Battery discharger/level indicator

[AshleyBrayson]

Hi,
Is there a battery discharger available that would let me to keep my batteries at a good level for storage if I'm not able to ride for a while? I have three bikes and it's on my mind that I shouldn't neglect any for long periods of time so I'd like something that could maintain them for longevity. It's not easy to use them in rotation due to time restrictions. I'm in the UK by the way.
Many thanks
Ashley

 

[vfr400]

What bikes/batteries are they? Some can't be discharged without special equipment.

 

[AshleyBrayson]

What bikes/batteries are they? Some can't be discharged without special equipment.

Two silverfish style and a Swytch. Maybe I'm thinking of a charger that I could set to charge to a specific level for storage rather than discharge from full.

 

[cyclebuddy]

Maybe I'm thinking of a charger that I could set to charge to a specific level for storage rather than discharge from full.

There are a few options on Ebay and Amazon that would/should/might work (EDIT: I did post an example, but the one I had posted may not work for you).

I also knocked up 4 x 12v 40w MR16 domestic halogen lamps in series to part-discharge a full 36v battery to a storage level (it's roughly a comfortable 3.4A discharge rate). I occasionally use this to artificially cycle a spare battery I haven't used in a while just to keep the cell chemistry active. You can also add a meter in series of the type vfr400 often recommends to discharge a fully charged battery and measure actual remaining capacity.

I'm sure there are options out there.

 

[vfr400]

It's nothing to panic about. The idea is not to leave your battery fully charged or fully empty. That shouldn't be too difficult without any special equipment. I can imagine that you could count on one hand how many people in the UK connect their battery to some special device before storing their bike.

 

[GSV3MiaC]

Fully charged is only marginally bad; come back x months later and it won't be. Fully discharged can easily get you into "BMS refuses to play ball" territory, which is beyond annoying, if you leave it that way for some months, although they are designed with a safety margin, such that 'empty' really isn't.

 

[mike killay]

I have been leaving my spare batteries for months on end for the past 4 years, they seem to be OK, as GSV3 says they soon lose their charge anyway, the trick is actually not to leave them too long.

 

[AshleyBrayson]

There are a few options on Ebay and Amazon that would/should/might work (EDIT: I did post an example, but the one I had posted may not work for you).

I also knocked up 4 x 12v 40w MR16 domestic halogen lamps in series to part-discharge a full 36v battery to a storage level (it's roughly a comfortable 3.4A discharge rate). I occasionally use this to artificially cycle a spare battery I haven't used in a while just to keep the cell chemistry active. You can also add a meter in series of the type vfr400 often recommends to discharge a fully charged battery and measure actual remaining capacity.

I'm sure there are options out there.

Thank you for your very interesting reply. A fascinating solution. You obviously know what you're doing.

 

[AshleyBrayson]

It's nothing to panic about. The idea is not to leave your battery fully charged or fully empty. That shouldn't be too difficult without any special equipment. I can imagine that you could count on one hand how many people in the UK connect their battery to some special device before storing their bike.

I agree, I'm probably overthinking the whole thing.

 

[AshleyBrayson]

Fully charged is only marginally bad; come back x months later and it won't be. Fully discharged can easily get you into "BMS refuses to play ball" territory, which is beyond annoying, if you leave it that way for some months, although they are designed with a safety margin, such that 'empty' really isn't.

Thanks for the input.

 

[AshleyBrayson]

I have been leaving my spare batteries for months on end for the past 4 years, they seem to be OK, as GSV3 says they soon lose their charge anyway, the trick is actually not to leave them too long.

Thank you for the reply.