Customer Reviews

Tenergy 14.4V 3800mAh NiMH Battery Pack for IRobot Vacuum Cleaner 400 series such as Roomba 4905 --New!! A Screwdriver included

5 star:		(9)
4 star:		(6)
3 star:		(4)
2 star:		(7)
1 star:		(11)

 

 

You need to know that iRobot corp. makes it difficult to change this battery. After removing the screws, I found that the yellow battery case lid is glued to the bottom of the case. You need a couple of straight, small screwdrivers to slowly tap open the glue seam much like a diamond cutter uses a tiny chisel to tap cut a diamond. I had to tap the seam every 1/4 inch to break it loose. Hit it too hard and your cost savings are gone if you break the case at the attachment points - you would need to buy the whole battery pack - so only do this if you are careful and patient. Removing the old battery pack also is challenging if you are not the careful type as it is glued to the base of the case internally. Cutting the wires and soldering the leads is easy but there is no room for any other attachment method so you had better be confident in your soldering skills. This is not a job for the impatient person and you had better have all the right tools but since I am a nerd geek, I enjoyed the challenge and IT WORKED GREAT!! CHOOSE YOUR BATTLES AND KNOW YOUR SKILLS and if this sounds fun and challenging (like I do), it is a great way to save $40.00 AND set it up to do future battery replacements more easily.

The good news is this product works as advertised and is significantly less expensive than other full battery replacements (which include the outer case). The bad news is you have to be prepared to do quite a bit of work to disassemble the old battery case, replace the old batteries inside, and reassemble the case -- all without instructions. This is why my overall rating is only 3 stars (due to the complexity of the install).

In detail, here are the steps you'll need to know:

1) For pictures and some basic online instructions, do a Google search for "batteryspace NiMH IRobot Roomba" (without the quotes).

2) Start by removing the battery case from Rumba (simple).

3) Using the provided screwdriver, unscrew the Rumba battery case

4) If the top lid does not easily come off after unscrewing the triangular screws, it is likely that your case is also glued shut (most seem to be this way). You'll need to use extreme caution and patience to carefully pry/cut/chisel off this lid without breaking it. To do this, I used a combination of some flat-edged screw drivers with some gentle taps and a sharp utility knife. This part alone took about an hour and is by far the biggest challenge in this build.

5) With the lid off, you can remove the old batteries and de-solder the leads that are connected to the 3 wires. I suggest you record which lead goes to which wire.

6) In my build, I had to shorten the wires with the new battery pack (far too long to fit otherwise). I determined the new length by installing the battery pack into the case, routing the wires the same as in the final assembly, and clipping each about 1 inch beyond where the lead would be located.

7) Solder each wire to its respective lead.

8) Put the new battery pack into the case and assemble leads into case.

9) Screw the top back on and pop it back into your Rumba.

10) I let mine then charge overnight for a solid first-time charge.

Having said all of this, I'd still do it again, especially since the hard part (taking the glued lid off the case) has been done. A future battery replacement will now be simple and pay me back a savings of $35 - $40 with each replacement.

My Roomba would only run a maximum of 10 minutes per charge, so I suspected the battery was the issue. I priced out replacement batteries, but it seemed the cost was prohibitive considering I could buy a entirely new Roomba for only $25-$30 more than the battery itself.

I finally located the Tenergy replacement cells and thought this was a good option. I replaced the cells of my Roomba APS battery (the yellow one) with minimal effort. I removed the screws of the battery case with the triangle shaped screwdriver which was included with the kit. The case of the battery was a little difficult to pry open but once it was I simply cut the three wires from the old battery and removed it.

I then soldered the new battery pack leads into place. There are three color coded leads (red, black, white) and you just need to match the colors. I suppose it wouldn't be absolutely necessary to solder these, but I didn't want to deal with a loose connection down the road. I also used a small piece of heat-shrink tubing on each lead, but electrical tape would work also.

Finally, I screwed the case back together. Note that the replacement cells were a tight fit into the case, but with a little adjustment to the position of the leads I was able to get the case back together with no major issues. I then used a multimeter to measure the voltage at the prongs of the battery and confirmed my connections were working. The new battery measured almost a full volt higher than my old one even after the old one was fully charged, so I am confident this will resolve my issues and thus far it appears that it has.

I run my Roomba while I am at work and haven't had an opportunity to time it yet, but I can tell by the amount of dirt in the bin and the tracks on the carpeting that it is back to it's old self. Based upon the size of the area it is covering, I would guess it is running at least an hour on one charge, so I have no complaints about battery life at this time.

I have no way of knowing if the lifespan of this battery will be better than the factory battery, but considering the factory one only lasted about a year I surely hope so. All things considered it was well worth my time to replace the cells as the five minutes it took saved me at least $30-40. In fact the longest part of the entire replacement was waiting for my soldering iron to heat up.

My only complaints are that there were no instructions included (not that I needed them, but I can see some people might find them beneficial) and the battery was shipped in a non-padded USPS envelope rather than a proper box to protect it from shipping damage.

This battery is difficult to install as noted in other reviews. But once it is installed it restores the run time of the Roomba to what it was initially.

The downside is that this new battery looses its ability to hold a charge much more quickly then the original Roomba battery. My impression of using the Tenergy battery for only a few months is that it's life is less than the original Roomba's battery was after a year of use.

Given the difficulty of installation and what appears to be inferior battery technology to the original Roomba, I would not recommend buying this product but would rather recommend buying an a new battery from iRobot.

4/25/09 update

Original battery pack died completely after four months. I opened up the pack and measured the voltage across each cell while under charge and discharge. From doing this it became clear that one cell in the pack (of 12 cells) had died and the others were fine. But one dead cell makes the whole pack unusable in the Roomba.

The manufacturer was willing to send me a new pack. I went through the hassle again of changing it. The new pack lasted about one month before it also stopped working.

At this point I would give this product the lowest rating. I will also avoid any other products from Tenergy since the quality of their cells, from my small sample set, is very poor.

I thought this battery would be better than the original NiCad battery given that it is NiMH and 3600mAh. But it was not. On a full charge it works for 110 mins. The original NiCad when new worked 120 mins. Not bad, but not as advertized and I worry that it will not last as long either.

I am glad I did this, but before you buy any battery you replace yourself, take apart your old battery case first if you can. It is pretty tricky and you may end up damaging the case so bad that it is not repairable. Also you will need to do some soldering yourself.

Good Luck ;)

After only 4 months of steady use the cleaning cycle duration supported by the battery can be measured in seconds. In contrast, the original battery lasted about 1 year under a load of 4-5 cleaning cycles per week. Even at twice the price, the authentic Roomba battery is a better buy.

I didnt seem to have the same issues others did when taking the original battery apart. Yes, it was glued... however it only took me about 20 minutes to separate the top from the rest of the battery compartment. This was accomplished by using two very small regular screwdrivers, and working my way along slowly (but i guess not as slowly as the people for whom it took two hours). I found it easiest to start at one of the ends, where the glue was lightest (under the latching mechanism where the contacts are.

All in all I think I spent less than an hour from start to finish (between opening the case, removal of old battery and connectors, sodering connecters on new battery, putting case back together). The most time consuming aspect was removing the new battery from the case after I had dropped it in to 'dry fit' it and measure the wires. It's a TIGHT fit.

First running after full charge - 65 minutes

2nd running - was not timed

3rd running - approx 75 minutes

4th running approx 75 minutes

At this time, obviously it's unknown how long the battery will last. Unfortunately, I'm not receiving anywhere close to 120 minutes as some other people have claimed. Maybe pot luck depending on the quality of the cells you receive. Even at running for an hour to 75 minutes, i'll be happy if the battery lasts one year of normal use. Otherwise, probably worth the extra $20 to purchase a true replacement.

Thanks to those who have shared their know-how. I followed the posted instructions to replace the APS battery with the Tenergy 14.4V 3800mAh NiMH battery pack for my Roomba Scheduler during the holiday break (took me 3 hours from start to finish) and ever since it runs like a charm - I mean it cleans up 4 rooms and still has some juice left.

It doesn't come with any instruction manual at all, but I for one propably think the same as the seller of this item. If you even had the thought to replace the battery inside the APS unit, you probably had all the knowledge to do so without any instruction manual.

Wires are clearly color coded, so its impossible to miss the positive/negative/ground.

They protect the end of each wire properly, its a good thing to know for some people out there that short circuiting 12 cells (14,4V) that can transmit around 40A WILL cause Sparks!

Regarding myself, I'm very experienced in handling various kind of battery, especially in RC vehicle Batteries, that is why I decided to replace my own Roomba APS battery.

YES, opening the APS is super difficult, took me good 2.5 hours to opened it with eXacto knife, hammer and flat screw driver.

The reason I give this 4 star is the difficulty on installing the battery inside the APS not OPENING the APS case.

The wired that comes with my battery is making the entire battery a bit taller that it should be, a bit modification with the wire arrangement works wonder and shortening the end wire significantly is also required.

Soldering and isolating each positive and negative contacts seperately is highly recommended, like I said above this batteries can deliver 40Amps at 14.4Volts, enough to cause fire if short circuited and most likely will burn your hand.

Overall the entire process worth the trouble, if you don't think you can get the APS opened, get the APS shell somewhere else, look on froogle. It probably only cost you around 15$.

My Roomba is now back to its tip top shape and performed like new :)

This battery does not have the 1000 recharge cycles as claimed! I have had it installed for less than 4 months, running twice a week, so about 32 cycles so far. The battery pack currently runs my roomba for 15 minutes before it heads back to the charger. As soon as it starts, the battery power indicator is already orange-red. Very poor performance for a replacement battery. Installation was not a problem, but as noted by other reviews, it does not fit easily into original battery case. You get what you pay for!