Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Batteries, Chargers, and Battery Management Systems.
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DogDipstick   1 kW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by DogDipstick » Jan 28 2020 10:09am

Thats my option two I thnk. I have beenon the lookout for big (plasma cutter) IGBTs and drivers.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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flippy   1 MW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by flippy » Jan 28 2020 12:13pm

DogDipstick wrote:
Jan 28 2020 10:09am
Thats my option two I thnk. I have beenon the lookout for big (plasma cutter) IGBTs and drivers.
get eh cheapest welder you can find on amazon that is IGBT based. it has all the goodies inside you need, just rip out the control board and replace it with a arduino.
Lithium beats liquid dinosaurs.

billvon   1 GW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by billvon » Jan 28 2020 12:23pm

DogDipstick wrote:
Jan 27 2020 5:27pm
Do you guys think I can throttle the load with a Curtis motor controller for a load regulator?
No.
This would give me 10Kw in the 36v range. Lotsa amps. Maybe I can find a higher power/voltage/current controller, but I got these 24 and 36v 250A jobbies like candy.
Go get a bunch of MOSFETs ($2 for 250V 50A mosfets) and use a current mode buck controller and an inductor to make a programmable switchmode current sink. You will still need a resistor but the switchmode approach will make it far more controllable.
--bill von

john61ct   1.21 GW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by john61ct » Jan 28 2020 2:21pm

Way over my head, but let's start with

links to suitable "current mode buck controllers"?
billvon wrote:Go get a bunch of MOSFETs ($2 for 250V 50A mosfets) and use a current mode buck controller and an inductor to make a programmable switchmode current sink. You will still need a resistor but the switchmode approach will make it far more controllable.
Could one control unit be designed that could CC control the testing of

little NMC cylindricals at 2000mAh up to 200Ah LFP cells at single-cell voltages 2-5V,

through 5000mAh LiPo packs at 6S

ebike packs at 80+V maybe even

EV packs at 300+V ?

Obviously different size loads, resistor arrays, but the same controller?

Data logging itself set aside for now, assume that may be separate?

billvon   1 GW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by billvon » Jan 28 2020 5:07pm

john61ct wrote:
Jan 28 2020 2:21pm
Way over my head, but let's start with

links to suitable "current mode buck controllers"?
Look up the UC1842. It is an ancient controller but is still used frequently for low cost switchmode converters. You will probably want to use a regular current sense resistor for sensing the current and a filtered current sense resistor for use with the feedback input (to set the exact current you want.)
Obviously different size loads, resistor arrays, but the same controller?
Sure. Use an isolated AC to 12V supply to drive everything so you don't have to deal with converting all those voltages to housekeeping voltages. The only thing that will see the full voltage are your FETs. You will have to switch out resistors to get the right general impedance (i.e. you don't want to use a 1 ohm resistor for a 300 volt battery.)
Data logging itself set aside for now, assume that may be separate?
Sure. The Logomatic from Sparkfun is a decent analog logger (8 channels) for $60, and can log to an SD card.
--bill von

john61ct   1.21 GW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by john61ct » Jan 28 2020 7:02pm

Ah, did not realize you meant a chip, thought an OTS plug and play user-level device.

As I said over my head, at least at this stage of the learning curve.

Noted for reference though, thanks!

john61ct   1.21 GW

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Re: Help me build a quality, datalogging, charging/discharge bank @ home, DIY.

Post by john61ct » Jan 28 2020 7:24pm

Interesting datalogger.

Does the software that makes the pretty graphs just accept the raw txt files as input, or . . . ?

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