Checking if a used bike has a reasonable battery

[damian]

Hi

I've posted a few questions already, so thanks to everyone who has replied to those.
I have noticed a few bargains (now sold of course) in the classified section but I'm assuming that how much of a bargain they are depends on the battery.
So if I saw something I thought was worth a punt is there any way the seller can check the state of the battery, other than giving their opinion? can they measure the voltage and that would tell us something?

Thanks

Damian

 

[Fordulike]

Hi

I've posted a few questions already, so thanks to everyone who has replied to those.
I have noticed a few bargains (now sold of course) in the classified section but I'm assuming that how much of a bargain they are depends on the battery.
So if I saw something I thought was worth a punt is there any way the seller can check the state of the battery, other than giving their opinion? can they measure the voltage and that would tell us something?

Thanks

Damian

I'm certainly no expert, but I'm sure that a voltage measurement would be a very poor indication of the condition of the battery.

I would personally put a known load of the correct voltage across the terminals of the battery (hot off the charger) and see how long it takes to drain to it's BMS cut-off point.

A 10 amp load should be kind enough to most batteries. Then with a bit of calculation, you can determine what capacity it has remaining.

Unfortunately, most sellers would probably be unwilling to accommodate this kind of procedure.

Also, I reckon battery age can be a bit misleading too. I'd rather buy a battery a few years old, that has had low current drawn all its life, than a nearly new battery that has been hammered beyond its max C rating.

Again, you're relying on the seller's word on how they've used their bike. It's a goddamn used battery minefield out there lol

 

[Cyclezee]

Hi Damian,

Unfortunately there is no quick easy method of establishing the condition of a used battery.

Voltage is not a good indicator unless it is very low, fluctuates or drops quickly when not under load.

Remaining capacity is more important along with testing under load neither of which easy to determine without having the right equipment or time to test the complete bike.

We often have customers who buy used bikes from eBay sellers assuming that they have got a bargain...until they discover that the battery is on it's last legs or dead.

 

[damian]

Hi Damian,

Unfortunately there is no quick easy method of establishing the condition of a used battery.

Voltage is not a good indicator unless it is very low, fluctuates or drops quickly when not under load.

Remaining capacity is more important along with testing under load neither of which easy to determine without having the right equipment or time to test the complete bike.

We often have customers who buy used bikes from eBay sellers assuming that they have got a bargain...until they discover that the battery is on it's last legs or dead.

Thanks for the replies. I think I got he reply I expected (though I was hoping against hope for a different one)

I'm wary of the warranty implications of buying online, never mind buying second hand. Looks like a new bike it'll be then...

 

[Cyclezee]

If anything your rights when buying online are better protected than buying from the high street, but as with any used item, electric bike, domestic appliance, motor vehicle etc. prior knowledge is always advantageous.

Going back a good number of years, I bought my first electric bike from eBay with no knowledge whatsoever, fortunately I was lucky on that occasion, but that was not always the case which was when my learning curve really started.

 

[soundwave]

http://www.ebay.co.uk/itm/321885348224?_trksid=p2060353.m1438.l2661&ssPageName=STRK:MEBIDX:IT

he can rebuild any batt so he says

 

[Fordulike]

http://www.ebay.co.uk/itm/321885348224?_trksid=p2060353.m1438.l2661&ssPageName=STRK:MEBIDX:IT

he can rebuild any batt so he says

Mmmmmm, I seem to remember some geezer selling home made bombs, I mean battery packs on eBay, that were less than satisfactory.

This one might be alright though

 

[Tomtomato]

Kalkhoff batteries have a built-in charge meter, and also hold capacity meter (e.g. 80% of original capacity still possible)

 

[danielrlee]

If you are unable to test a used battery in a meaningful way, either on the bike itself, or as Fordulike describes, then I'd assume it is worthless when factoring a price/cost.

 

[Fatgadget]

Assume the battery to need replacing and factor in the price of a replacement in the selling price!

 

[the_killjoy]

Can you not rig up a resistive dummy load?

 

[nmsraider]

Can you not rig up a resistive dummy load?

Yeah you could or there are chargers out there for lipos with abilities to test this at all different load drains and cut offs, but I am not sure a seller would want you to attach your contraption to his battery to test it in fear of you damaging it, you or him.

Agree with the above, best way if you are going down that road of buying second hand is to try and factor in the cost of replacement, and pray to the bike gods your got a good one

 

[Wander]

If it's a Bosch Bike you could ask the seller to obtain a diagnositcs report from their dealer. It says here that they can get loads of parameters:-

This can also be handy for anyone buying / selling their Bosch powered eBike. We can use this service to run off a diagnostics report and provide a print out of the eBike's history. This includes about 50 different parameters. Here are a few: Manufactured Date, Frame / Electrical Serial Numbers, Total Battery Charge Cycles, Current Capacity, Maximum Battery Temperature, Previous Faults etc etc. This is a really usefull tool for sellers as they can actually prove the history of the eBIke to potential buyers increasing interest and possibly even the price of their eBike.

 

[nmsraider]

If it's a Bosch Bike you could ask the seller to obtain a diagnositcs report from their dealer. It says here that they can get loads of parameters:-

This can also be handy for anyone buying / selling their Bosch powered eBike. We can use this service to run off a diagnostics report and provide a print out of the eBike's history. This includes about 50 different parameters. Here are a few: Manufactured Date, Frame / Electrical Serial Numbers, Total Battery Charge Cycles, Current Capacity, Maximum Battery Temperature, Previous Faults etc etc. This is a really usefull tool for sellers as they can actually prove the history of the eBIke to potential buyers increasing interest and possibly even the price of their eBike.

Think that could be a winner for me.
I didn't know that dealers would do that, I wonder how much they would charge... that peace of mind buying a used bike would be a lot greater than the gamble. might look in to that

 

[Wander]

I wonder how much they would charge...

Looks like no charge at all by this dealer when dealing with bikes bought by their customers directly from them.

 

[JohnMcL7]

On average what sort of usable life do people find they get from the batteries before they need replaced or is that very much a how long is a piece of string question?

My Mum has seen a Wisper 906 Alpino bike for sale locally second hand and the general running gear on the bike looks good, she's hired an e-bike a few times and loved it but wasn't considering one herself until she saw this one. My concern is the battery seems a real gamble and this thread confirms my thoughts, if it does need replaced that wipes a good chunk of the second hand saving off the bike. I've found the batteries on garden tools (strimmers and mowers) not to have a particularly great usable life before they need replaced.

John

 

[JohnCade]

It depends on the quality of the cells used and how the battery’s been treated. Wisper will have good cells I expect but has the battery been topped up if left unused? It should be every few months. Garden tool batteries die because they get left in sheds over winter and allowed to discharge.

Modern cheaper batteries should last three of more years if looked after, and good quality ones on some bikes are still going after five years and more. It all depends on how well it was looked after really and if they are used regularly they will last longer.