Battery tender

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graham,wa.
Newbie here to E-bikes, just wanted to ask if it is safe or a good idea to use a battery tender on my 48V 15ah battery to keep it charged while not being used, Thanks for any advice.
 
Do NOT USE A BATTERY TENDER ON YOUR EBIKE BATTERY !

1. Please understand to maximize the useful eBike battery life - the ONLY time you want to charge to a full 100% is when you know you will need that Full 100% for your next ride.

2. ALWAYS disconnect your Battery Charger after charging.

3. For "storage" (meaning long time till your next ride) NEVER store at more than 80%

4. In Cold Winter or High Summer Temperatuses remove the battery from the eBike and store inside.

.
 
4. In Cold Winter or High Summer Temperatuses remove the battery from the eBike and store inside.

.
I almost completely agree with what you wrote, but just to be very specific, lithium batteries suffer when stored at high temperatures, but contrary to what many people believe, and according to many sources, not at low temperatures. According to some source, storing SOME types of lithium batteries in a relatively cold environment (I mean, not liquid nitrogen...) can actually EXTEND their life.

However, they should NEVER be charged at low temperatures. And using them in the cold will cause a temporary loss of power and efficiency. But no permanent damage.

So, at the end of the day, as you wrote maybe easier to store them inside, and forget about all those complications.
 
I thought the same at one time. Coming from DIY auto mechanic, I didn't think twice I would keep the battery on the charger. But, as I got closer to buying a 48 volt eBike battery and read up on how to care for it, I found out the above offered info and more. This website appears to offer good overall info: From ElectrifyBike
 
No, it's not a good idea. fabbrisd told you the right things to do, but not why.

The reason is, since it's not a lead-acid battery, it doesn't need or want to be kept topped off, and doing so will drastically reduce the battery's life. As you can guess, these batteries are not cheap, most often costing over $500 to replace or rebuild.

Lithium-Ion batteries "like" to be kept between 20 and 80%, and closer to 50% if you're not going to use them for a month or more. Abiding by this will triple the life of your battery pack.
 
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I unsuccessfully searched for an Android app able to 1) read a number on a display (or a led status) and 2) shut off and on a programmable switch, or sound an alarm or take another action. It could be used for a huge number of application, including, for example, sound an alarm when the oven reach the desired temperature to avoid wasting time and $$$ :), perhaps using an old phone we do not use anymore, but still able to work.

A potential application would be to switch off the ebike, or phone, or whatever, battery charger when the battery reaches a certain value, and maybe switch it on again when it reach another level (20%?).

I searched extensively and, quite surprisingly (because the technology to do that exists!) couldn't find anything like that. Actually, the (many) programmable switches available in consumer shops do not come with open-source, programmable API, although devices allowing that exists.

I am working on it but I have liimited resources and skills in programming in Android and is a sort of fun project for myself.
 
To prevent burning your Garage or house down when storing your battery inside, as advised above, I recommend you keep it in a metal or fireproof container, that Cannot be pressurised. A smoke alarm nearby is also a good idea. You cant extinguish a Lithium battery fire very easily if at all. Spontaneous fires are uncommon but not unheard of.
 
Do NOT USE A BATTERY TENDER ON YOUR EBIKE BATTERY !

1. Please understand to maximize the useful eBike battery life - the ONLY time you want to charge to a full 100% is when you know you will need that Full 100% for your next ride.

2. ALWAYS disconnect your Battery Charger after charging.

3. For "storage" (meaning long time till your next ride) NEVER store at more than 80%

4. In Cold Winter or High Summer Temperatuses remove the battery from the eBike and store inside.

.
Furthermore when you connect, plug in the battery 1st, then the wall socket. The opposite when you unplug,
wall socket, then battery. Never leave it on charge for more than 6 hours. This will greatly prolong battery life.
 
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