bat cable

[christopher]

i have to run a bat cable from the battery to the generator. the battery is a 12v just for starting the gen. the run is about 20'.
what size do i need #4 or #6
who about where to buy it as well?
thanx
chris mci5c

[Nick Badame Refrig/ACC]

Hi Christopher,

What size genset? and what size battery?

Of course the larger the cable the better.....

Nick-

[Ncbob]

Chris, in this time of rising copper prices, fuel prices and everything else...bite the bullet and go for that biggest cable you can get...with a 20 Ft run...you're going to get on helluva voltage drop. If you can fine 20' of welding cable at a decent price...but it!

One cold night, when you are sitting along side an Interstate..you don't want to be kicking your backside for not taking the best, and most expensive, advice offered.

Bob

[Don4107]

Chris,

If the battery is dedicated to gen start, why not locate it near the genset and not worry about long runs?  You can use stock (cheep) and easy to work with cables and ground the battery directly to the genset.  All in all a simpler installation.

Don 4107

[DavidInWilmNC]

Another option... is it possible to dedicate a battery for the generator and locate it close?  20' of expensive cable will come pretty close (if not all the way) to buying a battery.  Of course, if it's impossible to locate a battery near the generator, disregard this!

David

(I replied to this before I saw Don's post above... )

[TomCat]

I mounted my genny battery on the exterior of the generator enclosure, and made up some 3 foot, tinned 00 cables that work just fine.

Jay
87 SaftLiner

[christopher]

The battery is going on the other side of the compartment. by the time you run the cable up,over, across, over again then down its probably 15-20' I am going  use one of the optima batterys. red top maintenace free. dedicated to the gen only.
christopher.

[NJT5047]

If you want good quality copper genset battery cables at a reasonable price, check Ebay for used welding cables. 
I've bought several sets for cheap.   
Welding cable is easy to work with too.  Soft and flexible.  Easy to cut with hand cable cutter. 
Take the cables down to your local welding shop for intallation of the correct ends.
Leave some slack in the cables when making them up. 
JR

[gus]

Chris,

Save yourself a lot of money and future problems by using a small lawnmower battery dedicated to and near the gen. Wire a solenoid with a toggle switch so that you can tie into the bus battery if you ever need a boost for starting. My old Onan was wired this way and it worked great.

Using an Optima for the gen is the very most expensive way to go, this is way overkill.

If you can, avoid the gen battery altogether and just wire into the bus system.

I know some gen require a separate battery, but not all.

[NJT5047]

A separate genset battery is a good idea, but, check the charge rate of the genset alternator before you use an Optima battery.  You might find the charge rate too high for gel or maint free batteries.   May work just fine too.  Be a shame to waste an Optima proving such.
If the generator was designed for lead/acid start battery, you may be ahead using that style battery.   Is the battery box area vented?  If not, maintenance free battery will be required.
Lead/acid will tolerate a less sophisticated charger. 
The ability to parallel the genset crank battery with a 12V bus battery is a great idea.
All you need is a Ford style solenoid and a little wiring. 
You only want temporary capability. 
If you need to charge the house or 24V bus batteries off the genset, use the 110V circuit and charger.
Jerry or Richard could elaborate on this subject. 

JR

[TomC]

I just wired my gen starting into the 2-size 31 batteries I have for starting the big engine-no need for an extra battery.  Even if the batteries are to low to start the big engine, they usually will start the gen.  If not, I have a jumper solenoid (2-150amp continuous duty in parallel) that I can get help from the deep cycle batteries.
So now the starting batteries are charged by the 300amp Delco 50DN and the deep cycles are charged by the inverter set at 85 amps at 3 stages-once again with the possibility of a the jumper solenoid.  Strange as it sounds, I had to disconnect the little 20 amp alternator on the generator because it was fighting with the big 300 amp Delco alternator on the engine. 
Once again-you DON'T need a separate battery for your generator.  Good Luck, TomC

[Sam 4106]

I agree with TomC, why do you want a seperate battery for a generator? It is just another thing to have to maintain and replace perodicaly. I start my generator off the house batteries and have a solonoid/cable that connects the house and engine batteries together. It may supprise some of you, but not all generators have a battery charging capability. My Onan Quiet Diesel doesn't. When I asked Onan about that, they said they don't put in a charging system because many RVs have the generator start off the house batteries so there is no need for a charging system. That is why I installed my generator that way.
You guys that are recomending welding cable for battery cables is useless unless you specify a wire gage along with your recomendation. Are you not aware that all welding cable is not equal? I have seen welding cables all the way from #4 on a small buzz box to 0000 on large portable welders on construction sites where the welder is a long distance from the weld location. I would suggest 00 if you are going to have 20' of cable on your instalation.
Good luck, Sam 4106

[Dale MC8]

Chris, check battery supply houses for cables. Some of them will/can make custom cables with the ends you want/need in the gauge you want/need. They have the experience, knowledge and the proper tools to do a first rate job. They may even have some ideas that never occurred to you (it could happen.)

HTH, Dale MC8

[christopher]

everyone
thanks for your imput.
all great thoughts. i may tie the gen into the house battery and keep one of the jumper cable boxes handy.
can anyone recommend one?
chris

[NJT5047]

You guys that are recomending welding cable for battery cables is useless unless you specify a wire gage along with your recomendation. Are you not aware that all welding cable is not equal?

NOOOOOOOOOOOOO!   I had no idea!  I'll bet NCBob knows!

To be more specific on cable size would require knowing what genset Chris is working with. Maybe I missed the description.   
Obviously, a 20kw diesel generator will require a larger starter lead (s) than would a 6kw gasoline unit. 
What genset you got Chris?? 
Keep in mind that even AWG 2/0 welding cable is easy to work with.     Magnum 70 lugs and sealing heat shrink will make some primo starter cables.   
JR