1987 MK 1 Electrical System Upgrade - Feedback Requested

[Jon W]

Hi mainesail,
Thank's for the clarification. Just when I think I got it, I don't. Amazing the amount of current potential these battery banks can generate if not handled properly.

Battery label now says 232 AH instead of 232 A, and moved the 150A MIDI fuse into a SafetyHub 150 located in the house bank battery box.

Hi Paul,
I'm showing an implied mechanical layout of the components with the blue boxes. A formal mechanical layout is a good idea and it will be one of the next steps. I have my hands full at the moment getting and understanding a proper and safe electrical design.

Jon W.

[J_Sail]

Paul,
Actually Ken is correct to be concerned about the max short-circuit current. While a simple view of a fuse is that it will fail long before that, reality is not so simple. When the instantaneous current is high enough, some fuses can fail in other catastrophic ways, such as arcing and/or exploding instead of simply opening.  AND circuit breakers can instantaneously weld closed from the massive flow of current and then fail to open. All fuses and circuit breakers have an "interrupting rating" (IR) or "breaking capacity"

https://en.wikipedia.org/wiki/Breaking_capacity
http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/solution-center/technical_library/BUS_Ele_Tech_Lib_Interrupting_Rating.pdf

One cannot predict the maximum short circuit current from a battery by simply knowing its AH capacity. AH capacity relates to the total energy stored in the chemistry when consumed over a number of hours. Instantaneous short circuit current (if shorted right at the battery) is mostly a function of the battery's voltage divided by its internal resistance. The former is 12v, but the latter is rarely specified (small number of milliohms). The Cold-Cranking-Amps gives one some sense of the answer; the short circuit current is always much higher than the CCA. Once you connect to the battery via wires the max current is reduced due to the resistance of the wire between the battery and the location of the short. I suggest asking a licensed marine electrician (e.g. MaineSail) but in general fuses for protecting heavy gauge wires connected to batteries should have a "interrupt capacity" of at least 5,000 amps, preferably much higher. A BlueSea MRBF has an Interrupt capacity of 10,000A.
https://www.bluesea.com/products/5189/MRBF_Terminal_Fuse_-_250A

[mainesail]

Spot on!!

I have blown literally hundreds of fuses in testing for the Lithium battery committee I am on and seen plenty unsafe failures. I have even seen an ATC fuse fail unsafely in a bilge pump circuit. In fact it is sitting right on my desk.

The only fuses for primary battery bank protection are ANL, MRBF and Class T.

While The ABYC AIC standards are simply unrealistic for banks over 500Ah's it is forcing more battery manufacturers to publish short circuit ratings.

ABYC E-11
11.10.1.2.2 For batteries or battery banks with a rating of 2200 CCA or 500 amp hours or less, battery overcurrent protection shall have a minimum ampere interrupting capacity (AIC) rating according to Table IV-A.

11.10.1.2.3 For batteries or battery banks with a CCA rating greater than 2200 CCA, or 500 amp hours, battery overcurrent protection shall have a minimum ampere interrupting capacity (AIC) rating at least as great as the battery manufacturer's short circuit rating or 100 times the battery's nominal amp hour (Ah) rating.


If you do the math this means a 600Ah bank needs an AIC rating of 60,000A AIC.... Best to call your battery manufacturer to get a short circuit rating.


Please, please, please do not be tempted to buy cheap Chinese car stereo ANL fuses. They are NOT safe!!

[britinusa]

Thanks mainesail & j_sail, that makes a lot of sense.

Is the image a pic of the type of fuse to use or the type of fuse to not use?

(Sorry folks, I'm British and ambiguity is a toughie for me.)   

Paul

[KWKloeber]

Thanks mainesail & j_sail, that makes a lot of sense.

Is the image a pic of the type of fuse to use or the type of fuse to not use?

(Sorry folks, I'm British and ambiguity is a toughie for me.)   

Paul

That's an anal (ANL) fuse and holder, which is fine -- the point was to buy reputable products (holders and fuses) not Chinese knock-offs that may fuse together or blow apart (the example shown) on high AIC and do not provide proper marine protection.

kk

[Jon W]

Another update to my proposed system upgrade, but still going back and forth on the external regulator. Hopefully I'm now close to a .

I've reverted back to the SmartGauge battery monitor after reading mainsails write up, and finding out that the LinkPro and LinkLite come with a shunt, but not the wires. Add the cost of wires and the Link system would cost more than the SmartGauge which is apparently both simpler and more accurate than the LinkPro/LinkLite.

The alternator fuse is back in the battery box. I have it slated as a 150A MRBF connected to the positive busbar. I asked if MRBF was an issue on the alternator output wire, but received no comments so drew it up. I also moved the backup bilge pump manual/off/auto switch/breaker to the distribution panel which will get power in either position #1 or #2. This is in case the house bank fails, I will still have an electric bilge pump.

Follow on question – If there is a catastrophic failure in the house bank, I can switch to #2 start the engine and power the distribution panel. However, the windlass would not receive any power in this scenario as currently drawn. What have others done to ensure power to the windlass?

Jon W.

[J_Sail]

It's shaping up nicely, with the physical locations shown, etc.  Couple of comments:
1. There should be a 20amp fuse in the wire from the Echo Charge to the Reserve battery within 7" of battery-end of the wire. The 250amp fuse at the battery won't protect the 12 gauge wire, and the one shown in the Settee is at the wrong end of the wire to do so. I would discard the fuse they provide with their 2' harness and add a 20amp fuse at the battery end. It can go on either side of the 250A fuse.

2. I don't see any electrical/performance issue with using a MRBF on the bus bar for the alternator wire, but since I have more theoretical than hands-on experience installing them I can't comment on any mounting tradeoffs compared to ANL fuse blocks. Maybe MaineSail will comment.

3. The bilge pump wiring shown is slightly inaccurate (for both pumps in different ways). For each there should be a single fused wire going to the on/off/auto switch and then two wires from there to the pump (one to its float-switch, the other direct to motor). Then, in addition, there is a negative from the pump back to ground.

4. It looks like you are leaving the 1-2-Both battery switch at the AC/DC Master Distribution Panel vs moving it to (or near) the battery box. Although the existing panel has a space for it, the advantages of moving it are several:
   a) Shorter cable lengths resulting in less voltage drop
   b) Easier routing of cables; eliminates heavy cables to/from that panel and in fact allows you to reuse the #4 that goes there today so that you don't need to pull any wires at all to/from the panel. The only heavy cables go to much easier destinations thru easier routes.
   c) Allows you to connect other loads such as the windlass to the C-terminal of the battery switch, solving your issue of the windlass running only from the house battery.

[KWKloeber]

Jon

a couple comments:

There's no problem using a MRBF on a bus -- I must have missed that question. :-(
apologies to RC for hijacking these photos....
http://www.pbase.com/mainecruising/image/131742930
http://www.pbase.com/mainecruising/image/149747336
http://www.pbase.com/mainecruising/image/124282533

What's your current ProMariner charger?

Where I have light conductors vs. heavy cables (no rule of thumb there, just intuition) I tend to physically tie down heavy cables near to minimize transferring rotation movement to the terminal/bolt/etc.  e.g., a 16 awg is flexible enough that it isn't going to impart a force to a #8 screw, but a 8 awg might (or a heavy, inflexible battery cable.)   See photo example below.

Overcurrent protection needs to be on the supply side of switches (bilge pump).  i.e., OCP feeds the switch, not the switch feeding the OCP device.

To reduce voltage loss and excess wire, I tend to run negatives to the nearest bus (back to the battery box may be longer than to the eng compartment?)

kk

[mainesail]

Ken,

If you click on and then add .jpg to the end of my pic address they will show up as a photo as opposed to a link...

There were a bunch of MRBF's off a busbar in this massive LiFePO4 install..


This is a much more simple boat...

[Jon W]

Hi Jsail,
I'll move the fuse to reflect 7" from the reserve battery and correct the b/u bilge pump negative connection.

The benefits of the 1-2-B at the house battery box make sense, but there is also a convenience to having it centrally located at the navigation station. It may be a sealed switch, but the back of the switch being exposed to fumes inside of battery box is a concern to me. I looked at nearby locations, but not happy with them. This is one of the reasons I spent time moving as many fuses out of the box as I could. Nothing is final yet.

Hi Ken,
My current charger is a ProSport 20, 2 bank. I looked at the boat today, and the current bilge pump diagram reflects the way the boat is today. I just realized you were probably talking about the future b/u bilge pump which shows an inline fuse after the switch/cb on the panel. It seems to me the switch/CB at the panel should protect the wire to the pump/level switch so will be deleting the inline fuse. Jon W

[KWKloeber]

Ken,

If you click on and then add .jpg to the end of my pic address they will show up as a photo as opposed to a link...

Yeah, but then your descriptions below on some of them don't show...  !

[Jon W]

Was using a laptop and it doesn't let me take a screen shot the size needed. I will post a better view tomorrow. Any suggestions for the reserve maintenance free reserve battery size and brand? I looked at US Battery to be consistent with the 4 GC 6vots, but they don't list a maintenance free battery. Jon W.

[KWKloeber]

Hi Ken,
My current charger is a ProSport 20, 2 bank. I looked at the boat today, and the current bilge pump diagram reflects the way the boat is today. I just realized you were probably talking about the future b/u bilge pump which shows an inline fuse after the switch/cb on the panel. It seems to me the switch/CB at the panel should protect the wire to the pump/level switch so will be deleting the inline fuse. Jon W

Yep, if fed from a breaker on the panel, can be deleted.

You might as well factor in a new ProMariner ProNautic charger.  The ProSport 20 charger will soon fry with that battery bank -- I learned a lesson (after the fact) from MaineSail that those waterproof series aren't appropriate for our use -- mine fried just out of warranty on three grp 31 flooded batteries.  For your bank you'll want (RC may correct me on this) a model 1240P, or probably a 1250P.

kk

[KWKloeber]

Jon, a couple more....

Bilge pumps -

    TBD - I use awg 10/3 cable for bilge pumps, water pumps, etc. no matter the amps, just to minimize V loss.  When I ran my neg elsewhere, I used 10 awg red and brown single conductor.  I also get 10/2 bonded tinned wire in any colors, but it's 19 strand, not 41 strand.

Reserve battery -
 
   The 12 awg "connect to load side of (MRBF?) fuse" - has to be fused w/in 7" of the MRBF.
   
   Unsure where the cut off RED feeds are going, but depending on wire size, it might be neater to jumper one wire (fused for the lightest feed) from the reserve MRBF to a positive bus, and then run the feeds from the bus.  Unless you're going to do a bus bar right on the pos terminal?

Alternator -

     Unsure of the purpose of the 150a fuse - the entire bus is already fused  (i.e., the cable is no different than the 1 awg to the Safety Hub.))

Windlass -
    Why a TBD breaker on the windlass (it's already fused at the Safety Hub)?

Echo - questions - (I'm not an EchoCharge user so Maine Sail is better suited to address these.)

    Why 20A fuse at echo end? (already fused by the Safety Hub)
    Is this the right unit? (per Xantrex "both banks must be the same .... type")
    Although limited to 15a, I would probably use 10 awg "just because" and to limit voltage loss.

ken

[KWKloeber]

Ken,

If you click on and then add .jpg to the end of my pic address they will show up as a photo as opposed to a link...

Rod,

Aahhhhh Ha.  I thought that when I clicked , I had to attach a saved photo, didn't know that I could link to a photo URL as well. 

WOW.  Live and learn.  Thanks for the head's up! 

ken