On 28 Sep 2017 at 16:35, brucedp5 via EV wrote:

> If you have to replace your pack, I suggest:
> http://www.sears.com/automotive-batteries-marine-batteries/b-1100201 >
>  select the appropriate size you currently have, either group 31, 27,
> or 24. I have had good cycle life with these ...  

Careful there!  Unless things have changed, Sears and other mass retailers 
buy their batteries from different suppliers at different times.  It 
probably depends on who bids lowest.  So, you might get batteries similar to 
Bruce's.  Or, you might get batteries like the Sears Diehards that went into 
the earliest Solectria Forces. Many of those failed in less than a year.

For flooded marine batteries, I would go with Trojan or US Battery brand 
instead.  At least you'll know who made them, and those two companies have a 
long history of making good EV batteries.

That said, the longest-lived 12v marine batteries I know of are East Penn 
Deka Dominator gel batteries.  

I have them in an Elec-Trak tractor and a New Idea riding mower.  They're 
getting close to 20 years old and are just now finally starting to lose 
capacity and fail.  Solectria Force and E-10 road EVs worked them much 
harder than my tractors, and routinely got over 5 years of life.

However, they come with some caveats.

1. They're not high power batteries.  Their voltage sags rather alarmingly 
at high currents.  You'll need to keep a light right foot and live with 
modest acceleration (many would say "slow").  Turning down the controller's 
current limit would not be a bad idea.

2. They have less capacity than similar flooded marine batteries, so give 
less range.  This is part of the secret to their long life -- you can't 
overdischarge them because they're acid-starved.  The electrolyte turns to 
water before the girds can be damaged.

3. They need a charger which won't push them over 14.3 volts per battery. I 
wouldn't recommend using your BC-20.  Bruce and Roger have discussed this in 
more detail.  

4. They're not cheap.

I didn't notice that Roger mentioned that he is (or was? I don't know his 
current status) involved with Delta-Q.  That's why he can write with 
authority about their chargers.  He knows his stuff!

FYI, in case it matters, AFAIK Delta-Q chargers are still designed in Canada 
and manufactured in China.

I somewhat reluctantly agree with Roger's recommendations about modular 
charging (one charger per battery).  

Intuitively, it seems like a great idea.  But like many others who've tried 
it, I've used it, and have had an individual charger fail. 

Fortunately in my case, the pack was only 36v, so I quickly caught the one 
incompletely-charged battery going flat.  The larger the pack, the less 
chance you have of noticing an undercharged battery before it's too late and 
that battery becomes what longtime EVDL contributor Bob Rice (RIP) used to 
call a "Trojan Teakettle."

Some other folks here on the EVDL will no doubt tell you that "lead is dead" 
and that you should convert your EV to lithium.  They have interesting 
arguments.  I won't either agree or disagree.

David Roden - Akron, Ohio, USA
EVDL Administrator

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