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Re: 12V battery BCI Size?

Tue Apr 16, 2019 4:44 am

Lead acid sucks as a storage battery, but it's hard to beat the safe, reliable, low maintenance, and dependable nature of a lead acid starter battery.

Tesla uses a regular lead starter battery just like everyone else.

To save weight and extend range, Boeing tried to use lithium as starter batteries for the APU on the 787 dreamliner. Even with using a complicated 4-level BMS with internal relay cutoff and dedicated external charrger, they had 2 to catch on fire. Now it is even more complicated with a fully-enclosed battery in a titanium housing with vent tubes. Makes you wonder how much of all that original weight savings has evaporated?
kiev = kenny's innovative electric vehicle

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Re: 12V battery BCI Size?

Tue May 21, 2019 8:29 pm

Hi Folks,

Last week Maeve would not go to Ready.
She is a 2014, so 12V starting battery is about five years old.
Checked the battery and water was low, added some, charged at one amp for an hour and everything was ok.

Bought a 21#, 9.5Kg Braille B3121 AGM battery.
These are marketed toward race cars and only have a one year warranty.
My past experience with AGM batteries has been good and long-term, but am taking a gamble...
The 17# Braille was an option, but the 21# one will likely have a longer life.

I cut a spacer board to go under the battery and lift it to the same height as the stock battery.
Battery length is short enough that I was able to leave some raised wood sections that hold the battery from sliding side-to-side.

The top hold-down should keep it from moving forward and backwards.

Hold-down at the top fit nicely.

Plastic top cover had to be notched, as the positive terminal isn't recessed from the edge like on the factory battery. Could have done a prettier job of cutting.

Pics here:

Price was a steep $240, including delivery and tax.
Hopefully it lasts a very long time!

Thanks and good health, Weogo

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Re: 12V battery BCI Size?

Wed May 22, 2019 11:24 am

Wow. It looks...... beautiful! Nice job.
Bought iMiev June 6, 2013, Now leaving electrons in my wake @ ~1000miles/month
Original owner Prius 2002 275,000+ miles
Original owner Prius 2009 125,000+ miles

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Re: 12V battery BCI Size?

Thu May 30, 2019 10:08 am

Don wrote:I *finally* got around to replacing the battery in our second car today. The OEM one was 7+ years old and had never shown any signs of getting weak, but I prefer to change things before they cause me problems. Used a Miata AGM again like I did in the first car 3 or 4 years ago. Ordered from Battery Mart for $107.95 with free shipping. Comes fully charged, sealed, maintenance-free and with a one year warranty...
Followed Don's advice and got the same thing as a preventive measure. Cut down a 2x6 to fit inside the tray (this battery is a bit wider than our tray so it must sit on top of that piece of wood). Put a strap around the battery for additional security as the clamp isn't a perfect fit.

After pulling it out I tested my seven-year-old OEM battery using a West Mountain Radio CBA and stopped the test prematurely at 31Ah while drawing a constant 5A - it was still going strong!
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
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Re: 12V battery BCI Size?

Thu May 30, 2019 11:03 am


I never noticed that the AGM is any wider - I saw it was shorter and measured by how much and that's why I sat it on a piece of 2 X 6. The factory hold down clamps worked fine after raising it up 1 1/2 inches, so I didn't need any other hardware to mount it

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