The Poor Man's Battery Saver/Satiator: a $10 Outlet Timer?

Like many of you I saw a timer as a good solution to my worrying about properly charging my battery. I have a problem with the battery discharging after the timer stops, though. If the battery remains connected to the adapter and the outlet is not electrified, the battery drains. Is that likely an issue with the timer, adapter, or battery?
 
Like many of you I saw a timer as a good solution to my worrying about properly charging my battery. I have a problem with the battery discharging after the timer stops, though. If the battery remains connected to the adapter and the outlet is not electrified, the battery drains. Is that likely an issue with the timer, adapter, or battery?

Timers can create a little discharge current. Unplug from the timer.
I think chargers do that too, discharging (a little) through capacitors or whatever is there inside.
If it drains notably, it's a battery issue.
 
@pedaliboi - Sorry, I got nuthin'.

As a data point this does not happen with my Specialized Turbo battery and charger, but this setup is miles ahead of the shark pack and 2A barrel charger on my last DIY rig. Never tried a timer on that one.
 
After getting used to using an outlet timer to charge my ebike, I also started using one on my laptop.

Great idea. In fact I am noticing the battery in my 4 year old laptop is almost worthless now since I leave it plugged in 90% of the time. It used to be able to do 4.5 hours, now it’s under 1.5. I’ll get a new battery and a timer to go with it. I’m really liking the push button one.
 
After Grin Tech told me they did not have the proper adapter for my Yamaha battery I bought this $9 timer from Amazon. It's very basic, only allowing hourly increments, but it works. One hour charges my battery for about 25 to 30%, two hours for 50 to 60%, etc. So, if after a ride my battery shows 25% charge left, I set the timer for two hours and the battery gets charged to just over 80%.

I would buy a Satiator fron Grin if it supported all my e-bike batteries. It has a Rosenberger plug add-on option which may work with my Brose battery, but then again it may not as Specialized's Brose batteries (which also use the Rosenberger plug) have changed what some of the pins are used for. That said, Brose mostly makes motors and the batteries are typically up to the OEMs, so there's some hope that iZip is using a standard Rosenberger plug may work.

But it's an expensive option for a maybe. And it won't charge Yamaha, Bosch, Shimano, etc., and I change bikes regularly. So for now, like you, I'll keep using a timer. :) Thank you to the many people on EBR that made the genius suggestion of using a timer! Works with every charger out there, you just have to have a sense in advance of how long the charger you're using takes to charge a given percentage of the battery. I find that a 4A charger charges 1% of a 500 Wh battery every 2 minutes, approximately. So if you are at 50% and want to go to 80%, you need to charge it 30% which will take about 60 minutes. That's not exact, but in my experience it's awfully close (and close enough for my liking).

I actually usually aim for charging to 70%, to allow a little wiggle room for going over while still staying below 80%. I also find that the next day the reported charge level is sometimes a little higher than the night before (perhaps up to 6% higher). I'm not sure if that's due to a change in the temperature, or the battery chemistry settling down, or some other factor. It sometimes happens, and sometimes does not happen. Perhaps someone more knowledgeable than me can weigh in on why that might happen?
 
You can do that with the timer I posted. Set your bike to charge between 6-8 am for an 8 am commute.

I like the idea of plugging it in with a timed charger so that it stays in a lowly charged state until sometime in the early morning (or whenever) the charging kicks in. Genius! Thank you for that suggestion, I'm going to get a charger like that!

What's the lowest ideal state for leaving it overnight? 50? 40%? 30%? In other words, as a best practice, what should I charge it up to after the ride, but before setting it up on the timer to finish the charge in the morning? I know they recommend long-term storage at 70% or so, but that recommendation is presumably a little on the high side to allow it to slowly discharge down to a lower safe level.
 
50% is good for storage.

IMO you're making a mountain out of a molehill on charge state, it's not going to make that much difference over the life of your bike. Maybe in ten years you'll improve by 5%. But it's fun for some to chase it. 👍

As long as you don't store it at 20% nor 100% you'll be fine. If you're using it the next day you can charge it overnight. Lots of machinations for very little payoff. After two thousand cycles it MIGHT make a few percent difference. I'll be dead by then. 🤣
 
A timer is a simple, inexpensive solution to optimizing battery life... YMMV. ;)
 
50% is good for storage.

IMO you're making a mountain out of a molehill on charge state, it's not going to make that much difference over the life of your bike. Maybe in ten years you'll improve by 5%. But it's fun for some to chase it. 👍

As long as you don't store it at 20% nor 100% you'll be fine. If you're using it the next day you can charge it overnight. Lots of machinations for very little payoff. After two thousand cycles it MIGHT make a few percent difference. I'll be dead by then. 🤣

Oh, you're totally right that it's making a relatively small difference. But I'm one of those weirdos who *enjoys* the strategy of it! It's satisfying to me to know that I'm treating my batteries optimally, however large or small the payoff is. :D
 
A timer is a simple, inexpensive solution to optimizing battery life... YMMV. ;)

I totally agree, I use one myself now thanks to many people on EBR suggesting it (and thanks to all those people!).

My question is what to do when I have, say, a 35% charge after a ride, and I intend to ride again the next day. Is it optimal to leave it at 35% for half a day, or optimal to top it up to something like 50% after the ride? This would be with the intention of further topping it up to 80% (or whatever I decide I need for the length of ride I have planned) shortly before the next ride.
 
I totally agree, I use one myself now thanks to many people on EBR suggesting it (and thanks to all those people!).

My question is what to do when I have, say, a 35% charge after a ride, and I intend to ride again the next day. Is it optimal to leave it at 35% for half a day, or optimal to top it up to something like 50% after the ride? This would be with the intention of further topping it up to 80% (or whatever I decide I need for the length of ride I have planned) shortly before the next ride.

Don't overthink this. It's more like a "best practices" guide, and much of it is guaranteed to work on paper but nowhere else. Also, I believe it's super important to get a full (balance) charge frequently for best performance/longevity. Point being, you need to weigh the need for that when going with the timer plan.

To answer your question, I would charge right away so I didn't have to try and remember to charge just prior to my ride.
 
Batteries should not warm on 2C discharge. They're likely rated for 25C or more.
Yes, if it's discharged, plug it in and charge it up.

For near daily riders there's no need for any special care. Just charge and go. The trickle chargers supplied are as safe as you can possibly get, and will condition/balance your cells on each full charge. It's better to charge them all the way up if you're going to use the bike.

L-ion cells don't have a 'memory' effect, think...cell phone. Charge and go.
 
I'm planning to make something based on a arduino type microcontroller that will be in-line with a regular charger to make it semi-smart ...

If I monitor the charge voltage, I can set this device to cut power (Probably just open a relay) when the battery reaches a set value.

If I include a knob and a small display, I can make the charge value whatever I want for a particular day.
Most likely be set to 80% most of the time, but would allow me to move it around if desired.

Initially, It will be just for my current 48V, 2A charger, but there is no reason I can't update the program in the future to have various pack voltages or chemistry profiles pre-set to make it easy to switch between chargers.

It won't have the monitoring / tracking / history capabilities of the satiator, and I won't be able to adjust the maximum charge current, but should only cost about $10 - $15 in parts, and be usable with any (48V initially) charger.

I'm sure this is possible - The main unknown at the moment is the best way to check the voltage (charging voltage going in Vs Voltage at the discharge port) and how that relates to the actual battery charge state - Basically, how much do I need to worry about the BMS . (Not too hard to figure out, just have to sit down and do it)

I'm also sure I can add other functions, such as:
a timer or even a 2-part charge profile like those 'fancy' timers mentioned above.
Total Charge info - ie, how many WHrs Just went in. (much easier than long term tracking)


If it works as expected, I may make up a proper housing for it and maybe even design a circuit board to make it really sleek.


Now to just find the time! (I barely even have time to ride the bike, other than my commute.)
Don't know if you are looking for a 110v relay, but I've used this one with good success.
 
Don't overthink this. It's more like a "best practices" guide, and much of it is guaranteed to work on paper but nowhere else. Also, I believe it's super important to get a full (balance) charge frequently for best performance/longevity. Point being, you need to weigh the need for that when going with the timer plan.

To answer your question, I would charge right away so I didn't have to try and remember to charge just prior to my ride.

I don't want to charge right away as I want to at least wait for the battery to adjust to room temperature, especially this time of year when it's pretty cold out and the battery is significantly colder than the ambient temperature of where it's being charged. By using a timer I don't need to remember to do it, it'll happen when the timer goes off to start the charging. And I always own multiple batteries for any bike I'm using regularly, so I'll always have another battery charged up to 70% or so in case a mistake is ever made, so I definitely feel no pressure to charge immediately "just in case".

I imagine the BMSs are pretty good for Bosch/Shimano, so they might be balancing the cells each charge without the need for a full charge or full discharge anyway? Good BMSs can do that on a cell by cell basis within the pack, and I'd imagine they're using pretty good cells and pretty good BMSs in those brands. Unless anyone knows otherwise? That said, they will get semi-frequent full charges right before big rides, and even occasional full discharges (again, on big rides).

I know that some of this stuff is all about marginal gains. I will again reiterate that I enjoy this kind of strategizing, so this is actually fun for me (believe it or not). :)
 
Strategize away my friend, but I would not share too much with a newbie. For the most part, they're already just hanging on to the technology by their fingernails.

This kind of play best left to those that already have a pretty good grip on battery technology....

And the next time you want somebody to reply with cold weather in mind, you should bring it up. Those of us in warmer climates don't think about that much....
 
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