DIY 3-Battery Rapid Charging Station $60 or less

[Mohan]

jackdakota any updates on my question posted 6 weeks ago?

 

[jackdakota]

Carlsberg...if you plan on charging all three batteries at approx 9A each using the older multi parallel charging plate (w/o resistor), does that mean that you would be supplying 27A to the charging board? Can you detail how you you'll be able to prevent the batteries from shutting down (due to their over circuit protection) if one of the three batteries completes its charge before the other two? If I understand correctly, the 27A would then be divided by 2 resulting in each of the remaining batteries receiving 13.5A? Is that correct or am I missing something?

Thanks for the guidance
KnightOwl

You can bypass the over current protection of the battery by turning it on before plugging into the "charger" I wouldn't recommend it as charging at that rate will definitely reduce the life of the battery and it will get hotter than usual during the charge.

 

[jackdakota]

I have tried this type of kit out but I am no expert on power/volts/amps etc. The problem is the build quality of the bar. 2 of the solder joints had a stray piece of solder shorting them. The little push down switch melted closed. One of the batteries indicated an over charge situation (flashing 3rd led). I was worried if it was lowering the life expectancy of the batteries so I stopped using it.

I completely agree with this. My original setup doesn't use the charging plate but it requires a lot more electrical work. If quality holds true, I thought the charging plate would be a better option for most DIYers.

My current setup doesn't use the charging plate and will charge at ~10a if you have one battery or 5a each if you have 3. With the metal enclosure it will cost roughly $250 and I don't think many people will pay that.

 

[Mohan]

Well $250 is reasonable for charging system including enclosure. I actually coughed up a lot more for the commercially available product.

 

[mgiara]

Sorry for gravedigging this post but I recently build exactly what jack posted. 24.5V 15A power supply, 3 battery charging plate with LCD display and soldered wires directly connecting the two.
I have a pre-wired barrel connector coming to clean it up a bit but it's been mostly working lately.
3 issues I noticed:
1. I charged a battery with the OEM 100W charger through the charging plate and noticed the following voltage changes:
25.9V with just the OEM power supply connected to the multi charging plate and no battery connected
24.1V read with a 'dead' (20-25%) battery connected
24.3V after 15 minutes of charging
24.6V with 3 lights blinking
24.8V with 3 lights blinking
24.9V with 4 lights blinking
25.1V
25.4V
25.9V charge complete
The power supply's voltage does not dip as dramatically when you set the voltage to 25.9 then connect a battery. It only dips a few tenths of a volt when connecting a battery.
2. For some reason, even though the power supply is supplying more current (5A/battery with ceramic resistors), it takes longer to fully charge a battery (charge until the battery's built-in charging board decides charging is complete) than with the OEM charger.
I tested this by connecting a battery to the OEM charger old-fashioned-style, and one equally aged (all of my batteries but 2 are brand new) and another to the power supply-multi charging plate
The battery connected to the OEM charger always finishes first for some reason.

I also noticed something Jack pointed out that concerns me: the battery(ies) connected to the non-OEM charging gittup continue blinking as if charging long after they'd be considered fully charged by the OEM charger. I noticed them charging for an awfully long time so out of curiosity I disconnected the batteries from the charging plate and connected to the OEM charger and they all showed no lights come on indicating that the batteries now considered themselves fully charged when connected to the OEM charger.

3. I left a few batteries charging overnight (putting a lot of trust into the batteries charging circuit/auto cut off) and woke up terrified to a 3rd LED double blinking indicating overcharge.
I put that battery into my Inspire 1 and turned it on for 5-10 minutes and once powered off the over charge light went off.

I have 10mm x 10mm MOSFET heatsinks on the way to keep the ceramic resistors cool.

This is important to me as I just started some freelance work that requires me to always have charged batteries and I don't want to buy 4 more DJI chargers.
I'm sure there's SOME way to make this setup work with constant reliability and I know we can figure it out together!!

On an aside, Alibaba is now selling the power supply in wholesale lots with the correct barrel connector and wire pre-installed as an "Inspire 1 battery charger"

 

[mgiara]

No dice huh
I guess everyone is switching over to I2