Headway 10AH pack

[Spanky]

I'm considering purchasing the headway 48 volt 10ah battery pack. I currently ride my bike to work 26 miles each way with a x5304. I peddle a lot and need about 9ah to make it. I've been running big heavey SLA's and use between 8 to 9 AH each way - I can recharge at work- question is will I be able to draw 9AH out of the headway 10AH pack? Thanks

 

[frodus]

how many amps does the x5304 draw? that 10Ah is at a 1C rate I think.

 

[Spanky]

On my ride to work I'll draw 40 to 50 amps for a very short time starting up a hill! Most of the time 20 to 30 amps!

 

[adrian_sm]

I am running the 48V10Ah headway pack with a crystalyte 408, with a crystalyte 35Amp controller.
I have only done a full discharge ride once, and got the full 10Ah, but was already starting to get the voltage drop effect by the end.

If I was you and regularly drawing 9Ah for my daily one-way ride. I would go for a bigger pack, say 15Ah.

This means you will increase the life by not discharging to 90% every day, less voltage sag under load, have a bit of headroom for headwinds, and the eventual drop in capacity. Remeber these things will drop in capacity over their life, so you don't want to be cutting it too fine.

My 2 cents worth....

 

[julesa]

If you can wait for the 15Ah cells, yeah. But if you go up to 20Ah I would guess you'll appreciate the extra range more than you might expect, and your cells will take less of a beating from the deep discharge and power draw. Or since you can just skate by with the 10Ah pack for now, you could get that, and then when you can afford it, get another 16 cells and rebuild the pack, putting the new cells in parallel with the old.

 

[swbluto]

If you can wait for the 15Ah cells, yeah. But if you go up to 20Ah I would guess you'll appreciate the extra range more than you might expect, and your cells will take less of a beating from the deep discharge and power draw. Or since you can just skate by with the 10Ah pack for now, you could get that, and then when you can afford it, get another 16 cells and rebuild the pack, putting the new cells in parallel with the old.

Agreed. I consider adding to the capacity when you need it to be a wise thing, as it allows you to minimize the calendar-life effect on the continually existing pack as a whole while also reducing the "ouch" factor on the cash-flow. Considering that it may take 2 years for that 10aH to drop to 90% of its original capacity, that's a lot of calendar life rot you could excise. And, even more importantly, there'll be better batteries/better deals in the future (Hopefully).

But, ideally, you'd get a capacity with some "head room" like 15Ah, just so you could extend your repurchasing cycle a bit, add more of a "buffer room" for those rare but inevitable heavy-energy usage days (wind being one), reduce wear on the batteries, etc.

 

[adrian_sm]

Oops forgot 10Ah cells. Sorry.

But I have a solution to get the headroom

Go for a 60v 10Ah pack Might be hard to stop yourself using the extra speed though.

 

[Kurt]

Go for the 20ah its only 18lb and no that big. The battery will have an easy life less voltage sag and you will have a longer range. Sounds to me like you have the 48a or 50a controller and the 10ah pack will run it but it wont be very happy.I run a 20ah headway pack with 5304 and 48a controller. I wouldn't want to go any smaller.

Kurt.

 

[dogman dan]

I agree with all the above posters. If you run a 10 ah pack down to 90% discharged everyday you will be cutting the lifespan quite a bit, and once cold weather or a big headwind comes you will be running it down 100%. Not exactly a recipe for lifespan. It's one thing to beat a battery like that for fun on the weekends, but as a daily transportation solution I think you need a pretty big reserve that is left unused most days. A 75% discharge should lessen the chances of killing an individual cell that is weaker than the others.

25-30% is what I like to use so you have plenty of range for that wonderfull day when your pack is not balanced so good, and you have a nice 25 mph headwind. You get to do 26 miles into that some day and you will find you need every watt of a 20 ah pack to make it. Or you can just ride 12 mph and get to work an hour late. You really need to have a big capacity more than you normaly use daily to make a practical replacement for the car.

Get one 10 ah pack for now if that is all you can afford, but plan on a second one ASAP so you will have a bike that can do the 26 miles at any speed you want to ride wind or not. Two packs in panniers will carry better than one big pack on a rear rack.

Meanwhile, if there is some life left in the sla's paralell them with the lifepo4. Heavy yes, but it will work great, and you will get a lot more than usual out of the sla's when paralelled with another battery. Size and chemistry won't matter with a parallel set up, Just use some shotkey diodes to keep the batteries isolated from each other.

 

[Spanky]

Thanks everyone for the help - I'm going to start with the 10AH and see how it goes and parallel another pack when cashflow improves!

Thanks again for the help!!