Transmitter battery - LiPo or NiMh?A well known topic in the internet. many people are not sure if they should modify their transmitter to the new LiPo batteries or if they should stay at the NiMh. But there are more pro's and con's you would think in the first moment. To make the decision easier, here are some of them.
GeneralAdvantage LiPo transmitter battery against NiMh:
more lightweight Advantage NiMh transmitter battery against LiPo: no danger of explosion no need for balancing can be stored with any voltage level over weeks As you can see, the advantages of the NiMh are quite much. A LiPo has the danger of an explosion, of course this does not happen very often, but i haven't heard of exploding NiMh cells. A LiPo needs to be balanced while charging, so this means some problems if you don't remove the battery for charging. This is also an important point: if you remove the battery for charging, the connection plug will wear, and this is the most critical part of a transmitter. So if you remove the battery for charging, always inspect the plug. Maybe the most important point is the storage: A NiMh battery can bes tored over weeks quite empty, full or half full, doesn't matter, but a LiPo should always be stored with the storage voltage. So this means, that you always have to discharge / charge the Lipo before AND after you have been flying, otherwise the lifetime will be shorten extremely and also the risk of a fault during flight gets higher. |
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Four cell NiMh against LiPo
Before thinking about a change of that type of battery, you need to inform you if it is even possible because a four cell NiMh does have a completely other voltage range then a two cell LiPo.
Four times NiMh does have full charged around 4,8V and empty 4,0V, as you can see that is not quite good for a LiPo. A two cell LiPo does have full charged 8,4V and empty 6,0V. If that is ok for the transmitter, then there should be no problem. But why should it be changed? in that case, there is one significant reason: runtime. The small NiMh are only available until 2200mAh, but LiPos with that size are available around 4000mAh, so you can nearly double up the runtime. Also the transmitter gets a little bit more lightweight. So if you want an more lightweight transmitter with a longer runtime, you can think about a change to LiPo, but you should also think about the danger of explosion and the problem with the storage voltage. Eight cell NiMh against LiPoThis change is quite easy to do because the voltage are of an eight cell NiMh is nearly the same as with a three cell LiPo. Only the under voltage alarm should be adjusted a little bit.
But also here are a few other things to think about. Beside the already said advantages and disadvantages there comes one important thing. nearly every one of us was unlucky and one cell died without any notification before. if that happens to an eight cell NiMh pack, nothing will happen, only the runtime will decrease drastically, but if that will happen to a three cell LiPo, the transmitter will be instantly go off. The weight of a LiPo is, of course an advantage, the transmitter becomes more lightweight, but in runtime there is no difference. NiMh and also LiPos in that size are available at around 4000mAh. So the only reason for changing to a LiPo is the weight, does this really stands for all other disadvantages? |
Conclusion
As always, there are no advantages without disadvantages. if you want to change the NiMh in your transmitter to LiPo must everybody know on its own. LiPo made a lot possible in our models, maybe we also want to put them because of that into our transmitters? but you should come down to the important things and decide very carefull if you should change or not.