 600W.

Thanks, Good confirmation. This all points to the packs being good for 1000W, or 20A. The 2P and 3P packs may be good for more, but we can't be certain of that since the tools are 1000W or less, as far as I've seen thus far.
 
mark5 said:
The Ego forum manager, an Ego employee, wrote their power head multi-tool motor is 2000W. A power head combo kit has a 5Ah pack.
https://community.egopowerplus.com/...t[settings][reply_id]=18399679#reply_18399679

Their snow blower is 2000W. They recommend using 2 4Ah packs, minimum, for best performance.

Does the Snow Blower have 2 battery slots or is that just keep an extra battery on hand?

One thing I determined is in order to get the batteries on Big Island I need to place an order, then they are shipped to California and then put on the barge with an estimated delivery of 6 weeks once they hit the ship and finally arrive at the Kona Home Depot. So I will need to order well in advance of leaving the mainland again.

Any reason I couldn't utilize a Buck unit to run my 36v folding bike w/ 260w geared motor with one of these batteries?
 
Grainger sale, BA4200
$251.30 / each
Offer Ends 06/30/18
Web Price $359.00
 
Tempting pricing on the 7.5AH pack. Those are getting a bit large and heavy compared to standard ebike packs, but they do have more protection and better ventilation than most.

I wonder how old these on-sale packs are? Do they warranty from date of purchase, or date of manufacture?? They have big date stickers on each pack.

The battery manual says warranty from date of purchase from an official dealer, I didn't check to see if Grainger was such a dealer but I would expect so. Make sure to keep receipts. I don't know if product registration is required for the warranty. Keep those receipts!

It also says warranty does not include rental use.
 
This is all really truly fantastic information. I really appreciate all the effort and research going into these batteries.
 
Raisedeyebrows said:
Does the Snow Blower have 2 battery slots or is that just keep an extra battery on hand?

One thing I determined is in order to get the batteries on Big Island I need to place an order, then they are shipped to California and then put on the barge with an estimated delivery of 6 weeks once they hit the ship and finally arrive at the Kona Home Depot. So I will need to order well in advance of leaving the mainland again.
The snow blower has 2 slots. If both are filled the packs work in parallel.

If Home Depot Kona works like Oahu, you'll have to go to their Customer Service desk to special order with store pickup. You pay for it then but the customer of record is a common account, probably specific to that store, they use for your and other customer's special orders. The only way they'll know it's yours is because of your name, address, & phone number that they'll enter in the order notes and the printed paper copy of the order they'll hand you afterwards. Don't lose this because you'll need it when you go back to the store to pick up your batteries.
If ordering on the mainland but picking up in Kona, I don't know how it's done. Probably the same. Not worse, I hope.

Alan B said:
[...] The battery manual says warranty from date of purchase from an official dealer, I didn't check to see if Grainger was such a dealer but I would expect so. Make sure to keep receipts. I don't know if product registration is required for the warranty. Keep those receipts!
This 2-year old topic suggests they recognize Zoro, a Grainger subsidiary, at least & would accept an emailed receipt:
Battery warranty if purchased from, say Zoro?
https://community.egopowerplus.com/...oro?topic-reply-list[settings][filter_by]=all
 
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