What CC/CV charger/balancers are you using?

[PdxSteve]

Thanks Steve, I did use a static load to set the current. I ended up moving the current setting to 5.5A to insure the 12VDC 30A charger doesn't overload. I really liked your graphs and see you also used 5.5A as the max current setting. Nice work by the way!

That was a typo in the chart label. It was actually 6A if you put the mouse over the red Amp line at the very first part of the graph at 0:00 time.

 

[PdxSteve]

On a related power system note....anyone thought of what they would do if all of their stock batteries died and how to hack a new lipo into the case? I heard a rumor someone has posted a video of opening one up, but havent had the time to try to track it down. Similarly....anyone have a acc bay connector and using it to carry a second lipo underneath?

There are no power inputs coming off the accessory bay, only output and at 16.8v/1A max.

 

[mikeo]

I really wanted to start a new thread to announce the discovery of an awesome charger for Solo batteries, but it doesn't seem to fit the style of this forum.

I've got 10+ batteries (I think 12) for 2 Solos and I fly where I'm near "wall power" (110V AC) about 40% of the time, the rest of the time I'm flying near, on, or around water an I typically only have 12V DC to charge from. I have 3 stock 3DR chargers for the smart batteries, and while they work they don't fit with Solo and all the features that it has. I'm also fairly good at "hacking" things together that aren't necessarily supposed to work together, so while working on another project I stumbled across the Ming He MPT-7210A MPPT Solar Charge Controller and I immediately thought this might work with Solo.

The MPT-7210A takes 12-60V DC input and will output 15-90VDC in any configuration not greater than 600W; all values are rated/advertized. It also has a color, backlit display, 20 memory function, auto-on/off w/timer, and internal cooling fan. All this for $37? I had to do some more research.

Based on some youtube videos where people were trying to determine if the MPT-7210A is a "real" MPPT solar charge controller (doesn't matter), I was able to determine that it might work for charging Solo smart batteries. I ordered one and tested it: the verdict? IT WORKS! It even turns the smart battery on when connected.

This thing is awesome, I set it for 16.8V DC, 6.0A CC (thanks to others on this forum), battery capacity of 5.2AH, and a timeout of 2 hours of charge time (safety). It displays CC status, CV status, full charge status, instant VDC, instant A, instant W, total AH or total WH, and total time. The information available on the display of the charger is wonderful, no more guessing how long it's going to take to fill that last LED on the battery, just some simple math if I remember what percentage rating was left in each battery when I landed. On a side note, I guess it's time I started using the battery tracking feature in Solex.

So, here's a picture of the "charger":


I used the following parts/pieces to make it happen:
car outlet to binding post adapter: https://smile.amazon.com/RadioShack-Vehicle-Power-Adapter-Plug/dp/B01M7OZRH4/
Molex 46437-1087: https://www.arrow.com/en/products/46437-1087/molex
plug_cases.stl: 3DR Solo Triple Charger by piratetv
MPT-7210A: https://smile.amazon.com/gp/product/B01HCL7LEW/ref=oh_aui_detailpage_o00_s00
...and some wire, heat shrink tubing, solder, wire terminals (narrow, 5mm for #6 post), etc.

Depending on sources, what you have laying around, and the volume of parts you buy (if you're making more than one) it should cost ~$50 to make a single charger. The economy of scale kicks in when you're making multiple and are getting the Molex connectors and housings in multiples.

Here's the display as it finished charging a battery:


If I do the math on the battery, it shows some good details. This battery was at ~25% when I landed, that's 1300mAh remaining or 3900mAh used. The MPT-7210A reports it delivered 3650mAh in to the battery; 75% of 5200mAh = 3900mAh - 3650mAh = 250mAh or 4.8% capacity loss after a year of use. I'll believe those numbers.

I'm now working on trying to make a 5-6 bay charging station in a carrying case...

 

[Goldie]

Sorry to up a dead post!

These look like they would work in place of the amazon link posted above.

Would these work?

Are there any factors other than the voltage and current when looking for these?

3Pcs DC-DC Step Down Adjustable Constant Voltage Current Power Supply Module Sale - Banggood Mobile