Dual ping chargers - fuse issues.

[Cargo_Tom]

I am having hiccups with my 5A ping chargers. They blow their grid side fuses instantly when powered up.

Story so far.

1) buy parts for ebike. 2x36v20Ah pings included.
2)top off pings twice while building bike. Chargers get painfully hot to the touch but all seems well.
3) EV grin at first cycle. use 9Ah, then recharge (hots chargers are hot) for 4 hours. Cant wait for balancing to kick in, just unplug, reset CA and drive.
4) use 17Ah of next cycle. CA voltage shows 76V (73v under load) when I get ready to hook up the chargers again.
5) Start charging at 7pm. Check on the bike at 11pm. No change. Odd, but whatevs. decide to let the keep going overnight.
6) 10am next day CA shows 76V. Something is amiss. No LED signals at all.
7) Unplug everything and grab multimeter: wall plug works, as does extension cord and power cords for the charger. I notice the cabinet power sockets have fuses and check them. BINGO.
8 ) replace 6A fuses with 6.3A fuses and connect everything again. When I turn power back up I immediately hear the fuses pop.
9) God dammit. Replace the fuses and try again. Yup. Fuses blown.
10) To make things more interesting I am now unable to turn the bike on again. The bike side charger fuses are fine.

I have no alternative chargers at present. But I might be alble to borrow something in a couple of days.

Do you gentlemen have any suggestions on how to proceed from here?
Cheers

-Tom

[deVries]

Are you using two chargers on the same charge at the same time? If yes, then try using only one charger to charge.

Reverse polarity?

Have you opened-up the charger to look for obvious issues... burn marks, loose part, etc. ?

How long have you been charging & using each charger? Cycles?

AC is set to right voltage?

Extension cord for AC side? If yes, try without extension cord if no probs w/above.

Plug-in AC first, then connect battery?

[dogman]

Cabinet fuses blown. What is this cabinet? Fuses on the AC side? Draw of 110v AC like we have here should only be less than 5 amps per charger

It might be you need to unplug the two batteries from each other, and charge them as seperated 36v units.

[Cargo_Tom]

Hi mate. Thanks for chiming in

- I have two batteries 36v20Ah, connected in series via a Ping-provided harness. I have one 5A charger for each, also provided by Ping. I hook a single charger up to each battery.

- Polarity should not be an issue, as the XLR plug can only connect in one way.

- Opening them up is next on my agenda

- Charges have been used five times each. Three top-offs and two regular charge cycles, where the last one failed. Ownership has been 3 months.

- I have tested for shorts on AC side with a multimeter and found nothing.

- I will try the AC first, battery second sequence as soon as I walk to the hardware store for spare fuses

Updates to follow

Edit: Dogman. Thanks for the suggestions.. I'll get plenty of fuses and start experimenting

[Spacey]

Just to confirm that you disconnect the series nature of the batteries before charging, this could be the issue maybe?

[deVries]

- I have two batteries 36v20Ah, connected in series via a Ping-provided harness. I have one 5A charger for each, also provided by Ping. I hook a single charger up to each battery.

Try disconnecting the series connection and charge each battery separately. See if chargers also get as hot as before?

Start charge: plug-in charger, wait 10 seconds, don't use AC extension cord, plug-in battery.

Stop charge: disconnect battery, then unplug charger.

Make sure to not reverse polarity at the AC side of socket/plug too.

[dogman]

Once a real electronic expert wakes up, we might learn more. I suspect that the chargers are not isolated electronicly ( whatever that means). All I know is that if they are not isolated, you have to break the series connection to use them. I believe charges get damaged, hopefully the blown fuses have prevented that.

But unfortunately, since they blow immediately now, It looks bad.

[Cargo_Tom]

Tried hooking a charger to the AC without being connected to anything else. BOOM. Another fuse went.
Tried hooking the other up the same way - Nothing? nothing happened when connecting a single battery to that one either.

So it seems the problems may have a common cause but different effects. I've just opened the first one up and yup. Blown FETs. It thought this hobby was all about blowing FETs when discharging the bike, not while being bored to tears recharging the bloody thing

Next issue then is to figure out why things went south so I can avoid similar events in the future. I am not tech savvy enough yet, so maybe I should just figure out whether to repair or replace the chargers.

After that the bike itself needs looking at. I cant seem to power it on any more, but I am hoping that this is just the LVC on the packs.

Destructive testing. Yay :]

[Cargo_Tom]

Magic smoke escape path just right of the caps

[deVries]

I know ES member "dnmun" will help you with charger repair help. Send him a PM with link to this thread.

Also, Heathyoung might offer some advice/help, as he knows chargers & is recovering from a bad eBike crash. Not sure how well he feels or can type though?

[deVries]

Are your AC plugs only able to plug-in one-way? In other words, you can not reverse the AC plug either side to flip it and plug-in too???

Do you recall the sequence you were using to connect the chargers to each battery?

Did you leave batteries in series when connecting each charger?

Did you connect battery first before plugging AC plug to charger?

[Cargo_Tom]

Are your AC plugs only able to plug-in one-way? In other words, you can not reverse the AC plug either side to flip it and plug-in too???

Nope. AC plugs are three pronged and contain ground.

Do you recall the sequence you were using to connect the chargers to each battery?

Connect charges to battery, chargers to extension cord, cord to wall socket. So simultaneous

Did you leave batteries in series when connecting each charger?

Yes I did.

Did you connect battery first before plugging AC plug to charger?

yup.

The other charger also had blown FETs.


Would repair be as simple as replacing FETs I wonder?

[jimw1960]

What is the voltage on electrical outlets in Scandanavia? If you are on 220-240vac grid, perhaps it is possible that Ping sold you a 110-115vac charger designed for electrical grid in North America. That would certainly cause the problems you observed.

[deVries]

Are your AC plugs only able to plug-in one-way? In other words, you can not reverse the AC plug either side to flip it and plug-in too???

Nope. AC plugs are three pronged and contain ground.

Your input may not be isolated with common ground???

Do you recall the sequence you were using to connect the chargers to each battery?

Connect charges to battery, chargers to extension cord, cord to wall socket. So simultaneous

How long is the extension cord? This is an extra long extension?

You should connect & disconnect as I posted before, imo.

Did you leave batteries in series when connecting each charger?

Yes I did.

This might be the problem with the common ground & not being isolated???

Did you connect battery first before plugging AC plug to charger?

yup.

Start charge: plug-in charger, wait 10 seconds, don't use long AC extension cord, plug-in battery.

Stop charge: disconnect battery, then unplug charger.

Would repair be as simple as replacing FETs I wonder?

The close-up pic seems to show 3 damaged resistors or a burn area that is underneath that same spot. Use caution... don't get shocked by the big capacitors, etc. You need advice about handling & touching the PS parts safely. Use rubber gloves and non-conducting tools if necessary. I can't help with repairs. Send a PM to dnmun and/or heathyoung.

Good luck, mate, damn what a hassle...

[Cargo_Tom]

Charger can use 90-265V, and was even supplied with europlugs, so our 230v grid should be fine.

My own guess is as follows: Maybe the serial connection between the batteries is indeed at the heart of the problem, but the first few shallow discharge/recharge cycles was not enough to burn the FETS.

When I then do a 4/5 DoD The following recharge then kills what is left of the chargers' integrity and I end up with a pair of crispy twins.

The print on the Fets is still legible, so I'll order replacements ASAP. The resistors should be easy enough to replace

[deVries]

Charger can use 90-265V, and was even supplied with europlugs, so our 230v grid should be fine.

Is there a switch for the voltage range? Many chargers have a switch for 110v or 220v, so you have to select correct voltage.

[Cargo_Tom]

Is there a switch for the voltage range? Many chargers have a switch for 110v or 220v, so you have to select correct voltage.

No sir.

I'm going to try to rustle up a temp fix by getting a 45V, 3A power supply and recharge the batteries one at a time. If I'm lucky only the chargers got damaged by my ignorant little stunt. Time will tell, eh?

-tom

[dnmun]

it looks like what burned up is the npn switching transistor in the front end.

send ping that picture with the burned spot and he will send you another charger.

the resistor are not damaged i suspect, just the transistor burned up imo. those are 600V npn transistors so its a hard life they lead.

[Cargo_Tom]

Yeah... I guess a letter to mr. Ping might be in order. Thanks.

How do I recharge in the meantime though?

Can I make do with a constant output 45v power supply or would that add insult to injury, messing up the pack?

Cheers
-T

[dnmun]

i only saw the one picture, not sure about the other charger. you can use a 45V charger or power supply to charge each portion by itself during the interval. 44V from the power supply is enuff.

you can take the charger apart and take more pictures, and take pictures of the how the other charger died too. did they both burn up the switching transistor?

[Cargo_Tom]

The damage in each charger is identical. The pair of transistors seem to have blown in each one and I can see nothing else amiss. I've discussed the situation over the phone with an engineer in the family, and his initial guess is that the AC side current limiting curcuit was not up to the task at hand, since a new deeply discharged lifepo battery tends to be rather thirsty.

[dnmun]

so both of those npn transistor blew up? on both chargers?

[teklektik]

I never assume 'isolation' in three prong devices because of ties between neutral and Gnd in the building distribution box and ties between 'frame Gnd' and (-) in devices... Two prong devices don't have the (same) problems.

(1) Were the charger-to-mains connections 3 wire all the way when things went bad? That is, three-wire extension cords, etc.

(2) When you got an initial successful charge (if I understand the story correctly) were either of the chargers connected so that they were effectively two-prong (e.g. one of those funky 2-to-3 prong adapter thingies or a two-wire extension cord?) (Not sure if you have them in scandanavia - they are all over in the US

Just for chuckles, when you get new chargers, plug one into the battery (so all connector/pack wiring is in play) but not the mains and test continuity from the Batt (-) to the mains ground prong on the charger plug. You could try this with a dead charger, but if it's open, it's not conclusive - if it's a short, then you have the culprit - a 'safe' charger with Gnd protection giving a backdoor short from BattA(-) to BattB(-) through the mains Gnd. (In this case, the two mains prongs may in fact be isolated from the (+,-) outputs when tested on the bench and not plugged in).

[dnmun]

in the picture you can see that the ground goes to the case. you can check continuity between the output negative and the case.

he used the charger for awhile before it blew up.

[Cargo_Tom]

so both of those npn transistor blew up? on both chargers?

Yessir And at the same time too.

Were the charger-to-mains connections 3 wire all the way when things went bad? That is, three-wire extension cords, etc. ?

Actually no. There were 3>2 adapters in place leaving no shared gnd between chargers

In other news both batts are now showing voltages in the 7-8v range. I sure hope that is the LVC of the BMS in play or my little stunt might be kinda expensive

-T