Willie via EV wrote:
I have a neighbor that copied a commercial golf cart conversion product.
He used 11 S 100ah LFP (~3.4v) cells...11 chargers. Which were pretty
expensive; I think he ended up paying ~$20 each. He's been running it a
couple of years with no trouble. So far. I think he checks charged
voltages regularly to make sure the chargers are working.
The key is to have some way to know that all cells got charged before he
drives off. If he relies on the chargers to "never fail", sooner or
later one *will* fail. He will drive off with a dead cell in the pack,
which will cause that cell to fail... maybe catastrophically!
On discharge, how will you know when the first cell goes dead?
There are some pretty cheap cell monitors available. ~$2 each, as I
recall. I think my neighbor just checks voltages before charging.
Again, that works as long as nothing goes wrong. But I can see checking
all 11 voltages will get tedious, and he'll stop doing it. Then you're
back in the same situation, where something can fail dramatically.
I have been using massively parallel ~4ah salvage hoverboard batteries
in my 36v golf cart for several years with good results. A box of 8 HB
batteries will run the cart ok. I am running four boxes right now.
Range with 4-5 boxes is 15-20 miles. Being parallel, it is VERY easy
to add or remove boxes. Everything is connected with SB50 splitter
cables.
What are *you* doing to know they are working correctly? If the packs
are directly in parallel, is there a fuse somewhere (inside the pack?)
so if one develops a shorted cell, all the others won't dump *all* their
power into the short?
I see operating with no monitoring or fuses like wiring your home with
no circuit breakers, and all circuits in parallel. It's fine when
everything is working. But when there's a failure, you burn your house down!
--
I have no special talents. I am only passionately curious.
-- Albert Einstein
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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