battery voltage question

[chizzler]

i was wondering if ALL 6 cell batteries are supposed to have a total voltage after a charge less than 10 volts. i have some that when peaked are slightly higher than 10 volts. is there any way to get them to drop in voltage?
my 1500 cheapo packs are around 10.50v the last i remember, and some of my 2000's are around 10.1

i dont think this is ok, and if anyone can tell me if there is a possible way to get them lower. (i dont think myself there is :()

also, how can i prevent the voltage from rising?
i always fully discharge after running my car slow and take perfect care for my cells!

thanks!

[Grizzbob]

Really, there isn't much you can do. That kind of voltage reading is typical of packs whose internal resistance is rising(which happens to all packs over time). However, it's not as bad as you might think, I've had several packs that would begin to peak at voltages like that, & while they had lost some punch at that point, they were still useable packs(especially for practice, or for making into a pack to run my lathe or to break in brushes on my motors). To give you a point of reference, my best current packs peak at about 9.4-9.8 volts on my Millenium(charging at 5 amps, different charge rates will change the voltage reading at peak too). I'm sure you don't really want to buy a bunch of new packs, I'm afraid that the higher resistance is permanent, it just happens to all packs as they get older & see more use, so ultimately the only effective solution is buying new packs.... :cool:

[HowieStern]

the higher the peak voltage of a pack, typically the higher the IR (internal resistance)... and that's a bad thing if you are a racer...

how do ya get it down??

you can try reverse pulse charging them if they are older packs and you have a charger that will do it (like the millenium, Comp Electronics chargers, some Tekins, GM commander, ect)...


peace out.. :)

ps- my best packs show that a millenium peaks out aroung 9.3 volts... my worst packs show around 10.2 or so....

[chizzler]

yeah, i use my millenium and those are some of the readings i get. the only thing is that for my 2k's, their mah rating is awesome, i get around about 2200 mah out of them!!, but the IR is slowly on the rise...

[HowieStern]

i saw Grizz and i posted at nearly the exact same time... then i looked at the actual time, it's getting late.. LOL... it's after midnight here.... LOL... i gotta rebuild a servo then hit the hay.... LOL...

peace out.. :)

[Crazy Canuck]

I think there is something you can do to them. My LHS does this. This is what they say on their website:
If you want to more punch from your battery pack, but you don't want to disassemble your pack, we can help to to zapp your battery pack in minutes. We are using the new Xipp DCX3000 Xapper to zapp your battery pack, it will increase the average voltage and lower the internal resistance of the cells.

[Railman]

Chizzler, All of the above methods may help. A reverse pulse charger may have the most effect though in my opinion. It breaks down the crystaline structue that forms on the batt plates. Thats basically what batt Zappers do. Whether zapping is worth it depends on how good , & how old the batt is. Cheaper batts normally don't have the life span of Sanyos RC1700 to RC2400 batts. If the batts are old, you might want to consider buying replacement batts of this type. The other thing you could try is to deadshort them. That works real well on the RC Sanyos, but I don't have any experience on any other cells. Lower resistance is one of the benefits of dead shorting, but it's a little iffy on some batts, due to the reverse polarity issue. How long have you had these packs? How many time have they been discharged? How many packs do you have? Do you recharge them more than once in a day?

[chizzler]

the pack have ALWAYS been taken care of. usually charge at 3.5-4.0 amps. i usually run the battery until the car slows, and then i bulb discharge. They are getting old though, 2 years, and i only run them maybe once or twice A WEEK, no two ever in the same day. i have more than one set of batteries........

[Grizzbob]

Yeah, I'd say they're just getting old, that's why the resistance has gone up & also why the mah reading on your Millenium is as high as that(it tells you how much it put into the pack, but not exactly how much the battery accepted, higher resistance always makes those numbers go up over time). Reverse-pulse, zapping & dead shorting may help them some, but I doubt they'll ever be as good as new again, but they may at least extend the useable life of them...... :)

[chizzler]

so in theory i want a mah rating that is less than the specified pack.

because i know my new 3000's peak around 9.45 volts, and the mah is usually much les than 3000

so that would mean they were much "healthier" in that their IR is still low and not sucking up all the power from a charge :confused:

[ 08-31-2001: Message edited by: chizzler ]

[Railman]

Chizzler, The mah numbers that you see on the charger are for the amount it took to charge the pack, & not the total thats in the batt. You can only get that by discharge testing. When you charge a pack there is already some juice in the batt. That is unless you are charging a pack that's been dead shorted. Joe