Help! Replace/refurbish Giant Enerypak 400 battery

[JohnMcL7]

My Mum has a Giant Prime+ ebike (or something like that), it's a stepthrough hybrid with derailleur gearing and the battery is an Energypak 400 which slides into the top of the rear rack. The battery hasn't been used in the last couple of years and when the charger is attached is shows a solid red light then changes to a flashing red light so I'm pretty sure the battery is dead and not charging.

I've had a look around and unsurprisingly with it being an older battery I can't find any compatible ones for sale. It appears the only viable option would be to use a battery repair/refurbishment service although I've noticed some explain that they replace all the cells for older batteries as they don't think it's worth replacing individual cells. If this is the only option I'd appreciate any recommendations for a company to use and a rough estimated cost, most of the sites I looked at were not showing prices although one seemed to quote around £400.

 

[saneagle]

My Mum has a Giant Prime+ ebike (or something like that), it's a stepthrough hybrid with derailleur gearing and the battery is an Energypak 400 which slides into the top of the rear rack. The battery hasn't been used in the last couple of years and when the charger is attached is shows a solid red light then changes to a flashing red light so I'm pretty sure the battery is dead and not charging.

I've had a look around and unsurprisingly with it being an older battery I can't find any compatible ones for sale. It appears the only viable option would be to use a battery repair/refurbishment service although I've noticed some explain that they replace all the cells for older batteries as they don't think it's worth replacing individual cells. If this is the only option I'd appreciate any recommendations for a company to use and a rough estimated cost, most of the sites I looked at were not showing prices although one seemed to quote around £400.

This situation is quite complicated. Giant generally use Yamaha stuff, which is hackable, but on many bikes, they have their own versions which have their own software and communications protocols. If you have such a system, the Yamaha hacks that allow you to run any battery don't work. First thing would be to look at your battery and see if it has Giant or Yamaha written on it.

Batteries have an internal management system in them that needs some power to work even when not even on the bike. That means that if you don't charge the battery for a long time, some cells can drain down below the point when the management system allows charging. In that case, the first step would be to open the battery and measure the voltage on the cells to see how bad it is. In many cases, it's pretty easy to get the low cells up to where the charger can be used again. All that can be done by a competent repairer if you can't do it yourself.

 

[JohnMcL7]

I've looked over the battery but I can't see any Yamaha badges, only Giant ones. I'm not an electronics person and would be concerned about frying something so if there's any known good repairers are worth giving a shout, I'd appreciate any recommendations.

 

[soundwave]

if it works and charges it can have the cells replaced if the bms is dead and lost its can bus programming its a bin job.

you could try the guy in my sig and see if he can do anything with it but i doubt it as giant use there own controllers bms and displays and can bus locked.

the original Yamaha motors use uart so more easy to get a standard batt to work with a mod chip but it wont work on giant yamaha motors

 

[JohnMcL7]

I've been having a hunt around and ebike24 seem to have an Energypak 500 for sale with the five pin socket:

Giant EnergyPak luggage rack battery 500 Wh

The Giant EnergyPak luggage carrier battery with 500 Wh is your reliable companion in the city and on tours. The practical positioning of the…

www.ebike24.com

I'm assuming this would be compatible with the bike and they seem to ship to the UK plus the few posts I've seen on ebike24 here seem to be ok. Assuming I get hammered on VAT it will come to a bit over £600 which doesn't seem too bad for a brand new battery given at the moment I'm struggling with options.

 

[JohnMcL7]

I've spoken with Giant who have helpfully provided the following part number as a compatible battery with the bike:

244M36500R-03V - EnergyPak 500 Carrier Type UART 36V-500Wh

I found variants of the battery with three, four, five or six pins and some listed as with energy recuperation and some without, I had wondered if I bought a compatible charger would that work with this bike. However I've found the battery with the three pin charger socket is not compatible because it has different contacts (non-can vs can) although not clear if with or without energy recuperation makes any difference.

I've ordered the battery through my local Giant dealer although the price looks like it's going to be hefty but at least it will be in the UK with warranty. Although there's none of these batteries available in the UK so it's going to have to be shipped from Europe.

It's likely discussed elsewhere but it does make me wonder what other people did with their Giant E-bikes that used this battery type given it's likely most of these batteries now will have failed due to age. I expected the main problem to be cost when it came to replacing the battery but I didn't expect it to be so difficult to even source one.

 

[saneagle]

It's likely discussed elsewhere but it does make me wonder what other people did with their Giant E-bikes that used this battery type given it's likely most of these batteries now will have failed due to age. I expected the main problem to be cost when it came to replacing the battery but I didn't expect it to be so difficult to even source one.

Probably, they get an Amazon bike for £500 and wonder why they didn't do that in the first place.

 

[AntonyC]

If you ordered a replacement battery for your particular bike a retailer would be responsible for it working, and I'd have thought a consumer order through a dealer would count as retailing. If you ordered the specific battery and a minor variation catches you out, batteries sometimes aren't accepted as returns due to the nature of the goods, as others here have found to their cost. If the latter and you can't cancel the order, you could maybe have the new battery fitted in the shop and point to Giant's advice if it doesn't work. Excuse the beard stroking but with car parts it's not uncommon for the correct part number to be no guarantee.