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[Paranemertes]

Last summer I built an ev motorcycle for my first year of college to help save on costs (and cause I've always wanted some sort of ev). Its been working great for the first month or so of heavy riding, but the last few weeks I've been getting some issues. I seem to be experiencing shorter than normal battery life, but get this, its not a constant problem. It seems to only happen when I let it sit on the charger over the weekend or for longer than overnight. I tried disconnecting the charger right after its fully charged but I get the same issues. A new reason to hate Mondays for me. My charger is mounted on board, my ride is about 11 - 14 miles one way. I can charge at school. But this makes no sense, I should be getting way better mileage that 11 - 14! One range finding equation I found predicted with my setup I would get 38 miles! So far haven't tested max mileage, I don't have anyone to come and rescue me!  The 38 miles seems pretty far fetched, but I would think at least 30. The batteries weigh 60 lb each, I'm 160 lb, I would estimate everything else at about 120 lb, so estimated total weight
500 - 520 lb. Sorry, I'm kinda rambling out any info that might be useful.

I am using:

4x Werker 80Ah AGM deep cycles
NOCO Genius 4 bank charger

I just can't wrap my head around what the problem could be. If it happened every time I would start tearing her down looking for shorts or the like, but it only seems to happen when I leave it on the charger for long periods of time. My charger says that it trickle charges after it gets done with the main cycle to keep the charge up. Hmmm.

Thanks for looking, I would really appreciate any/all help. You have no idea how embarrassing it is to be riding in the bike lanes at about 10 mph for 3 miles every Monday. In the winter. Thanks!  

[frodus]

I think you said the magic word here: "Winter"

My gas car is harder to start in the winter than it is in the summer, because the battery is cold and doesn't perform as well as it would when warm (in the summer).


Where do you keep the bike?

When you charge Lead Acid during the bulk charge, the heat from bulk charging actually keeps the batteries warm. Warmth actually helps Lead Acid batteries, they will perform better. Overnight the batteries might not get time to get down to the ambient temperature by the time you go to ride.

Now, if the batteries are fully charged, then enter trickle, they're not really doing much to keep the batteries warm. They will just trickle a small amount of current into the batteries to keep them from self-discharging, but doesn't do much (if anything) to keep the battery warm. Also, if you disconnect the batteries after the full charge, and let the batteries sit all weekend, they'll be able to get down to ambient temperatures. If weather is fairly cold, the batteries will perform worse than if they were warm(er).

If you have to store it outside, then consider heating blankets/wraps/etc. Turn them on a bit before you have to leave to pre-warm the batteries. If you can keep it in a garage, and keep it warmer, that would help too.

I'm pretty confident it's got to do with the temperatures. Batteries don't like freezing/near freezing temperatures.

[Paranemertes]

AHA! That's gotta be it. I keep the bike in the garage, but there is no heater out there, so it gets really cold. Thanks for the quick reply, I'll look into some way to heat those puppies up. Thanks again frodus!