Unprotected Ryobi One+ Battery?

Batteries, Chargers, and Battery Management Systems.
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Sunder   100 MW

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Unprotected Ryobi One+ Battery?

Post by Sunder » Feb 07 2017 10:32pm

Hi all,

I bought a Ryobi One+ 18v lawnmower two days ago, against my better judgement. I knew it would be weak... How weak was what surprised me.

The thing is, I've noticed it's the battery pack that cuts out, not the mower itself. 1. It cuts out more when the battery is low, and 2. The new battery cuts out less than an old one.

So, I'm thinking of gutting one of my old batteries, and putting like a high rate 5S battery in there with no protection except maybe a fuse.

So my question is:

1. WIll a fuse be enough?
2. What kind of rating should I try?

Thinking of just rigging one up with a current meter, and see what it takes to trip the standard battery, then raise it 10% at a time until either I feel it's unsafe or it doesn't trip the fuse under any circumstance, but if anyone has any ideas or starting points, I'm keen to hear them.
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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dogman dan   100 GW

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Re: Unprotected Ryobi One+ Battery?

Post by dogman dan » Feb 08 2017 6:58am

Personally, I'd just let er rip with no fuse, and some lipo. The motor itself will have an overheat protection in it. But if you just want short circuit protection, go with at least 50 amps automotive blade fuse. Mowers can really pull a spike if there is no controller.

The only thing to avoid is overvolting it to the point where the blade rpm is dangerously high, or the controller smokes, if your mower has one. My old B&D 24v is very crude. No controller at all. Just a brushed motor, and a safety switch.

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parabellum   10 MW

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Re: Unprotected Ryobi One+ Battery?

Post by parabellum » Feb 08 2017 7:17am

Do you already use the strongest P108 4Ah battery?

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Sunder   100 MW

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Re: Unprotected Ryobi One+ Battery?

Post by Sunder » Feb 09 2017 12:13am

Looks like there is a motor controller in it according to the service manual, but it just treats it as a black box. There are so few cables coming out of it, it could be no more than a couple relays so that it doesn't start until both switches are on, but allows it to run as long as only one switch is on.

I am starting to think that unless I basically completely lock the blade from moving, surely I couldn't burn the motor out on grass, no matter how many amps the battery is willing to supply.

I have ordered a counterfeit 1.2A battery for $18. It's actually cheaper than 3D printing a blank, or hacking an adaptor.

@parabellum - yes, a 4.0Ah battery came with the mower.
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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dogman dan   100 GW

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Re: Unprotected Ryobi One+ Battery?

Post by dogman dan » Feb 09 2017 5:56am

Motor should not burn itself out, but it will very likely have a breaker that stops it from pulling too much amps too long. Just like a table saw with a small motor has,, shove too much wood through it too fast, it pops to let the motor cool off.

I found mine would pop too soon if I overvolted too much, like 8s. So mine is made for 24v, and runs good on 6s. If it rains so much the grass gets too thick to cut with 6s, I'll run it on 7s. But 8s is just too much for the motor for long.

Yours will be different of course, but you can try 5s I'd think.

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Sunder   100 MW

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Re: Unprotected Ryobi One+ Battery?

Post by Sunder » Feb 09 2017 6:32pm

Oooh, now you've got me thinking about doing a 6S build. Fully charged, the "18"v batter is 22v - I've measured. So since common capacitors are 20/25/35v, they must be using at least 25v.

So charge my 6S to 4.1v per cell should be safe, and it stays in higher end of the voltage for most of the cycle
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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parabellum   10 MW

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Re: Unprotected Ryobi One+ Battery?

Post by parabellum » Feb 10 2017 10:34pm

Sunder wrote:Oooh, now you've got me thinking about doing a 6S build. Fully charged, the "18"v batter is 22v - I've measured. So since common capacitors are 20/25/35v, they must be using at least 25v.

So charge my 6S to 4.1v per cell should be safe, and it stays in higher end of the voltage for most of the cycle
I have a line of Ryoby one + tools and those I got apart for some reason have no warranty seal. If it is same case with your mover, pop it open and identify components, I would expect better engineering from ryoby then 25V components in 22V environment.

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Sunder   100 MW

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Re: Unprotected Ryobi One+ Battery?

Post by Sunder » Feb 11 2017 2:13am

I would hope so too. I don't want to open it up because even without a seal, too many scratches on the screws and they may start asking questions I don't want to answer. Playing with the voltage is already dodgy enough.
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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Sunder   100 MW

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Re: Unprotected Ryobi One+ Battery?

Post by Sunder » Feb 28 2017 7:00am

Alright, been 17 days, I finally got off my fat ass and rebuilt the battery today. A temporary rig at least - just soldered a XT-90 connection to the top half of a battery, and connected the other side to a 6S 16Ah Multistar.

The thing runs like a dream. Absolute worst conditions I could possibly give it - wet, long grass, cut to the second lowest level. Only time it stalled was when the catcher was full and stopping more heavy, dense, wet grass from being pushed into it.

The fact it stalled is also a reassurance - there is definitely protection circuitry on the mower side.

Could not be happier with the outcome
foto_no_exif.jpg
foto_no_exif.jpg (156.79 KiB) Viewed 1130 times
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

Swe   100 W

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Re: Unprotected Ryobi One+ Battery?

Post by Swe » Apr 16 2017 11:46am

Is everything fine now because you have more Ah on battery? Or was it the higher voltage making the positive change?

I am interesting in same solution, though it seems not be possible to buy larger lipo in EU so have not decided yet (and have not yet bought any Ryobi lawn mower either).

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Sunder   100 MW

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Re: Unprotected Ryobi One+ Battery?

Post by Sunder » Apr 16 2017 10:58pm

It's the ability of the pack to resist voltage drop that makes the difference. When the blade is slowed, the current required to keep it moving increases. If that current required is beyond what the pack can deliver, the voltage drops. If the voltage drops, the current required to keep the same power up rises. Vicious circle.

The higher voltage might help a little, since higher velocity = higher momentum, but considering the blade weighs almost nothing, I would guess it's not the main contributor.
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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mxer   1 kW

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Re: Unprotected Ryobi One+ Battery?

Post by mxer » Jun 11 2017 2:28pm

Cool I have 2x spare 16ah multistar and a ryobi 18v lawnmower, just need to find a cheap battery adapter to mod, thanks for the thread!

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dingoEsride   100 kW

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Re: Unprotected Ryobi One+ Battery?

Post by dingoEsride » Oct 25 2017 8:08am

Sunder wrote:Looks like there is a motor controller in it according to the service manual, but it just treats it as a black box. There are so few cables coming out of it, it could be no more than a couple relays so that it doesn't start until both switches are on, but allows it to run as long as only one switch is on.
If it's brushed I think it is a soft start PCB module, circuit or whatever, this recently went on my 36v ryobi stopping it with no other faults and I was wondering whether I could just bi-pass it or not
ride like the wind

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Sunder   100 MW

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Re: Unprotected Ryobi One+ Battery?

Post by Sunder » Oct 25 2017 7:34pm

Wish I could give you an answer, but I've never taken mine apart.

If you run out of options, I think a lot of people would be appreciative if you tried and posted your results here.
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 on 36S
eCar: Mitsubishi Outlander PHEV... Waiting for warranty to expire
eHouse: Still on grid, but with LTO batteries and 3kw LF inverter...

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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dingoEsride   100 kW

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Re: Unprotected Ryobi One+ Battery?

Post by dingoEsride » Oct 25 2017 8:37pm

This is the culprit, but with no visual signs of any burns it does have that burnt out stink inside, I did all checks, switch is fine, brushes all check out and I connected directly from battery to motor (blade removed) and it spins fine and after reading Dogmans post seems I have nothing to lose seeing as my weeds are getting long.
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dingoEsride   100 kW

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Re: Unprotected Ryobi One+ Battery?

Post by dingoEsride » Dec 19 2017 5:41am

Well I did give it a go, it ran fine without blade but when I tried to mow it ran then cut-out and there seemed to be more sparking at the brushes, the part cost $40 from USA and also brakes the blade, I'm cutting again :D
ride like the wind

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