Battery Tender ok to use on ‘23 ES300h?
11-19-23, 02:15 PM
#1
7th Gear
Thread Starter
Battery Tender ok to use on ‘23 ES300h?
So my 300h sat for about 2 months (SoCal) and when I went to start it, DOA😳my question is is it ok to use a tender, and if so, connect it to the battery in the trunk? TIA🇺🇸
11-20-23, 01:45 PM
#2
Yes and yes. You should be fine using a tender on the 12V battery. And in my opinion, directly to the 12V battery would probably be best. They have jump points in the engine bay, but for a tender, I'd connect directly to the battery. I don't think charging through the jump points would be a great idea.
In fact, had I known how weak the 12V stock battery was, I would have done the same. I left mine for about a month, albeit it, in the freezing cold, and had the same problem. I thought that because it was only used to power the computer, not an actual engine starter motor, that it woudl be fine. I was wrong. If the battery is significantly under 12V, the onboard ECU won't power on, even if the hybrid battery is perfectly fine. Unfortunately it appears I did some damage to the stock 12V battery because it never held a very good charge after that. I ended up replacing it with a Duralast Gold which has done a great job for the last 6 months or so. I hope yours didn't suffer the same fate.
In fact, had I known how weak the 12V stock battery was, I would have done the same. I left mine for about a month, albeit it, in the freezing cold, and had the same problem. I thought that because it was only used to power the computer, not an actual engine starter motor, that it woudl be fine. I was wrong. If the battery is significantly under 12V, the onboard ECU won't power on, even if the hybrid battery is perfectly fine. Unfortunately it appears I did some damage to the stock 12V battery because it never held a very good charge after that. I ended up replacing it with a Duralast Gold which has done a great job for the last 6 months or so. I hope yours didn't suffer the same fate.
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Birddoggie (11-22-23)
11-21-23, 08:45 AM
#3
Pole Position
Yes and yes. You should be fine using a tender on the 12V battery. And in my opinion, directly to the 12V battery would probably be best. They have jump points in the engine bay, but for a tender, I'd connect directly to the battery. I don't think charging through the jump points would be a great idea.
In fact, had I known how weak the 12V stock battery was, I would have done the same. I left mine for about a month, albeit it, in the freezing cold, and had the same problem. I thought that because it was only used to power the computer, not an actual engine starter motor, that it woudl be fine. I was wrong. If the battery is significantly under 12V, the onboard ECU won't power on, even if the hybrid battery is perfectly fine. Unfortunately it appears I did some damage to the stock 12V battery because it never held a very good charge after that. I ended up replacing it with a Duralast Gold which has done a great job for the last 6 months or so. I hope yours didn't suffer the same fate.
In fact, had I known how weak the 12V stock battery was, I would have done the same. I left mine for about a month, albeit it, in the freezing cold, and had the same problem. I thought that because it was only used to power the computer, not an actual engine starter motor, that it woudl be fine. I was wrong. If the battery is significantly under 12V, the onboard ECU won't power on, even if the hybrid battery is perfectly fine. Unfortunately it appears I did some damage to the stock 12V battery because it never held a very good charge after that. I ended up replacing it with a Duralast Gold which has done a great job for the last 6 months or so. I hope yours didn't suffer the same fate.
11-21-23, 12:41 PM
#4
I wouldn’t try to “generalize” the stock 12V batteries simply because you had a bad experience with yours. I leave my ES as well as the last hybrid ES (owned 5 years) for weeks at a time quite often. Easily for a month at a time - although garaged so never below freezing. I haven’t had to replace a battery or even get a jump start. While a battery tender can be a good idea depending on circumstances, my experience wouldn’t suggest it is necessary for just a few weeks. That said, batteries can fail - just like any other component.
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