LIthium POlymer batteries come in many shapes and sizes. Good Lipos can cost a lot of money. When I moved from brushed with NiMi to brushless with Lipo I was a little surprised at how much the branded batteries cost. Being the cheapskate I am, I immediately went to eBay to find an alternative.
Information is freely available on the Internet as to what makes a good Lipo. I’m not going to cover it anymore than the following: The higher the capacity (mAH) the longer the runtime. The higher the C rating the faster it can be discharged. Higher is always better.
In this review I’ll be covering the Winforce 5000mAH battery. Winforce batteries are for sale on eBay for very little money. I paid between £13 and £16 for them including delivery from Hong Kong.
The 5000mAH battery is rated at 30C. So in theory it should be able to supply a sustained 150Amps until it’s empty. Some sellers state that the battery has a burst discharge rate of 40C (200amps).
The battery I’m testing is a 2S unit. So thats 2 cells providing 7.4V.
Dimensions are L140mm W46mm H20mm. These dimensions are very close to a standard NiMi or NiCd 7.2V pack.
The battery is not hard cased. This means that you have to take a little more care if you are going to be banging these batteries about.
The batteries do not come with any connectors on the end. They have quite thick wires connected to then and this is plenty thick enough for the 200amp max draw these can support.
I soldered 5mm Gold Bullet connectors on to the battery as this is what I use in all my cars.
I’m not doing any scientific tests. I’m using the batteries for a long run of about 35-40 mins.
I’m testing the battery using a HPI RS4 PRO 2 road car with a Brushless no name sensored speed controller and 6000kv motor. This is a continuous run with the only breaks being when my car is off the track (Normally on it’s roof 🙂 . These sort of tests are similar to how most users will use the batteries.
I’ve been keeping records of how much power is going back into the battery. I always charge the battery using an Imax B6 Lipo charger. I use the Balance charge at 3 amps. I selected 3 amps for no more reason that this is a rating I can use with all my batteries. Batteries like this could be charged at 1C (5 amps) or greater but I’m never in a hurry.
To ensure no damage occurs to the battery through over draining I connected a lipo alarm to the balance leads. This device will emit a very loud high pitched alarm as soon as the voltage in a cell goes below 3.3v. Another great eBay purchase. It only cost me £1.50 delivered. I have tested the alarm and it indeed is calibrated to 3.3v.
The above graph shows the amount of power that was put back into the battery after a run. In all but the fist run the lipo battery alarm was sounding on at least one cell. In the first run the alarm sounded and then went off without returning. In the remaining 9 runs the battery warning started only under hard acceleration and then after another 5 mins was continuous.
As can be seen these figures fall short of the specified capacity. The average charge placed into a battery after the runs was 4083mAH. This is 20% less than the stated capacity. Whilst it would probably be safe to reduce the current below the safe 3.3v level this is never recommended with Lipo batteries.
The speed of the car when running with the WinForce battery is not as fast as that with other batteries I have. I have a 2S2P 30C battery that is able to drive the car at greater speeds. Whilst both batteries are rated at 30C I think the WinForce cannot sustain this over the complete charge. Or at least the rated burst charge is not 40C as some sellers state. No damage has been observed to the battery and no puffing has occurred at these drains so whilst the battery is not able to fully support the 40C rating it is coping admirably with the 30C drain..
The batteries are cheap. They cost MUCH, MUCH less than named brands from UK shops. As such I believe the they are a very good alternative
Whilst the batteries don’t contain the full rated capacity they are excellent for having fun with. If you are a professional or club racer you will need BRCA approved batteries anyhow so you wouldn’t be considering these.
If you want to have a few batteries in you pack so that you can take an afternoon off for some uninterrupted racing then I think these are very worth considering. I now have 3 of these batteries in my box and they come out most days. One of the batteries has been in my 10th scale basher for a while and I use it frequently in the local skate park. The battery is looking a little bashed about but has never failed to provide loads of fun.
Do other batteries retain more charge? Yes.
Are other batteries faster? Yes
Will I recommend these batteries? Yes, definitely, other batteries cost a lot more than these do and if you are not concerned about speed and would rather have longer fun then don’t hesitate to go look them up on eBay and purchase a few.
I hope this review was of some use.