Good Sam Club Open Roads Forum: Adding a new battery...questions....(venting/gassing)
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Do It Yourself Modifications a...

Open Roads Forum  >  Do It Yourself Modifications and Upgrades (DIY)

 > Adding a new battery...questions....(venting/gassing)

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 3  
Prev  |  Next
SJ-Chris

San Jose, Ca

Full Member

Joined: 09/24/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 03/04/21 12:06pm Link  |  Quote  |  Print  |  Notify Moderator

jdc1 wrote:

pianotuna wrote:

Unless the batteries are almost unused, adding a 3rd battery may not be a great idea. If you can afford it, replace all three.


Or, put the 4 older batteries on one bank, and the 2 new batteries on a separate bank.


I believe all the batteries are about 14 months old. To me, that makes them relatively newish. Assuming they are all in good health, I'm willing to add a 3rd battery which is brand new (same manufacturer/size/etc). If this new battery ends up eventually dying 14 months earlier than it would have normally because one of my existing batteries goes bad and takes the other two with it, I'm okay with that. When that time comes, if I still even own this RV, I'll replace all 3 batteries at that time. I've been having pretty good luck buying Group 29s (RV/Marine Deep Cycle) batteries from Walmart usually for ~$90 each which to me seems pretty cheap.

I believe the "only put batteries of the same age" mantra is really trying to protect people against a scenario where you might, for example, have one very old battery that is about to die. If you add in parallel a 2nd brand new battery in that scenario, it is likely that the bad battery will very quickly kill the good battery and then you pretty much just wasted money on that new battery.

-Chris


San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 03/04/21 12:31pm Link  |  Quote  |  Print  |  Notify Moderator

SJ-Chris wrote:



I believe all the batteries are about 14 months old. To me, that makes them relatively newish. Assuming they are all in good health, I'm willing to add a 3rd battery which is brand new (same manufacturer/size/etc).

-Chris


Please at least wire the new batteries in a balanced manner. Method #3 is the only way to do so for odd numbers of jars.

http://www.smartgauge.co.uk/batt_con.html

I suggest adding some plywood to the compartment you are going to use--and if all 3 batteries will fit there it would be better.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, soon to have SiO2 batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

SJ-Chris

San Jose, Ca

Full Member

Joined: 09/24/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 03/04/21 12:48pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

SJ-Chris wrote:



I believe all the batteries are about 14 months old. To me, that makes them relatively newish. Assuming they are all in good health, I'm willing to add a 3rd battery which is brand new (same manufacturer/size/etc).

-Chris


Please at least wire the new batteries in a balanced manner. Method #3 is the only way to do so for odd numbers of jars.

http://www.smartgauge.co.uk/batt_con.html

I suggest adding some plywood to the compartment you are going to use--and if all 3 batteries will fit there it would be better.


I am happy to say I am using Method #3.

CA Traveler

The Western States

Senior Member

Joined: 01/03/2004

View Profile


Offline
Posted: 03/04/21 05:29pm Link  |  Quote  |  Print  |  Notify Moderator

SJ-Chris wrote:

pianotuna wrote:

SJ-Chris wrote:



I believe all the batteries are about 14 months old. To me, that makes them relatively newish. Assuming they are all in good health, I'm willing to add a 3rd battery which is brand new (same manufacturer/size/etc).

-Chris


Please at least wire the new batteries in a balanced manner. Method #3 is the only way to do so for odd numbers of jars.

http://www.smartgauge.co.uk/batt_con.html

I suggest adding some plywood to the compartment you are going to use--and if all 3 batteries will fit there it would be better.


I am happy to say I am using Method #3.
Are you sure? Method 3 requires equal amps and voltage from all 3 batteries. How are you doing this with one battery located 8' away?

A 900W MW draws 65A+ and not the best for starting batteries which a Marine battery is - ie a compromised starting battery. Might be OK and might cause a low voltage fault.

50% SOC batteries start charging in bulk and ramp up to absorb with about 14.4V and certainly are drawing more than a few amps. They stay there until the absorb stage starts to taper amps.

Any old charger and any wiring situation will eventually get the batteries charges. But there are cons including longer charging, shorter life and lower voltage under load. What you are doing may work for you. Sometimes it's try it, see and learn.


2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob


pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 03/04/21 08:46pm Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:



Are you sure? Method 3 requires equal amps and voltage from all 3 batteries. How are you doing this with one battery located 8' away?

A 900W MW draws 65A+ and not the best for starting batteries which a Marine battery is - ie a compromised starting battery. Might be OK and might cause a low voltage fault.



Hi CA Traveler,

He could do method #3 if the leads to the battery bank go to a buss bar that is 5 feet from any battery. i.e. all wires the same length.

I'd suggest that a 900 watt microwave may draw about 100 amps. I know my 1570 watt Dometic draws 185 amps.

I was able to successfully operate the Dometic microwave on 3 Marine jars for more than a few minutes. I have two banks--and one was 3, the other was 4 batteries. Switching allowed me to do either/or/both/off.

SJ-Chris

San Jose, Ca

Full Member

Joined: 09/24/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 03/04/21 09:42pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

CA Traveler wrote:



Are you sure? Method 3 requires equal amps and voltage from all 3 batteries. How are you doing this with one battery located 8' away?

A 900W MW draws 65A+ and not the best for starting batteries which a Marine battery is - ie a compromised starting battery. Might be OK and might cause a low voltage fault.



Hi CA Traveler,

He could do method #3 if the leads to the battery bank go to a buss bar that is 5 feet from any battery. i.e. all wires the same length.

I'd suggest that a 900 watt microwave may draw about 100 amps. I know my 1570 watt Dometic draws 185 amps.

I was able to successfully operate the Dometic microwave on 3 Marine jars for more than a few minutes. I have two banks--and one was 3, the other was 4 batteries. Switching allowed me to do either/or/both/off.


Yes, Method #3...All my positive wires are connected on a buss bar, and all my negative wires are connected on a different post...HOWEVER...the wire lengths are different. It's the best I can do currently. I'll do a voltage check at each battery to see if there is a difference when the batteries are in bulk charge (highest amps trying to enter batteries and therefore largest potential voltage drop). If one of the batteries is significantly lower in voltage (...how much is too much? 0.2v? 0.3v?) I can run a 2nd cable to that battery and I suspect that will fix the issue.

Actually, the two batteries that will be added (one already added) have much longer wires BUT the cables are a fair amount thicker so that will help already with any voltage difference during charge.

Make sense?
Chris

SJ-Chris

San Jose, Ca

Full Member

Joined: 09/24/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 03/04/21 09:45pm Link  |  Quote  |  Print  |  Notify Moderator

Quote:



I'd suggest that a 900 watt microwave may draw about 100 amps. I know my 1570 watt Dometic draws 185 amps.

I was able to successfully operate the Dometic microwave on 3 Marine jars for more than a few minutes. I have two banks--and one was 3, the other was 4 batteries. Switching allowed me to do either/or/both/off.


100 amps is what I was assuming from my 900w microwave.

Question: Are you saying you were able to run your 1570w microwave for several minutes with 3 batteries? If so, then it seems like I should not have a problem running my 900w microwave for even longer.

I guess I'll find out and report back.

-Chris

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 03/04/21 10:36pm Link  |  Quote  |  Print  |  Notify Moderator

Chris read the information at the smart Gauge site re voltage differences.

SJ-Chris

San Jose, Ca

Full Member

Joined: 09/24/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 03/04/21 10:58pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Chris read the information at the smart Gauge site re voltage differences.


Do you have a link? I googled a bit but it didn't seem like it was pointing me to the right place.

SJ-Chris

San Jose, Ca

Full Member

Joined: 09/24/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 03/06/21 01:59am Link  |  Quote  |  Print  |  Notify Moderator

SJ-Chris wrote:

drgslayr wrote:

We had a Majestic 24a. When I added an extra battery we didnt have the storage space to loose so I added one of these.

We went with AGM so we didn't have to worry about adding water or anything else.

https://www.torklift.com/rv/hiddenpower.


That is a very interesting option which I had not thought about....THANKS for the suggestion.

I did some more searching around and found this also:
https://www.amazon.com/Steel-Bolt-Battery-Mounting-Tray/dp/B076666P81/ref=pd_aw_sbs_1/144-3145342-8767014?_encoding=UTF8&pd_rd_i=B076666P81&pd_rd_r=f1726189-410c-4871-b170-b3d24a36a906&pd_rd_w=BEsmu&pd_rd_wg=CqbHc&pf_rd_p=1b60d0cd-e691-440f-aa83-cc788b983d0c&pf_rd_r=WHJTWV7J842SEVSR758V&psc=1&refRID=WHJTWV7J842SEVSR758V

I'll have to crawl under my RV and see if there is a convenient place for something like this. The one drawback I see is access....seems like it would be a tremendous hassle anytime the battery needed to be checked/maintained/etc. If I was able to mount such a bracket, I'm not entirely sure how I'd be able to lift the battery up into it.

-Chris


The torklift solution looks like it costs over $200. Would be nice to find a less expensive solution.

This looked like a good solution (I like all the mounting holes), but it isn't big enough for a Group 29 battery: $48
https://www.amazon.com/Steel-Bolt-Battery-Mounting-Tray/dp/B076666P81/ref=pd_sbs_1?pd_rd_w=0sM5W&pf_rd_p=527ea27c-adf6-4b67-9c5f-265eb29e0622&pf_rd_r=ABK60C0DF1AWM22PBZ97&pd_rd_r=51e07f18-ddeb-415c-b1a6-a27605c30b6c&pd_rd_wg=sYElr&pd_rd_i=B076666P81&psc=1
Has anyone seen something similar that will fit a Group 29 battery? (Group 29 battery is 13" long by 6.75" deep by 8.5" tall). This is really the style I'd like to find.

I googled for a bit and found this: $89
https://www.steinertractor.com/OLS035?crawlparam&gclid=EAIaIQobChMIgdXbgpub7wIVpCGtBh0HfgxOEAYYByABEgLjgfD_BwE
Looks like it could work, but would require drilling several mounting holes through the back plate. Should be doable.

Gonna keep looking though...

-Chris

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 3  
Prev  |  Next

Open Roads Forum  >  Do It Yourself Modifications and Upgrades (DIY)

 > Adding a new battery...questions....(venting/gassing)
Search:   Advanced Search

Search only in Do It Yourself Modifications a...


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.