# Modifying Makita reciprocating saw to use diff battery. Bad idea?



## mikegp (Jul 17, 2011)

Just bought a Makita BJR182Z reciprocating saw which is supposed to use a BL1830 battery. I have BL1815 batteries. I noticed the tool just had a little plastic nub stopping the battery from working. Ground it off and now it works. Any danger of damage or injury if I run it like this? Any help is greatly appreciated. Thanks -Mike


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## princelake (Feb 19, 2012)

i know exactly what your talking about! i know for sure that it wont work with the circular saws either which is annoyyying! i dont understand way they did this other then so ppl dont complain that the little batteries die to quickly. i dont see any issues, i was going to do that with my batteries cause some of my fellow employees had the smaller batteries and working on the same job ppl borrow tools including batteries. i didnt have enough guts to cut the nub.


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## user1007 (Sep 23, 2009)

Bad idea. Pay the piper.


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## mikegp (Jul 17, 2011)

sdsester said:


> Bad idea. Pay the piper.


Can you expand on that? I'm trying to make sure they have a real safety reason for doing it, not just so people have to pay for more batteries. I figure they would make it so the battery wouldn't work at all if was that big of a deal. Or maybe I'm in for trouble.


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## Hardway (Dec 28, 2011)

*Makita BJR182Z* 18-Volt LXT Lithium-Ion
*Makita BL1815* 18-Volt Lithium-Ion Battery


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## mikegp (Jul 17, 2011)

So you're saying it's ok?


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## Hardway (Dec 28, 2011)

mikegp said:


> So you're saying it's ok?


I am saying that the batteries are the same voltage, so the voltage is not an issue.


_Writer’s information is for discussion purpose only and should be confirmed by an independent source._
_I am not an expert and don’t claim to be, these are just my views and opinions._


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## mikegp (Jul 17, 2011)

One is 1.5Ah and the other is 3.0Ah. I know nothing about electricity, does it matter?

More amps means more power or longer lasting?


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## woodworkbykirk (Sep 25, 2011)

the thick batteries are just the same as having a bigger gas tank on y our car.

as for reason not to use the compact batteries on a cordless recip or circ saw.. they use up the charge much quicker with a compact battery as opposed to the 3.0 amp ones.. personally i hate using cordless saws. you dont get anywhere near the power you get out of a corded one


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## Hardway (Dec 28, 2011)

mikegp said:


> One is 1.5Ah and the other is 3.0Ah. I know nothing about electricity, does it matter?
> 
> More amps means more power or longer lasting?


A 3.0 Ampere-Hour will last twice as long as an 1.5 Ampere-Hour which is the amount of electrical charge capacity which gives you a relative measure of how long the battery will last, therefore the higher the Amp- Hours the longer a battery will last before it well need to be charged.

So the amp hour is not an issue.
 
_Writer’s information is for discussion purpose only and should be confirmed by an independent source._
_I am not an expert and don’t claim to be, these are just my views and opinions._


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## mikegp (Jul 17, 2011)

Ok, thanks. So beside amps and volts, any other reason not to do this? I know they make some tools that can use either battery and I believe both are charged by the same charger. Thanks again.


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## Hardway (Dec 28, 2011)

_The volts and the amp hours are not an issue that I can see, any other issues I don’t know._

_Writer’s information is for discussion purpose only and should be confirmed by an independent source._
_I am not an expert and don’t claim to be, these are just my views and opinions._


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## woodworkbykirk (Sep 25, 2011)

one thing i can guarentee though.. if you have issues with it and try to take it in for service.. warrenty wont cover it


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## mikegp (Jul 17, 2011)

Yea, I already altered it. Wouldn't expect them to warranty it. It was only $70, so it's worth it if it's not going to hurt me.


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## mikegp (Jul 17, 2011)

Just used it to cut down 12 small trees. So far so good. Recharged the battery and it's still good. Going to cut some more now.


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## mikegp (Jul 17, 2011)

Quick update in case anyone happens to have the same situation in the future. Ended up cutting down and stripping the branches from about 35 small trees on four charges total. I have two batteries, so took two trips. Everything seems to be functioning fine, both the unit and the batteries. As of now, I would say it's safe to do.


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## Hardway (Dec 28, 2011)

mikegp said:


> Quick update in case anyone happens to have the same situation in the future. Ended up cutting down and stripping the branches from about 35 small trees on four charges total. I have two batteries, so took two trips. Everything seems to be functioning fine, both the unit and the batteries. As of now, I would say it's safe to do.


that is what is called field testing.:thumbsup:


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## Duckweather (Mar 26, 2012)

Just basic info from my military training. Volts are volts, if it uses 18 volts it should run on anything with 18 volts. 30AH rating means at a draw of 30 amps consistently it will take 1 hour to drain the battery. The motor will use however many amps it requires at at given time. (Ohm's Law) Just hold it at arms length in case it blows up.


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## Bondo (Dec 8, 2007)

sdsester said:


> Bad idea. Pay the piper.


Ayuh,.... *Why* is it a Bad idea,..??
'n who's gonna pay the piper, What,..??

The batteries are completely interchangeable...


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## teamcampreder (Jul 23, 2011)

If the only difference is the Ah (Amp hours, or Amps per hour), then the difference between the two batteries is literally the "size of the tank". Using the smaller one is like filling up your gas tank 1/2 way.


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## mikegp (Jul 17, 2011)

So what we've learned is that Makita is trying to sell more batteries.


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## aslmodai (Apr 10, 2012)

So, not for nothin’, but volts and amps don’t give you the full picture. There’s also discharge rate. That is: two given batteries could both be 18v & 1.5ah, but one of those could be capable of powering a saw which drains the 1.5ah in 10 minutes, while the other (perhaps designed for a drill) used under those conditions would overheat and damage the battery—or even rupture {although that’s an outside possibility}. You know how your cellphone battery gets really hot when you browse, or talk for a good while? That's the change in discharge rate. 



My understanding is that safe discharge rate is dictated by the cells' configuration, cooling, and specific battery chemistry. 



I think it’s TOTALLY possible that the 1.5ah batteries are designed with slow discharge in mind. Using them in a fast-discharge tool might shorten their life. 



Of course, I have no way of knowing that. The batteries might be clones, and it might be just fine. Either way, I like the battery warranty, and don't want to sacrifice it. Better to modify the tool. They probably won't check that. =]


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