Topic: RC Batteries - Fuses and Power Meters

[terrapinj]

I have a couple of questions regarding RC remote power. I will eventually be using 2 9.6 v RC batts rigged together to power a UA-5 and a JB3.

1) I read in a post by Skalinder that he reccommended using a PTC resettable fuse on the lead wire from the battery. If I have two RC batteries should I use a fuse for both of the pos wires or can I use one just on the line to the UA-5 since the JB3 ext will have a 5v regulator, or do I even need one for RC batteries (I believe he was writing in reference to an SLA)

2) Is there any way to gauge how much juice is left in the batteries without trying to calculate how much is being pulled for how long etc.? I have searched the boards here and looked on quite a few hobby sites and could only seem to find gauges/meters to measure the output voltage and amps. I don't mind keeping track of time and draw, but it would be nice if I could simply watch a charge gauge instead.

I know that the wallyworld li-ion or substitute has a gauge on it but I am planning on going RC at least initially so I can have back up batteries that are reasonably priced and I like the fact that they are hot swappable as well as the smart charger that can charge within a 90 min for 3300 maH.

Many thanks for any help. If there is an existing post out there already I appologize but I have been searching for some time and can't seem to find specific answers to these questions.

[JackoRoses]

no real answers but I am considering buying some rc packs for quick recharge time.
I was considering running 2 3300 packs in parallel to give 6600 mah which is a little
more then a Li-Ion can put out. There are some really nice
Ni-MH chargers out there that will discharge your packs etc. Plus they will
charge much faster then a Li-Ion will at this point..
It would be nice to have both at the disposal to use.
Quick recharge at a vendors spot and the long charge at home for the
Li-Ions.

I do see your point on the not knowing how much power is left in the pack,
Would be interested in hearing how others may be gauging that.

[Brian Skalinder]

Quick [RC/NiMH] recharge at a vendors spot and the long charge at home for the
Li-Ions.

Sure you don't have that backwards?  All the NiMH chargers I've used are far slower than their LiIon counterparts.

[JackoRoses]

Quick [RC/NiMH] recharge at a vendors spot and the long charge at home for the
Li-Ions.

Sure you don't have that backwards?  All the NiMH chargers I've used are far slower than their LiIon counterparts.

with the new fast smart chargers they claim 100 mins for a rapid charge.
A normal slow charge still takes up to 12 hrs. where as the lithiums take about 6~?

[terrapinj]

Here is one of the smart chargers I found.

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1111

They claim 90 min for 3000 maH. I have seen packaged deals on ebay for 2 9.6v 3300 maH Airsoft batts and a smart charger for ~$65 BIN.

[Brian Skalinder]

Here is one of the smart chargers I found.

with the new fast smart chargers they claim 100 mins for a rapid charge.

Learn something new every day!  Last I was in the market for an RC charger, they didn't have (or I didn't know about) the rapid chargers.  Thanks for the info. 

[terrapinj]

Hey Brian,
Do you know the answer to the fuse question, since it was one of your posts that made me inquire. 2 fuses- 1 fuse - or none for a DIY pack running 2 rc batts?

[F.O.Bean]

i have the 'chun' smart charger for rc packs and it states about 90min. for a 3000mah pack

[Brian Skalinder]

Do you know the answer to the fuse question, since it was one of your posts that made me inquire. 2 fuses- 1 fuse - or none for a DIY pack running 2 rc batts?

Right!  Forgot about that one.  I would strongly recommend against none.  Either one or two will work, just make sure you use fuse(s) with the appropriate current rating.  If you use a single fuse through which current will flow to both devices, you'll need a higher current rating.  If you use two fuses, effectively one for each device, use fuses that'll accomodate each device's current individually.

[JackoRoses]

i have the 'chun' smart charger for rc packs and it states about 90min. for a 3000mah pack

what is this "chun" charger? no other name on it? Is it handmade? I have seen
the basic charger set up, add PSU and wires and a box and your ready to go.

[terrapinj]

Thanks a lot Brian. I can't even begin to tell you how helpful you and TS.com have been.