Dual Battery Wiring Help (1 Viewer)

[wearsabrowncoat]

You can build your own system with self jump option following these instructions on Slee's tech section: http://www.sleeoffroad.com/technical/tz_dual_batteries.htm
I've been running it now for about 8 years. I run everything off the main and keep the spare in reserve for winching and self jumping. The only downfall is that I think it is wise to replace the batteries at the same time so you double your battery price every 7 years or so.

 

[serenity]

I'll be doing this setup since I got the controller for nothing, seems pretty simple. I just want to run my fridge and a camp light, maybe use it to charge the battery for my boat.

 

[iptman]

What size fuse would you put on if you wanted to self jump across the 7622?

 

[warezdog]

I would say a 250. You can find them on ebay from fords super cheap and the holders as well. I think I had about $2 each in the fuses and $8 for the holders.

 

[Cruiserdrew]

What size fuse would you put on if you wanted to self jump across the 7622?

The size of the fuse has nothing to do with the 7622. The fuse is to protect the wire. You can look it up on an ampacity chart, but with 1/0 Marine Cabling, 250 would be about right.

https://www.bluesea.com/resources/529/Allowable_Amperage_in_Conductors_-_Wire_Sizing_Chart


ANL fuse holders run the gamut from cheap audio related holders, to fairly expensive marine holders from Blue Sea with plated conductors and stainless hardware. Mega fuse holders are about the same price, but are not quite as well shielded from dirt or spray. I used several of these:

https://www.bluesea.com/products/5005/ANL_Fuse_Block_with_Insulating_Cover_-_35_to_300A

Good price on Amazon.

 

[iptman]

I assumed the starter draw would be more than 250 amps, no? That's what I meant by referencing the 7622 since it can handle short bursts of 750+ amps as can 0/1 wire (I think?). Also if using the 7622 in combined mode for a hard winch pull would you not potentially exceed 250 amps?

 

[TomH]

I really like the self jump feature and have used it many times. I run the Blue Sea 9112 which only required three wire and a switch for the ability to run in automatic mode, isolate or combine batteries. I think it's a pretty nice feature.

 

[LFD2037]

I assumed the starter draw would be more than 250 amps, no? That's what I meant by referencing the 7622 since it can handle short bursts of 750+ amps as can 0/1 wire (I think?). Also if using the 7622 in combined mode for a hard winch pull would you not potentially exceed 250 amps?

run winch and starter off main battery. Then they don't come into play in the equation.

 

[Douglas S]

run winch and starter off main battery. Then they don't come into play in the equation.

They still come into play. When the batteries are combined engaging the starter or winch will still pull from both batteries.

 

[LFD2037]

They still come into play. When the batteries are combined engaging the starter or winch will still pull from both batteries.

With the 7610, the 2nd battery isn't combined when starting so that's out. When the main battery drops below 13.7 it disconnects from the 2nd battery so when the winch is engaged that'll happen extremely fast so that's out. Not sure what ACR he's using, though.

If this isn't correct, please correct me. Thanks!

 

[Douglas S]

With the 7610, the 2nd battery isn't combined when starting so that's out. When the main battery drops below 13.7 it disconnects from the 2nd battery so when the winch is engaged that'll happen extremely fast so that's out. Not sure what ACR he's using, though.

If this isn't correct, please correct me. Thanks!

You can force the batteries to combine with the 7622, which is useful for winching.

 

[Steve D]

With the 7610, the 2nd battery isn't combined when starting so that's out. When the main battery drops below 13.7 it disconnects from the 2nd battery so when the winch is engaged that'll happen extremely fast so that's out. Not sure what ACR he's using, though.

If this isn't correct, please correct me. Thanks!

This matches my situation. I have a Diehard 31 marine battery for house/accessory power, a second battery for the normal vehicle starting/operations, a Blue Sea 7610 ACR, and will be installing a winch soon. Should I connect the winch wiring to the marine battery and just not worry about the 7610's inability to combine the two batteries while under winch loads? Or should I add a manual switch to combine the two?

 

[Dave 2000]

This often happens with dual battery installs, it starts off as 'I just want to add a fridge and light', then comes the 'need to jump start yourself' and then onto the winch.

Each requires careful thought, I have wired mine in (link in sig) and it works perfect, and now after 'testing' for nearly five years (I have been busy )I am fine tuning the install. Make a decision of what you want to do now. Yes the costs will be higher initially but when you move from that fridge supply to a winch then the extra money spent on the VSR or cabling will come back to you.

So to the fuses and what the 7610. It is about the current that the 7610 and cabling can hold CONTINOUS. I am unsure of the 7610 VSR's amperage but, if it is for example 150 amps and you pull 200 for a few seconds no big deal, Blue Seas gear is some of the best around. A starter is only engaged for a few seconds and I am going to assume you are using the typical 2.2kw starter? Then you will during cranking pull an initial 180 ish amps, this will fall away as the motor starts to spin, perhaps 140 for 5 seconds and the motor starts? So the starter is no big deal but, a winch is another ball game altogether, a typical winch would pull say 250+ amps CONTINOUS, and this is where the 'wheat is sorted from the chaf' when it comes to VSR's, cabling, and fuses.

The fuse is to protect the cable, a typical fuse will hold (while heating) about double the rating, of course a dead short will cause it to blow.

So you need to know the maximum amps your winch will ever pull, it is unlikely you would be winching with the engine off, and if you were surely you would stop the winch before cranking right? So simultaneous draws do not need to be factored in, so your fuse choice is based primarily on the cable (copper not inc jacket) thickness, and the maximum amperage the winch when in good working order will pull. If the winch stalls but current continues to flow then things are going to get hot very quickly, amperage rises and the fuse blows, hopefully protecting the winch and more importantly the cable.

Spend some time on this and get it right, despite having a good knowledge of electrics I have posted on here a number of times for others opinions, someone may see something that I missed.

regards

Dave

 

[LFD2037]

My winch is on the 1st battery and will stay that way. I have jumper cables if I need them.

 

[Steve D]

It is about the current that the 7610 and cabling can hold CONTINUOUS. I am unsure of the 7610 VSR's amperage but, if it is for example 150 amps and you pull 200 for a few seconds no big deal, Blue Seas gear is some of the best around.

Thanks for the feedback. The 7610 is rated at 120A continuous, 210A intermittent (5 min). It has been wired up and working fine for 3 years although the vehicle is new to me.

So you need to know the maximum amps your winch will ever pull .... If the winch stalls but current continues to flow then things are going to get hot very quickly, amperage rises and the fuse blows, hopefully protecting the winch and more importantly the cable.

The specs on my winch (Warn Zeon Platinum 12-S) show a maximum draw of 446 amps. The installation instructions show that the cables should be connected directly to the battery with no provision for fuses. I understand that shows the simple installation with one battery, but I found it curious that they don't even mention the option of fusing the winch cables.

 

[Dave 2000]

Not unusual to not fuse winch cables , in the same way not to fuse starter main cables. If you plan to pull that kind of amperage through your 7610, and of course assuming the battery connected direct to the winch is getting low, then the VSR WILL see that load and fail, mine has the 7622 fitted and it can handle that kind of current. This is what I was talking about when someone does an installation. Your was probably with the intention of jump starting 'yourself', this would explain the current rating, it fits right in with the expected current draw of a (gasoline) starter.

regards

Dave

 

[Funner]

run winch and starter off main battery. Then they don't come into play in the equation.

^^this

 

[koifish]

Need some help with my setup, here's what I have so far:
Bluesea 7611
#1 AWG marine battery cables
Bluesea ANL fuse blocks(2)
150A ANL fuses(2)
Winch is connected directly to house battery

Should I opt for 175A fuses instead based on Bluesea chart? Is 200A overkill?

 

[george_tlc]

Also, which direction do I install the fuses? Which end points to the battery and which end to the 7611?
View attachment 1470149

A fuse is not polarized. Works the same in either direction (since there is no 'direction').

cheers,
george.

 

[JaketheSSnake]

Need some help with my setup, here's what I have so far:
Bluesea 7611
#1 AWG marine battery cables
Bluesea ANL fuse blocks(2)
150A ANL fuses(2)
Winch is connected directly to house battery

Should I opt for 175A fuses instead based on Bluesea chart? Is 200A overkill?
View attachment 1470148

Also, which direction do I install the fuses? Which end points to the battery and which end to the 7611?
View attachment 1470149

If you have any sort of ocd, the fuse needs to go in the direction that it's readable. You don't want the lettering upside down!