Recent content by andrew

The PDF doesn't really say anything substantial. 700 cycles---thats super great, but what's the DOD? Without that information, then "700 cycles" means nothing. At 50% DOD this is probably about normal for Optima yellow tops. The pulsing may have lessened the damage done by overcharging when...

Unsupported, and wrong. I'm running my motorcycle with a current limit of about 17C (actually it's higher, but I don't exceed about 17C). Electric motorcycles and large EV conversions commonly go more than 5C current limit. For some reason safe never responds to my posts :(

safe, have you considered gel cells for replacements? SLA (sealed lead-acid) seems to be another term for valve regulated lead-acid (VRLA), which can mean either gelled electrolyte (gel cells), or absorbed electrolyte in glass matting (AGM). Being so concerned with cost, did you research the...

I don't know how draining them flat could help. Usually it hurts them because the cells all don't have the exact same amount of capacity. This will result in one or more cells being reverse charged, which is extremely bad for lead-acid. Like bad enough to kill them in 1 minute. Maybe if the...

Where did you get that information? To me it sounds like the charger slowly killed the batteries. Trickle charging batteries should be done with temperature compensation because it needs to be pretty close. That's why it is probably better to leave the batteries off the charger, and charge them...

I have some 35ah B&B batteries in my motorcycle. I've pulled up to about 600 amps from them. I've tested them at 600 amps with a hall effect DC amp meter, and backed with the load tester shut & amp meter. I don't see how the chart you posted supports this conclusion. What's not given is how...

Craig, I think you need to do a motorcycle.

Maybe used bicycle or motorcycle tubes? I used these to cushion my motorcycle batteries. They can be mounted in solid, and don't move or bounce around at all with some give for battery expansion. Though they may help start a fire in case of a short causing a lot of heat.

I think it is hard to find a rechargeable (secondary) battery commercially available that will last as long in terms of shelf life. I have some old NiCad AAs that I took out of something's battery pack. They may be over 15 years old and still hold a reasonable amount of charge. I also have some...

electricscooterparts.com carries lots of misc stuff for scooters, and I've had good experience dealing with them. I've placed a few orders from powerwerx.com for anderson connectors. They seem to have pretty good prices. For other stuff, check an electronics supplier, hardware store, auto...

safe: I haven't heard of that. Any details? I thought it was merely an issue of design. The subC cells are popular for high-rate applications like power tools, while the D cells may be more popular for applications requiring more capacity at a lower rate. There are some SAFT NiCads here...

The energy stored in a microwave capacitor would not be enough for an explosion. But, maybe it's enough to have some fun shocking stuff though :twisted: .5 * .000001 * (2500^2) = 3.125 joules or enough to power a 400w ebike for .0078 seconds. I was running some numbers on energy storage with...

fechter: But at 3,500 volts things may not behave the same. An arc might bridge the gap. And the amount of energy is scary. 52,000 whrs released in .2 seconds is 936 million watts of power, or almost a gigawatt!

This is a very informative thread! Digikey carries some IGBTs that appears to be able to handle 4,000v, and 40 amps for $62.57 each. Here's the data sheet for IXEL40N400 Could a circuit be used to increase the voltage with these? My thinking is that all of the circuitry and voltage...

A way to get around the battery range limitation of a battery electric vehicle, would be to electrify an ICE vehicle, and leave the stock engine/transmission in place. If the electric drive system can be integrated without modifying the existing ICE drive, than a few batteries, motor, and...