[PSUBS-MAILIST] Magnacom SW-1000-sc Battery

[David Colombo via Personal_Submersibles]

Hi Alan, one of the fuse is a self reset fuse based upon temperature. The
other im not so sure.  The original batteries were 1.2 volts (5) total for
12v. If i go with the 16050 li batteries I have as new cells, they are
3.7v, charge to 4.2, discharge to 3.0v. I was thinking that I would go with
4s2p for a total of 8 batteries at 14.8v I could be wrong, but dont I even
need a bms even for this small quantity? As I have never built a Li battery
before, I figured that a small unit will be the start to be a bigger
battery pack.

Best Regards,
David Colombo

804 College Ave
Santa Rosa, CA. 95404
(707) 536-1424
www.SeaQuestor.com



On Fri, Dec 18, 2020 at 5:35 PM Alan James via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> David, the electronics may be a low voltage protection circuit, or a low
> high voltage protection circuit so you don't overcharge the batteries.
> As Sean says, if you replace with lithium you have to match the battery
> voltage. Lithium Iron batteries have a nominal voltage of 3.7 but can be
> charged to 4.2, & discharged to a minimum of 3V. So that gives 2 options, a
> 3 cel or 4 cel configuration. So 4 cel would be just above 16.6V and could
> be used down  to 12V (very minimum) or 3 cel 12.6V & 9V minimum.
> Alan
>
> On Saturday, December 19, 2020, 09:24:43 AM GMT+13, David Colombo via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Hi Alan, The unit in the sub I can. The topside unit I was hoping to keep
> the unit intact in case it could also be used as a diver unit.
>
> Best Regards,
> David Colombo
>
> 804 College Ave
> Santa Rosa, CA. 95404
> (707) 536-1424
> www.SeaQuestor.com
>
>
>
> On Fri, Dec 18, 2020 at 12:03 PM Alan James via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> David,
> can you just wire them in to 12V in the boat & forget about the battery
> packs, or are you intending to use them for scuba diving.
> Alan
>
> On Thursday, December 17, 2020, 06:39:22 AM GMT+13, David Colombo via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Hi guys, I torn down the one battery I got with my magnacom units so I can
> build a couple more.  Attached are photos of the teardown. Only problem is
> one component that only had labeling on one side. The other side had only
> the letters va with a smudge over other data. I think it's a fuse based on
> the fact it interrupts the circuit.  I sketched out the circuit for
> reference. I thought taught there might be a BMS, but apparently not.  Jon,
> to recreate the circuit board component, would you recommend having done by
> a fabricator? Any ideas or thoughts would be appreciated.
> Thanks,
> David
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