ProfitOfDoom

I just got my supervee in the mail and it came with 2 4200 packs.
Im discharging just to be on the safe side,cause I dont know if there charged or not. I plugged them up and sat it in the bath tub and it seem to have a charge,but dont want to get to the pond and have it crap out on me
Im discharging at 3 amps,is this ok? And when I charge what amp should I charge at 3, 4?
I also got 2 more 4500 packs coming and want to keep them around awile,my packs always seem to be no good after a season,could someone give me some tips on what,or what not to do?
When your not going to use them for awile do you store them charged?
I use the superbrain 969 for my charger

guver

My Feedback: (325)

I would not discharge batteries, but if you must then 3 amps is an ok rate (nearly any rate is ok) the damage may occur if any one cell is pulled to negative voltage because of capacity difference or imbalance.

Any charge rate on the 969 is also ok. I'd use the max of 4.5 if the ps will maintain, it may only maintain 3 amps x 2.

For storage it won't matter , but it is rather the process done after the storage that's important. It should be a constant c/10 charge for 15 hrs with a wall charger.

ProfitOfDoom

Im charging at 3.5 it seems to take the charge ok so far,I hope these batteries are in good shape and I will be able to run it today.
Im going to race against the boys kyosho "stock" viper,he is in for a upset, Muhahaha. I'll try to get the race on vid,Im so excited to see this thing run,I never owned anything brushless only heard great things about them,we'll see

guver

My Feedback: (325)

If I remember correctly the stock ps is 12 volts and 5 amps , but can at least charge a pair of 6 cell packs at 3 amps. It is nice that 3 amps is the default settting. Plug in push start and go.

I can't wait to hear and see "the race" It'll be funnier if "Dad" gets beat.

ryan_t888

I'd also recommend keeping the cells above 0.8v. I've lost hundreds of dollars in dead cells. They must be charged every 2 weeks while in storage or they WILL drop below this level.

Ryan

guver

My Feedback: (325)

If the pack is ok, then it will remain somewhere near nominal voltage regardless of time. If it is dischargeing by itself then it may have a short internally. Here's a pack that sat all winter dead, then dead shorted for 24 hrs and the voltage springs right back up to over .9 volts/cell. I suspect that it may settle ay 1 volt per cell or even higher. http://www.rcgroups.com/forums/showp...2&postcount=70

It seems the newer high capacity cells develop the self discharge and shorts. This is an older very well used pack.

A few packs that sat up to 5 months (same cells) http://www.rcgroups.com/forums/showp...90&postcount=5

ryan_t888

Decent cells with low internal resistance have a high self discharge rate. IB 4200 cells, which I assumed from the original post, will not stay above a safe voltage. They will drop. I've been there done that, and moved on to much more cost effective technology.

Ryan

guver

My Feedback: (325)

Yes, I have heard that IB are some of the worst for that. I'm kinda glad I never jumped on that bandwagon.

ProfitOfDoom

Ok,so for my run yesterday I ran maybe 4-5 minutes then flipped it and didnt run no more after that,so I assume that I have a half a charge or so left in my packs,would I just start the charge from where there at,,or discharge them and then start the charge?

guver

My Feedback: (325)

No need to discharge, just start the charge at whatever level they are at.

ProfitOfDoom

Last night I charged up my batteries for a run today on my sv27,I charged them about 1am last night and hit the pond at noon today.
I got there ready to try out my new prop and it was doing like 5mph,I ran it for maybe 5 minutes trying to see what was wrong and every couple of minutes it would catch at go a decent speed,but all and all it was very slow.
Is it possible that one of the batteries discharged some over night? If so why would that be?
When I got home I put one battery in a rc car of mine and it ran strong for a min then died,,,the other battery ran stronger longer.
So then I charged them both and ran them in my rc car again,both batteries did pretty well and lasted pretty close in time,whats the deal here? These batteries are SMC High Performance brand,the cells say Intellect 4200.

ryan_t888

Exactly what I have said before.
IB cells which I assumed you were using have an EXTREMELY high rate of self discharge. I lost about 800mAh per 24 hours of sitting. These cells must be peaked just before running them.

Also, high performance NiMh cells have very negative characteristics. It is more than likely one of your cells have dropped below .8v and greatly increases the internal resistance of the cell. In a series circuit current is limited by the cell in which has the most resistance. Thus, the dead/weak cell is the weak link and preventing high discharge which may contribute for your boat not running well.

Boats pull high current and demand high power all the time. Cars only demand high current/power during acceleration. They unload as speed increases.

I have been down this road before, and as I said dumped 100's of dollars in replacing dead cells. The best alternative is don't waste your time go LiPo.

Ryan

guver

My Feedback: (325)

My guess is that one battery was charged, the other one stopped chargeing too soon for some reason and wasn't charge up all the way.

Same as this thread. http://www.rcuniverse.com/forum/m_73...tm.htm#7362816