Battery Care over Winter

[Ray Winder]

I bought these : lamps link
But you may find cheaper, I also bought ceramic holders from tool station they were less than 90p each.
Using four in series ups the resistance and lowers the amps drawn from the battery

 

[matthewslack]

I prefer my switchable 26/52 ohm resistor in its metal, well ventilated box. No chance of unintended fireworks if left unattended.

 

[Jodel]

I may be oversimplifying things, but I just bought 'normal' low-voltage incandescent bulbs in 100 watt and 60 watt power ratings. I made up a battery holder wired to a standard 13 amp trailing socket and I connect an ordinary lamp fitting to that.

https://www.lamps2udirect.com/standard-incandescent-light-bulbs/48-50-volt-60-watt-bc-b22mm-clear-low-voltage-gls-bulb/144680

After all the dire warnings about power losses following the recent storms, it's quite handy to have an emergency light source too.

 

[georgehenry]

I am my own dis-charger

The cost of replacing the 400Wh Yamaha battery on my 2015 Haibike incentives me to look after it as well as possible.

On those reasonably rare occasions that I have fully charged the battery and something happens to prevent me riding, I will at the earliest opportunity and certainly the same day ride the bike to a steep hill a few hundred yards from my house with a roundabout at the top and the bottom and ride it up and down to take 20 to 30% out of the battery.

I do this by using the maximum assist and letting the bike as much as possible do the work. I can reduce the battery down to a safer storage level surprisingly quickly, probably about a half an hour.

It helps that I live close to a steep hill.

The rules I have followed to look after this battery are pretty simple.

Always bring the battery into the house to store

Store it at around 60% capacity plus or minus the odd 10%

Fully charge the battery before you use it, but as close to when you plan to use it as possible.

Try to use your bike regularly, however my battery has on occasion been stored for around 6 weeks + or - without being used.

My battery will be 7 years old in around a weeks time and still works very well and I have so far ridden my 2015 Haibike Yamaha 15,230 miles.

However having said all this the silver fish battery on an old 2011 rear hub bike I use a lot lives on the bike in my unheated garage and is always ready to be used fully charged.

The last battery I bought for it was a relatively cheap (under £200) Yose one of Ebay and although I can tell that battery is losing some capacity it still works well enough and is now four years old. I use a timer plug so that the power is cut to the charger after a set number of hours.

I do use that bike pretty much daily for shopping trips and many other errands, and it is so convenient to know I can just jump on it whenever I need to, and simply plug it back into the charger/timer plug on my return before going into the house with my panniers.

So for me the expensive battery gets really well looked after and the cheaper one just gets used.

 

[Bikes4two]

I am my own dis-charger

Ha ha, there's nothing better than keeping things simple - it get's my vote for sure.

However, although not an essential, I'm an inveterate tinkerer and couldn't resist the discharging gizzmo as I'd like to measure my Amp Hours as of now and maybe over time to see how (my cheap) battery is holding out.

I recently experienced a battery problem and I thought the battery might be knackered but it turned out to be the BMS - if I'd had the 'discharger' at my disposal then, I'd have found the BMS issue somewhat sooner than I did.

PS - the 18ohm 100w resistor in my device listed above, went open circuit today. I guess I was pushing my luck at running at 276degC!!! - onto plan 'B' but that's all part of the fun of it .

Thanks to those who have pointed me towards affordable lamps, but I'm sticking with resistors for the mo as halogen lamps are getting increasingly harder to find at reasonable prices. So this time around I'm spreading the heat dissipation across three 40 ohm resistors in parallel on a better heat sink and thermal paste.

 

[Ray Winder]

Taking advantage of my new discharge device i looked at my 4 batteries
Tesco shopper original
Full charge 29.2v
Take it down to 22v gives out 8.5 Ah 212Wh
New battery
Full charge 29.2v
Down to 22.2v 9.98Ah 252 Wh
Original carrera battery
Full charge 41.2v
Take it down to 32.5v 9.9Ah 359Wh
Replacement carrera
Full charge 41.6v
Take it down to 33.5v 10.1 Ah 370Wh

Of course it's pretty cold and the batteries probably aren't at their best

 

[matthewslack]

Taking advantage of my new discharge device i looked at my 4 batteries
Tesco shopper original
Full charge 29.2v
Take it down to 22v gives out 8.5 Ah 212Wh
New battery
Full charge 29.2v
Down to 22.2v 9.98Ah 252 Wh
Original carrera battery
Full charge 41.2v
Take it down to 32.5v 9.9Ah 359Wh
Replacement carrera
Full charge 41.6v
Take it down to 33.5v 10.1 Ah 370Wh

Of course it's pretty cold and the batteries probably aren't at their best

How do those measurements compare with the Ah and Wh on the battery labels?

I found my brand new cheap 48V 20Ah gave 17.8Ah and just over 820Wh, which I attribute to low temperature (10degC) and the BMS not allowing the same depth of discharge as the manufacturer's test.

 

[Ray Winder]

The Tesco shopper batteries (24v) are labeled 10 Ah, the original one is at least 4 years old but never really used the new one should also be 10Ah and is very close.
The original halfords battery (36v) is 4 years old and I thought it may be weak but not too bad, it should be 11.6 Ah as should the new version of this one I bought from Ali express
I wonder if the two new ones could Improve slightly if I use them.