The NorthStar AGM Battery + Voltage Booster Upgrade

I have a question. I have an aftermarket 250A alternator, that dead nuts cold, starts around 14.4-14.5. When hot, it's 13.8 at idle in gear. I have the adjustable voltage booster in, and from a dead nuts cold start, it's at 14.93. My question is, am I safe with that? I haven't run it to operating temp., because I'm scared to drive it anywhere with that starting voltage. Help!!

 

The short answer is NO - you don't want anything over 14.8V, which overcharges an AGM battery.

You should adjust the voltage booster to provide nothing higher than 14.8V.

 

Thanks for the concise and straightforward answer. Much appreciated.

 

So today after 24 hours at absolute rest, this is what my meter said:



My Northstar 27F is 17 months old, I have been finding info on line that says that an AGM battery should have a resting V anywhere from 12.6 to 12.9. Where can I found exactly how much it should be for this AGM Northstar battery?

Also, with the above mentioned resting voltage, where is the current charge percentage of my battery? 80-90%? 90-95%?

Just curious where is my battery’s charge level at??

Cheers

Rick

 

My Northstar 34 is also 12.60 and it's brand new, but i haven't put in the replacement fuse which ups my charging voltage of 13.8 when driving.

 

Well, I bought a 31F for my 2019 today, then committed to a battery tray, only to find this thread and realize it was all for nothing, unless I dropped even more coin to have it plugged in. Seems like I may be better off buying a Goal Zero

 

Why do you say it's all for nothing?

 

Can’t get a booster, would have to also buy a charger and plug it in monthly. I was hoping to simplify things, not have to start throwing my truck on a charger regularly

 

If you are concerned get it tested for free at a Parts store for its Cold Cranking Amps. I wouldn't worry about it.

 

For me, if I could charge it, drive for a day, then camp for a couple without potentially harming it or worrying it will die, it might be worth it

 

Don't worry about it, I ran my dual group 34 Sears Plantinums for 8years on the primary(now a northstar), and I'm at 6 years on the secondary with my IMS battery manager and sometimes I run a 3rd 155amp hr AGM for long camping and powering my CPAP/fridge and other items while using a 100watt solar panel and MPPT controller to charge when I don't move my truck. Worst case run the truck for 15 minutes and it tops off the batteries. I had a goal zero 1000 lithium and it's a POS. it's not a Lithium Fe Iron battery. It's the crappy lithium that can only be charged 500 times to failure. it takes 29hrs to charge with a single AC adapter which died on me after 2 weeks of testing before an 11 day trip. So I had to quickly buy a 155amp/hr AGM, Solar controller with USB/Cig adapters and wire it into my IMS as 3rd battery. The other HUGE problem with the goal zero is I left it in my truck cab overnight when it was like 90 degrees out, and the fan came on full blast all night long till I went to my truck in the morning. the fan drained the battery 27% overnight just trying to keep the lithium battery cool and it's loud. This was definitely not going to work in the desert at 115 degrees and trying to charge it via solar. I contacted Support and they said that is normal the battery has to be cooled. My Shorai lithium Iron's in my motorcycle don't have that problem at 115-120 degrees and a load??? Also the Goal Zeros' mostly use PWM solar controllers and special solar connectors only for their panels which suck. PWM controller are only 40-65% efficient vs MPPT are like 95-99% efficient. so, for example, 100watt panel at full light gets you 40-65 watts on PWM and 95-99 watts on MPPT. That's a huge difference in real life because you are rarely getting 70-100% light on your panel most of the day. If you are only going to run one big group 31 battery, make sure to buy a Lithium Jump pack as a just in case you leave something on etc. Life saver when you are out and about. I did just order this fuse thing to step up my voltage from 13.8 to 14.6. I also periodically ran a Battery Minder which has a desulfator on my AGM batteries and that has been key to motorcycle batteries (not Lithium) to keep them fresh and increase capacity. They make an industrial desulfator that plugs to the battery connectors that desulfates it when you startup and stop. Industrial golf carts and big equipment run these since they can't be charged up on location.

 

If you buy a quality fridge like ARB or a Dometic, they have an adjustable shut off to stop pulling current from your battery at a threshold you set 11.2 11.6 12.0 etc.. so make sure you buy quality items. The reason I have an IMS and dual batteries is the IMS will let me run the 2nd battery all the way down and part of the primary but keep the primary from going below 11.6-12.0 so the truck will always start. Plus it will charge up the primary battery first, and if you start to lose cells like I have, it will let you combine both batteries automatically or manually to start or winch. Totally cool and expensive device but I haven't had to worry about my truck starting in remote situations. but with a large 31 and lithium jumper is also a really good way to go for less money.

 

I ran this Ctek DC to DC charger with built-in Isolator and built-in MPPT controller. between my 3rd battery and my 2 battery IMS setup under the hood. worked like a charm with 100watt solar panel

CTEK 40-256 20A Off Grid Bundle - D250SA and Battery Monitor

https://www.amazon.com/CTEK-40-256-...+charging+bundle+20+amp&qid=1582788766&sr=8-3
This also has a CTEK smart charger that has 5 charger stages for battery health.
"Also confirmed voltages on the separately installed, LCD display of the charging voltage (and also shows discharging of the amps). It's a great way to see how much current is being charged and being drained. Have not fully tested the accuracy of the % capacity left (as have not yet drained the battery dead), the LCD can be set to show how many hour capacities left of the battery at the going current draw."

 

Cytocycle, you said a lot of things there. I definitely took away that you don’t like lithium solar banks, or portable power banks or whatever you wanna call Goal Zero, etc.

Turning the truck on for 15 minutes would give the battery some juice, but My main concern is the potential for triggering the fridge shut-off (I bought an Engel btw) really quickly into the trip. Especially if the battery is supposed to be charged at 14.6-14.9 and I’m charging it at 13.9 as I drive. Essentially the extra battery storage and power I’m paying for is lost.

 

I mean, its not like its a total loss.. You still have an extra battery with XYZ more capacity than the single truck battery. Just pop it on a good AGM charger once a month before big trips and call it good. Someone will eventually figure out how to boost the voltage on 3rd gens

 

Thanks Rob!

 

Installed a new X2 Premium 27F yesterday along with the Ford 1 amp diode in the ALT-S fuse location. This morning it seemed to work great, charging at 14.62 at peak after starting the engine. Thanks for the write-up!

 

Just curious and to obtain knowledge on why you didn't choose to use a voltage booster with your X2 Premium 27F battery?

 

If I had to guess max 10$ vs 100$

 

While I won't answer for him, it's the same functionality. One is a "fused" (thermal reset) diode, the other is strictly a standard diode, but they do the exact same thing.

They create resistance which tells the alternator that the battery needs .5v more juice than it's currently receiving because the battery is extra low.