Charger faulty?

[flecc]

The problem with the original line of Twist (Panasonic) chargers was rectified by encapsulating the whole PCB and its components in a form of potting compound.

Not so, the original Panasonic charger supplied with the Twist was fully encapsulated from the outset.

The replacement Panasonic charger has also failed twice to my knowledge, and it was the first of these I learnt of that triggered me to find a better replacement from UK and US suppliers and publish it online. A lot cheaper too.
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[Flying Kiwi]

Well the charger I have (which is a Panasonic NKJ019) has the components deeply submerged in the stuff as opposed to the picture of the older EKJ006 in the Twist workshop manual page 6.2. I think its an issue of the extent to which the components are coated - with fully submerged parts having better heat dissapation ability (assuming the potting compound is designed with this in mind). I cant otherwise explain why mine has been 100% reliable -although I have always ensured it was plugged in and unplugged in the correct order.

I agree that original charger costs are high and it's great that you've provided better value alternatives to Twist owners, not only for chargers but also replacement batteries. They may realise they have some competition and provide bettter value eventually as a result - well at least in an ideal world

 

[flecc]

Though the old ones had all the electronics submerged but with the heat sink fins sticking up, there could well have been a difference in the depth.

It always seemed to me that the trouble stemmed from changing the original thermistor circuit design that was for Panasonic's own bike into a variation akin to Chinese practice, but still using very different component values from the Chinese chargers. And as we know, it was premature action of the thermistor that caused the charge cut out troubles. Probably the circuit change was for the Twist series larger battery, but a pity they didn't fully redesign for it.
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[Flying Kiwi]

Though the old ones had all the electronics submerged but with the heat sink fins sticking up, there could well have been a difference in the depth.

Looking at the picture in the manual it looks more like the older ones were coated rather than submerged - certaily the one I have has the components fully submerged and only wires emerge, thats the difference in terms of heat. As you mentioned and as the change in part numbers suggest, there's also been some other design changes along the way. I've no reason to believe that these very latest chargers, when treated correctly, don't work anything other than reliably.

 

[andrewelectricbike1]

Ahh well. My charger just seems to react to "over warmth"...

 

[Flying Kiwi]

I'm not being funny here but the Suede charger is a different kettle of fish to the Twist one. The Suede manual shows the charger for that bike has a fan, the Twist Panasonic chargers on the other hand do not. Does your charger contain a fan or does it differ to whats in the manual? If there's a fan, is it possible it's seized or binding or can you feel good airflow? I put these important questions earlier in the thread but haven't noticed answers (yet)...

 

[andrewelectricbike1]

It has a fan, but it is poor.
I think the small charger box is too cramped with components and cables. The airflow is too restricted for the fan to make a difference..

 

[Flying Kiwi]

It has a fan, but it is poor.

It looks as if at least one of the latest Giant Twist (hub motor powered) bikes has a charger with a fan so at least they're going to the trouble of considering thermal issues, not something that can be said with certainty about all electric bike manufacturers. If the fan output has deteriorated from when it was new then that may be something that can be fixed with a drop of sewing machine oil on the bearing (administered by a suitably qualified person). A few ordinary thin round wires within the box won't significantly impede airflow so you've nothing to be concerned about there.

 

[andrewelectricbike1]

I think charging outside at work (under cover) might have affected the bearings over that last two winters. I`ll probably replace the fan as it is standard RS stock.

Is the new twist 36v then? Sounds suede e running gear..

 

[Flying Kiwi]

Is the new twist 36v then? Sounds suede e running gear..

I only have the Dutch manual and AtoB review to go on but yes it's 36 V and it looks to also have the same brand Sanyo hub motor. Perhaps the chargers for the NiMH version (Twist 2.0) may be similar to the Suede's as well?

 

[flecc]

I only have the Dutch manual and AtoB review to go on but yes it's 36 V and it looks to also have the same brand Sanyo hub motor. Perhaps the chargers for the NiMH version (Twist 2.0) may be similar to the Suede's as well?

Sorry to correct, but the new Twist uses a 24 volt motor derived from the same US source design as the Suede unit. Like the Powacycle Lithium bikes, the Lithium model one uses 27 volt Li packs, but two on the Twist, each of 10 Ah.

The NiMh version two uses 24 volt packs.
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[Flying Kiwi]

Sorry to correct, but the new Twist uses a 24 volt motor.

Sorry Andrew, you're correct flecc, it was a blonde moment. The rest is correct about the motor being the same brand. It does make me wonder why they stepped back to 24 V, especially with the additional resistance of the long hub motor supply cables to deal with.

 

[flecc]

It does make me wonder why they stepped back to 24 V, especially with the additional resistance of the long hub motor supply cables to deal with.

Yes, that baffled me Kiwi, it seemed perverse to go for a higher resistance run than necessary. The only reason I could think of is battery price, given that the replacement pair of Li-ion packs are £600, the prospect of much higher for 36 volt packs seen as commercially impractical.
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[andrewelectricbike1]

They might be using lower resistance wires perhaps? The original dynamotor design was rated at 24v by rabbitool, sanyo have made it for quite a while too.

 

[flecc]

They might be using lower resistance wires perhaps?

If you man one of the newly developed medium temperature ceramic superconductors, virtually no chance. I don't think Giant are electrically very aware, mainly depending on others for know how, and costs would prohibit.

It'll just be copper wire, either heavy gauge, or inefficient thinner gauge, probably the latter, given the emphasis they've put on range over performance.
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