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Search: Posts Made By: KTP
Forum: Electrical: Batteries, Generators & Solar 05-08-2018, 08:27
Replies: 188
Views: 10,964
Posted By KTP
Re: Lipo vs lifepo4

20mOhm internal resistance with 125A peak discharge current?

At that current level, I^2 * R says about 300 watts will be dissipated by heat in the battery!
Forum: Electrical: Batteries, Generators & Solar 04-08-2018, 12:46
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

I am not quite getting the 4x energy density figure but could be overlooking some things.

LFP was about 110 wh/kg IIRC while lead acid is 40wh/kg, so around 3x, although getting 80% out of a lead...
Forum: Electrical: Batteries, Generators & Solar 04-08-2018, 12:10
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

There are extremely few experienced cruisers on here who know anything about electric propulsion. Quite a few though who seem to be overly reliant on their diesel engines though. Wonder what they...
Forum: Electrical: Batteries, Generators & Solar 04-08-2018, 07:46
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

Well obviously we are going to install the system ourselves (I am a EE). I do get what you are saying, that I could rebuild the diesel myself and know everything was done correctly.

I am not...
Forum: Electrical: Batteries, Generators & Solar 03-08-2018, 12:07
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

First, it was not a perfectly good PS34. It was a poorly maintained PS34 that we are slowly bringing back to decent condition. I really don't get why people think it is so crazy to try out...
Forum: Electrical: Batteries, Generators & Solar 02-08-2018, 17:39
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

For me it is not so much green ideals (the batteries have a detrimental effect on the environment although lead acid does have a very high recycle rate). It is:

1) quiet

2) cleaner (no oil or...
Forum: Electrical: Batteries, Generators & Solar 01-08-2018, 19:43
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

Well ok if all we are talking about is devaluing at resale time then I guess there is no issue. We are at the point where we have no motor in the boat already. We have the old Yanmar undamaged that...
Forum: Electrical: Batteries, Generators & Solar 01-08-2018, 10:16
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

This is just a failure of the installer and possibly improper maintenance or ignorance of the owner. Quite a few cruisers out there are running with fairly big battery banks and using things like...
Forum: Electrical: Batteries, Generators & Solar 01-08-2018, 08:21
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

I already deducted the $25K when I purchased the boat as I was placing little value in the 28 year old Yanmar which had been poorly maintained. Pulling the engine was also necessary to access the...
Forum: Electrical: Batteries, Generators & Solar 01-08-2018, 07:24
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

I plan on having 1600 watts or more of quickly deployable solar, so if we are on the hook all day with no wind and some sun, it should get the batteries back to near full. If it is overcast it might...
Forum: Electrical: Batteries, Generators & Solar 30-07-2018, 17:18
Replies: 186
Views: 16,482
Posted By KTP
Re: LiFeYPO4 1000Ah Winston prismatic cells and all electric galley...

People in the USA will buy something when it gets mainstream. Case in point is the mania over Tesla model 3.

When you can go into a Costco and buy LFP, it will sell quite well.
Forum: Electrical: Batteries, Generators & Solar 30-07-2018, 15:46
Replies: 9
Views: 608
Posted By KTP
Re: S/Y Herminia going green

Definitely stiffen them. Look into the twin wall polycarbonate in either 6mm or 8mm thick. It will both add rigidity to keep them from flexing in the wind and also provide some amount of airflow. ...
Forum: Electrical: Batteries, Generators & Solar 30-07-2018, 08:51
Replies: 72
Views: 19,854
Posted By KTP
Re: Rolls versus AGM Batteries

Look in the battery compartment in a golf cart and notice all of the corrosion and crystals. Do you really want to sleep or eat on top of that and have it next to your electronics?
Forum: Electrical: Batteries, Generators & Solar 30-07-2018, 08:47
Replies: 186
Views: 16,482
Posted By KTP
Re: LiFeYPO4 1000Ah Winston prismatic cells and all electric galley...

Lab conditions @ 25 degrees F

But anyway, that would be 19 years at 365 discharges per year. Assuming a 4% per year degradation due to age, the capacity would be down 40% at the 10 year mark.
Forum: Electrical: Batteries, Generators & Solar 29-07-2018, 14:17
Replies: 9
Views: 608
Posted By KTP
Re: S/Y Herminia going green

Oh I was thinking more of just hooking them on when at anchor, not while underway in heavy seas. I would make it where they just clip on to the lifelines and plug in to connectors that you have...
Forum: Electrical: Batteries, Generators & Solar 28-07-2018, 18:46
Replies: 9
Views: 608
Posted By KTP
Re: S/Y Herminia going green

Why limit the rail panels to just one on each side of the cockpit? It looks like you could have up to four on each side of the boat, at least while at anchor.
Forum: Electrical: Batteries, Generators & Solar 24-07-2018, 13:34
Replies: 62
Views: 3,539
Posted By KTP
Re: Blocking diodes for paralleled panels?

Yeah but I need probably a lot more than you because I am going to be running eventually with a 20kWh battery bank and using a 10kW electric motor for propulsion. Harvesting 2kWh to 4kWh a day...
Forum: Electrical: Batteries, Generators & Solar 24-07-2018, 13:31
Replies: 74
Views: 6,335
Posted By KTP
Re: Recommened Flexible Solar panels.

Well that would kind of be playing right into Trump's hand then.

Although I don't know why a $800 panel can't be made in the USA and still be able to compete with a Chinese $150 panel...

USA...
Forum: Electrical: Batteries, Generators & Solar 24-07-2018, 06:13
Replies: 62
Views: 3,539
Posted By KTP
Re: Blocking diodes for paralleled panels?

They are like $500 (for the Kid). I know that is only half a boat unit but still...
Forum: Electrical: Batteries, Generators & Solar 23-07-2018, 21:42
Replies: 62
Views: 3,539
Posted By KTP
Blocking diodes for paralleled panels?

If you had a boat with four 22V open circuit 100 watt panels in series on the starboard and four 22V open circuit 100 watt panels on the port, would it be required, advantageous or disadvantageous to...
Forum: Electrical: Batteries, Generators & Solar 23-07-2018, 21:28
Replies: 74
Views: 6,335
Posted By KTP
Re: Recommened Flexible Solar panels.

Quite an imagination there.

I was planning on using marine grade chewing gum to attach the aluminum backed panels to the sailboat, not some cheap stuff.
Forum: Electrical: Batteries, Generators & Solar 23-07-2018, 19:48
Replies: 74
Views: 6,335
Posted By KTP
Re: Recommened Flexible Solar panels.

Yep, I haven't owned one before but I understand that if they are allowed to flex the cells will develop micro fractures and power will decline (possibly even to zero output).

I plan to mount them...
Forum: Electrical: Batteries, Generators & Solar 23-07-2018, 18:59
Replies: 74
Views: 6,335
Posted By KTP
Re: Recommened Flexible Solar panels.

I just ordered two of the Renogy 100 watt super flexible panels (bend up to 248 degrees). They had them back in stock again at $199 ea. but I found a coupon code WELCOME10 which gave another 10% off...
Forum: Electrical: Batteries, Generators & Solar 22-07-2018, 19:20
Replies: 127
Views: 10,283
Posted By KTP
Re: Realistic non-bs comparison of lithium to lead

I disagree with you but feel free to point out the 90% of my OP which was nonsense. Making a general statement doesn't do much to promote your case.

LFP has some big things going for it:

1) ...
Forum: Electrical: Batteries, Generators & Solar 18-07-2018, 15:14
Replies: 70
Views: 4,813
Posted By KTP
Re: What crimper do you guys use for larger cables?

We are in Blaine, WA. There really is no good close by rental store or place where I could hop over and get something when I need it. This is a conversion of our sailboat to electric drive so...
Showing results 1 to 25 of 122

 
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