Stand alone starting battery for generator

[noteven]

I am thinking about adding a dedicated starting battery for the Onan generator in our C-Force. I have a Sure Power isolator on hand, and space for a battery. Are there any issues I need to be aware of wiring through an isolator?

On the other hand replacing the two 12v batteries with 2 or 4 - 6v golf car batteries and carry my long booster cables may give the overnight battery power we need without doing a project...

Has anyone installed a dedicated starting battery like this?

[noteven]

pianotuna wrote:
Hi Fargo,

I'm glad it is working for you. What sort of battery did you get for the dedicated generator battery?



I'm a little surprised at the low voltage on the house batteries under load. Are they nearing the end of their lifespan?

Starting battery - is a 1000CCA starting battery threaded terminal.

Deep cycles kaput?

Yes I think so. They were new last year but they were left connected (batt switch "on" - not connected to shore power) all winter by the PO. Detectors and sound system flattened them. My experience with Optima type batteries is they do not like this. I have a pair of T105 6v in the TC I am going to move between the units for now as we don't camp in both at the same time.

[KMLsquared]

FYI. The two generacs I have owned have their own charging circuit. No idolaters needed.

[pianotuna]

Hi Fargo,

I'm glad it is working for you. What sort of battery did you get for the dedicated generator battery?

I'm a little surprised at the low voltage on the house batteries under load. Are they nearing the end of their lifespan?

[noteven]

Yesterday I installed and connected a dedicated starting battery and an Amp-L-Start isolator recommended by pianotuna. Straight forward and easy to do. The battery was shelf charged at 12.6 volts and started the generator no problem. The Amp-L-Start indicated "charging" - both house and gen batt charging at 13.6 volts. I switched to shore power and left everything charging for 5 - 6 hours.

This morning I put a load on the house batteries ( 2x 12v Optima yellow) that came with the trailer. I turned on a bunch of lights, 3 ventilation fans, 1 stove top fan, stereo on FM radio mode.

At the start of the load test the Optima's tested 12.56 volts at rest, before switching on the battery switch.

Gen starting battery at 12.75 v.

Within 30 mins house batts reading 8.5 volts, and after switch off the batt switch and resting them 30 minutes they are at 10.6 volts.

Connected shore power and brought house batts back on line - after 10 minutes charging at 13.6 volts.

Gen battery receiving 13.4 volts through the Amp-L-Start.

[noteven]

I want the generator to start and supply power when needed without boosting / hooking up the truck etc. After looking at the info for the Amp-l-start device it is what I need to connect a dedicated starting battery. It is basically an isolator that allows current (from whatever source - generator, truck, shore) that is charging the house batteries to top up the generator starting battery. It does not allow current to flow "backwards" from the starting battery when the house batteries are supplying DC loads.

I'll report in once I have it set up.

[nayther]

I just got done dry camping for a week and had some issues with this as well. Found loose connections on a couple battery posts :S but after running the generator for a few hours still no charge. Poked around with my meter and found the converter was not charging the batteries. Since we were leaving the next day just hooked up my battery charger and got enough juice to get me by. When I got home I found that the converter output wires were loose, now all is good.

Did the same thing with the truck, plugged it in and ran for about 10 minutes and started genny. I don't see a need for a dedicated battery since its not that hard to do the above.

[KATOOM]

Strabo wrote:
I use the truck battery's circut if need be.....Just start the truck

I've done this too. Heater ran the batteries down so low one very cold night that the gen wouldn't start the next morning. I hooked the truck/trailer plug up and let the truck idle for about 10 minutes to start the gen. Worked but I felt that needed to have a dedicated battery for the gen so this didn't happen again. Unfortunately I found that my gen doesn't have a separate charging system so I'd have to have that dedicated battery connected to the house batteries, and that wont work unless I wanted to get involved.....or more involved than I wanted. 🙂

So after poking around, I found that the gen was only connected to one battery so I connected it in parallel with the batteries to double the starting amps. Haven't had a chance to see if that helped while under the same cold night conditions but if it doesn't and I have to jump the gen with the truck again, I'm going to get one of those portable power supply's and just have it around for just in case. They're handy for many other things anyways.

[tinner12002]

I've not ran the battery down so low but I have thought about getting a trailer cord extension...basicly a cord with a 7 pin male and 7 pin female ends that I can plug into truck and then plug into trailer.

[Strabo]

I use the truck battery's circut if need be.....Just start the truck

[pianotuna]

Hi,

Batteries will "push back" to a certain extent. There are a lot of variables. My understanding was that the issue was being able to start the generator for sure. That would imply a large battery. Therefore the isolator is to prevent run down during boondocking use. The generator starting battery will only get charged when driving, or when the generator is actually running. That would depend partly on how the isolator is wired. It might also be charged on shore power.

In my case all 8 batteries are identical--so I have no issues of over charging one.

[noteven]

pianotuna wrote:
Hi,

A continuous duty solenoid will do the charging at a much lower price.

A trik-l-start may also "fill the bill", or its big brother the amp-l-start.

06Fargo wrote:
If a diode based isolator will cause too much voltage drop for a converter/charger to handle, do I want to use one of these?

http://www.allbatterysalesandservice.com/browse.cfm/4,4018.html

They appear to be designed to prevent overcharging the starting battery while the house batteries are recharged?

These look like what I need.

Thank you

[pianotuna]

Hi,

A continuous duty solenoid will do the charging at a much lower price.

A trik-l-start may also "fill the bill", or its big brother the amp-l-start.

06Fargo wrote:
If a diode based isolator will cause too much voltage drop for a converter/charger to handle, do I want to use one of these?

http://www.allbatterysalesandservice.com/browse.cfm/4,4018.html

They appear to be designed to prevent overcharging the starting battery while the house batteries are recharged?

[noteven]

If a diode based isolator will cause too much voltage drop for a converter/charger to handle, do I want to use one of these?

http://www.allbatterysalesandservice.com/browse.cfm/4,4018.html

They appear to be designed to prevent overcharging the starting battery while the house batteries are recharged?

[26_2_2go]

I have a 2013 FR 40' XLR 395AMP and plan to do the same for similar reasons. I plan to add an (1) extra battery for the house power and add another (1) extra battery for the Lippert Leveling system and Oman 5500 Gen. I want this battery separated from the house power for same reason. For a total of 2 12v batteries for house power and 1 isolated 12v battery for Gen and Lipper system.

At some point, I may plan to add solar panels to supplement onboard power to limit Oman use.

Any help with direction or electrical diagrams would be helpful.

thanks in advance.......