7ah bottle battery left fully Charged

[Turkeylegs]

Hi guys,
Iv not used my bike in months and realised I had left it fully charged when I got it out the other day.
Is they're a way off telling how much capacity it might have lost going on the reading before going out to coming back.?
It was charged to 41.7 before going out and 38.6 after nine miles.
How low can it go to be useful without draining it, and what would be classed as the lowest recommended to use it to?
Many thanks guys.

 

[Nealh]

Batteries can be drained down to LVC or approx. 32 - 33v. I tend to use a low safe level of about 34v and charge to approx 37/38v when I get home.
I doubt you battery will have suffered much if at all, high discharge rates are what usually lessens capacity.

Mileage is dependant on power levels used, 38.6v is approx. 65% left so you could still have about 12 - 16 miles range left.
Your 7ah is a nominal 252wh so potentially approx. 25 miles range, one may even be able to eke a few more out.
A watt meter fitted and then ride till LVC locally will tell you WH used and an idea of any capacity loss, if any at all. Otherwise ride around locally until LVC or close and if you can get near 25 miles then your battery is fine. A rudimentary test is to ride with the voltage of varying levels of voltage between 35v - 38v and if you can apply throttle or use highest PAS level for up to 20- 30 secs secs with out the motor cutting out, then the battery is able to deliver the power/load without issues.

A battery that has lost capacity can still hold a full charge but will sag badly and cut out in highest power level after a few seconds use.

If out on a ride once I hit 35v, I baby the use a little and use lower PAS levels.

 

[Turkeylegs]

Thanks for that Nealh, that's very helpful and answers my question fully.
I was able to use full assist on a steep hill coming home with no cut out, though the bars on the display went down to one out of four then returned to two bars after a little while.
I was also able to use the throttle and it held between 12 and 14 mph on a flat. Fully charged it would hold 14 to 15 on a flat.
But it seems I'm worrying needlessly about it losing its capacity.
Thanks again Nealh, you've put my mind at ease.

 

[Nealh]

Your battery is fine, after each ride leave it at the SOC it ends at unless it is silly low volts like 32v - 34v. If you are ab infrequent user then charge it before the next planned ride tbh little harm in charging it ready 12- 24hrs before next use.
I try and leave mine at approx. 38 -38.5v and then needs about 4 hrs to top up.

The battery bars sagging under throttle is normal and to a degree all batteries will sag, as you noticed when load is removed/reduced the sag (bars) recover.

I have a pair of 29E batteries that I abused with current and they have capacity issues, quite good in PAS 1 range wise then after that the range halves in Pas 2 then is less in 3, Pas 4 or 5 I don't use. Once they are at about 60% if I use throttle power cuts out after a few secs, they are only for local use so not an issue to worry about.
I have built a smaller lighter 6ah/264wh LG HG2 drinks bottle battery to replace them so just need to fit the water bottle holder and adapt the wiring to use it.

 

[Turkeylegs]

I was going to get another battery to extend the range but it seems the cyclotricity bottle type are no longer available, only the box shaped ones which use a different bottle boss connection which would make my battery redundant and would be a waste.
Unless there's a way to use my battery too it looks like I'm unable to do anything with my present bike to improve range without effectively wasting this battery.
An option is to get another bike and use my present one for work, or even a donor bike and get another conversion kit.
I have to say this conversion is solid and I like it, and added to a good donor bike as I did too my old raliegh royal could be an option.
The choice for my price range is mind boggling as there are a couple that grabbed my attention.
For example, the Whoosh Big Bear, Cyclotricity the Stealth and a few more similar as I'm 20 stone and 5, 11 tall.
I'm still deciding which way to go.

 

[Nealh]

The cyclotricity uses normal generic battery connection (just two wires) so one can spur another set of wires to supply another battery singularly or in parallel to carry elsewhere on the bike.

 

[Turkeylegs]

So if I got a rack battery from cyclotricity and put it on my bike it would be an easy job to connect it to my other battery Nealh?
My bike has a rack so I'm guessing the battery rack would swap straight out?
Also with my electrical skills being zero, is this something I could do myself?

 

[Nealh]

One needs to be able to solder and know their left form their right to get polarity correct.
A pair of new wires need soldering to the controller battery wiring and then extended to the rear mount battery mount. Any batteries when used as pairs or paralleling need to be connected at the same voltage charge.

14g silicone wire is needed.
A soldering iron.
A meter ( volt meter).
heat shrink.
Solder.
And the ability to make sure wiring is soldered correctly V+ to V+ & V- to V-.

 

[Turkeylegs]

That's something I could possibly try.
Though I was wondering if the connection plug from the bottle battery is the same from the rack battery and it could just be a case of changing the plug from one battery to the other at the connection point from the controller box?

 

[vfr400]

You don't have to use a Cyclotricity battery. You can use any 36v battery you want. Whichever you get, it won't have the same connector, but you can buy that connector from Ebay and solder it to your new battery wires so that you can swap it over.

It's a very awkward connector, and because of that, frequent unscrewing damages the wires, which can make it short out, so what I'd do is cut the wire a few inches from it and solder in a pair of XT60s, which are much easier to connect and disconnect. That way, you can leave the stupid Cyclotricity one permanently attached and not have to worry about the difficult soldering to that type of connector. Solder an XT60 to your new battery and bob's your uncle.

 

[Turkeylegs]

That sounds like a good idea and easier too, thanks vfr400 and thanks Nealh you've been very helpful.
The thought of a second bike is still very appealing too, my present one for work and a new one for everything else.
With the options I have with your help here, I have some thinking to do.
Thanks very much guys.

 

[Turkeylegs]

Iv decided to go for the Big Bear plus guys.
The one I have will be used for local and work, and the Big Bear for my rides out further afield.
Many thanks for the help guys, but I think with more than twice the battery capacity and the stronger motor, its the better option for me.
It's arriving on Friday thanks to the lovely lady at whoosh, and I'll let you know how I get on with it.