Lipo or Nimh

[Leonine]

It's a CQB event so semi auto only and they would be 1200mha 

I would get 2 just in case then like Ad said but it may last the day in my opinions LiPo will last longer. I have used small LiPos in CQB before and been fine in my old MP5

 

[Adolf Hamster]

in general i can get a full day's shooting from a 1100mah 11.1v, but it's a really hard question to answer because it depends as much on how the gun is setup and how you shoot it as anything else.

 

[Iceni]

have a read of this thread as to why you need to take your charging equipment seriously:

I think I killed that thread

Anyway there are rules for all batteries, but for lipo's the effects of ignoring the rules can be catastrophic.

Using a Lipo over NiMh is a night and day difference. Lipo's are just plain better, they have better capacity in a smaller form factor and they can deliver more amps faster.

Lipo is also a battery you have already dealt with, It's in your phone, tablet, laptop, vape, drill ect ect, It's unbelievably common. 
 

So would a 7.4v lipo last a all day skirmish if charged correctly?

That depends on the battery and your trigger finger. I find about 3000mAh of capacity will last me a day of regular play in woodland using 3000 bb's. I always swap at lunch - it doesn't matter how many shots I've fired.

For me that is usually 2x  7.4v 2200mAh 35/70C batteries. Giving me 4400mAh.

You can mix and match to suit what you need so If you are looking at 1500mAh you will be looking to buy 2 batteries. If you are looking at smaller capacity than that then you will perhaps need to take a charger or pick up a 3rd battery. You could also be more frugal with shots. So instead of spamming 3000 shots you might find 1000 shots only requires 1 battery for all day, even in that situation I would want 2 batteries and I would swap at lunch.


When a lipo discharges it has a very distinct voltage curve. You get an initial drop that is pretty steep, but then it will level out and remain very constant for the majority of the discharge. Then all of a sudden the gun will start to slow down very quickly. This is the very last point you should take a battery to. Once you hit that final slowdown it is very important that you stop and swap. Never use a lipo to the point where it is fully discharged.... As when you come to charge it you may find it causes a nasty fire.... A good charger will tell you to fuck off if you try to charge a dangerously discharged lipo.

Looking after lipo's is pretty simply.

If they don't look perfect - Bulges - Torn wraps - Exposed wire - Crushed --- Dispose of them
If the charger tells you to fuck off --- Dispose of them
Use the correct charging mode.

Store them in protective cases, Separate from each other, And out of the sun/heat/water/moisture exposure. A shed is perfect - in something fireproof is even better.

Always keep an eye on charging lipo's. Charge them away from things that burn - a pan with a heavy lid or charge bag are good investments. Failing that charge them outside on a paving slab if you are unsure.

If you do everything safely it should be no more dangerous than charging your phone or battery drill.

 

[Rogerborg]

the charging process [for lipo is] more complex

From the charger's point of view, it's easier.  With lipo, it knows what voltage the battery should be, so it won't (if it's half decent) over-charge it.

With nimh, it has no idea and just has to pump in energy until it sees the resistance spike - and it has to charge at a high rate in order to see that spike.  If it misses it (hellllo, Nuprol) then it'll charge and charge and charge and...

Lipos can be charged at a slower, lower rate. Granted, if a lipo does brew up, you're going to have a bad day.  But given how many are out there, and how few people are dying, it's high risk but low likelihood.

Trigger contacts getting burnt out will happen regardless of battery type - I personally wouldn't use any gun without having a MOSFET fitted.

A V2 or V3 trigger trolley is about £5.  It's not rational to fit a mosfet that costs two or three times that just to protect the trigger contacts.  Yes, you can get higher current flow, but if you're dicking with the wiring you can stuff 16awg in there anyway.  Mosfets are nice, but you don't need them.

It's a CQB event so semi auto only and they would be 1200mha 

Chances are you'll be fine with one, but given the prices at https://hobbyking.com/ you might as well get a pair and swap at lunch. You'll be paying more for the charger. SkyRC S65 or iSDT Q6 Nano are what the Glorious RC Master Race are currently recommending.

 

[Cannonfodder]

I've found lipos also aren't affected by cold weather as much as nimh batteries. 

A V2 or V3 trigger trolley is about £5.  It's not rational to fit a mosfet that costs two or three times that just to protect the trigger contacts.  Yes, you can get higher current flow, but if you're dicking with the wiring you can stuff 16awg in there anyway.  Mosfets are nice, but you don't need them.

This. My AK has been run with only lipos for around ten years now and is still going strong (sod's law now means it'll now stop working in Sunday) 

 

[Ad_]

From the charger's point of view, it's easier.  With lipo, it knows what voltage the battery should be, so it won't (if it's half decent) over-charge it.

With nimh, it has no idea and just has to pump in energy until it sees the resistance spike - and it has to charge at a high rate in order to see that spike.  If it misses it (hellllo, Nuprol) then it'll charge and charge and charge and...

With NiMH constant current is supplied as long as the battery voltage increases, and charging stops when the voltage begins to drop. This drop is quite small & can be very tricky to detect though, so many chargers also include failsafes such as a voltage based cutoff, timer based cutoff, and/or temperature cutoff.

LiPo uses the normal CC/CV charge algorithm as per other Li-Ion chemistries - provide constant current for the first stage, up to the full charge voltage (4.20V in this case), then maintain constant voltage while decreasing the current supplied until it drops off below a certain threshold. Where LiPo gets more complicated though is balancing & cell/pack health. You *can* charge them without balancing etc, but it greatly increases the risk of self-immolation in use...

They're both a little more complex than that in practice, but that's the gist of it. If you want a lengthy read on battery tech, this is a good resource: https://batteryuniversity.com/

A V2 or V3 trigger trolley is about £5.  It's not rational to fit a mosfet that costs two or three times that just to protect the trigger contacts.  Yes, you can get higher current flow, but if you're dicking with the wiring you can stuff 16awg in there anyway.  Mosfets are nice, but you don't need them.

A good power MOSFET and a couple of resistors only costs £2-3 and it's very simple to put together. It's well worth it IMO, not just to protect the trigger contacts but to improve efficiency & trigger response, reduce occurrences of cutoff lever lockups on semi-auto, increase ROF and prevent it dropping off over time (the decline is so gradual you won't notice it over time, but use an AEG for a while without a MOSFET and then simply clean the switch contacts and the difference will be night and day. It's even worse if you use semi-auto a lot).

 

[Rogerborg]

A good power MOSFET and a couple of resistors only costs £2-3 and it's very simple to put together. It's well worth it IMO

Oh, I actually agree, I've just made a bunch of them.  Whether it's worth it if you're not already set up for soldering is perhaps the issue, versus the cost of some 16awg and replacing the trigger contacts every so often.

Not that I'd want to put anyone off getting fluxed, I'd highly recommend it, but it's not for everyone.

 

[Ad_]

Whether it's worth it if you're not already set up for soldering is perhaps the issue, versus the cost of some 16awg and replacing the trigger contacts every so often.

Well if someone's going to be replacing the trigger contacts and putting in some 16awg they'll need to be set up for soldering anyway... might as well put in a MOSFET too while they're at it

 

[Adolf Hamster]

plus it's worth mentioning that whilst replacement contacts are generally easily available, at least for the common platforms, you run the risk that an aftermarket part might not quite fit the box properly, for example the COL might not trip or the trigger might not reset.

 

[Rogerborg]

Well if someone's going to be replacing the trigger contacts and putting in some 16awg they'll need to be set up for soldering anyway... might as well put in a MOSFET too while they're at it

That's... a darn fine point, actually.