Anyone done a bad boy charger or something similar for a pack voltage above 168 volts? I guess if I want to charge my battery pack of 168 volts I am going to need 195 to 200 volts 13.8 volts per battery and I don't have the option of charging off of 220 only 110. From what I understand bad boys are just and an inductor.
Bad Boy Charger for higher voltage
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You can do it with a variac. (a variable autotransformer). Get one rated for 220V, 60hz and a current rating sufficient to charge your pack in a reasonable amount of time. Make sure that it has a fixed tap in the middle (or close to the middle) of the winding. put the 110V across the fixed tap and one end of the winding. You will get 220 across the whole winding, and variable 0 to 220v on the adjustable tap. Just don't exceed the max amps rating of the variac (easy to do when charging) on either the input or the output side or you will burn it up. You can install circuit breakers, thermostats, etc in your charger to prevent damage. Also keep in mind all the safety issues such as the fact that it is non-isolated, etc.
one example of a variac:
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A variac like above is small enough to fit in a tool-box sized charger, and will charge at around 10A. Also weighs about 25lbs.
You can buy new ones easily enough but they all come from china and many are rather poorly made (my personal experience). Older USA made ones from superior electric, general radio, etc. show up on ebay all the time and are built to withstand armageddon.
I built a variac-based bad boy using a very similar unit to the one in the picture (except wound for 120V) to use as a backup charger and bench tool. It's been very handy. Another handy tip: larger used computer UPSes are dirt cheap to free and contain many useful components such as relays, breakers, fuses, fans, frequently anderson connectors, and heavy wiring that can be used in the construction of your bad boy.
one example of a variac:
A variac like above is small enough to fit in a tool-box sized charger, and will charge at around 10A. Also weighs about 25lbs.
You can buy new ones easily enough but they all come from china and many are rather poorly made (my personal experience). Older USA made ones from superior electric, general radio, etc. show up on ebay all the time and are built to withstand armageddon.
I built a variac-based bad boy using a very similar unit to the one in the picture (except wound for 120V) to use as a backup charger and bench tool. It's been very handy. Another handy tip: larger used computer UPSes are dirt cheap to free and contain many useful components such as relays, breakers, fuses, fans, frequently anderson connectors, and heavy wiring that can be used in the construction of your bad boy.
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good info in the other posts, but here is what im using for my bad boy charger, It is capable of 230v and 20 amps. it works just like a variac but much smaller and makes for a cleaner looking charger. it is adjustable for 0-230v ac then you need the caps and a full wave bridge rectifier.
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sorry i dident see that you dont have 220v cababilities. so use it to control the voltage output of an old microwave transformer, set the voltage by turning the pot that comes with it to the voltage that you need.
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