Author Topic: House Battery  (Read 107 times)

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Rbob

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House Battery
« on: February 22, 2021, 09:36:03 PM »
Just wondering what others have used or recommend.

My prior boat had one house battery, only electronics with hd pot puller, no windlass or diesel heater.

I was thinking about 2 6v agm batteries as house battery but that may be overkill and 150lbs +/- of batteries but capacity is 210Ah that is a lot.

Edited, running 6v in series capacity remains the same, thanks Json

Just dont want to kill a battery running the heater all night.



« Last Edit: February 23, 2021, 07:42:51 AM by Rbob »

json

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Re: House Battery
« Reply #1 on: February 22, 2021, 10:23:40 PM »
I think you would need to run those in series to get the voltage to 12v +- for the house system, so your Ah capacity would only be 210 total. I thought this was a good amount until I started doing the 'add up everything and make a day estimate of usage' exercise. My bait tank pump alone is 8 amps @ 12 volts dc, so if I run that thing continuous off house for 24 hours that's 192 amp hours... Something else to consider is the usable capacity, which from my understanding is about 30% of your lead acid bank if you want your batteries to last (using partial state of charge between 80% and 50%), so this brings your 210 amp hour bank down to around 65 amp hours.

I read an article today that got my inner mad scientist all riled up about building a lithium iron phosphate bank from chinese cells. It doesn't seem very difficult and for a fraction of the cost of buying a commercial lithium iron phosphate system you could have a pretty high capacity bank that you knew in and out. The downside of course is if you screw up the cost could be very high, up to and including a fire on board in a not so great situation... a couple years ago I built an electric skateboard that has a 60 18650 cell lithium ion battery in it, and while the battery works great (and the skateboard too) it is downright scary how much energy is in that thing and thinking about what would happen if it got into a thermal runaway.

https://www.svavocet.com/2021/02/22/powered-by-home-built-batteries/

Rbob

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Re: House Battery
« Reply #2 on: February 23, 2021, 08:07:41 AM »
Yes on the 6v in series = 12v, thanks for the info about capacity staying the same.

I need to do some more research.  Most fishing type boats I have been on / seen have one house battery so maybe it will have to be enough. 

Looking into Firefly AGM Foam Core:
https://www.pysystems.ca/resources/ask-pys/firefly-oasis-vs-agm-vs-flooded-increasing-effective-bank-capacity-david/
« Last Edit: February 23, 2021, 10:49:36 AM by Rbob »

json

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Re: House Battery
« Reply #3 on: February 23, 2021, 10:51:35 AM »
Not sure which heater you have, assuming a wallas, the spec for the 30DT says it uses 0.8-1.8 amps, so also assuming middle of that running non-stop you would use around 30 amps per day... You can always start small and scale up if/when the need arises and after you get a feel for how much NRG you will be using. You can also supplement with things like solar or wind, although solar panels would probably be kind of grumpy most of the time in the pacnw :P

Rbob

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Re: House Battery
« Reply #4 on: February 23, 2021, 04:07:29 PM »
I found a great video explaining battery types pros and cons.  Looking like Firefly Oasis might be a good choice:

https://www.youtube.com/watch?v=X6rwFN35oBY
« Last Edit: February 23, 2021, 04:12:54 PM by Rbob »

rhenryinoregon

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Re: House Battery
« Reply #5 on: February 23, 2021, 06:51:32 PM »
Iíve been watching the guys who buy off AliExpress and build their own packs. Itís very intriguing but I have trust issues. Iím a year out from that decision so maybe Iíll feel more comfortable by then. I am figuring on flexible solar panels on top though, and maybe a little egg beater generator as well. I just donít want my boat to look too much like a Christmas tree.
Randy Henry, SILVERTON Oregon
Randy_Henry@msn.com

ghelland

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Re: House Battery
« Reply #6 on: February 23, 2021, 11:19:07 PM »
I know the price sounds tarible ($1600) but the best option i have found so far is the Dakota lithium battery, 200Ah and you can use almost all of them.   Made in America and the company sounds solid.  I currently have 2 golf batteries in a camper and run a fan on the heater all night when it is cold.  The drain on the batteries is too high for me so my boat will have a larger bank.  There is a power usage calculator on the Ranger tug sight that might be a good place to start.

Djeffrey

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Re: House Battery
« Reply #7 on: February 25, 2021, 01:54:52 PM »
I used one firefly AGM for the house and one optma AGM as a starter. I have no fridge and 100% LED LIGHTS. I have very little power needs when Iím not moving and recharging with alternator.

Rbob

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Re: House Battery
« Reply #8 on: February 25, 2021, 02:40:46 PM »
I am pretty set on the Firefly AGM house battery and a Lifeline AGM Start battery also, only thing I would be running at night is some led lights and the Wallas heater, which is under 2 amps per hour.

Dakota lithium is awesome but probably would do the 100 amp if I change my mind, roughly $900 vs  $550 approx. Probably not much difference in the long run.

On a side note, I purchased a Sterling Alt to Battery charger over a year ago and I called Sterling yesterday to discuss charging options which he replied that even though the alt/bat charger has a lithium setting it is not ideal and recommended the batt to batt charger. 

I told him I had already purchased over a year ago on Amazon he offered to take it back with a full refund so I can go the Bat to Batt charger.  That is customer service that made me smile.


Rbob

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Re: House Battery
« Reply #9 on: February 25, 2021, 05:46:10 PM »
Gees, 

Got side tracked studying Lifepo4 and things are changing quickly, they have starting batteries fwiw:
https://www.youtube.com/watch?v=NhOCe-dF_g8

https://www.lithiumion-batteries.com/lithium-marine-batteries

json

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Re: House Battery
« Reply #10 on: February 25, 2021, 11:11:14 PM »
I feel like we have gotten to a point where lifepo4 is mature enough that it's actually the cheapest option now. If you look at the number of cycles you get plus the usable energy per battery and also the weight for the capacity it's really a no brainer to me. A small bit of one time cost up front buys you at least double the life, likely much more.

For another rabbit hole, check these out: https://www.proboat.com/2015/02/capacitor-power/

Rbob

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Re: House Battery
« Reply #11 on: February 26, 2021, 08:45:46 AM »
That is amazing, never wears out.  You could probably set it up to an on off switch for charging from the house battery.

tom e

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Re: House Battery
« Reply #12 on: February 27, 2021, 09:28:53 AM »
Why not just buy two to start?  Or at least make provision for it where you would install a second one.

Amazon has Northstar batteries for $400+/-   

te
Building a Tolman Jumbo, but there's a lot of ideas and recommends here that apply to a Jumbo.