[zsnemeth]

What I'd prefer, is not really a basic charger but a low power one.

Ok, here is my list:
- 1500-2000W 110-220V dual voltage or selectable
- 2 charge profile lead and LiFe
- output voltage adjustable in 20% range, like between 120-156V
- optional PFC
- PCB with pre-programmed controller chip(from You) + BOM (Mouser?) purchase option

less important, but useful option would be a built in RTC for timed charging.

I think this is my sort list.
Thanks for reading.

[mckemie]

Originally Posted by Yabert

I think a fix output voltage can be acceptable if this simplifie the design and lowered the cost.

A charger that does 165-175v will serve nicely for 48 cells and probably for 45 and maybe for as few as 40 if your BMS cuts the power to the charger.

Some while ago, I added 3 cells to my 45 cell pack and also switched to low voltage miniBMS modules. I was somewhat surprised that my old KingPan and Elcon chargers continued to serve well. My Zivan wanted lower voltage to start.

[mckemie]

Originally Posted by mckemie

I did finally receive the charger a few weeks ago; mid-June, I guess. Charger seems to work, but I haven't thoroughly exercised it. I struggled to get the external wiring done. One of the problems is that the outside screw terminal strip is too small for the needed wire and lugs. Finally used 8ga for the battery side and 10ga for the ac side and filed down some lugs. When attached to the screw terminal strip, the wires are uncomfortably close to one another.

After some experience using the charger, I offer the following:
1) I started with mostly 10ga wiring. After finding too much heat in the cables, I went to 8ga. I still can't use full power for very long so I'm searching for suitable 6ga wire. It seems a 10kw charger really needs at least 6ga. As noted above, the screw terminal strip is too small to nicely accommodate such large wire. It would be nice if the terminal strip had some protection against accidental touching.
2) The software that uses the display uses four colors. Two of those colors, red and blue as I recall, have poor contrast. At least, to my eyes.
3) The charger won't run on 120vac the way I have it wired. The other chargers I use take either 240 or 120 on the same two wires; I have an adapter cable at the vehicle inlet (upstream of the BMS relays) that is used to supply 120vac when desired. The 10kw charger apparently wants to get it's 120 off of different terminals. Since the ac power runs through BMS controlled relays, it is not at all convenient to retain BMS control for both 120 and 240. I wonder if the odd 120v terminal on the charger should be jumped to one of the 240v terminals?
4) The software at times refers to right or left buttons. While viewing the display, those directions are reversed. That is, the "right" button is on the left side. Or vice versa.

Other than the above, the charger has worked nicely with no problems. I have used it for short periods of time in parallel with an isolated Elcon charger. I have hopes of eventually charging at close to 60 battery amps with two chargers. I use about 1.7 ah/mile, so that would be around 35 mph. Woo Hoo! I used to think that 10-15mph was a high charging rate.

[valerun]

Originally Posted by zsnemeth

What I'd prefer, is not really a basic charger but a low power one.

Ok, here is my list:
- 1500-2000W 110-220V dual voltage or selectable
- 2 charge profile lead and LiFe
- output voltage adjustable in 20% range, like between 120-156V
- optional PFC
- PCB with pre-programmed controller chip(from You) + BOM (Mouser?) purchase option

less important, but useful option would be a built in RTC for timed charging.

I think this is my sort list.
Thanks for reading.

the problem with this setup is that it will cost the same as Chinese 1.5kW chargers that work fine for 95% of people (e.g., http://evsource.com/tls_HFPFC_1_5KW.php unit for $560 retail...). 5% of people who need programmable low-power charger with bells and whistles won't be enough to make economic sense for anyone to develop such a product...

So the meaningful opportunity in my opinion lies in 2 extreme areas:
1. High-power (10kW+) charger with all bells and whistles at substantially lower price than alternative. This is our charger
2. Low-power (1.5-2kW) bare-bones charger discussed in the last few posts. If can be made for ~50% of the abovementioned $560 chinese charger, this could be a large-volume product, thereby offsetting time / $ investment into R&D around it. And yes, even for such a design, I estimate ~2 months of work getting it to perform just like you want it - across multiple battery voltages, capacities, thermal conditions, etc.

[winzeracer]

Valerun,

How difficult would it be to make your charger, a balance charger for Lipo? I am going to run this charger either way, but it sure would be nice if it balanced. Here is the quick specs on my pack. 111v nominal 30ah can handle 5C charge here is my pack build ( http://www.diyelectriccar.com/forums...ild-76807.html )

EDIT: I have been advised that this would not be useful or necessary

Thanks,

[rwaudio]

Originally Posted by winzeracer

Valerun,

How difficult would it be to make your charger, a balance charger for Lipo? I am going to run this charger either way, but it sure would be nice if it balanced. Here is the quick specs on my pack. 111v nominal 30ah can handle 5C charge here is my pack build ( http://www.diyelectriccar.com/forums...ild-76807.html )

EDIT: I have been advised that this would not be useful or necessary

Thanks,

I'm sure Valerun will explain "why" this can't be done, but having built one of these chargers I can say it's not possible based on the current design. You would be better off with a string of RC type chargers (if any of them are isolated that is) that already do balancing, it would be difficult to get near the same power level and efficiency though.

[valerun]

Originally Posted by rwaudio

I'm sure Valerun will explain "why" this can't be done, but having built one of these chargers I can say it's not possible based on the current design. You would be better off with a string of RC type chargers (if any of them are isolated that is) that already do balancing, it would be difficult to get near the same power level and efficiency though.

Thanks Robin for jumping in here.

The easiest way to do this is to get BMS for each cell and let them do the balancing. miniBMS work well.

[valerun]

update on charger:

1. Efficiency of the charger has been tested a bit more thoroughly. The range is from ~90% at 110VAC 1.5kW to 96% at 230 VAC 10kW. This is for the PFC version, with power factor better than 0.97. So pretty good.

2. We have changed the design of the inductors (to big toroids). As a result, we now are successfully testing 80A continuous outputs at up to 15kW. With high-power fans (~20W total), getting heatsink temps at just 30C over ambient

3. Implemented gradual temperature derating: starting to reduce the output current at 55C linearly to zero output at 85C (heatsink temp).

4. Testing smaller & lighter heatsinks. Again, with high-power fans can get away with half the surface area. So can fit the PFC version into a 10x10x8" box.

Happy to answer any questions.

As usual, more into on kits and chargers is available at http://www.emotorwerks.com/cgi-bin/VMcharger_V9.pl

Thanks,
Valery.

[Zak650]

Hi Valery can you make a few things more clear in the build notes below:

Button:

iii. Connect a normally closed button between 2 horizontal vias on top of the vertical LCD connector – below the top 6-pin row of Arduino mounting pins

This is the last and only mention of this button, I suppose it might be a reset button or for some other purpose, but you can't tell from the instructions

Wiring in the AC adapter:
9. Prepare the off-board components. Note that connectors are best made out of Pololu wires and connector housings (http://www.pololu.com/catalog/category/71 , http://www.pololu.com/catalog/category/70 – note that these are not included in kits).
a. Cut AC adapter’s cord at 12” from the adapter; solder one line input wire to Out “-“ copper bracket on the doubler board, another line input wire – to Out “-“ bracket.

This sounds like you are saying to wire both input leads to the AC adapter to the same place, where is the second input line actually supposed to be attached to?

J1772 connections:

v. BMS/EOC/J1772 connector. Split wires between a 3-pin and 4-pin connectors. Solder other ends to a 7-pin round connector.

This is all you say on how this charger might interface or connect to a J1772 system

Some sort of wiring diagram for these small harnesses is needed.

[valerun]

Originally Posted by Zak650

Hi Valery can you make a few things more clear in the build notes below:

Button:

iii. Connect a normally closed button between 2 horizontal vias on top of the vertical LCD connector – below the top 6-pin row of Arduino mounting pins

This is the last and only mention of this button, I suppose it might be a reset button or for some other purpose, but you can't tell from the instructions

Wiring in the AC adapter:
9. Prepare the off-board components. Note that connectors are best made out of Pololu wires and connector housings (http://www.pololu.com/catalog/category/71 , http://www.pololu.com/catalog/category/70 – note that these are not included in kits).
a. Cut AC adapter’s cord at 12” from the adapter; solder one line input wire to Out “-“ copper bracket on the doubler board, another line input wire – to Out “-“ bracket.

This sounds like you are saying to wire both input leads to the AC adapter to the same place, where is the second input line actually supposed to be attached to?

J1772 connections:

v. BMS/EOC/J1772 connector. Split wires between a 3-pin and 4-pin connectors. Solder other ends to a 7-pin round connector.

This is all you say on how this charger might interface or connect to a J1772 system

Some sort of wiring diagram for these small harnesses is needed.

Thanks Zak for correcting us! We have updated and re-uploaded build instructions to our site.

Valery.