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Asked — Edited
Resolved Resolved by DJ Sures!

Long Life 7.4V Lipo Battery And Charger For Ez-B V4

Hi everyone.

I need a little advice in regards to LiPo batteries for the EZ-B v4. I have been waiting for my dev kit, balance charger, 7.4 LiPo, and a few extras to be delivered for quite a while now, and after I sent of an email to the very helpful EZ Robot guys and gals inquiring what the delay was, it turns out that there is a shipping issue with sending loose batteries from China which has been holding up my order being sent. I have requested a refund for the LiPo and charger which has been honored, so no problems there.

So what I need the community's help with is advice on what I can safely use with the EZ-B v4. Can anyone recommend a good, reasonably priced LiPo battery pack that can hold a long charge, say about 2500 mAh or more that will work well with the v4, and a good charger to go with it? A balance or auto cut off charger would be preferred as I hear that LiPo batteries can be a bit finicky and care needs to be taken to avoid killing them.

Any advice or recommendations anyone can offer would be greatly appreciated.

Cheers,

Steve.


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United Kingdom
#2  
I use a 5000mAh 2S LiPo with my first V4 and it works great. I picked a couple up off of ebay a while back after undervolting my first 5000mAh 2S LiPo.

This is what I use

Although any 2S LiPo will work just fine.
#3  
....If you're not picky and as DJ mentioned do not need the battery to fit inside a Revolution robot you can use a 7.2v niMh.... Technology is a bit old but they provide good juice and are pretty cheap.... I am using a couple myself.... eBay is a good source...
PRO
USA
#4  
steve.gibbs.5
Here is what I use in my Mini 6 fabricated robot after a similar battery email. One 1700 battery provided ample run time, two in parallel for extended play.
Also used low voltage alarm.
I use this setup with a EZB3, but plan to use it with EZB4. (check size if fitting in an EZ robot)
Very reasonable, and fast shipment.
I converted my Mini 6 robot over to XT60 battery connections, which I think are good.

7.4 Turnigy Lipo

Turnigy balance charger

Low voltage arm
Steve S
#5  
I use a couple of venom 7.4V 2000 mah 35C batteries in parallel. I did this because I had to seperate my batteries due to limited space in specific locations of my robot.

I like them and the robot runs for quite a while and charge quickly. I use the IMAX B6 charger and it has worked well so far. It can charge 2-6s batteries lipos and many other types of batteries. .
#6  
Turnigy batteries have always worked well for me. I used them all the time in R/C racing and rock crawling and never had one puff or fail.

This is the charger that I use:

Turnigy Multi Charger
United Kingdom
#7  
Thanks for your replies DJ, rich, Richard and Steve S.

I have had a look at the links DJ and rich supplied so thanks for that. I should have mentioned that the battery will be going into a revolution bot, but rather a home made bot, so I have some room to play with.

I have never used LiPo batteries before, and I just wanted to double check that even though they might be the same voltage, larger mAh batteries may differ on amperage and didn't want to risk damaging my v4 when it arrives.

I think I may have been miss informed by someone I spoke to earlier, but can I use any 7.4v LiPo battery charger to charge any LiPo battery? I was told that I couldn't but I get the impression from what I have seen so far that this info was wrong. If this is the case, I wish I never cancelled the balance charger now.

Steve.
#8  
You need to use one that has the capability of doing LiPo batteries. A lot of LiPo chargers will do other batteries too, but you need to make sure what you get specifically says it does LiPo.
United Kingdom
#9  
Thanks for your input Steve S, Zap and D.Cochran. My EZ Robot order should be with me in a couple of days so it's time to get the battery/charger sorted.

I think the Battery Rich mentioned might be the one I will go for. The

IMAX charger that D.Cochran mentioned looks good as it also has a built in AC adapter. Would the adapter function on the IMAX have enough amps to power the v4 with say 6 HD servos/camera for example?

@ Richard

This may sound like a silly question, so bare with me. What are the main differences between a LiPo and a niMh battery?

Rich

How many cells does the 50000 mAh battery you linked too have?

And one last thing, what is the battery connection type on the v4 when using a LiPo, just so I get the right adapter. Or do I cut off the connector that comes with the battery, and use the barrel jack that comes with the dev kit?

Steve *confused*
#10  
Good questions.
I am following this topic.
J
#11  
My imax did not come with an AC adapter. I use a power supply that I used to use on an ameture radio. It is a 15 amp 13.8V output power supply which is overkill for a battery charger, but it is what I had laying around. a 5000 mah battery would take an hour to charge with a 5A charger. This is 1C which is safe to charge lipo batteries at.
#12  
niMh (nickel metal hydride) are just older technology batteries. They are heavier and larger than lipos but are safer to charge and in general. This means less shipping restrictions...They are also ubiquitous which makes them easy to get anywhere... They also produce a lot of current which is great when using them for servos... There voltage rating is 7.2V as opposed to 7.4V lipo (which is a non issue)... I buy mine from eBay...
PRO
USA
#13  
They (Lipo) have much better performance, and fast discharge out to your robots activity needs.
They also r much lighter!
Steve S
#14  
@Steve S... rest assured niMh can provide enough current as well
United Kingdom
#15  
Sorry Steve S, but could you explain what you mean by "and fast discharge out to your robots activity needs." as opposed to what other batteries do?

@d.cochran. I mis read the description on the IMAX charger. It doesn't have a built in adapter, but rather an external one which is supplied. I thought what it meant was that you could use the charger as an adapter, which would have been great for powering a robot while stationary or EZ-B testing ect. My bad. Although in the description , it does say however, "AC adapter Feature: Apply to 10 meter led strip light".

I would like to use LiPo, but I don't like the fact that it sounds quite easy to ruin the battery, as apposed to what Richard mentioned about niMh batteries being a bit safer, which now I'm more tempted to get. It sounds to me (and please correct me if I'm wrong here) that LiPo batteries are a little bit of a backwards step in battery technology is some respects, as I have seen many other people saying they have ruined LiPo batteries, even seasoned robot builders like Rich. Or am I missing something?

Also, any answers on how LiPo's or niMh batteries connect to the EZ-B 4?

Steve.
#16  
LiPo batteries certainly are not a step backwards. They are smaller, lighter, carry more capacity, and can dump more power all at once than NiMh or NiCd. They also don't have the "memory effect" of other battery technologies. NiMh and the like should be fully discharged before they are recharged. LiPo does not require that and partial charges doesn't result in loss of capacity. The downside is that you have to treat a LiPo more gently and they need to be charged carefully and never fully discharged. As I said, I have used them for years and have never had a problem.
#17  
Although I don't use LI-poly, I do use LI-ion cells to power all my EZBs both version 3s as well as version 4s. I've used LI-ion cells to build my own power packs. The cells I used to build the packs are surplus cell phone batteries that include their own Power Control Boards that control the charging and discharging voltage of each cell. Most built packs were 14.4 vdc 2100 mAH packs to power Roombas, Creates, and Dirt Dogs. I've recently converted to a LI-ion pack that is 14.4 vdc and 4400 mAH that has not only a power control board but also a cell balancing circuit. So far (about a year now) this new 4400 mAH LI-ion pack is performing very well.
United Kingdom
#19  
@Zap.

Thanks for your informative response. I stand corrected about my "step backward" remark *blush* (although I did say "in some respects").

I take on everything you said about longer capacity, smaller/lighter ect, and "step backwards" was probably the wrong phrase to use. It's just taking the extra care not to let the LiPo's fully discharge and remembering to recharge them before they completely drain, even keeping them charged if you don't use them for long periods of time, and seeing £20 or £30 go up in smoke if you forget.

But as yourself, djebay, and others have said, you have used them for a long time now with no issues, so fair play to you, and I am probably over thinking things (as I sometimes do) *eyeroll*

@djebay.

Thanks for the link you supplied. Very interesting and is a good read.

Cheers,
Steve.
United Kingdom
#20  
My EZ robot goodies have been delivered today :D:D:D

So now I need to order my battery and charger. While I have been looking for a battery to buy, I am seeing that there are different connection types. Which one do I need to connect to the EZ-B v4, I do I cut the connector that comes with the battery off, and attach the barrel jack that comes with the dev kit to the battery?

Steve. *confused*
#21  
If you just have the ezb with power shell you will need a barrel connector... Yes, you can snip off the aa pack barrel connector that came with your development kit... Just be aware of the polarity when soldering it to your new Lipo...
#22  
this what i did from battery to adapter.


User-inserted image


to charge i pull out wires that i stuck into the deans (not micro deans) connector.

j


:):):):)
#23  
Deans connectors like the one shown by jdebay are pretty good. It would be pretty easy to solder on a male deans connector to wires from the adapter. That way you don't have to think about polarity again once you solder it up the right way. Not all batteries come with that type of connector however. I say buy the battery you want with whatever connector it uses and then order a male version to match to solder to your adapter.

Another type of battery connector that I like to use is the Traxxas type connector. It's not as compact as the Deans type but it's easier to solder up and has a very solid connection. I usually cut off whatever the battery comes with and add these.


Traxxas connector
#24  
@Zap .. Thanks for the info. I previously had thought that LiPos had the "memory effect" and that most of them get ruinrd by not fully discharging them.

I cant remeber where but I saw a post where DJ Sures recomended NiHm batteries in the battery packs of the v3 for alot of the same reasons you listed as benifits of LiPo.

Maybe I misread some of the details but he definatly recommeded HiHm recargables. I remember being very happy reading it because it was the route I was going so I didn't have to keep buying batteries.

I'm not trying to confuse anybody but now I'm a bit confused on this.:(
#25  
Lipos and Li-Ion have basically zero battery memory effect and you can damage them by over discharging them... You can however, charge them any time you want.... NiMH have some memory effect, but very little... NiMH can benefit from the occasional deep discharge to regain some lost battery life. They can be charged at any time as well, even if just to top up... NiCad have the most memory effect... NiCads need to be fully discharged every time they are used before recharging....
#26  
I could be wrong but DJ may have been referring to using rechargeable AA batteries vs standard alkaline AA if you go that route?
United Kingdom
#27  
Thanks for your replies guys. I've just ordered myself a balance charger and decided to go for the 5000 mAh LiPo battery Rich mentioned, which should be with me in a couple of days.

@Richard. Yes it is just the EZ-B and power shell I will be using, but when I mentioned using the barrel jack, I meant the stand alone jack that comes with the dev kit. Thanks for pointing me in the right direction. :)

@jdebay. Thanks for the photo. That's what I had in mind, so thanks for confirming. ;)

Steve.
#28  
@Steve.... sorry, the stand alone barrel jack is what I meant.... You can use it with your 5000mAh lipo no problem......
United Kingdom
#29  
No problem. Thanks Richard. :)
#30  
@Richard Thanks for clearing that up for me.:)

@Zap Yes I am in fact talking about the AA's;)
#31  
Hi everyone

I have just bought this "bad boy" which is a Venom LiPo 2S 7.4V 10,000mAh 35C. I am pretty confident that I can just connect it up to my roli and it will work fine but can anyone confirm this?

User-inserted image


Also can anyone advise of the best setting to charge it? My lipo charger will charge up to 5 amps.

And can I also presume that the low voltage warnings on the EZB will continue to work when a higher rated battery is used?

Thanks for any advice - I would prefer to be on the right track before connecting.

Regards

Chris
#32  
@ZebraStripes Yep... plug and play dude.... With that battery I am pretty sure Roli could drive across the outback on one charge....:P

Your charger should work too. However being a very large capacity battery it will take much longer to charge.... If it were me (and I am not knocking ez robot's lipo charger) I would grab a better lipo charger off of eBay...

Remember amps are "pulled" by a device not "pushed" into it by the battery... What you have effectively done is buy a bigger gas tank for Roli... Roli is still going to draw the same amount of power it did with it's original battery, however now with the larger capacity battery it will have a much longer runtime...
#33  
Thanks once again Richard for your very helpful response. Happily I have a good lipo charger and so should be able to shorten the charge time. Sending roli out into the outback is a great plan but I will need to extend my wifi range by just a little ...

Regards

Chris
#34  
Can anyone tell me if it is safe to leave the lipo battery plugged into the ezrobots when they are turned off and not being used? I was reading that lipo batteries should not be left plugged into devices and sit unused. I read that you should unplug batteries when not in use and kept in a fireproof container. Are they really that unstable? Can they stay safely connected to the ez robots in the off position and checked periodically to make sure they aren't drained? Or should they batteries always be removed from the ez robots when not in use?
#35  
Also, can anyone tell me where I can a battery replacement for the ez robots here in the United States? I see them all over the Internet but can't seem to find the dimensions that will fit the ez robots. Everything I come across is just too big to fit.
#36  
They shouldn't be left plugged into the charger but are okay to leave inside the ez-robots. The way these burn up are if they get punctured or if they get gassy. The shell helps prevent them from getting punctured. They should be checked periodically to see if they are puffy. Following the instructions for charging will prevent them from getting puffy for a long time. Store them charged and they will keep the charge for many months. I would avoid storing them drained.

I would pickup the batteried from the EZ-Robot store. I don't stock them, but i do buy them from EZ-Robot.
#37  
Hey thanks for the info. That helps a great deal