# [EVDL] Need a new battery for a 24-volt Ryobi lawn mower?



## EVDL List (Jul 27, 2007)

It is time to replace the 24-volt, 15 amp-hour, lead-acid battery in a Ryobi 
electric mower. (18" blade)

I was thinking of using a few of the Milwaukee lithium-ion V-28 volts packs 
in parallel, and charging them individually. 

I really like this mower but would rather have a lighter, more reliable 
battery. The area to mow is rather small, only about 1/10 acre. 

My feeling is that both the electric motor and 18" blade will handle the 
increased rpm from the standard 28-volt pack. 

Has anyone on this list had success with a mower modification like this, or 
something similar? 

Thanks.

Lawson Huntley
**************Feeling the pinch at the grocery store? Make dinner for $10 or 
less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001)
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

I've been using a 24volt Black and Decker mower for years now, but I have n=
o experience with the Ryobi. I replaced my batteries last year, but just w=
ith clone 17ah lead acid batteries. My mower usually draws between 20 - 30=
amps while mowing. If I am remembering correctly the Milwaukee batteries =
are about 3 ah each which means two of them would provide about 6 ah. That=
would run my mower for 10 - 15 minutes. If that's all you need then it wi=
ll likely work just fine. I doubt the slight bump up in voltage will make =
much of a difference. If your motor is like mine, it will probably increas=
e the brush arcing a bit, which will wear the brushes faster, and also draw=
more current which would give you less runtime. =


damon

> From: [email protected]
> Date: Sun, 5 Apr 2009 19:51:40 -0400
> To: [email protected]
> Subject: [EVDL] Need a new battery for a 24-volt Ryobi lawn mower?
> =

> It is time to replace the 24-volt, 15 amp-hour, lead-acid battery in a R=
yobi =

> electric mower. (18" blade)
> =

> I was thinking of using a few of the Milwaukee lithium-ion V-28 volts pa=
cks =

> in parallel, and charging them individually. =

> =

> I really like this mower but would rather have a lighter, more reliable =

> battery. The area to mow is rather small, only about 1/10 acre. =

> =

> My feeling is that both the electric motor and 18" blade will handle the =

> increased rpm from the standard 28-volt pack. =

> =

> Has anyone on this list had success with a mower modification like this, =
or =

> something similar? =

> =

> Thanks.
> =

> Lawson Huntley
> **************Feeling the pinch at the grocery store? Make dinner for $1=
0 or =

> less. (http://food.aol.com/frugal-feasts?ncid=3Demlcntusfood00000001)
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
> =


_________________________________________________________________
Rediscover Hotmail=AE: Now available on your iPhone or BlackBerry
http://windowslive.com/RediscoverHotmail?ocid=3DTXT_TAGLM_WL_HM_Rediscover_=
Mobile1_042009
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Damon,
=

Thanks for that information. I may just replace with a lead acid, but was =

hoping someone might know of an easy "fix" in hooking up some newer types o=
f =

Li-Ion cells. 15 minutes run time time will work for me, but even that may =

"over tax" a smaller pack if it draws the battery too low. In any event, t=
hanks =

again for this information as it is helping me make a decision. =

=

Lawson
=

=

In a message dated 4/6/2009 12:57:20 A.M. Eastern Daylight Time, =

[email protected] writes:


I've been using a 24volt Black and Decker mower for years now, but I have =
no =

experience with the Ryobi. I replaced my batteries last year, but just =

with clone 17ah lead acid batteries. My mower usually draws between 20 - =
30 =

amps while mowing. If I am remembering correctly the Milwaukee batteries =
are =

about 3 ah each which means two of them would provide about 6 ah. That wo=
uld =

run my mower for 10 - 15 minutes. If that's all you need then it will lik=
ely =

work just fine. I doubt the slight bump up in voltage will make much of a =

difference. If your motor is like mine, it will probably increase the bru=
sh =

arcing a bit, which will wear the brushes faster, and also draw more curre=
nt =

which would give you less runtime. =


damon

> From: [email protected]
> Date: Sun, 5 Apr 2009 19:51:40 -0400
> To: [email protected]
> Subject: [EVDL] Need a new battery for a 24-volt Ryobi lawn mower?
> =

> It is time to replace the 24-volt, 15 amp-hour, lead-acid battery in a =

Ryobi =

> electric mower. (18" blade)
> =

> I was thinking of using a few of the Milwaukee lithium-ion V-28 volts =

packs =

> in parallel, and charging them individually. =

> =

> I really like this mower but would rather have a lighter, more reliable =

> battery. The area to mow is rather small, only about 1/10 acre. =

> =

> My feeling is that both the electric motor and 18" blade will handle the=
=

> increased rpm from the standard 28-volt pack. =

> =

> Has anyone on this list had success with a mower modification like this,=
=

or =

> something similar? =

> =

> Thanks.
> =

> Lawson Huntley
> **************Feeling the pinch at the grocery store? Make dinner for $=
10 =

or =

> less. (http://food.aol.com/frugal-feasts?ncid=3Demlcntusfood00000001)
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
> =


_________________________________________________________________
Rediscover Hotmail=AE: Now available on your iPhone or BlackBerry
http://windowslive.com/RediscoverHotmail?ocid=3DTXT_TAGLM_WL_HM_Rediscover_=
Mobil
e1_042009
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


**************Feeling the pinch at the grocery store? Make dinner for $10 =
or =

less. (http://food.aol.com/frugal-feasts?ncid=3Demlcntusfood00000001)
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)
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----------



## EVDL List (Jul 27, 2007)

Lawson,

I am using the DeWalt 36 volt battery powered tools and like them a lot.
Your idea of running two or more in parallel is good. The DeWalt
batteries have an internal fuse that is not replaceable, and running a
decent load with one battery will cause the fuse to open. I heard from
a fellow using the DeWalt batteries on a bicycle with a hub motor and
controller, and he said that once charged, the voltage was very close,
and connecting the batteries in parallel was not a problem. Be careful
not to over discharge the batteries as, at least with the DeWalt, the
charger will not begin to charge when one or more cells is too low.

Alan Brinkman

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Sunday, April 05, 2009 4:52 PM
To: [email protected]
Subject: [EVDL] Need a new battery for a 24-volt Ryobi lawn mower?

It is time to replace the 24-volt, 15 amp-hour, lead-acid battery in a
Ryobi 
electric mower. (18" blade)

I was thinking of using a few of the Milwaukee lithium-ion V-28 volts
packs 
in parallel, and charging them individually. 

I really like this mower but would rather have a lighter, more reliable

battery. The area to mow is rather small, only about 1/10 acre. 

My feeling is that both the electric motor and 18" blade will handle the

increased rpm from the standard 28-volt pack. 

Has anyone on this list had success with a mower modification like this,
or 
something similar? 

Thanks.

Lawson Huntley
**************Feeling the pinch at the grocery store? Make dinner for
$10 or 
less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001)
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

A 20 Ah 24 volt lithium would certainly have the capacity, but $400 is a b=
it =

more than I was wanting to spend. The new lead-acid batteries of good =

quality may cost in excess of $200. I was hoping to find a 24-28 volt Li-i=
on set up =

for under $300. If I used the power tool batteries I was just going to =

parallel the standard packs for discharge, but charge individually in the =
standard =

charger. =

=

I'm presuming I could safely parallel the A123 packs without a BMS on =

discharge. Perhaps that was an erroneous presumption.
=

Thanks for the suggestion. =

=

Lawson
=

a message dated 4/6/2009 4:40:09 P.M. Eastern Daylight Time, =

[email protected] writes:
What's the upper limit on you budget?

I have seen 20 Ah 24V lithium packs for E bikes for about $400 =

including BMS and charger. That seems a bit much to me to spend on a =

lawn mower, but every has their own sense of what is reasonable.

Sent from my iPhone



> [email protected] wrote:
> 
> > Damon,
> >
> ...


----------



## EVDL List (Jul 27, 2007)

I'm not exactly sure what you mean about discharging without BMS, but you m=
ust be extremely careful... I would not use any lithium without monitoring=
 every cell for undervoltage.

My experience is with having replaced 27 pounds of lead in my B&D lawnmower=
with 3 pounds of A123 cells. One cell _will_ drop below 2.7V before the o=
thers, and it is very unlikely you will notice by watching the meter on the=
mower, or noticing the mower slowing down (like it did with lead). Also, =
I would recommend adding a contactor that will disconnect the pack from the=
mower when one cell drops below your low voltage cutoff; the temptation to=
do "just one more row" is too great; even for me who should know better! =


Based on my experiences, I don't think Black and Decker will be offering an=
A123 lawnmower; there is not enough warning that the mower is running out =
of juice like lead, and the damage done to the lithium when pushed just a l=
ittle too far is much greater than what happens to lead. Discharged lead b=
atteries just sag too much to be useful when they need a charge; A123 cells=
will try too hard to keep going, and end up hurting the pack.

On the plus side; I recharge my lawnmower in 15 minutes!

Steven Ciciora

> =

> I'm presuming I could safely parallel the A123 packs
> without a BMS on =

> discharge. Perhaps that was an erroneous presumption.
> =

> Thanks for the suggestion. =

> =

> Lawson
> =

> =



=


_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Alan,

Thanks for this information. The part about the non-replaceable fuse is good 
to know. I imagine the 28-volt Milwaukee packs may be similar. 

Right now it seems I may just repeat lawn mowing with a lead acid battery. 
It seems nearly all power tools have made the switch to Li-ion over the past 
few years, but we're not quite there yet with cars and mowers. But almost. The 
pack in my car needs replacing too, and I was hoping to use the mower to 
play with a bit before putting Li-ion in the car. 

Lawson


In a message dated 4/6/2009 5:00:06 P.M. Eastern Daylight Time, 
[email protected] writes:
Lawson,

I am using the DeWalt 36 volt battery powered tools and like them a lot.
Your idea of running two or more in parallel is good. The DeWalt
batteries have an internal fuse that is not replaceable, and running a
decent load with one battery will cause the fuse to open. I heard from
a fellow using the DeWalt batteries on a bicycle with a hub motor and
controller, and he said that once charged, the voltage was very close,
and connecting the batteries in parallel was not a problem. Be careful
not to over discharge the batteries as, at least with the DeWalt, the
charger will not begin to charge when one or more cells is too low.

Alan Brinkman

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Sunday, April 05, 2009 4:52 PM
To: [email protected]
Subject: [EVDL] Need a new battery for a 24-volt Ryobi lawn mower?

It is time to replace the 24-volt, 15 amp-hour, lead-acid battery in a
Ryobi 
electric mower. (18" blade)

I was thinking of using a few of the Milwaukee lithium-ion V-28 volts
packs 
in parallel, and charging them individually. 

I really like this mower but would rather have a lighter, more reliable

battery. The area to mow is rather small, only about 1/10 acre. 

My feeling is that both the electric motor and 18" blade will handle the

increased rpm from the standard 28-volt pack. 

Has anyone on this list had success with a mower modification like this,
or 
something similar? 

Thanks.

Lawson Huntley
**************Feeling the pinch at the grocery store? Make dinner for
$10 or 
less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001)
_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

**************Feeling the pinch at the grocery store? Make dinner for $10 or 
less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001)

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Steven,

Did you purchase individual cells and assemble your A123 cells into a 24 
volt pack, or did you start with an already assembled pack and simply attach it 
to your mower in some fashion?

I've looked at using a few of the Milwaukee packs as is, but together in 
parallel. And I've also considered buying individual cells, and assembling them 
into a pack. However, I was trying to keep this project relatively simple and 
around $300.

What I meant by a BMS system on discharge was this: 
I did intend on doing some basic monitoring to prevent undervoltage. But if 
using the Milwaukee packs in parallel, I simply intended to charge them in 
their standard charger. My overall goal for this project was to learn a little 
about Li-ion (or LiFePo) and at the same time keep things relatively simple. 

When the time is right, and it seems we are almost there, I'd like to use 
lithium batteries of some sort in my car. However, I knew this was going to be a 
lot more complex than battery management of a VRLA.

Thanks for the information you have shared. 

Lawson

In a message dated 4/7/2009 9:42:17 A.M. Eastern Daylight Time, 
[email protected] writes:

I'm not exactly sure what you mean about discharging without BMS, but you 
must be extremely careful... I would not use any lithium without monitoring 
every cell for undervoltage.

My experience is with having replaced 27 pounds of lead in my B&D lawnmower 
with 3 pounds of A123 cells. One cell _will_ drop below 2.7V before the 
others, and it is very unlikely you will notice by watching the meter on the 
mower, or noticing the mower slowing down (like it did with lead). Also, I would 
recommend adding a contactor that will disconnect the pack from the mower 
when one cell drops below your low voltage cutoff; the temptation to do "just 
one more row" is too great; even for me who should know better! 

Based on my experiences, I don't think Black and Decker will be offering an 
A123 lawnmower; there is not enough warning that the mower is running out of 
juice like lead, and the damage done to the lithium when pushed just a little 
too far is much greater than what happens to lead. Discharged lead 
batteries just sag too much to be useful when they need a charge; A123 cells will try 
too hard to keep going, and end up hurting the pack.

On the plus side; I recharge my lawnmower in 15 minutes!

Steven Ciciora

> 
> I'm presuming I could safely parallel the A123 packs
> without a BMS on 
> discharge. Perhaps that was an erroneous presumption.
> 
> Thanks for the suggestion. 
> 
> Lawson
> 
> 




_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

**************Feeling the pinch at the grocery store? Make dinner for $10 or 
less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001)

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------

