[Guardsman]

The 2 year old Honda OEM battery in my car is beginning to die. Extreme cold temps here are not helping either. I know Honda will replace it under warranty but I would rather replace it with an XS Power D5100. Both the EOM and the XS Power batteries are group 51 so fit, even with the slight variations which are common in this group from what I’ve read, shouldn’t be an issue. My question is this. Is there anything in a hybrid system that could be damaged by replacing the OEM with an AGM. I’ve read and read but nothing says yes or no that I’ve found. Everyone I’ve asks just warns me that the electrical requirements are far more picky with a hybrid and I shouldn’t do it. As this is only the starter battery and used for powering electronics, I don’t see how having more power would hurt. I should add the reason I want to replace the OEM with an AGM is to also add a second AGM in the trunk separated by an automatic charging relay. The second battery will be used to power some high power amateur radio equipment. Thanks in advance.

 

[Vegashybrid]

More power as in what CCA's? That wouldnt really make a difference. If it fits in the normal battery spot your really cant put "too big" a battery there. Mostly because its simply giving you more storage really not more power. Unless your trying to change voltages you will be fine. So whatever companies AGM you use, Optima Interstate ect, just stick with the proper size group. The AGM should def help with the cold climate ect. What I would NOT be doing is adding a second battery in the trunk. You really should not be running that much draw on the hybrid that you need a second battery for audio equipment in the first place. Especially if your already replacing it with an AGM, just run a power capacitor. If you need more power than that for your audio equipment, you really chose the wrong vehicle. I know someone on here is running a 1500w system or something without problems, but Crutchfield and many other professionals highly recommend against adding anything more than around 300w (mine sounds amazing with the extra 300w). See if the dealership will pay the difference between the cost of the two batteries.

 

[Guardsman]

More power as in what CCA's? That wouldnt really make a difference. If it fits in the normal battery spot your really cant put "too big" a battery there. Mostly because its simply giving you more storage really not more power. Unless your trying to change voltages you will be fine. So whatever companies AGM you use, Optima Interstate ect, just stick with the proper size group. The AGM should def help with the cold climate ect. What I would NOT be doing is adding a second battery in the trunk. You really should not be running that much draw on the hybrid that you need a second battery for audio equipment in the first place. Especially if your already replacing it with an AGM, just run a power capacitor. If you need more power than that for your audio equipment, you really chose the wrong vehicle. I know someone on here is running a 1500w system or something without problems, but Crutchfield and many other professionals highly recommend against adding anything more than around 300w (mine sounds amazing with the extra 300w). See if the dealership will pay the difference between the cost of the two batteries.

Thank you for the

More power as in what CCA's? That wouldnt really make a difference. If it fits in the normal battery spot your really cant put "too big" a battery there. Mostly because its simply giving you more storage really not more power. Unless your trying to change voltages you will be fine. So whatever companies AGM you use, Optima Interstate ect, just stick with the proper size group. The AGM should def help with the cold climate ect. What I would NOT be doing is adding a second battery in the trunk. You really should not be running that much draw on the hybrid that you need a second battery for audio equipment in the first place. Especially if your already replacing it with an AGM, just run a power capacitor. If you need more power than that for your audio equipment, you really chose the wrong vehicle. I know someone on here is running a 1500w system or something without problems, but Crutchfield and many other professionals highly recommend against adding anything more than around 300w (mine sounds amazing with the extra 300w). See if the dealership will pay the difference between the cost of the two batteries.

Thank you for the quick response. Yes, I should have said more cold cranking amps rather than power. Definitely needed right now in my area. My radios are only 500 watts and 200 watts so I should be fine with a single battery. The reason I wanted a second one was to run the radios for extended periods without the car running. As for additional draw from the hybrid, I thought as long as the batteries are separated by an automatic charging relay, there would not be any additional draw on the hybrid. Is this not correct? Thanks again.

 

[Vegashybrid]

Should be correct but not something I would want to start testing personally with the hybrid system. You are already a couple hundred watts over what i have seen been recommended. A power capacitor would do the same thing and is basically a mini battery.

 

[InTotalAccord]

I posted in another "dead battery" thread, about recently needing to replace the 12V Group 51 battery in my 2018 Hybrid Touring. The failed battery was about 2.5 years old. I opted to get a replacement Honda battery (free, under warranty). The original battery was marked as having 410 CCA (even though this is not too relevant, since this battery is never used for cranking a starter motor). The Honda replacement battery (also group 51, of course) was marked as having 500 CCA, so it is at least a little different than the one that came with the car (FWIW).

I also had wondered if the charging circuitry for the 12V battery was charging it only while the gas engine is actually running, or also charging while the gas engine is off (but car is "on").... It turns out that charging voltage (roughly 14.5 volts) is being applied whether the gas engine is running, or not. I assume that it is basically a tap off of the higher-voltage hybrid battery pack. So in that sense it is kind of similar to having a traditional alternator (on a gas-engine car), that is always applying a charging voltage, once the car has started.... You need enough voltage on the 12V battery to at least let the electronics operate enough so that the car turns "on" (Ready indicator). But once that happens, charging voltage is present.

I can't comment on whether an AGM-type battery would be OK. But I did notice that Autozone also had Duralast and Duralast Gold (regular flooded-type batteries) in Group 51. I was tempted to simply buy the Duralast Gold battery (also rated at 500 CCA), as that brand has been reasonably reliable and long-lived for me, in other cars. But in the end the free replacement from Honda won out....