Im using 800mah ni-mh as well for my receiver pack. I think they also have 900 or 1000mah ni-mh by Panasonic but you would have to assemble it yourself. I may be wrong on the numbers but im sure there is something higher than 800 because the time I bought mine I had the option to get higher mah batts. The battery mentioned you cant really solder them because of the battery shape on the positive side. The head looks for similar to the Duracell ones you buy at the stores. Maybe the bump is too big? My 800mah runs good all day. But I do charge it every 7-10 runs just for the heck of it while im working on my car. I had them die out one time from a day of racing but luckily my fail-safe kicked it