# Questions about a Hi-Power BC3 Charger



## Jimdear2 (Oct 12, 2008)

I just bought a battery charger on eBay to use for my 6 AGM battery, 72 volt pulling tractor. The charger does not have a manufacturers name on it. The sellers listing advertized it as a Hi-Power BC3 charger.

It was advertized as a charger originally made to be used on a lithium pack with 24 Cells. It originally had a BMS board in it that was removed. The BMS board had no connection with the charger. So what I bought was some kind of smart charger set to 88 volts and 25 amps. The price was so attractive I bought one, figuring if I couldn't use it for charging the parts and enclosure would be worth that much. Since I plan to build Simon/Jack's charger next winter I figured some of the stuff inside should work.

My electrical wizard friend and I pulled the cover and found three pots installed. By fiddeling a bit we found found that one of them controlled voltage. We reset that pot to limit the charger to 82 volts. I ran it on my pack and it brought all of the batteries to about 13.6 volts and shut itself off.

So it looks like I might have a suitable smart charger for a 72 volt system for $50.00. I went back to buy another and found that all 17 that he had were gone in just a couple of days. Rats

My questions for the fourm is, has anyone any knowledge of/documentation for this Hi-Power brand and experience with their BC3 model. I would like to discover what the other two pots control. 

The next time I run the charger I will have an amp meter installed to see if the charger changes from CC to CV at any point. 

Thanks for any help. When it stops raining and I can uncover the tractor I will open the charger again and take some pictures.


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## Jimdear2 (Oct 12, 2008)

Anybody?????


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## UBCECC (Sep 5, 2009)

post photo of the charger?


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## genawin (Oct 1, 2008)

Here's a picture of the Hi-Power BC3 Charger.


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## Jimdear2 (Oct 12, 2008)

genawin said:


> Here's a picture of the Hi-Power BC3 Charger.


That's quite similar the charger I have I'll post pictures tomorrow when I get on a system that will allow me to add pictures to a post (win 7 bug problems)

Do you have any documentation?

Do you know what the three pots adjust? I know that one of them adjusts voltage, but not the other two.

The charger I have does put out 25 amps at 82 volts. I've adjusted it down from the original 88 volts for my AGMs. 

It also WANTS!!!! 20 amps from the grid. Picture fuses poping and breakers breaking. I had to start up the big generator to use it. Got some rewiring to do.

Do you have any idea what the charging map is? 

It seems to be constant voltage right to the end. I haven't wired in the amp meter yet so I don't know what the current profile is. The charger has three LEDs that show state of charge and it seem to shut itself down.

Any help or information would be helpful


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## dexion (Aug 22, 2009)

I have several bc2 chargers (48V 25amp) they are the the same it looks like perhaps but I cant be sure (except they run on 15amps input) my 3 trimpots
if looking down on the pic
|% of cc to shut off charger **| |voltage output dc| |amps output dc|

ymmv

Shouldnt be too hard how I found out was to get it near shutoff and then found voltage trim and then when it was starting a charge I found the amps output. The third is a guess ** (% cutoff) I havent messed with it since it was ok. Adjusting them on the fly didnt seem to make it unhappy for me.
Oh as for 20 amps ac input. I can adjust mine to pull less or more current on the input side. So perhaps you can lower dc amps out and get it to be happy on a 20 or even 15 amp breaker. I dont know how it affects longevity but I have 4 of them heh.


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## david85 (Nov 12, 2007)

Can you give a little more details on how much you adjusted the trimpots? Half a turn? 5 full turns? I have the larger BC5 charger and I noticed it has three trim pots on the control board as well. The charger is pushing a bit more juce out than I would like and turning down the amps might be something to try. Would also like to be able to control the top end voltage shut off.

I don't suppose the circiut bord has a label next to each trimpot? Mine are labeled VR1, VR2 and VR3.


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## dexion (Aug 22, 2009)

Round and round and round until its where I want it. I adjust em up down sideways depending on what I am plugging into/how fast I want to charge.

For instance to reduce output current 3 amps is perhaps 6 turns ( i never counted it seems like forever heh)

Voltage isnt as much perhaps 1 full turn for 2 volts.

No labels that I can tell.
But its not the same model as you have.


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## david85 (Nov 12, 2007)

Woohoo! figured out VR2 is the current reference. Turned it down by one amp. Now I'm almost tempted to run a pot right to the surface of the charger case........maybe....... 

I have a tester that has a current sensor on it and measured the AC feed going into the charger. Sure enough, it dropped the amps nice and smooth as I turned the screw. Sensitivity is close to what you describe too.

The charger isn't the same model, but so far there is some similarity in how they are controlled since its made by the same company. Mine seems to use a programmable microchip in it though, not sure why they felt that was needed.

Just wanted to make sure it wasn't something like half a turn and the magic smoke gets out. Guess I'm used to ICEs where half a turn on anything can make a big difference (mixture or fuel pressure etc). I looked up the specs for the 3296 series trimpots and it seems they have something like 25 turns across the range. But again, I don't know for sure if its safe to go that far, maybe it is.

Here's the link for the trimpots if it helps anyone else: http://www.datasheetcatalog.org/datasheets2/12/124367_1.pdf

So for the other 2 controls how did you figure out what affected the voltage?

Should I be able to see an instant change like I did for the current? or is it only something that only affects the auto shut off voltage? I want to make sure I don't overcharge the battery if I get the setting wrong.


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## Jimdear2 (Oct 12, 2008)

david85 said:


> Woohoo! figured out VR2 is the current reference. Turned it down by one amp. Now I'm almost tempted to run a pot right to the surface of the charger case........maybe.......


Thanks for that info



david85 said:


> Here's the link for the trimpots if it helps anyone else: http://www.datasheetcatalog.org/datasheets2/12/124367_1.pdf


I'll look that up



david85 said:


> So for the other 2 controls how did you figure out what affected the voltage?


It was one of the two end ones, My freind did the initial adjustment so I don't know which end (I'll look for the ID numbers).



david85 said:


> Should I be able to see an instant change like I did for the current? or is it only something that only affects the auto shut off voltage? I want to make sure I don't overcharge the battery if I get the setting wrong.


We did see an instant change when we did the initial adjustment.

We went to a pull over the weekend and I didn't recharge before we left. Since it will finally stop raining tomorrow I'll go out and recharge. I'll spend more time on the identifying pot adjustments and report tomorrow.

For those who might be interested at the pull we kicked butt on all garden tractors up to 20 HP including the twin cylinders. The nicest part was while they needed to use low and second gear in their Cub Cadet transmissions, our Cub was in top gear at 60 volts and we were still not pulling max controller amps. We are going to have to go to an overdrive primary reduction set. 

The people watching just can't beleive something that doesn't make a ton of noise can have that much power.

I didn't have my cub there, I ran the ultralight at 72 volts, I'm still working on the primary reduction. I went a gear too low but still did a full pull against the 20 horse garden tractors, I also didn't see anywhere near the 450 amps the controller is rated for. A couple more pulls and I'll be dialed in. I'm still tied a bit to ICE thinking and always pull in a lower gear then I need to.

I'll let you know what goes with the charger tomorrow.

Jim


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## dexion (Aug 22, 2009)

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.)


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## david85 (Nov 12, 2007)

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!


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## david85 (Nov 12, 2007)

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.


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## genawin (Oct 1, 2008)

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|


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## ken6881 (Oct 7, 2011)

Where are you all buying these chargers?

Thanks


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## genawin (Oct 1, 2008)

ken6881 said:


> Where are you all buying these chargers?
> 
> Thanks


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


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## timpootle (Jun 3, 2011)

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.uk/bvsorguk/forums/viewtopic.php?f=6&t=1503&start=110


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


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## david85 (Nov 12, 2007)

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.


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## timpootle (Jun 3, 2011)

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.


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## david85 (Nov 12, 2007)

Cool project

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


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## baerfoot (Jan 2, 2011)

It's been a couple of years since the last post here, but maybe I can still get some advice:
I bought this charger (BC3) and Hi power cells in 2008. Since that time I have sold the cells but still have the charger, but have not used it. I recently added a port to my car to charge at charging stations at 220 v. I am using 4 switching 48 v power supplies right now to charge, but it is a little slow.
I would like to use the BC3 charger, but it is configured for 110V charging. Does anyone know if I could change it so that it could use 220v current?


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## timpootle (Jun 3, 2011)

I bought mine configured for 240v for use here in the UK. There are some photos up at https://www.flickr.com/photos/timpootle/ of the BC3 with the lid off. I have added a relay controlled by the separate BMS - I removed the balance board from the BC3, which was electrically separate from the charger anyway.

I hope the photos help you. I was unable to see an easy pick off or changeover switch for 110v.


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## baerfoot (Jan 2, 2011)

timpootle said:


> I bought mine configured for 240v for use here in the UK. There are some photos up at https://www.flickr.com/photos/timpootle/ of the BC3 with the lid off. I have added a relay controlled by the separate BMS - I removed the balance board from the BC3, which was electrically separate from the charger anyway.
> 
> I hope the photos help you. I was unable to see an easy pick off or changeover switch for 110v.


Thanks for the link. I don't see any obvious change either. I will attach an image I took of the inside of mine.


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## timpootle (Jun 3, 2011)

Notice the transformer leads going to different sides, as highlighted in these 2 images. May be your answer, or maybe not. You will have to see if this transformer has tapped windings.


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