Test Pilots: What's your status?

PJD,

I have a J1772 port but haven't installed it yet on the e-moto. I just got the 14.3A charger up and running. I now need to figure where the charger and charging ports will be installed.

Sure beats the 120V only, 9A charger that came with the e-moto.

Hi IBScootn,

What type of charger did you buy, what are it's dimensions and where did you purchase it?

Going from 9 amps to 14.3 amps while charging would completely change the complection of using my bike for long rides. My office is about 43 miles away and my bike gets me there easily in less than an hour. The problem is once I am there I am a bit of a hostage to the 4 1/2+ hours it takes to charge it for the return trip. That would be whittled down to under 3 hours with your charger. That is easily bearable.

If one does install the J1772 port can one still use a traditional 120V plug? I enjoy the convenience and availability of being able to plug into any wall socket to charge.

Thanks!

I bought two Mean Well HRP-600-48; they give a DC voltage output range of 80-111Vdc when two are placed in series, and are easily adjusted to your HVC. Input AC voltage can be 120 or 240V so automatically handles switching between 120V outlets, 240V outlets and J1772 connections (which is 240V). These supplies have built in current limiting, so they work well for CC/CV charging needs.

Each HRP-600 is 9"x4"x2.5" and weighs 3.3Lbs. I bought them from TRC Electronics. Be careful when buying mean well supplies off fleabay as lots of fake ones out there.

This was the best solution I could fine based on cost, reliability, size and weight.

I bought two Mean Well HRP-600-48; they give a DC voltage output range of 80-111Vdc when two are placed in series, and are easily adjusted to your HVC. Input AC voltage can be 120 or 240V so automatically handles switching between 120V outlets, 240V outlets and J1772 connections (which is 240V). These supplies have built in current limiting, so they work well for CC/CV charging needs.

Each HRP-600 is 9"x4"x2.5" and weighs 3.3Lbs. I bought them from TRC Electronics. Be careful when buying mean well supplies off fleabay as lots of fake ones out there.

This was the best solution I could fine based on cost, reliability, size and weight.

Thanks IBScootn!

I need some translation of what are probably obvious terms you used. Please explain "HVC" and "CC/CV" as I am an ICE kinda guy.

I appreciate your help.

IBScootn-

I am not clear as to whether these power supplies are used in addition to the on board charger or replace it. Do you have a diagram or description of the hookup?

Thanks again!

Jon,

The 14.3A charger I am using would replace your existing charger. Ask the folks here or out on endless-sphere.com and find someone in your city that can help you install a new charger like the one I mentioned. You don't want to make changes to your E-moto's charging system w/o the proper knowledge.

HVC - High voltage cutoff. This is sometimes used two ways: for the total battery pack voltage or for a single cell that reaches the max voltage. I meant battery pack voltage. So for 24 cells that would be 87.6Vdc.

CC - constant current mode charging

CV - constant voltage mode charging

The two supplies would each be adjusted to (HVC)/2, then put in series. Add a large diode (I used a 400V 35A diode b/c I already had one) in series between the supplies and the point where your current charger connects. The diode, if properly installed, will keep the battery from driving back into the supplies when the supplies are off or set too low. Once the supplies are charging the battery pack, you can fine tune the supply's output voltages so they match more closely and provide HVC + diode voltage drop.

If the above isn't crystal clear to you, you need to find someone local that can do this work for you.

Good luck

Jon,

I forgot to mention to discuss adding a higher current charger with CuMoCo techs to make sure the BMS and wiring can handle 55+% more charging current and whether there is any impact with the BCU.

BTW, I also bought a 320mA CC charger ($11 shipped) to play with. On my GBS cells, the shunts draw about 350mA. So in theory, if I use only 320mA, I should be able to gently bring all cells into full balance w/o a single cell tripping the cell level HVC. This could be used for: rebalancing a pack that was deeply discharged; for safely raising the voltage on a grossly discharged pack where the voltage is too low for the charger to kick in, or for shunt LED diagnostics. Don't know if I really will use it much, but it seemed like a fun tool to gently verify all shunt LEDs.

Oops, I've been using Jon instead of LCJUTILA. Sorry Jon.

The reply feature doesn't show the last message; only the first message and I wasn't paying enough attention to who I was replying to. My bad. I'm on vacation and trying to reply from my phone which isnt as easy as as another device with a bigger screen.

One thing that adds a lot of time to the CumoCo scooter charging is that it does _not_ follow the CC-CV protocol.

It works like this:

1. Plugging the power cord into the bike starts it in constant current (CC) mode at about 9 amps in the case of the old charger with the fan. I don't know the amperage of the new fanless charger. Probably similar.

2. The charger runs at 9 amps until the BMS detects the first cell hitting 3.60 to 3.65 volts - it sends a signal (just closes a circuit) to the charger that switches it to 0.5 amps constant current - which is the safe shunting current for the BMS. The BCU detects this and switched the indicator light to the short-long "balance mode" indication - but it is not actually balancing the pack yet.

3. The cell's voltage drops a good bit under the lower 0.5A current, stays there a looong time - especially in cold weather (due to higher low-temp internal resistance causing the cells to hit the switching voltage too early), then slowly rises.

4. As each cell reaches about 3.6 volts, the BMS starts shunting current past the cell - one by one as each cell fills up and hits the max voltage. The BMS keeps the cell voltage (on my bike anyway) at 3.62 to 3.74 volts until the last cell hits shunting voltage; when this happens, the BMS (through a BCU instruction) then signals the charger to shut down. If it is a healthy pack, all the cells come up the full voltage very close to each other.

In contrast, in the CC-CV protocol as the cells hit the maximum voltage the charger holds a constant voltage (equal to 3.65 * no of cells) while it tapers the current as needed to keep the voltage constant - instead of abruptly switching the current down to 0.5A and letting the voltage fall willy-nilly as the CuMoCo system does. If the CumoCo scooter used true CC-CV, full charging would complete much more quickly. There are some tricks to integrating this with the BMS, but I don't think CuMoCo ever found the necessary charger or setup that would allow for CC-CV charging with their BMS. Because of this, the "balance mode" which is actually balancing the cells only in the last bit of this cycle for a normal healthy pack, can take me hours in cold weather - and it is getting worse as the pack ages.

But to shorten the story a bit, using another charger with the CumoCo scooter would take some work, becasue the BMS and BCU are integrated with the existing 2-stage charging management system and I have yet to have seen any signs that we will be getting any kind of wiring diagrams or comprehensive service information that would help with tinkering with it. AS a minimum you would probably also have to use different BMS with the new charger, and the "fuel gauge" system would no longer work.

IBscootin,

How much did the Meanwells cost?

$305 shipped (for two units). Rated for 5G vibration, wide temp range, constant current limiting, I can see why the e-bikers are using them.

There is an HRPG-600-48 version that cost about $10 more with remote on-off function that might be nice to interface with the BMS HVC signal. Limitations of the HRP-600-48 version are its not water resistant so a splash shield might be desired, and supply does not completely shut off when it hits HVC. So it seems the HRPG with the remote off function would be nice to shut down the supply once full pack voltage has been reached. But I have used a AC timer to shut power off; it's just a nice safety feature in case a supply fails to shut off for some reason.

I was concerned the BCU might get in the way. I use the industry standard Cycle Analyst to provide vehicle stats on my e-moto, and I'm very happy with it.

How is your charger current "throttled down" when the BMS shunts start coming on? I assume all BMS's can shunt no more than an amp at most, so a means of the BMS throttling down the charger current when they come on is needed.

Setting the charger voltage limit to a level just a bit below the sum of the shunt voltages is one thing to do, but does not entirely fix the problem because the situation will arise where one cell comes up to voltage way ahead of the others when the pack is still below the charger max. voltage. The BMS I'm most familiar with, (I built an early version of one for my other scooter), is the Goodrum-Fecher BMS (Endless sphere forum) in which the negative side of the charger circuit is routed through a MOSFET which is turned on and modulated by the on-off duty-cycle of the shunts - the effect is to simulate CC-CV charging for all of cells, even though my charger voltage is not adjustable and is a bit too high. The downside of this early version is that it does not shut charging off entirely (The later version, which I haven't assembled yet does), so the once every cell is fully charged, the shunts cook away, producing a lot of heat. So I use a timer switch or I have to watch charging like a cake in the oven.

First of all, my current charging solution isn't ideal but the best I could find based on what was important to me. High amperage, quality production chargers were just too expensive, too heavy and too large.

Here's how in theory the charge is handled: CC until the voltage rises enough that CV can be used. My cell balancers start shunting at 3.65V. If any cell hits 3.9V, the relay to the charger is opened putting charge on hold until the cell comes back down to 3.8V, then the relay to the charger is closed again allowing the balancing to continue. Once the pack reaches its full voltage the relay is opened. Now this process is easier on a pack that is fairly well balanced to begin with. That is why I also picked up a 320mA constant current LED driver to occassionally fully balance the pack at a current below the shunt current.

It works. I will be adding individual balance lines to the cells so I can use Cellogs to verify proper operation and health of the cells. The same lines will also provide for higher shunt currents if desired.

It's a work in progress.