Battery information Trickle charger for my winter stored 914, Battery recommendation 1.25 Amp or 4. Amp better?? Options

[TJB/914]

(IMG:style_emoticons/default/sad.gif)

Looking for a battery trickle charger recommendation.
1.25 Amp or 4. Amp best for winter storage on my 914?
Price range?

Tom in cold Michigan.

[technicalninja]

I like the NOCO products.

This is designed for AGM batteries, it will work on the others fine.

If you haven't changed over to AGM you should (no acid release).

https://www.amazon.com/NOCO-GENIUS2D-Direct...49385f&th=1

The little "jump boxes" are BAD ASSED!
I have one, probably 9 years old now, a small one...

I've jump started Diesel one-ton trucks with it.

It will jump 10 normal cars between charging that take less than on hour from a USB charger.

We give them away as Christmas presents...
You always get the call, in June or July.
"Wow, the tiny jump box just saved my ass. I only charged it once, 6 months ago"...

[fiacra]

(IMG:style_emoticons/default/sad.gif)

Looking for a battery trickle charger recommendation.
1.25 Amp or 4. Amp best for winter storage on my 914?
Price range?

Tom in cold Michigan.

Price range can be into the low hundreds. It can depend upon what type of battery you have (lead acid, AGM, etc) and the features you want. I recently bought two UltraPro Elite trickle chargers, but I only picked them because Costco had them in stock. 2-6 Amp depending upon setting. $40 at Costco, $65 at other on-line stores. Suitable for a wide range of batteries, and so far them seem to be just fine on my AGM batteries. Comes with a harness you can leave in place and quick connect/disconnect the charger. I have four vintage cars in rotation so all of them now have a harness installed. Don't have to worry about winter storage in my area so I drive year round, but sometimes a car will sit for several weeks between being driven. Your battery manufacturer may have a list of chargers they recommend, although I don't think you necessarily have to follow that recommendation. Good luck!

[Artfrombama]

I have several of the small battery tenders (1.25 amp) that I keep on my cars tractors and equipment. I’m a believer that the battery tenders can increase battery life dramatically. I have one battery that stays on the tender since 2016 and it still tests good.
Had one incident where the battery tender overcharged and ruined the battery and made quite a mess. I contacted the company and was given a replacement charger.

[windforfun]

0.75 A. 15 years old & works like a champ.

[ClayPerrine]

0.75 A. 15 years old & works like a champ.

(IMG:style_emoticons/default/agree.gif)

I have one in each garage bay, and all 3 of the 914s and the BMW have pigtails for them.

I even hung them from the garage door opener so they are always easily accessible but out of the way.

[chmillman]

Battery Tenders here also, both for the cars and formerly for my motorcycle. I have larger ones though, like 5A. They work great. I included the motorcycle one with the sale when I sold my previous ride, a Honda with a standard battery. As my new ride is a BMW equipped with a lithium battery, I thought it wiser to get the official BMW charger for it. About twice what a Battery Tender goes for...

[mb911]

Battery tender for me as well. I have the 2 boat batteries, 2 944 batteries and the 914 battery lines up on the floor and each day I switch to the next battery. Has served me well. The one boat battery is from 2013 and still works perfectly

[mb911]

[dtmehall]

i use the same charger as shown above (battery tender 800) for both my 914 and lawn tractor.

the batteries have both lasted longer than specified

[fixer34]

Maybe look at an Autozone/Duralast BC40DL .
Full on charger, but works with wet/AGM/Lithium, switches to Float mode when fully charged. Has a deep discharge/charge function and also alternator test.
For about twice the price of a Battery Tender.

[SirAndy]

0.75 A. 15 years old & works like a champ.

I have the same one (IMG:style_emoticons/default/biggrin.gif)

[TJB/914]

Thanks all & Andy.
That's the one I purchased.
Tom

[L-Jet914]

I have two Schumacher 1.5amp charger/maintainers. I'm not sure if they're doing what they are supposed to anymore, so I purchased 2 CTEK battery maintainers.

[fiacra]

Just watched a Hagerty Barn Find video and they did a promo for Battery Tender, 20% off with code HDC20OFF.

[chmillman]

Actually, I lied... I was convinced I had a Battery Tender, but actually not. I now remember why - they're not readily available for sale in this country.

What I have is an Optimate 6. Great unit. Had a smaller one for the motorcycle. Looks like the company is based in Belgium, offices in the US and Canada.

[chmillman]

Thought this might be interesting to relate.

When I bought the car this summer, the battery was already 5-6 years old, it still seemed in fair condition, but I said what the heck and went ahead and got a new one anyway - 52 AH sealed lead-acid (original spec is 45 AH I think).

Later I installed a new audio head unit (Blaupunkt) and also a subwoofer (Panasonic). Both of these want a direct always-on +12V connection, plus a connection to +12V ignition on. In principle, they only then can be on when the ignition is on (internal solid-state switch), the always-on 12V connection keeps the internal clock and other stuff in memory in the head unit – I guess because they are too cheap to have a battery or capacitor protected memory in the thing. Not sure why the subwoofer needs this. The +12V always-on - which I assume is also the main power input - I wired directly from the input side of the fuse panel and through my own 15A fuse.

Anyway, recently I hadn’t driven the car for about three weeks and when I got in to start it, it turned over, but much slower than usual. Hmm, something is draining the battery more than normal...

So I got out my trusty original Fluke 77 (10 years younger the car) and measured the current flow between the battery negative terminal and ground with the ignition off. It read 60 milliamps. Doesn’t seem like a lot... Then I pulled the fuse on my line going to the audio components, and the current draw dropped to 8.5 milliamps. What’s pulling that? The original VDO clock. Disconnected the clock and the current draw dropped to 0. So the audio components alone are drawing around 52 mA – even when turned off.

Doing some math – let’s say one would not like the battery to go down below about 50% of full charge. That means a discharge of about 26 AH. If the discharge rate is 60 mA/h, it takes 433 hours to get down to 50% charge. Divide that by 24 and you get…18 days. So in a little over two weeks, half the battery charge is gone. A lead-acid battery also has a self-discharge rate – which varies depending on temperature, battery style and age – but let’s say 5% per month. In 2 weeks, that’s 2.5% of the 52 AH, about 1.3 AH, so relatively negligible, but still there. But in a month, the 60 mA pull plus the self-discharge will drain the battery completely.

So, I ended up putting in a relay so that when the ignition is off, the audio units get no power at all. Only the clock is running with its 8.5 mA pull. That will pull a fully-charged battery down to 50% in about 3 months (including a 15% self-discharge). So, yeah, a trickle charger is a good idea if you are not going to drive the car for awhile.

[windforfun]

Google has much to read about on this topic. Great homework here.

Many modern electronics systems never fully shut off unless you pull the plug, so to speak. But come on now, how many mA do you need to keep a car audio system happy when it gets lonely. Hmm...

Thanks for posting!!!

(IMG:style_emoticons/default/dry.gif) (IMG:style_emoticons/default/dry.gif) (IMG:style_emoticons/default/dry.gif)

[PlaysWithCars]

I have to put in a plug for BatteryMinder brand chargers. They have the added desulfation feature that combats one of the battery degradation modes caused by age and deep discharges. I've used them for years on the fleet of stored cars and have batteries that have gone 10+ years and still working. Not much more $ than battery tender, but a better feature set.

[flipb]

Just to chime in, I've got an Optima Red Top and wasn't sure if I could put a standard battery tender on it so I bought the Optima maintainer/charger. It's been great.

https://www.amazon.com/gp/product/B00DHGPVKI

(IMG:http://www.914world.com/bbs2/uploads_offsite/m.media-amazon.com-10752-1731506105.1.jpg)