Newbie battery questions

[Bobsiii]

10 months ownership of my Magnum Metro, over 3,000 recreation riding miles, no problems save one sidewall flat. So far my longest ride has been 55 miles w/1,000ft climb - left me with 45v. I live in Denver and want to take longer rides further up into the foothills so I'm looking for more battery than my current 48v 13ah Dorado. There is a battery builder locally, offers both 13h and 16 ah models that will fit.

I know nothing about Lithium batteries so I have some questions about the best way to go.

1. How much mileage gain could I expect with 16ah? I know there's no all conditions definitive answer but surely someone could make an educated guess?

2. Would 13ah and 16ah batteries be interchangeable on my Bike during a ride?

3. How sturdy are these batteries? I'm a path/road rider so I encounter a lot of small/medium bumping around; would I have to wrap a spare with some protection to carry it on my rack or in my Wald baskets? Any suggestions?

BTW - 67 degrees Saturday, 72 Sunday. 3-6" of snow today. Riding in shorts over the weekend, bike stuck inside for a few days now. Crazy.

 

[rich c]

Ah is just a capacity number, nothing to do with compatibility. Of course voltage should be the same. 13ah to 16ah is roughly a 20% increase in capacity, so should relate pretty closely to that much increased range.

 

[Bruce Arnold]

Depending on how much you rely on the motor, you'd likely get another 10 miles. No problem with compatibility -- if the battery has the same hardware, it will work. Don't get a 36 volt battery, you'd get less mileage out of it. Stick with the 48 volt. Being knocked around is not really good for batteries so yeah, you might want to cushion it in some fashion. Don't go overboard -- wrapping in a towel ought to do it. I love my Wald baskets and would have no qualms about putting a spare battery in one, suitably swaddled.

 

[Bigal1463]

Hello Bobsiii, I wrap a yoga mat around my spare battery and carry it in a pannier. I also use bubble wrap around the outside of the mat to give it an extra layer of protection should I go down. Perhaps overkill, but batteries are very costly.

 

[theemartymac]

A second battery of similar or slightly larger capacity would do you very well, but I wouldn't feel the need to go overboard unless you have a clear need. Two of your 13Ah batteries would give you comfortably over 100miles of range. Even at a fast 20mph (fast for gravel for sure), that's 5+ hours of non-stop riding. If you did substitute a larger 21Ah battery, you could probably get 140+ miles of range combined, and that's a heck of a long gravel trail day (but a reasonable big road day). I would say the first question you should ask is whether or not the 13Ah is meeting your needs day to day (occasional rides not a factor). If you find you have range anxiety regularly during your normal routines, but don't need to actually double your range with a spare battery all the time, then a bigger main one might be called for, and relegate the small one to backup duty for long rides. If you just want to be able to make a longer run on the weekends from time to time, then a matched spare might be more practical and economical.

There is also a potential value in two matched batteries in that you can rotate them, alternating at each charge to extend their collective life quite a bit. If you have two similar ones, you won't have to mentally adjust your range based on which battery you used that day. And if you do buy a big new one, you might tend to want to leave it in all the time for 'peace of mind', and then you won't see that benefit of the extended life by sharing the charge cycles between them.

Your call though, and a timely great deal on a particular unit trumps all.

 

[harryS]

Those long packs can be awkward to carry. If you use the builder, buy the 16AH model, enjoy the extra 12-15 miles you might get out of it. Ask him what cells he uses.