Ryobi 40v's - What works and doesn't.

Hyo

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Hey there! Newbie to Forums! I did a little research to see if anyone mentions any of this but I didn't see much yet.

So I've been experimenting with Ryobi 40v batteries in my Razor EcoSmart Metro scooter. It's a 36v 500w brushed motor scooter. Normally runs off of 3 12v 7ah SLA's that are heavy, slow to charge and lose power over time of the drive. With the SLA's I was getting max, about 8 miles in pretty flat terrain.

Enter my experiment with Ryobi! I was given a Brushless 40v mower, which came with the battery and charger. And I thought, heck, 40v isn't much higher than 36v, and there are people on youtube who have converted this particular scooter to 48v without much issue. Ripped out the SLA's, took apart an extra Ryobi 40v charger and used it as the interface for the battery to connect to the scooter.

It worked!... Sorta. As I found some others mentioning in the forums, People were using the 4ah and the 5ah batteries in their setups that ran 36v, and the batteries have a built in BMS that will trip if ya give the battery too much throttle from a stop. The fix for this? I found out you can parallel two batteries that are equally charged to double the power output! So off to the store I went to match the lawn mower with a weed whacker and a leaf blower too! Each come with their own 4ah batteries and a charger for 99 USD on sale during the summer. Cheaper than just a battery alone! (I'll never understand that...)

The two 4ah batteries, totaling 8ah would get me about 12.5 miles. The speed gets a boost at the start of the drive, from 16mph to 19mph for about 2.2 miles, then it tapers off back to 16mph, but for almost the whole rest of the drive. Even the scooters "dash" tells you when the batteries are getting low. Neat!

But wait! There's more!

I recently found a deal on eBay where a dude was selling Ryobi 40v 6ah batteries! And not just the little ones, but the kinda huge Ryobi "HP" 6ah 40v batteries. These are almost double the size of the normal 4ah or regular 6ah batteries. They were 70 USD a pop. Were labeled used, but working fine.

I bought 4. All charged and good to go! I plopped two into my setup, pulled the throttle and all good! The same, but hopefully more range! But I was curious! Can just one be used? I took one out. Leaving one plugged in. Pulled the throttle aaaand it works!

(Edit: I later found out on the test drive it will still need a second battery in parallel... The 6ah defo has more power, just still not quite enough.)

The Ryobi "HP" 6ah batteries can power my 500w scooter with just ONE battery! (Edit again: no it didn't...) This will help a lot because I had to raise the deck to accommodate the two smaller batteries before. Hah, I was going to need to raise it further, but with just one battery under the deck, I can actually put the deck all the way down! I will be taking these out for a test run later today to see how far they go compared to the old 2x4ah batteries.

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So anywho, TLDR:

Ryobi 40v 4ah batteries can push somewhere up to around 350-400watts before their BMS kicks in and shuts the party down.

Ryobi 40v 6ah "HP" batteries can push 500w+ ! The batteries need to say "HP" on them. I'm guessing it stands for High Power.
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The only unfortunate thing is, the 6ah HP batteries dont fit my lawn mower... But I did buy them just for my scooter so. Eh.

I know a lot of people find these batteries on ebay as scrap, but all they need is to be taken apart, rebalanced, and then they work again! These could be a super cheap way to go far! Mine were only 70USD a pop. I should be able to go 30 to 40 miles on these now. Too cool!

20210407_170809.jpg
 
Have you done the rebalancing effort on one of the "scrapped" Ryobi batteries?

Also could you share your connection method? Did you get a 3D printed part from ebay and wire them that way?

I ordered some of those scrapped batteries at a great price last year but a porch pirate made off with them. Out 50 bucks but the thief got junk that needed rebalancing so no good to him lol.
 
Update already. I was wrong sorta. Its weird. If I full throttle, sometimes it will cut out still with just one battery. Not while at take off, which is really weird. It will get to 5mph, and Sometimes cut out, other times it will hiccup then continue. Not sure. If I feather it just a little it goes just fine. Did 6.5 miles on one of the 4 batteries and it seems to be holding up pretty good! If you guys want I can post the link to these batteries. I plan to run them all down today to test their capacities individually. Even though they still cut out, they definitely have more oomf than the 4ah by themselves. However I will still be putting them in parallel. So much for fitting it all under the deck like stock. xD

MorbidlyObeseKoala said:
Have you done the rebalancing effort on one of the "scrapped" Ryobi batteries?

Also could you share your connection method? Did you get a 3D printed part from ebay and wire them that way?

I ordered some of those scrapped batteries at a great price last year but a porch pirate made off with them. Out 50 bucks but the thief got junk that needed rebalancing so no good to him lol.

I have not done any rebalancing of Ryobi 40v batteries yet, thats the next project soon, but I have done it with the 18v ones. The newer 18v silver batteries seem to have a chip in them, that if any of the cells go below a certain point, the chip will permanently shut itself down. However almost all of the black and gray 18v batteries (Ones without the fuel gauge) if you rebalance the cells, it will come back to life. I've recovered about 10 batteries I got from home depot by just asking if I could have a battery or two to experiment with for free. It's hit or miss. Find the cool and chill manager, they will help ya out. I've tried Makita batteries as well, the 18v ones. I've had 4 recycled ones, and NONE of them will charge, even after you rebalance. Charger will just say defective.
 
Another update. I was able to drive only one of the batteries down to nothing.

Nothing meaning the low battery light was coming on and the speed was dropping quickly from 16mph down to 12mph in just a quarter mile.

To remind, two 40v 4ah batteries, totalling 8ah, that are brand new, in parralel did 12.5 miles just the other day.

Today just one 40v 6ah "HP" battery did 10 miles. By itself. These are used! I'm not sure how that equals out, but it did it!

Same course as the other day! A long 4 mile road with stop lights here and there. Back and forth.

I was feathering the throttle though, because of the BMS issue that... I thought wasn't a thing anymore. Maybe being nice on the throttle really does make a huge difference in distance. Maybe I should be nicer to the throttle and the battery. Iunno.

battery 1.jpg
 
Hyo -

I’m also new to the forums, but I wanted to add some additional info to your thread. First off, thanks for posting your results about using 40V Ryobi batteries. I was running into similar issues and the info you provided has been very useful.

I while back I ran a 12V Power Wheels using Ryobi 18V batteries. The smaller 4AH batteries would cut out under load, but the 9AH versions never dropped out. In fact, the 40A automotive fuse that I had inline would blow before the 9AH battery cut off.

But when I tried a Ryobi 40V 6AH pack in my kid’s 36V Razor dirt bike the battery would turn off under full throttle just like you found with your scooter. The Razor MX650 dirt bike uses a 30A motor controller (it might even be the same model used in your scooter).

After reading your post I load tested a couple Ryobi 6AH batteries. The regular 6AH battery would disable itself at 22 Amps. The HP version would turn off at 24 Amps.

I’m assuming that Ryobi is making the new HP style batteries taller so they can fit another row of cells. Based on what I’ve seen online the 6AH batteries are a 10s2p configuration. Does anyone know if the 7.5AH battery pack is a 10s3p? I'm hoping the 7.5AH battery has a higher current output if it contained a 3rd row of cells.

Otherwise, if the 7.5AH version has the same current limitation, my next option is to run a couple batteries in parallel like you mentioned.

I found a 90V/160A Schottky diode rectifier that may be useful for a 2 battery parallel setup. It can be found on eBay if you search “FST16090”. They are obsolete parts, but quite a bit cheaper than the new versions. I ordered one and I’ll post back later after I get a chance to try it out.

The diode may not be necessary if you’re using balanced batteries, but I’m planning to add the diode to my build just in case I screw up my battery swaps.

Roger
 
Good info Roger. I have seen a diode mentioned many times on this forum when paralleling power tool batteries but never seen anyone share a design or test results using them. It seems people have been comfortable running milwaukee ones without them but I do wonder if the milwaukee has additional features in its BMS to limit inflow current or something.

As I have said in other threads, my interest is in electric toys at the moment (scooters, razor bikes, etc) so any way to make leftover batteries or existing power tool batteries work would be awesome for me. I can lend it to a friend and they know how to use and charge a power tool battery at least. Typically have some good impact resistance compared to shrink wrap and paper that comes on the custom packs.

Please do share your design and test results when you get them.
 
RogerThat said:
Hyo -

I’m also new to the forums, but I wanted to add some additional info to your thread. First off, thanks for posting your results about using 40V Ryobi batteries. I was running into similar issues and the info you provided has been very useful.

I while back I ran a 12V Power Wheels using Ryobi 18V batteries. The smaller 4AH batteries would cut out under load, but the 9AH versions never dropped out. In fact, the 40A automotive fuse that I had inline would blow before the 9AH battery cut off.

But when I tried a Ryobi 40V 6AH pack in my kid’s 36V Razor dirt bike the battery would turn off under full throttle just like you found with your scooter. The Razor MX650 dirt bike uses a 30A motor controller (it might even be the same model used in your scooter).

After reading your post I load tested a couple Ryobi 6AH batteries. The regular 6AH battery would disable itself at 22 Amps. The HP version would turn off at 24 Amps.

I’m assuming that Ryobi is making the new HP style batteries taller so they can fit another row of cells. Based on what I’ve seen online the 6AH batteries are a 10s2p configuration. Does anyone know if the 7.5AH battery pack is a 10s3p? I'm hoping the 7.5AH battery has a higher current output if it contained a 3rd row of cells.

Otherwise, if the 7.5AH version has the same current limitation, my next option is to run a couple batteries in parallel like you mentioned.

I found a 90V/160A Schottky diode rectifier that may be useful for a 2 battery parallel setup. It can be found on eBay if you search “FST16090”. They are obsolete parts, but quite a bit cheaper than the new versions. I ordered one and I’ll post back later after I get a chance to try it out.

The diode may not be necessary if you’re using balanced batteries, but I’m planning to add the diode to my build just in case I screw up my battery swaps.

Roger

You have 9ah Ryobi 40v? Thats amazing! I've been thinking about getting some of those next! The more mileage the better! And being able to pull that throttle all the way would be ideal.

There is 2 versions of the 6ah battery apparently! A 10s2p, that looks the same size as a 4ah 40v battery, then there is the larger version that I believe is 10s3p. I haven't taken mine apart to find out yet. Which I should as these don't have a warranty on these. The 7.5ah should definitely be 10s3p, as there isn't a way otherwise for them to hit that target capacity from what I know. 3ah being about as high as you can go with a set of lithium ion cells before having to parallel them.

Also, does anyone know what the terminals on top of the HP batteries do? Not the ones hidden inside the usual block of 4 terminals, but above that, there are two flat terminals up there, that none of my ryobi tools use. Do these terminals possibly enable higher output? These are only on my 6ah HP batteries.

Thanks for your input! I think I might need to keep a look out for these 9ah batteries, see if I can get a deal or something for one. If anything, getting close to 15 miles on one single battery would be pretty amazing!
 
Sorry for the confusion from my last post. The 9AH Ryobi batteries I was discussing are the 18V version, not 40V.

The only reason I brought the 18V version up in this thread is that the 9AH batteries can output more than 40A. Since those 18V batteries are a 3p configuration I was thinking that the bigger HP 40V batteries would also put out the higher current if they used the 3p configuration.

As far as the extra terminals on the HP batteries, I’ve heard rumors that they communicate with the tool and enable higher output like you mentioned. Unfortunately, I don’t have any of those high power tools that use the extra contacts, so I can't snoop the terminals and see what they do.

I’m still debating on using a two battery Ryobi setup or looking for a different battery option. The diode I bought seems to work well. I tested it using a bench power supply at 10A and it only drops 0.7V, so the part seems legitimate. But I haven’t mounted everything on the Razor dirt bike yet.

In theory, the Ryobi BMS should detect if two mismatched batteries are connected in parallel because the current will spike above 24A and trip the overcurrent protection. The diode is just an extra level of protection.

I was trying to keep this Razor conversion simple and use a single battery, but only solutions I’ve found so far require multiple packs or bypassing the BMS.
 
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