Test/Review of Charger Xtar SV2 Rocket
- Thread starter HKJ
- Start date
Help Support Candle Power Flashlight Forum
vadimax
Flashlight Enthusiast
Be aware of one "feature" of the charger: it has no memory. In case you charge a small battery that is capable of 0.25A charging current and power supply cuts off and then recovers, the charger defaults to 1A charging. In worst case scenario you may get fireworks... I guess 
In any case that would be no good to the battery.
In any case that would be no good to the battery.
Last edited:
That's a fairly serious design flaw. If this can occur while charging Li-ion cells then that could prove to be quite dangerous, since charging Li-ion at too high current is one of the primary causes of thermal runaway.
It would be very helpful if reviewers tested charger behavior in exceptional cases like this. Typically reviewers do not perform such testing. Yet knowing how chargers handle such exceptions is essential knowledge required in order to properly assess their performance across the entire safety spectrum.
This is especially a concern for chargers like this that are designed to make automatic choices (for novices, or for convenience, etc). Often, as above, they do not have access to information required to make decisions, so they are forced to choose between making very conservative (but inconvenient) safe, default choices, vs. agressive (more convenient), but possibly dangerous default choices (e.g. default charge current). And, what's worse, in some cases the designer may not have even considered some exceptional conditions, which increases the chance that unsafe (default) choices might be made by the firmware.
With competent design you get a plug-n-play charger. But with incompetent design you get a plug-n-pray charger. To accurately distinguish the two requires much more extensive reviews that test performance in cases like these.
This is an area where everyone can contribute,since many such tests do not require any special knowledge or equipment. Rather, it requires only that we devise some standard safety test [procedures (tweaked as need be based on the features of each chargers).
Last edited:
StorminMatt
Flashlight Enthusiast
Be aware of one "feature" of the charger: it has no memory. In case you charge a small battery that is capable of 0.25A charging current and power supply cuts off and then recovers, the charger defaults to 1A charging. In worst case scenario you may get fireworks... I guess
This is a BIG reason why it is a good idea to have multiple chargers. I feel like the Rocket is probably best reserved for rapid charging of larger cells. Although the Rocket has .25A and .5A settings, it is probably better used for cells that can tolerate a 1A or 2A charge. For smaller cells, something like the VP series might be better.
asleep
Newly Enlightened
- Joined
- Mar 10, 2011
- Messages
- 28
So, would this be the charger to get for solely charging an 18650(AW protected 3400), if I can get one for under $20?
I've read nearly every @HKJ review.
This'll be my first charger, so safety and simplicity are important to me.
I've read nearly every @HKJ review.
This'll be my first charger, so safety and simplicity are important to me.
StorminMatt
Flashlight Enthusiast
It would be a good charger for 18650 only, as 1A is perfect for them. And you can currently get this charger for under $20 at Illumn.
asleep
Newly Enlightened
- Joined
- Mar 10, 2011
- Messages
- 28
Thanks, appreciate your help.
Now I just need to get up $50, otherwise the shipping from www.illumn.com adds about 60% back to the cost.
I just had this happen to me too. I was charging a pair of 18650s and a few minutes after the start I suddenly heard a loud click/pop from that direction that startled the heck out of me, and now the slider is completely loose (grrrr). Thank you so much for your great idea scintillator, I might try doing that myself.
scintillator
Enlightened
Thanks for the picture scintillator, very helpful!
EDIT:
I ended up going back to Illumn.com with this (my purchase point) and they have shipped me a replacement (I'll be sending the broken one back to them, they'll take care of shipping). I'm satisfied with their resolution - next time I think I'll try what you did above, it would probably be easier.
EDIT:
I ended up going back to Illumn.com with this (my purchase point) and they have shipped me a replacement (I'll be sending the broken one back to them, they'll take care of shipping). I'm satisfied with their resolution - next time I think I'll try what you did above, it would probably be easier.
Last edited:
vadimax
Flashlight Enthusiast
Some news from Xtar: asked them via e-mail regarding SV4 and the answer was "yes". But no details about "when".
vadimax
Flashlight Enthusiast
And, by the way, I decided to use the authority of the CPF for the evil cause
I am a CandlePowerForums member and there are a couple of issues detected with the SV2 model:
1. When there is a power outage the charger has no memory and defaults to 1A charging that is absolutely no good for small batteries.
2. Sliders' internal spring connect points are too weak and tend to snap broken. As a result people have to open a charger and drill new connect points in the electric board:
Would you be so kind as to address these problems in the upcoming SV4 model?
Yours faithfully, Vadim.
So I'm not very happy with my charger any more! The one slot spring also broke out while I was inserting a battery!
I really hate it when manufacturers create a product with an excellent algorithim, but the construction is poor.
I hope the retailer can sort this out for me.
I really hate it when manufacturers create a product with an excellent algorithim, but the construction is poor.
I hope the retailer can sort this out for me.
Gene
Flashlight Enthusiast
I realize this is an older thread but I had a question maybe HKJ or someone could answer about this charger or has an opinion on this.
I purchased this SV2 Rocket primarily for NiMH c & D cells as I still use quite a few of them. Now I will admit my C & D NiMH cells are quite old, maybe almost 10 years but they've always charged up nicely. The D cells are Powerizer 9500mAh and the C cells are Powerizer 4500mAh. They continue to read right at 1.2V off the charger.
The first couple of times I charged them in the SV2 at 2A as recommended, at the end of the charging cycle, they were quite warm but not overly so. This last time I charged them in the SV2, at the end of the cycle, they were very, VERY warm. I noticed a couple of the C cells and a couple of the D cells negative bottoms were very slightly bowed out. I had never noticed this before. They still read 1.2V and still work fine in my devices but I know very, very warm is not good for any cells. It took them awhile to cool down.
I realize this is a fast charger and has no cooling fan and cells will get warm using it but even though these cells seem to charge up to just about 100% and still work fine, I'm wondering if the charger may be defective and charging at a higher rate or maybe the cells are just wearing out. Any thoughts?
I purchased this SV2 Rocket primarily for NiMH c & D cells as I still use quite a few of them. Now I will admit my C & D NiMH cells are quite old, maybe almost 10 years but they've always charged up nicely. The D cells are Powerizer 9500mAh and the C cells are Powerizer 4500mAh. They continue to read right at 1.2V off the charger.
The first couple of times I charged them in the SV2 at 2A as recommended, at the end of the charging cycle, they were quite warm but not overly so. This last time I charged them in the SV2, at the end of the cycle, they were very, VERY warm. I noticed a couple of the C cells and a couple of the D cells negative bottoms were very slightly bowed out. I had never noticed this before. They still read 1.2V and still work fine in my devices but I know very, very warm is not good for any cells. It took them awhile to cool down.
I realize this is a fast charger and has no cooling fan and cells will get warm using it but even though these cells seem to charge up to just about 100% and still work fine, I'm wondering if the charger may be defective and charging at a higher rate or maybe the cells are just wearing out. Any thoughts?
terjee
Enlightened
I'm not HKJ, but...
I'd order some replacement cells.
It's more likely the cells than the charger. Charging at a significantly higher rate is unlikely. Some heating towards the end of the charging cycle is normal (terminating on temperature rise has actually been suggested for NiMHs), but it's hard to comment over the 'net on if the heating is normal or not. It sounds likely to be more heating than expected though. Bulging of the bottom isn't exactly a good sign either. ;-)
It could even be simplified: after 10 years, they've had a good run. No matter how you look at this, their life is probably nearing an end.
I'd order some replacement cells.
It's more likely the cells than the charger. Charging at a significantly higher rate is unlikely. Some heating towards the end of the charging cycle is normal (terminating on temperature rise has actually been suggested for NiMHs), but it's hard to comment over the 'net on if the heating is normal or not. It sounds likely to be more heating than expected though. Bulging of the bottom isn't exactly a good sign either. ;-)
It could even be simplified: after 10 years, they've had a good run. No matter how you look at this, their life is probably nearing an end.
HKJ
Flashaholic
I can guess at two reasons for the cells getting warm:
1) The internal resistance has increased over age, this will generally mean a warmer cell when charging at the same current.
2) The -dv/dt signal is very weak due to age/wear and the charger has problem detected the full cell. This means it will continue to charge for some time on a full cell where all the energy is converted to heat.
1) The internal resistance has increased over age, this will generally mean a warmer cell when charging at the same current.
2) The -dv/dt signal is very weak due to age/wear and the charger has problem detected the full cell. This means it will continue to charge for some time on a full cell where all the energy is converted to heat.
