[dexion]

I just cut out a slot and have a long screwdriver but i suppose you could remote the pots.

Get the charger near its shutoff (you know when it starts blinking the finishing charge light which means its cc on mine) and snag your amp meter on the ac side watch what its putting out then turn it a bit so it take more current. Wait until its nearly off (low draw however mine always takes about 230 watts all the time so figure that in fans, the burn off resistors using power from the batts to get hot which takes power from the wall to keep em hot etc.) When it starts taking more you are going up in final voltage, if it shuts off you went the wrong way. For mine as long as it didnt shut itself off I could see the change right away. Ive had mine up to 20 amps draw from the wall and down to about 12 and ive adjusted the voltage down 4 volts or so and no pop (but i do have 4 of them so I can be brave.)

[david85]

Looking at the ratings for the pots, they aren't really intended for constant adjusting but I guess it would take a while to wear out all 200 rated cycles anyway. Being able to access was the other reason I was thinking of replacing them with something remote mounted that is hopefully rated for a longer service life and won't mind being adjusted as often. Probably getting ahead of myself though.

Congrats on the tractor pull, Jim!

[david85]

Think I found the one that controls the 80%+ down ramp. There actually IS a down ramp now!!! Before it would just jamb a full 20 amps right up to shut off if I allowed it. In most cases I couldn't because several cells would pass 3.8V if I did. Needless to say, when the charger is pushing 20 amps its not possible for the BMS to keep up. Now it gently drops down under 1 amp and the separate BMS burn off module can actually control the high cells and keep them from going beyond 3.8V. It might actually be a little low right now but I'll gradually bring it up manually until all the burn off lights come on. Probably will take a while though.

Another nice feature is I can turn the max charging current down too. Now I can actually charge the car AND have the main shop lights on at the same time

Still have to figure out the last one. Maybe thats what controls the final shut off?

What a relief!! Up to this point I had to constantly baby sit the charger for fear of overcharging some of the cells.

[genawin]

Was the quote below correct and if so what is a rough guide to the direction and ratios ?

if looking down on the pic
|% of cc to shut off charger **| |voltage output dc| |amps output dc|

[ken6881]

Where are you all buying these chargers?

Thanks

[genawin]

Originally Posted by ken6881

Where are you all buying these chargers?

Thanks

I bought mine as part of a battery pack deal direct from China 3 years ago.

[timpootle]

Adding my info just as a data-point for this conversation.

I have a Hi-Power BC3 set for 162V10A, max voltage 198.1V
240V input for use here in the UK. Been sat in my garage for 3 years while I finished my project. Finally in use yesterday!

Drawing 1950 watts / 11.25 amps from the wall, just right for a 13 amp supply but a long time to charge my 90kWh pack!

I haven't fiddled with the pots inside the charger, but I have removed the balance board and fitted a mains relay to allow my separate Guantuo BMS to shut-off the charger when the first cell gets to the trigger voltage (3.85V max for HiPower LiFePO4 cells)

http://www.batteryvehiclesociety.org...1503&start=110


I found this 72V25A BC3 with 110V input while googling:
http://www.evdrives.com/special_deals_BC3.html

[david85]

YOW! 90 kwh???

I have to ask - what's that going into?

Does your charger have any factory installed relays in it? Mine was intended for three phase and had a relay for each line before feeding into a rectifier. If yours is set up this way, you could control the main contactor(s) directly without the need to add your own to the internals.

[timpootle]

Citroen Berlingo van. I'm aiming for 300 mile range :-D
http://evalbum.com/2296

I'll put some photos of the charger up on flickr soon. There were relays in there, but I couldn't figure out what they were doing or how to trigger them, so added my own.

[david85]

Cool project

You appear to be running the exact same cells as me. Good to know I can still get them if needed.