Buying a 2nd battery

[jann71]

I've considering buying a 2nd battery to use on some longer full day/weekend rides/touring where I may not have the option to charge the battery.

The current battery is Bosch 400 power pack.
Cheapest I can find a new 400 is about £420 or more if I go for a 500.

Any advice (apart from buying a 2nd ebike) on buying 2nd hand? There are few on eBay.

 

[Pale Rider]

Bosch batteries have a longer service life than some of the cheaper 'no brand' Chinese batteries, but buying second hand is still a risk.

£420 is a good price for a new 400, although you can never have too much capacity so I would consider lashing out on a 500.

 

[ColinJ]

Bosch batteries have a longer service life than some of the cheaper 'no brand' Chinese batteries, but buying second hand is still a risk.

I bought a cheap 'no brand' replacement battery for my laptop. It only took about a year to lose 50% of its capacity!

 

[Pale Rider]

I bought a cheap 'no brand' replacement battery for my laptop. It only took about a year to lose 50% of its capacity!

Use, as in current draw, plays a part.

One of the reasons the Bosch batteries last a long time is the system is set very conservatively, so it doesn't thrash the battery.

I've seen several laptops at work with knackered batteries.

My guess is laptops from the 90s and 2000s thrashed the batteries with high current draw to achieve a working life of a few hours.

Lots of laptops these days will run all day, yet I don't hear of so many knackered batteries.

Battery technology will have improved a little, and I suspect modern laptops need less power to run.

 

[ColinJ]

Use, as in current draw, plays a part.

One of the reasons the Bosch batteries last a long time is the system is set very conservatively, so it doesn't thrash the battery.

I've seen several laptops at work with knackered batteries.

My guess is laptops from the 90s and 2000s thrashed the batteries with high current draw to achieve a working life of a few hours.

Lots of laptops these days will run all day, yet I don't hear of so many knackered batteries.

Battery technology will have improved a little, and I suspect modern laptops need less power to run.

The new laptop that I am using today doesn't have a removable battery so I hope that the battery lasts at least 5 or 6 years! (It is still ok after 2.5 years.) Its LED backlight possibly uses less power than the fluorescent tube in my old laptop. The processor can cut its power consumption right down when running undemanding applications, but ramp up when more oomph is needed - a bit like the motors on your e-bikes. When the browser was idling, the battery power display estimated 6 hours remaining run time. Now that I am actually doing something, it has cut that to 4 hours. If I run something more power-hungry and/or turn up the screen brightness then that can fall to 3 hours.

I bought an Android tablet back in 2012 and that still has a decent battery life. I use that for 30 - 90 minutes every day. A couple of years ago I looked up how to take the thing to pieces to solder in a new battery but that has not been necessary.

OTOH, I have had phone batteries die after a couple of years. Those have all been removable ones. The battery in the phone that I use now is soldered in so I will probably just replace the phone if/when that goes. (That is probably what manufacturers want - provide enough life so that people don't feel angry when the batteries finally die, and then sell them new kit!)

 

[Mark pallister]

I've considering buying a 2nd battery to use on some longer full day/weekend rides/touring where I may not have the option to charge the battery.

The current battery is Bosch 400 power pack.
Cheapest I can find a new 400 is about £420 or more if I go for a 500.

Any advice (apart from buying a 2nd ebike) on buying 2nd hand? There are few on eBay.

Someone has a nearly new one for sale on adrians bike community

 

[Blue Hills]

Someone has a nearly new one for sale on adrians bike community

How can you judge how new it might be/how much use it has had?

 

[Mark pallister]

How can you judge how new it might be/how much use it has had?

I think you can find out how many charges it’s had and hours used as you can with a phone
i think the newer type head units display this info

 

[Pale Rider]

A Bosch dealer with the appropriate software can interrogate the battery to get its condition and pattern of use.

Not practical when buying used, unless the seller is offering the battery with a printout as proof of provenance.

 

[Mark pallister]

A Bosch dealer with the appropriate software can interrogate the battery to get its condition and pattern of use.

Not practical when buying used, unless the seller is offering the battery with a printout as proof of provenance.

Pay your money you take your chance then

 

[rualexander]

Is there any adapter system to charge a proprietary branded battery from a more generic or budget battery?

 

[Pale Rider]

Is there any adapter system to charge a proprietary branded battery from a more generic or budget battery?

The Bosch system is known to be locked down - think of it as the Apple of ebikes.

No pattern batteries are available for the latest battery shapes, although there were some for the previous shape battery which was discontinued in 2014.

The OP has a newer bike, so it's Bosch branded batteries only.

 

[rualexander]

The Bosch system is known to be locked down - think of it as the Apple of ebikes.

No pattern batteries are available for the latest battery shapes, although there were some for the previous shape battery which was discontinued in 2014.

The OP has a newer bike, so it's Bosch branded batteries only.

Yeah but if you had a cheaper generic/budget battery that could output the same voltage/current as the Bosch (in this case) charger and a suitable connector then presumably it could be done, unless the Bosch charger communicates with the battery?
Or maybe an inverter between the budget battery and the Bosch charger and battery would work, although that would no doubt be inefficient.

 

[Mike_P]

Bit off thread but why is there no dynamo charging system for ebike batteries topping it up as you ride?

 

[neil_merseyside]

Bit off thread but why is there no dynamo charging system for ebike batteries topping it up as you ride?

Perpetual motion like that was outlawed by the energy companies.