OK, the old batteries are 1400mah and the new ones are 1250? Huh? Can this be right? I thought the new (red) ones had MORE capacity than the old ones. I hope someone can shed a bit of light on this apparent paradox.

Brian,
If weight is not a issue-yes you can use a bigger size pack-but keep the SAME voltage example: 6 cell 1400mah pack or a 6 cell 3000mah pack-the VOLTAGE remains the same-just like when you replace your car battery with a LARGER size one-BUT they are ALL still 12 volt batteries.Just make sure the pack you use is NO more than 6 cells. Maybe these newer 6 cell 1250 packs have lower internal resistance so they can pass more current and get less voltage drop-lets say a 30amp load for 10 secs. and the voltage still stays at 7.90 volts-that would be REAL good. My 6 cell 1400mah Sanyo pack just off the charger wiill drop to 6.72 volts when starting a cold engine.


Jackjet

While NOT being a battery expert this it how it was explaind to me. The new pack has batteries that can provide a larger rush current then the old one. Given all the physics involved they actually last longer (charge wise) then the older packs. Bkf

This means lower internal resistance cells= more current dump power.

Jackjet

And a good way to loose $$.

If in doubt, send it in for evaluation. "It is always better to be late than the late"

........ghost rider........out.

Jack

You are exactly correct! That is why we went to 1250 SCR cells.
We have used 1800 - 2000 mah SCR cells with good success too. Larger batteries and more weight is the down side.

Dean Wichmann
RAM Marketing / Sales
Canada

Hi Guys,
I'm primarily an electric flyer so I am somewhat familiar with batteries used in this application. When I received my RAM 500 I saw the type of battery and immediately saw room for improvement. The KR 1400's are not ideal for higher amperage draws such as the Speed 300 sees during start. We're actually abusing that little motor pretty bad but they are cheap. The 1400's do show a good capacity for their size but the voltage gets quite depressed when there's more than a 10 A load on them. Even though the SCR 1250's have a lesser capacity rating, they are MUCH happier at that amp draw and will deliver more useful capacity than the 1400's. I have personally used the 1250 SCR type in applications that were drawing 90 A !! If you have the room and can carry the weight, by all means use RC or CP 2400's. I am using the CP1700's that are the same size and weight as the 1250's. The 1250's are older technology so can be had quite cheap.

Marc

Good to see you and thanks for your input! Hope to see you with the 500 powered Reaper at Belleville this year?

Dean Wichmann
RAM Marketing / Sales
Canada

I am in the hammer lane !!!! I'm going to finally be a jet pilot this year, uh I mean a model jet pilot !

Marc, I didnt know that the RAM cells were merely the KR 1400s and you are right, the SCR cells may well be the answer to inconsistent starting on the 500. . I know these cells are used by car racers and I use them in my Aveox powered sailplane with great success. I belive RAM are introducing a few surprises soon so perhaps an upgrade to SCR cells may be on the cards.

I see JetmanRich is based in Omaha, Nebrasaka. Anything to do with Offutt Air Force base ? I took a RAF Bomber Command Victor there in , would you believe, 1966. ! Had a really great time on my first visit to the US.

David Gladwin