Society of Robots - Robot Forum

General Misc => Misc => Topic started by: Admin on April 15, 2008, 05:18:50 PM

Title: do not buy from onlybatterypacks.com
Post by: Admin on April 15, 2008, 05:18:50 PM
I try to do my best to protect you guys from dishonest sellers by only listing trusted companies in the robot parts list (http://www.societyofrobots.com/robot_parts_list.shtml). In this case, the seller has been marking up the specs much higher than they really are. I hope this saves you guys from the frustration of buying products that don't work!

My complaint email to onlybatterypacks.com is shown below. I also noticed the mAh is lower than they claim too, but I didn't do a full test on it so left that out:

Quote
Hi

I am the author of the popular site, societyofrobots.com.

I am a recent customer of this product:
http://www.onlybatterypacks.com/showitem.asp?ItemID=10417.7

You make a claim for a 35A discharge rate, however my own measurements say its much closer to a 3.5A discharge rate! Just by drawing 2A from a fully charged battery, I already get a 1V drop.


I also bought this product:
http://www.onlybatterypacks.com/showitem.asp?ItemID=11724.12

You make a claim that it can do 3000mah in 1.5 hours. However the above 4200mah takes ~5 hours to charge! The 1.8A selectable rate does not work - it claims the battery is fully charged (within 30 minutes) when it isnt! I have to use the .9A setting for it to work.

Either the battery has a charging rate of only 1A, or your charger has a serious flaw.

Now I can't recommend your site or products any longer on mine until this problem is rectified and I'm assured this won't happen again. I will also no longer be able to purchase your products, because I can't be sure if the specs are honest.

thanks,
John Palmisano

Robotics Specialist
Naval Research Laboratory, Washington, DC
B.S. Mech. Eng., Robotics, Carnegie Mellon University
www.societyofrobots.com
Title: Re: do not buy from onlybatterypacks.com
Post by: pomprocker on April 15, 2008, 06:14:00 PM
whew...luckily i purchased from allbattery.com (tenergy)
Title: Re: do not buy from onlybatterypacks.com
Post by: pomprocker on April 15, 2008, 06:14:58 PM
Robotics Specialist
Naval Research Laboratory, Washington, DC
B.S. Mech. Eng., Robotics, Carnegie Mellon University
www.societyofrobots.com


Nice resume....ahem signature.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on April 15, 2008, 06:32:03 PM
Now that I think about it, I was really really dumb to believe those specs . . . all other things the saame, even lithium polymer batteries can't do 35A discharge!

I've bought tenergy AA NiMH's in the past, and they do as they claim :)

But let this be a lesson to all of us: companies specs can be wrong, so use your brain!
Title: Re: do not buy from onlybatterypacks.com
Post by: JonHylands on April 15, 2008, 06:42:53 PM
I use http://www.all-battery.com/ and I've been very happy with their batteries and chargers...

- Jon
Title: Re: do not buy from onlybatterypacks.com
Post by: airman00 on April 15, 2008, 06:54:09 PM
I use http://www.all-battery.com/ and I've been very happy with their batteries and chargers...

- Jon


me too

everything is very cheap there and all the specs are accurate
Title: Re: do not buy from onlybatterypacks.com
Post by: jman571 on April 15, 2008, 08:01:13 PM
Errrr....I WAS going to pruchase my batteries from www.all-battery.com until someone from this forum suggested this site in my thread asking for advice  >:(

I have unfortunately purchased 2 products:

Admin's charger: http://www.onlybatterypacks.com/showitem.asp?ItemID=11724.12

and this battery: http://www.onlybatterypacks.com/showitem.asp?ItemID=11128.37

However, I have not recieved either yet, though I believe they've shipped already, and will be recieving them by this Friday.

What do you guys suggest? Should I send the whole thing right back to them? Or is this going to cost me more money than it's worth, at the very least I need about 2-3 A out of this battery, but i'm wary of this charger's abilities now.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on April 15, 2008, 08:19:05 PM
sorry about that jman571 . . . I got burned really bad - the battery I got I need for my competition in 3 days, but its too weak to power the robot arms on my ERP :'(

The arms require 2A peak . . . but drawing just that causes a voltage drop so large it resets my microcontroller . . .

Anyway, the battery you posted appears to have very realistic specs. I think you are fine on that. For the charger however, yea, you won't be able to get more than .9A charging rate. It will take about ~3 hours to recharge your batteries. I'll leave it up to you . . .

If you decide to keep the battery, I encourage you to multimeter it and see how low the voltage drops when you use it.
Title: Re: do not buy from onlybatterypacks.com
Post by: jman571 on April 15, 2008, 09:14:27 PM
sorry about that jman571 . . . I got burned really bad - the battery I got I need for my competition in 3 days, but its too weak to power the robot arms on my ERP :'(

The arms require 2A peak . . . but drawing just that causes a voltage drop so large it resets my microcontroller . . .

Anyway, the battery you posted appears to have very realistic specs. I think you are fine on that. For the charger however, yea, you won't be able to get more than .9A charging rate. It will take about ~3 hours to recharge your batteries. I'll leave it up to you . . .

If you decide to keep the battery, I encourage you to multimeter it and see how low the voltage drops when you use it.
Yea, I was just looking at allbattery, and they didn't really have what I was looking for. I'm sure my uncle (he's an electrician) has a multimeter, and I'm going over there anyways to do some soldering, so I'll let you guys know if my battery charger is messed up as well. Because if it is...*rubs hands in anticipation of consumer boycott* ;)(http://www.hmc.psu.edu/ume/fcmonline/case27/images/mr%20burns.jpg)
Title: Re: do not buy from onlybatterypacks.com
Post by: cooldog on April 16, 2008, 05:35:16 AM
Robotics Specialist
Naval Research Laboratory, Washington, DC
B.S. Mech. Eng., Robotics, Carnegie Mellon University
www.societyofrobots.com
[/quote]

your signature is intimidating

"naval research lab"
Title: Re: do not buy from onlybatterypacks.com
Post by: GHF on April 19, 2008, 08:35:45 PM
To be honest, it's a terrible idea to expect a lot of current from NiMHs. They aren't exactly known for their superior current-delivering abilities.  ;) That's why battlebots, which tend to draw amps in the hundreds, use big fat NiCds -- they're just irreplaceable when you want a durable, cheap, high-amperage battery. Also, battlebots people tend not to care about the environment or weight.

Also, the charger thing was more of an user error. NiMHs are best charged at C/10 (capacity over ten hours; the hours is just their to make the units work out), so in your case, about 4.2Ah/10hr = 0.42A. One of the symptoms of charging too fast is of course voltage spiking, causing false peak detection by the charger and then premature end of charge. Also, heat becomes an issue. The 3000 mAh battery in 1.5hours would be perfectly reasonable for a NiCd pack though -- NiCd has a endothermic charging process, and will thus cool itself off while charging. Plus, they just charge faster. Some "fast" or "quick" chargers actually go for 1C.

Anyways, high current capacity stuff should just be left to the lithiums. LiPo/LiIon provide a lot of energy density and a lot of current. Take a look through Tower Hobbies and the like, and you can find 30C discharge LiPos. However, they are much more finicky about voltages. Overcharge them a tiny bit and they explode. Undercharge them by 0.1V and they stop working (or explode). Drop them and they die (sometimes explode). Charge/discharge them too fast, and they explode. The 30C figure doesn't go together with the lifetime either; discharge them at that rate and you might only get a hundred or so cycles before hitting 60% capacity.

For a sumo robot, I used four A123 M1 cells (2300mAh, 70A capacity, approximate sub-C form factor, about $18/cell), which have begun to have legends circulating about their ruggedness. Cells unbalanced to 5.0V with no damage, discharge to 0.5V, etc. They also come it aluminum cylinders, so they're more durable than the foil pouches LiPos come in and lighter than steel-canned NiCds/NiMHs. http://www.flyelectric.ukgateway.net/lithium-a123.htm (http://www.flyelectric.ukgateway.net/lithium-a123.htm) The most telling difference is this: these are used in power tools and electric cars, while lithiums are used in cell phones and iPods. ;D

-Xo W.
Title: Re: do not buy from onlybatterypacks.com
Post by: AndrewM on April 20, 2008, 09:35:23 AM
Anyways, high current capacity stuff should just be left to the lithiums. LiPo/LiIon provide a lot of energy density and a lot of current. Take a look through Tower Hobbies and the like, and you can find 30C discharge LiPos. However, they are much more finicky about voltages. Overcharge them a tiny bit and they explode. Undercharge them by 0.1V and they stop working (or explode). Drop them and they die (sometimes explode). Charge/discharge them too fast, and they explode. The 30C figure doesn't go together with the lifetime either; discharge them at that rate and you might only get a hundred or so cycles before hitting 60% capacity.

Li-Mn batteries are a less volatile option with similar discharge and burst rates to NiCads and LiPos, but without the explosive results of LiPos.  But about 2X the price.  http://duralitebatteries.com/flight/batteries-mg.php#Electric
Title: Re: do not buy from onlybatterypacks.com
Post by: superchiku on April 20, 2008, 09:42:12 AM
li-ion rocks ....
Title: Re: do not buy from onlybatterypacks.com
Post by: jman571 on April 21, 2008, 07:46:50 PM
Alright, I recieved my stuff, I'll keep you guys up-to-date on whether I have any problems. Though it might be some time before I "test" out all my components, as I realized I will need an additional connector, and some soldering to do as well.
Title: Re: do not buy from onlybatterypacks.com
Post by: ALZ on April 24, 2008, 02:07:53 AM
Hi:

I took a look at some of these places you have been buying batteries from. I hate to break it to you but those are some high prices you are paying! "www.all-battery.com"
wants $26 for a 14.4 Volts 2400 MAH battery. Then they want $14.99 for just a wall charger that can only put out 300 ma. and they called that a sale! Some of the other places you talk about even want more. Shop around guys. I can tell you that I didn't pay anything close to those prices. Also my charger has a base for the battery pack that cuts off if the battery overheats and it can put out 1.2 amps. I bought a few, so if any of you want to buy 1, let me know. BTW the battery pack (C cells) that comes with the charger is  14.4 Volts at 2400 MAH

I use http://www.all-battery.com/ and I've been very happy with their batteries and chargers...

- Jon

Title: Re: do not buy from onlybatterypacks.com
Post by: airman00 on April 24, 2008, 06:54:11 AM
Hi:

I took a look at some of these places you have been buying batteries from. I hate to break it to you but those are some high prices you are paying! "www.all-battery.com"
wants $26 for a 14.4 Volts 2400 MAH battery. Then they want $14.99 for just a wall charger that can only put out 300 ma. and they called that a sale! Some of the other places you talk about even want more. Shop around guys. I can tell you that I didn't pay anything close to those prices. Also my charger has a base for the battery pack that cuts off if the battery overheats and it can put out 1.2 amps. I bought a few, so if any of you want to buy 1, let me know. BTW the battery pack (C cells) that comes with the charger is  14.4 Volts at 2400 MAH

care to tell us where you bought your batteries from?
Title: Re: do not buy from onlybatterypacks.com
Post by: Trumpkin on April 24, 2008, 09:03:30 AM
I paid $11 for my 2400mah 6volt battery from www.all-battery.com I think that's pretty dang cheap. please tell us where you bought your batterys.
Title: Re: do not buy from onlybatterypacks.com
Post by: superchiku on April 24, 2008, 10:17:52 AM
plzz tell iam in  process of buying my battery so it would be good if u can
Title: Re: do not buy from onlybatterypacks.com
Post by: pomprocker on April 24, 2008, 10:24:48 AM
I paid $11 for my 2400mah 6volt battery from www.all-battery.com I think that's pretty dang cheap. please tell us where you bought your batterys.


so did i. that was a sale price.
Title: Re: do not buy from onlybatterypacks.com
Post by: superchiku on April 24, 2008, 10:52:59 AM
easy for u to say, i ordered my battery pack adn charger from the site all-battery pack , it was good only 40$ fro both i proceed to checkout and what do i see international shipments cost is around 60$ what a waste is this economical ordering batteries for 100 $ , better do without the batteries doesnt anyone give free samples??
Title: Re: do not buy from onlybatterypacks.com
Post by: pomprocker on April 24, 2008, 01:11:06 PM
easy for u to say, i ordered my battery pack adn charger from the site all-battery pack , it was good only 40$ fro both i proceed to checkout and what do i see international shipments cost is around 60$ what a waste is this economical ordering batteries for 100 $ , better do without the batteries doesnt anyone give free samples??

Yeah I think my total was $44 for battery, charger, and shipping.
Title: Re: do not buy from onlybatterypacks.com
Post by: Trumpkin on April 24, 2008, 06:35:23 PM
I just used an adapter thingy for my charger. (it was free)
Title: Re: do not buy from onlybatterypacks.com
Post by: superchiku on April 24, 2008, 11:13:16 PM
Quote
Yeah I think my total was $44 for battery, charger, and shipping.

with shipping how come ???? was it overseas

and trumpkin
Quote
I just used an adapter thingy for my charger. (it was free)


what kinda charger??
Title: Re: do not buy from onlybatterypacks.com
Post by: ALZ on April 25, 2008, 12:57:25 AM
Hi Guys:

I got them on Ebay a few months ago. The company was selling off all the Lentek robotic vacs and parts. All the parts were new, some of the vac were lightly use, others new.   The shipping cost much more than the parts but still a great deal. So when the bids were low I picked up a battery here and there along with a vac. Then they listed a box of 12 chargers. No one wanted that many so I got them cheap.  The transformer part that plugs into the wall is really a DC power supply that gives 24 V at over 1 A. That plugs into a base that looks like it has some kind of switcher power supply in it.  If you are looking for NiMH AA cells "www.mcminone.com" sells them for 99 cents each. Like I said you just have to look around a bit.

I paid $11 for my 2400mah 6volt battery from www.all-battery.com I think that's pretty dang cheap. please tell us where you bought your batterys.
Title: Re: do not buy from onlybatterypacks.com
Post by: Trumpkin on April 25, 2008, 08:16:43 AM
Ummm...so it's not such a great deal. I think we all know that you can get NiMH AA cells, but who wants to go through the trouble of soldering them all together then getting a molex connector kit and putting the molex connector on the wires. It isn't worth the trouble and in the end it ends up costing pretty much the same. You can get 12 hitec male molex connectors for $8 and if you want a 4 cell battery pack and each cell is 99 cents that's ~$4 if the connectors are $8 that's $12 plus shipping and you have to do extra work!!!! I would feel uneasy buying batterys and stuff on ebay for some reason.....
 
Title: Re: do not buy from onlybatterypacks.com
Post by: ALZ on April 26, 2008, 12:53:20 AM
Hi: Why in the world would you want to wired the cells together & pay $8 for a connector!
4 cell battery holder with connector, 78 cents from Jameco.   

Ummm...so it's not such a great deal. I think we all know that you can get NiMH AA cells, but who wants to go through the trouble of soldering them all together then getting a molex connector kit and putting the molex connector on the wires. It isn't worth the trouble and in the end it ends up costing pretty much the same. You can get 12 hitec male molex connectors for $8 and if you want a 4 cell battery pack and each cell is 99 cents that's ~$4 if the connectors are $8 that's $12 plus shipping and you have to do extra work!!!! I would feel uneasy buying batterys and stuff on ebay for some reason.....
 
Title: Re: do not buy from onlybatterypacks.com
Post by: Trumpkin on April 26, 2008, 09:39:55 AM
I couldn't find a battery holder with the molex connector on jameco.
Title: Re: do not buy from onlybatterypacks.com
Post by: ALZ on April 27, 2008, 12:57:33 AM
Hi: I didn't say the connector was a "molex" connector. My point was that you don't have to spend the time soldering and tapeing cells together to make a battery pack when you can buy a battery holder at low cost. 

Yes, when you buy on Ebay you should use some sense. If you can try looking for a comany that is dumping lots of the same item, this way you can buy one and see if it meets your needs. Also this way you can buy only when the bid is low. The most the 14.4 V packs cost me was $5 for S/H and $2 for the battery pack; many of them only cost me 99 cents.   

I couldn't find a battery holder with the molex connector on jameco.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on May 03, 2008, 12:08:33 PM
It appears that the charger they shipped is bad and not the batteries.

They told me that the charger is bad and to ship it back. I suspect they whole product line was bad . . .

jman571, your post:
http://www.societyofrobots.com/robotforum/index.php?topic=3173.msg31171#msg31171

suggests they have made a replacement recently to a new type of charger . . .

I'm going to mail back the charger, try the replacement, and see how things go.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on May 20, 2008, 08:43:01 AM
An update on the saga . . .

They *finally* tested the charger this morning and told me it was working fine.

I guess then maybe its the battery, so I'll be shipping that back soon for them to test . . .

arggghhhhhhh
Title: Re: do not buy from onlybatterypacks.com
Post by: jman571 on May 20, 2008, 12:32:35 PM
An update on the saga . . .

They *finally* tested the charger this morning and told me it was working fine.

I guess then maybe its the battery, so I'll be shipping that back soon for them to test . . .

arggghhhhhhh
Sorry to hear about your ongoing problems Admin  :o But for me the battery is the least of my worries, I think a company shipped me a defective transmitter & receiver and I spent a lot of money and got very aggravated trying to continue with my robot project, but fortunately I'm now back on track. I just hate it when I planned so hard and long, but could not take into account the possibility that an online company would screw me over. It really makes me think how a good reputable robot parts company could make a killing. I'm pretty sure there's a sufficient demand for it, and it's just sad that there isn't an end all and be all in terms of robot stores. On the other hand...I'm really happy with Lynxmotion's motors, wheels, and accessories. They're expensive, but they're good quality. 

EDIT: I just noticed looking at the thread, the I do have to mention my battery works perfectly fine, that being said, I did not perform any multimeter tests or any of that sort on the battery, so I really don't know if I'm being ripped off a mA here, or a mV there, but my charger charges pretty fast, and the battery provides adequate voltage to my two 12V motors. But in the end, all I can say is that THIS CAN HAPPEN TO YOU regardless of where you order from, my opinion is when dealing with sensitive electronics, or even batteries, this kind of thing can happen. HOWEVER, stores which sell wares (no not warez) of this kind are then judged on their customer service, and it seems it is in this respect that onlybatterpacks.com is seriously lacking. Just my 2 cents...
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on May 20, 2008, 01:04:35 PM
Robotics in the hobbyist market is a relatively new industry, with most companies less than 5 years old and having serious growing pains.

The entire market is basically ripe for tons of 'management' mistakes :P

Its our job as customers to offer reviews to counter it . . . bad companies don't survive long on the SoR partslist :P

If they declare nothing wrong with my battery, then I'll cut my losses and try out some lithium ion batteries I've always wanted from another company 8)
Title: Re: do not buy from onlybatterypacks.com
Post by: AndrewM on May 20, 2008, 10:07:54 PM
I had place an order back in March from all-battery.com for a pair of 8.4 v nimh with charger.  The price was incredible (and jumped up $20 the day after I placed my order).  Of course the combo went into back order until Apr 30, and they were kind enough to notify me, so I decided to wait.  Come week 2 of May, the back order got moved back until the end of May, so I cancelled.  Their customer service was really good however, so despite not having the packs I needed for the You Design It Hoverbot, I will likely use them again.

Anyway, back from my little side track story, while I waited for the batteries I invested in some Li-Ons, balancer and charger for the second robot I am working on. From now on I will be sticking with lions (lipos and limns) for my robots.  For the power to weight ratio, there just in no comparison.  Of course the two robot shells I am making are carbon fiber, so I don't have to worry about the explosion causing too much damage, so that might be part of it for me  :P
Title: Re: do not buy from onlybatterypacks.com
Post by: kirit on November 21, 2008, 09:14:02 AM
Should I buy from onlybatterypacks? I see they are still on the $50 robot tutorial parts list.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on November 23, 2008, 07:23:03 AM
I guess I forgot to update this. So they tested my stuff, said it was all ok, and shipped it back.

But I never got around to rechecking it myself, got distracted . . . it happened around the time I started shipping my Axon, followed by finishing up with work and planning my move to Bangkok.

I have the battery/charger with me, and when I get the time I'll get back to testing it out again. Its just not at the top of my priority list right now . . .

I'll leave the link up for now.
Title: Re: do not buy from onlybatterypacks.com
Post by: Metal Slug 2 on November 23, 2008, 07:21:57 PM
Oh dear.  i almost bought a battery for the $50 robot from Onlybatterypacks.com.  luckily before i did, i read this.  i checked out another battery website found on this thread : http://www.all-battery.com
i checked out their stuff.  They have a sale on a battery pack which i think could be used for the $50 robot, it costs only ~$11.  HOWEVER the shipping comes to a Massive  $62.72 - and that's the cheapest option!

Where can i get a battery suitable for the $50 robot (ill need a charger also) for a reasonable price with a reasonable shipping cost??
Title: Re: do not buy from onlybatterypacks.com
Post by: kirit on November 24, 2008, 06:20:33 AM
Oh dear.  i almost bought a battery for the $50 robot from Onlybatterypacks.com.  luckily before i did, i read this.  i checked out another battery website found on this thread : http://www.all-battery.com
i checked out their stuff.  They have a sale on a battery pack which i think could be used for the $50 robot, it costs only ~$11.  HOWEVER the shipping comes to a Massive  $62.72 - and that's the cheapest option!

Where can i get a battery suitable for the $50 robot (ill need a charger also) for a reasonable price with a reasonable shipping cost??
Huh? What zip code are you using? I did a 16$ pack from all-battery and i got a shipping price of 7 bucks for 48091 (detroit).
Title: Re: do not buy from onlybatterypacks.com
Post by: Trumpkin on November 24, 2008, 09:11:52 AM
Quote
HOWEVER the shipping comes to a Massive  $62.72 - and that's the cheapest option!
Are you sure you didn't do overnight shipping?
Title: Re: do not buy from onlybatterypacks.com
Post by: Metal Slug 2 on November 24, 2008, 02:33:12 PM
OOOOOPS.... :P.....i never noticed the USPS shipping options.  the cheapest USPS shipping option is still $18.70...which is still a bit pricey.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on December 19, 2008, 10:00:10 AM
I finally got around to retesting the battery and charger. The problem is still there, the battery kept running out of charge after very little use.

Then it happened, when trying to recharge the battery, the charger died. So I'm fairly sure it was the charger not working and probably had a ghost short/failure. That would explain why it sometimes worked.

I spoke with onlybatterypacks and Jeffrey asked me to send it back for a replacement after I'm back in the US (shipping in Thailand is very expensive and packages 'disappear' all the time). That won't be for a long time . . . and unfortunately I need a new charger now so will still have to buy a new one . . . at least with the new charger I can test out the battery again.


As for the link to the battery on the $50 Robot, I found some much cheaper batteries so I changed the link.
Title: Re: do not buy from onlybatterypacks.com
Post by: Admin on May 27, 2009, 06:30:37 PM
And the conclusion . . .

I got a hold of a professional battery charger, turns out the battery is fine, nothing wrong with it.

It was definitely the charger. In the beginning it would say the battery was charged but it wasn't. Now it'd just show a red light or no light at all. I shipped it back again simply asking for a replacement, but they insist it's working fine . . .

The final conclusion of Onlybatterypacks.com is:
Quote
As stated before there is nothing wrong with the charger. Just like the battery you returned...nothing wrong with that either. We are not going to replace it.

and

Quote
We think that it would be advisable to go back to Carnegie and focus on getting a EE as you seem to be totally confused with the use of electricity.

and yea, no need to comment on that . . . time for me to buy a professional charger! ;D
Title: Re: do not buy from onlybatterypacks.com
Post by: SmAsH on May 28, 2009, 12:31:36 AM
Quote
We think that it would be advisable to go back to Carnegie and focus on getting a EE as you seem to be totally confused with the use of electricity.

and yea, no need to comment on that . . . time for me to buy a professional charger! ;D
phssst
i don't see them running any robotics websites?
Title: Re: do not buy from onlybatterypacks.com
Post by: Razor Concepts on May 28, 2009, 03:58:47 AM
For a charger I would reccomend a DuraTrax Onyx 230, for $80 you get a AC/DC charger that charges all chemistries (even A123).