Hello, I bought my KID ('marine version') last year, but finally getting around to setting it up. My intent is to use three 120W PV panels (27V open-circuit each) in series to charge a 44V nominal Li-ion (NMC chemistry I think? 46.2V final charge voltage) pack with its own built-in BMS. Specifically, the pack is the 1 kWh battery for the ePropulsion Spirit 1.0 electric outboard motor, which has a separate charging port rated for 5A. When I charge it using the OEM ePropulsion wall charger or solar charger, I plug into this separate charging port. These 'separate charging port' BMS typically have diodes on the charging port so they can only charge, not discharge through this port (I don't consistently measure any voltage across any pins on the charging port even when the pack is fully charged). The problem is that apparently the KID draws its power solely from the batteries it's charging, foiling my plans (this was not at all clear from the description of the KID, or I probably wouldn't have bought it).
Do I have any options other than splicing the KID into the 'discharge' port of the pack and hope the BMS allows it to charge this way? Or is there some other way to power the KID while it charges batteries (through the USB port, for instance)?
P.S. I searched and didn't see a similar question, which is surprising to me because 1. the KID is marketed as a solar charge controller for marine applications and 2. every electric outboard I know of (Torqeedo, ePropulsion, etc) uses a 'separate charging port' BMS for their OEM lithium packs. I thought I was going to be a 'typical usage case' for the KID, but it seems like everyone is doing something much more 'home brew' than charging an off-the-shelf lithium pack.
Thanks
Not sure the answer to your question but I was looking at BMS awhile back and some of them have the charging and discharging combined instead of separating them.
Look around on this store and you will see what I mean
https://daly.aliexpress.com/store/all-wholesale-products/4165007.html?spm=2114.12010608.nav-list.1.5eeb18a4SVr7Dd
Larry
Quote from: ClassicCrazy on August 17, 2019, 09:27:10 PM
Not sure the answer to your question but I was looking at BMS awhile back and some of them have the charging and discharging combined instead of separating them.
Look around on this store and you will see what I mean
https://daly.aliexpress.com/store/all-wholesale-products/4165007.html?spm=2114.12010608.nav-list.1.5eeb18a4SVr7Dd
Larry
Indeed, but I'm not about to void the warranty of my ePropulsion lithium pack to install a new BMS, when the OEM BMS works just fine. I (apparently wrongly) assumed when shopping for a solar charge controller that the only things that mattered were the input voltage range, charging voltage range, and current rating. But that minor detail about where the power to run the controller is coming from (I assumed it was the PV array, like many other solar chargers) has left me with a $500 paperweight, apparently.
All DC charge controllers get their power from the battery, I have run into this a few times and the battery manufacturer has approved a resistor across the BMS to allow enough voltage and current the charge controller will start.
if not then you have an issue and the battery is not designed to accept a charge from solar as such IMHO
I've often considered, in the case of some sort of failure, of being able to jumper the PV Input to the Battery Output, to directly feed the PV array directly to the batteries, till there is enough voltage to start the charge controller.
Quote from: FNG on August 19, 2019, 10:46:52 AM
All DC charge controllers get their power from the battery, I have run into this a few times and the battery manufacturer has approved a resistor across the BMS to allow enough voltage and current the charge controller will start.
if not then you have an issue and the battery is not designed to accept a charge from solar as such IMHO
Not to be argumentative, but the OEM MPPT solar charger from ePropulsion charges directly through this 'separate charging port' (which doesn't reliably read a voltage across any pins, even when fully charged):
https://www.epropulsion.com/product-page/spirit-solar-charger-1 (https://www.epropulsion.com/product-page/spirit-solar-charger-1)
...so it must be getting its power from the PV array. But this charger has a variety of flaws (gets very hot and randomly stops charging for long stretches, mainly), so I was hoping to use the KID instead.
Fair enough, I was mostly referring to all the solar controllers in the industry like Ours and Morningstar etc
Ryan