# Milwaukee M18 Batteries to power Jr Dragster



## heyjude076 (Apr 8, 2013)

Hello,

Four years ago I built a EV JR Dragster powered by 12 Milwaukee M28 batteries. I connected 2 six packs of batteries in series which gave the controller 56V. The car has run flawless and consistent. I now want to build another dragster for a faster class. My plan is to take 12 Milwaukee M18 9AH batteries. Connect 6 in series for a total of 108V.
Is anyone familiar with the BMS of these batteries that will limit their output when I connect 6 in series?
Before anyone suggest that I build my own battery packs that is not an option. As with the M28 batteries I want to be able to swap the batteries back and forth with power tools. On race day I snap them into connectors on the car and race.
Thank You


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## Ampster (Oct 6, 2012)

The current carrying capacity of the connectors should also figure into your calculations. In creasing the voltage will reduce the current, given the same power.
Are you putting 6 in series or 12 in series? The voltage in your example doesn't add up.
Sent from my SM-N910T using Tapatalk


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## puddleglum (Oct 22, 2008)

Hey, it's cool to hear you successfully ran a car off the Milwaukee batteries. Sorry I can't help answer your question, hopefully someone can. Have you tried contacting Milwaukee to see if they will tell you the current limit of the M18's? Do you already have one that you could attach to a load and see if it will put out what you need? The 9ah pack is designed to run their compound miter saw so I would think it should be capable of some pretty high discharge currents. hope it works out.
I'm hoping you can maybe answer a question for me. Where did you find the connectors you used (are going to use) on your cars? I'm toying with the idea of doing something similar and using a couple to power my e-bike but I haven't been able to figure out how I would mount them.


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## heyjude076 (Apr 8, 2013)

Ampster said:


> The current carrying capacity of the connectors should also figure into your calculations. In creasing the voltage will reduce the current, given the same power.
> Are you putting 6 in series or 12 in series? The voltage in your example doesn't add up.
> Sent from my SM-N910T using Tapatalk


Thank You for your response.

The batteries are individually connected to copper buss bars that should handle the current.

I will make up 2 packs of 6 batteries in series. The 2 packs will be parallel.


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## heyjude076 (Apr 8, 2013)

puddleglum said:


> Hey, it's cool to hear you successfully ran a car off the Milwaukee batteries. Sorry I can't help answer your question, hopefully someone can. Have you tried contacting Milwaukee to see if they will tell you the current limit of the M18's? Do you already have one that you could attach to a load and see if it will put out what you need? The 9ah pack is designed to run their compound miter saw so I would think it should be capable of some pretty high discharge currents. hope it works out.
> I'm hoping you can maybe answer a question for me. Where did you find the connectors you used (are going to use) on your cars? I'm toying with the idea of doing something similar and using a couple to power my e-bike but I haven't been able to figure out how I would mount them.


Thank You for your reply.
The connectors on my first car were given to me by a friend. The connectors for the M18 batteries ???? . I have found a parts list for a milwaukee tool that list the connectors. I am still waiting word from a supplier to see if they can be ordered.


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## Ampster (Oct 6, 2012)

I would guess that the contacts for a tool would be designed for max loads versus the contacts for chargers.

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## Yabert (Feb 7, 2010)

heyjude076 said:


> Is anyone familiar with the BMS of these batteries that will limit their output when I connect 6 in series?


There is no output limit controlled by the BMS.
If you feel there is a limit, it's simply the limited power capacity of those battery.
The 18650 cells generally find in those battery don't like to be discharge at more than 10x the capacity (10C) for more than few seconds.
Let say you have 12 M18 battery block (108v 18Ah). At 10C, that 108v x 180A = 19 Kw or roughly 19 hp at the motor shaft... kind of low power for a racing dragster!!


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