Alternative to Ping Charger

chrisrenwick

Finding my (electric) wheels
Aug 3, 2008
11
0
Hi I was wondering if anyone new of an alternative to ping's 36v LifePO4 battery charger?
 

Jeremy

Esteemed Pedelecer
Oct 25, 2007
1,010
3
Salisbury
I don't know of one, but they come free with the battery plus Ping can supply spares for just a few pounds each, so it hardly seems worth the bother of trying to find an alternative.

I know that other have bought spare chargers from him at a reasonable price, so your best bet might be to just send him an email and ask.

I doubt the charger circuitry is that complex, so it might be possible to build an alternative. Mine runs at a constant current of a couple of amps until the BMS starts to limit, then it switches to constant voltage and just allows tyhe current to trickle down to a very low level. As the BMS balancing process starts, the charger will occasionally trip back into constant current mode for a few minutes, before reverting to constant voltage.

It may be that a straightforward current limited DC supply set to the right end voltage would be as good.

Jeremy
 

chrisrenwick

Finding my (electric) wheels
Aug 3, 2008
11
0
I have already had two of ping's chargers had both suffer from the same problem (see my thread entitled Ping Battery Charger). Can anyone give me any idea where I can locate an alternative. Many thanks,

Chris
 

Jeremy

Esteemed Pedelecer
Oct 25, 2007
1,010
3
Salisbury
Chris,

Sorry, I'd not seen the Ping charger thread before you pointed it out.
As you can't get either charger to work, I suspect some other problem, as, although possible, it seems unlikely that both chargers were "dead on arrival". The problem might be a fault in the battery BMS, if the BMS is open circuit then the charger will just show both LEDs all the time and won't charge.

I would be more than happy to have a look at one of your duff chargers to test it, see what's wrong with it and whether it can be easily repaired. My own 36V Ping battery and charger works flawlessly, so I could compare the two circuits to find out where the problem is and test the charger out on my own 36V Ping pack for you.

I'm near Salisbury.

Jeremy
 

chrisrenwick

Finding my (electric) wheels
Aug 3, 2008
11
0
thankyou for your kind offer but I have already disected the chargers and disposed of them
 

Jeremy

Esteemed Pedelecer
Oct 25, 2007
1,010
3
Salisbury
John,
That Yesa charger looks pretty similar to the one I have that came with my Ping pack,so may have a same sort of high failure rate.


Chris,
What did you find to be the cause of the failures in the two defective chargers you dissected? It'd be very useful to know in case mine fails at some future date.

Jeremy
 

Jeremy

Esteemed Pedelecer
Oct 25, 2007
1,010
3
Salisbury
Thank for that information Chris.

Out of interest, did you do the output voltage check with the pack connected? I have a feeling (but would need to check with my own set up) that this charger needs to see the battery voltage on the output before it will turn on. Testing it with no battery connected may well result in getting a zero volts indication.

I've got another charger (albeit a sealed lead acid one) that I know for sure behaves like this, because I also thought it was dead.

I'll check my set-up tomorrow and let you know how mine behaves.

Jeremy
 

Blew it

Esteemed Pedelecer
Jun 8, 2008
1,472
97
Swindon, Wiltshire
Hi guys,

Hope you don't mind my sticking my nose in, I have two nine month old Ping batteries, One 24 volt 15 a/h and a 36 volt 10 a/h.

When preparing these batteries for use, and after soldering the XLR plugs to the charger output leads, I remember that I checked the polarity was correct.

These checks were carried out WITHOUT the charger connected to the batteries. The open voltage measured at the charger lead XLR pins were: 39.9 volts for the 36 volt charger. 28.9 volts for the 24 volt charger. It may well be Jeremy, that the chargers in fact do not need to see a voltage as you thought. I'm not very good with electronics, so please don't be offended if I'm wrong.

The chargers are a bit suspect regarding quality, but in fairness to Li Ping, I would be inclined not to be too critical of them. After all, they are £20 chargers.

I remember when my 24 volt pack arrived, as soon as I unpacked the charger, I could hear something rattling about inside. This proved to be a reverse current diode which had "fallen off" the PCB. With this component re-soldered to the board, the charger worked fine, except, it sometimes needs a "barney flinstone" tap to persuade the cooling fan to start.

I hope this may help in some small way.

Regards

Bob
 

Jeremy

Esteemed Pedelecer
Oct 25, 2007
1,010
3
Salisbury
You're right, Bob, I checked mine this morning. Unlike my SLA charger the Ping LiFePO4 charger does seem to work fine with no battery connected, so it seems pretty certain that Chris was unlucky enough to get a couple of DoA chargers.

I'm not too surprised at the diode falling off; the state of some of the packaging I've received from the far east leaves a lot to be desired. I think that some parcels are literally thrown on and off trucks/trolleys/aircraft from the look of them when they get here.

Jeremy
 

Blew it

Esteemed Pedelecer
Jun 8, 2008
1,472
97
Swindon, Wiltshire
Wrong readings

Hi Jeremy,

Please ignore those figures in the above posting, they are the open contact voltages of the batteries.

These are the open pin (battery not connected) figures for the chargers:

24 volt charger.....31.3 volts

36 volt charger.....45.2 volts

Sorry about the mistake.

Regards

Bob
 

gary Gadget

Pedelecer
Apr 24, 2008
29
0
Lifepo4 - charging

I also had a DOA charger from China, though not from PING. After some reserch I have done the following:-

Any lifepo4 with full BMS just needs a less than 5amp charger as the BMS shuts off each fully charged cell. You just need to work out the cell number and set the voltage accordingly

So for a 25.6 volt battery (24volt) would be 8 x 3.2 volt cells you can charge each cell at up to 0.7 volts over nominal max therfore set the charger voltage below 31.2 volts, the replacement charger I got (free of charge!!) outputs 28 volts which is a good middle ground at 3.5 volts a cell.

38.4 volt battery (36volt) is 12 x 3.2 and charge at 12x 3.5 = 42volts

You must ensure the current output is limited to 5 amps as this is the max for most cheep lifepo4 batteries due to thermal constraints.

The BMS will also shut down the battery if it detects a large drain on any cell - dont panic as you just need to plug in the charger again to reset -I have had this once when the battery was new and I had not realised the charger was not charging. After a few cycle charges the battery capacity has increase.

Below is a link to a little youtube vid, you can see the battery and charger mentioned. You might also notice no duct tape as this one seems better constructed than ping's and others - for a start it is fused and has a proper charging connector also heavy duty black plastic shrink and insulating sheets have been used and the BMS is part of the battery and not swinging around by its wires in a plastic tube!

YouTube - lifepo4 battery fitted to my cyclone electric bike
 

Blew it

Esteemed Pedelecer
Jun 8, 2008
1,472
97
Swindon, Wiltshire
Gary,

Thanks for sharing the results of your research, that's a whole lot of very useful data for others to use. It could well be you have clarified one of the mysteries of LiFePO4 charging.

Many thanks

Bob
 

Advertisers