receiver battery drainage

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sperera

sperera

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Has anyone come accross their receiver battery using more mah once it gets older?

Ive noticed for a while now my receiver battery seems to drain the mah quite quickly over the last couple of months compared to when new.

The battery is the PSR 4600mah that actually takes 5400 mah. If I run 1 tank it will take 1200+mah to peak off and say full where as when new it hardly used anything! The batter has done 60.5 tanks so allot of usage!

I think it might be my switch, before I just used to run plugs but since using a switch it seems to loose mah just sitting there.

Is this normal?
 
Well taking 5400 mah in a battery that is rated 4600 isn't right. considering you never fully drain them (unless you have discharged them). that said you will lose some juice going in due to heat loss.

have you ever cycled the battery... completely drain it then charge it up? as batteries get older they get a crystalline structure (some call it memory) and will take less and less amps in. to break this down you need to discharge at a fairly decent amperage until drained then charge back up, sometimes doing it 2-3 times helps. if you don't have a discharger, an automotive headlight soldered up to a plug works good. connect both high and low beam and you get a hvy discharge.

and ya switches wear out. I don't like them in off roads myself

with nicads, we used to dead short them to drain them right down
 
drained it once when it was fairly new, never done it since, didnt think it was needed with nimh.

might discharge them fully and charge them up again, see how much it takes.

if I use my charger to discharge what should I set the cut off voltage to? 5 cell 6 volt im assuming to go down to something like 0.8 per cell that would be 4 volts. problem is when it discharges puts a load on it and that is used as the cut off so i would need to use a lower cut off if that makes sense.
 
http://www.greenbatteries.com/nibafa.html#NiMH memory

this site is pretty good info, if you google nmh batteries and memory effect you get lots of hits. I think yours are just suffering from voltage suppression. a cycle should fix most just don't go below 0.9v per cel. batteries get old, and they lose voltage faster in the upper end as they wear out. just don't totally discharge the pack. if you have a weak cel it could kill it. going 0.9v per cel will allow the power from a better cel leach into the weak one to help even things out
 
I raced electric like 25 yrs ago. I still remember going from those 1200 mah nicad sport packs to my first pack of the best 1700 matched pack nicads out. those were the days gearing was more about having enough juice to make a 5 min race than worrying about moror temps like today. I was lucky to know guys that battery match to teach me about batteries back then. Just a lot of info has left this noggin with the brain cels that have evicted themselves
 
I suppose it's where the hobby's going.

This is such a specialist individual topic - matching and balancing, charging / discharging - that 'why should I have to do that?'
'I just want to switch it on, pull the chord and blast. It's not my fault that battery manufacturers can't make proper batteries'. !!!

That's modern thinking I reckon.
It's not too wrong I suppose, as it is about having fun, but like 'the dark side' of NASCAR, F1 IndyCar, OzzieSupercars, it's what the others don't know that wins the races.

Al.
 
So true Al. I left electric racing because it got so out of hand. guys were bringing motor lathes to races and turning comms right there just to get the edge and the costs grew exponentially. brushless and lipo has really evened out that part of the paying field (though you have tweaks and such you can do and now need a laptop or netbook with you).

I only run nmh batteries in one rc now, and only because it's what fits the motorcycle (until I find an alternative). it's experiencing the same thing as Sohan's though and needs to be replaced soon. Lipos now cost way less and have less "memory" effect than nmh or nicad. I'll still use memory as it's what most call it, even if the wrong term. just don't over discharge them, and have a higher c rating han you can use and they last a long long time. and about half the weight and price of the others. a lot safer than people say. I've bent lipos to look like hockey sticks in heli crashes LOL. never had one go up in flames. had a nmh go up before in a touring car... ripping it out cuz it was mounted beside the gas tank in a yokomo..
 
If LiPos were THAT dangerous - nobody's doubting the potential for an accident if being really stupid - then why have we had them in mobile 'phones for the past .... years ?
My house must have 12 or more RC LiPos of various descriptions, from 240mAh 2S Losi for the micro Raminator, to 2x 3S 5Ah for the E-Maxx (its 6S in series with Castle and a Feigao 580L motor and it is REALLY insane).

I'm on the border of a little knowledge is dangerous I suppose and should get shut, but its all part of the fun !!
Al.
 
Well my charger did exactly what I expected it to. Set it to 3.5v cut off, took out 3850 mah and said it was 3.7v, put some multi meters on it and its reading 5.8v!

so now ive set the cut off to 0.1v and just going to check it every 30 mins with multimeters until it hits about 4.0v and then give it a full charge and see how much it takes.
 
ok in total ive taken a max 3900mah out of it, charger will not take any more what so ever.

chekced with multi meters and its down to 5.08volts.

so now im charging again, just at 1amp, lets see how much it takes.
 
don't think so, ive had this charger for a while and its never missed a beat, I use it for all my charging and everything else seems spot on.

i think it was because the battery was very flat initially and it took a bit more that specified which I think is normal for good quality cells, im not fussed how much it takes to be honest, just trying to work out why it seems to be using allot for not much running these days.
 
I'm with pipe on this these batts need to be discharged and change often to keep them at correct compacity. I had a similar problem an was going to trash at pack an some suggested to cycle it an it is one of my best packs now I keep it on that practice . good luck
 
ok just peaked off charging at 1 amp. The battery took 4,900mah.

ill hit it again tommorow at 0.5amp and see how much it takes.

pretty impressive though, if all ive lost over 60.5 tanks is 500mah im stoked! (first charge when new it took 5400mah).
 
well charged it day after it took the 4900mah at 0.5 and it took another 600mah so it appears its lost very little if any after all that usage, Impressive!
 
i charged it last night after running 1 tank the other day, took 400mah. before the cycle it was using 1200mah per tank! the cycle definetly put it back to normal.

nimh or not fellas a cycle can help allot!
 
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