Looking for a great charger for your electric unicycle?

[Chriull]

6 hours ago, WI_Hedgehog said:

How can this be? Well, as the battery terminal voltage approaches the charge cutoff voltage (such as 4.20V for a 1S battery) the charge slows down. If the charge voltage was 4.20V, the battery would form a surface charge of 4.2V and stop charging. As the surface charge dissipated the true battery voltage would be 4.18V (or something similar). Therefore, the charge voltage for 4.2V is something higher, say 4.4V and the current cutoff is set at some percentage of the charge current, related to the charge voltage.

This effect can also be seen nicely in the "(almost) standard charge graph" of the ncr18650ga (cells used for veteran?) from https://lygte-info.dk/review/batteries2012/Sanyo NCR18650GA 3500mAh (Red) UK.html 

Charging is performed with 1A ~0.3C and stopped at ~0.1C. Cell voltage settles within some half hour/hour to a bit below 4.2V.

If the chargery charger really has some smart fast charging mode, that uses higher charge voltage than 4.2V per cell this would be an explanation for premature charge input cut off - as each EUC BMS cuts of once any cell reaches 4.2XV!

So such a mode should will not work with any EUC, not only Veteran!

[WI_Hedgehog]

I'm wrong, the Chargery reportedly uses 4.20V as do other EUC chargers. Simple, cheap, light, and fairly safe. Fast--no, but "faster."

From the information I've seen I would guess the Veteran BMS does seem to stop the charge cycle to check the battery state and if the battery test comes back "sane" the BMS continues charging the battery, which works fine with a standard power supply that doesn't care about the lack of current draw and continues supplying power as needed. 

The Chargery, from the manufacturer's site, seems to be a smart charger in the respect that when the charger detects output current has fallen below a certain setting it stops the charge to prevent trickle charging the battery, so a "sanity check" by the BMS is causing the Chargery to stop charging.

I have to thank @Chriull, @mrelwood, and @RagingGrandpafor continuing to help me understand how EUC chargers & BMS units work vs. what I'm used to. It's a constant "you've got to be kidding me" situation. I'm happy to lean though, and they've been great.

[Giffy]

On 10/27/2020 at 4:03 PM, EUC Addict said:

The first time I saw this charger was watching trip updates from Archee Jan Bloch as he rode his modified Gotway 3108W Monster from Boston to New York City and back, traversing 625 miles of continuous riding and charging.

I was just talking to him about this trip https://www.relive.cc/view/v8qkd4pXGKv

[OldFartRides]

Epic ! Looked like they did a lot of night riding. Less traffic ?

[Giffy]

@OldFartRides ya, I'm thinking so. Also, less competition at the EV charging stations. 

[EUC Addict]

The Chargery balances just fine. I use it all the time. However, for the Sherman it can't balance the battery due to the BMS. So only power supply mode works on the Sherman. That works fine for out on the ride, but you couldn't use it to balance your Sherman's batteries.

[Killian253]

On 10/30/2020 at 1:53 PM, EUC Addict said:

@RockyTop My dream is that the charger will eventually be built into the wheel. I know someone who is designing a seat for the Monster Pro that will house his 25 amp charger so he doesn't have to carry it in his backpack.

Did anything ever come from this. Thats a great idea! I'd love my charger in my seat on the monster pro.

[PharmaCyclist]

On 4/30/2021 at 2:01 PM, EUC Addict said:

The Chargery balances just fine. I use it all the time. However, for the Sherman it can't balance the battery due to the BMS. So only power supply mode works on the Sherman. That works fine for out on the ride, but you couldn't use it to balance your Sherman's batteries.

Do you know of a good source for different terminations for the charger or did you just solder your own?  I'm inter but want to be able to use this on multiple connection types and would prefer professional adapters rather than making my own if possible.

[Giffy]

On 5/1/2021 at 1:21 AM, Killian253 said:

Did anything ever come from this. Thats a great idea! I'd love my charger in my seat on the monster pro.

I'm not sure if @EUC Addict and I are talking about the same person but I also know someone working on the same thing. He 3D printed the seat that has room for a fast charger capable of 20 amps and two additional Gotway battery packs. This would make it a 5400wh wheel. 
Unfortunately, while riding it, he realized that the vibrations and bumps from the road are being directly transferred into the battery packs in the seat and he didn't feel comfortable with that. Here are some pictures of it so far.