# Thread: difference between 2 amp and 4 amp charging?

1. ## difference between 2 amp and 4 amp charging?

what is it?

2. Its how many amps the charger is using to put energy into the battery. 4 amps will be faster and 2 amps will be slower
-Brendan

3. One time, I had a charger that charged batteries with 2.5 amps and now I have a Black Widow Peak Charger and I can charge batteries with 2 amps and 4 amps and well, when I charged batteries with the charger that charged with 2.5 amps, I had shorter runtime than I had with the charger that charged batteries with 2 amps and 4 amps. So I think you get shorter runtime when you charge batteries with a lower amp.

4. this is how I understand it.. I've not had specific real world experience so look to others to confirm what I say.

When you charge at a lower amp rating it will take longer but you should see a bit longer run times. Perhaps not as much punch either.

When you charge at a higher amp rating you will get faster charge time, more punch initially, and perhaps slightly shorter run times in comparison to a lower amp charge.

Since I'm not 100% on this I usually throw these posts out and then arcee/highlanduh/misbehavin/swami confirm if I'm close.

5. Originally posted by eri3f0g

When you charge at a lower amp rating it will take longer but you should see a bit longer run times. Perhaps not as much punch either.

When you charge at a higher amp rating you will get faster charge time, more punch initially, and perhaps slightly shorter run times in comparison to a lower amp charge.

You are correct in your assesment eri3f0g.

More current = more punch and shorter run times.
Less current = less punch and longer run times.

I have question to throw out on this subject as well. It isn't really an RC question more of an electrical one, but here it is anyway.

According to ohms law voltage = current * resistance. If this is the case, how is the current being increased through the charger? Is it just by increasing the voltage going to the battery? That would make sense mathematicaly, but i am not sure this is the way it is done.

6. Originally posted by eri3f0g
Since I'm not 100% on this I usually throw these posts out and then arcee/highlanduh/misbehavin/swami confirm if I'm close.
Wow. How flattering to be grouped with those guys...

7. ## Surprising Charging instructions from Trinity..

I have read a lot of place to charge NiMH batteries at 3 amps. The instructions with my Trinity GP3300s said 3-4 amps to balance perf vs runtime.

The web site says 5 amps.. nothing like consistancy from a vendor

1) What amp rate should I charge my NimH batteries at?
We recommend to charge at 5 amps for race conditions. If you charge higher, you'll get more acceleration early, but in some cases they flatten out toward the end of the race. This is also harder on the cell and will decrease the overall life of the cell. We do not recommend charging at 7 amps or higher.
http://www.teamtrinity.com/tips/batts.asp

STnewbie

8. ## ill use my racer knowlege to basher here

generally STnewbie,

racers with put there batteries to the max to get the most punch possible for a race due to them only needing it for 5 mins.for a basic battery charging rule to go by i have always used for nicads just messing around is say you have a 1500 nicad.what you wanna do is multiply the mah by 2....1500x2=3000 and add a decimal after the 1st number=3.0 and that is what you would generally charge a 1500 nicad at for best ovral perfomance.

now if you have a charger which only goes 2 or 4 amps you can go 2amps and get more of a run but the pack will feel flat.ive used a dynamite peak at 4 amps for 1500s here and it a better way to go.nicad
1500=3.0amps
1700=3.4amps
1800=3.6amps
2400=4.8amps you get the idea
thought you can round up like 2400 at 5 amps max for bashin or 15-1900s at 4 amps max without toasting em
nimh is different they get hotter when charged faster than nicads do

9. ## Thanks

Thanks xmans revenge,

I do follow your post and it will change how I charge the kids diff sized nicads.

STnewbie

10. Constantly charging at a high amp rating will also keep your batteries from lasting as long as they would with a low amp rating. This is why racers have to spend so much time taking care of their batteries. Alot of cycling is involved. My buddies and I charge our packs at around 5-6 amps when we get to the track, and re-peak them before every race.

Word of wisdom....dont get into racing if you dont like/or dont know how to maintain batteries and motors.

Preston

11. DaveO
The way chargers change Amps is by lowering it... How, the charger is actually rated at lets say 4.5A max, so you get to choose from a smaller amp rate of 2A up to 4.5A. There is ways to increase voltage but at the cost of the amperage decrease... The charger will not generate more amperage than that what is put out by the Power Supply...
Was it clear, thats as lame as I can put it.
Joey

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•